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-rw-r--r--synapse/__init__.py2
-rw-r--r--synapse/api/auth.py6
-rw-r--r--synapse/api/errors.py1
-rw-r--r--synapse/api/filtering.py2
-rw-r--r--synapse/app/_base.py13
-rw-r--r--synapse/app/appservice.py7
-rw-r--r--synapse/app/client_reader.py11
-rw-r--r--synapse/app/event_creator.py10
-rw-r--r--synapse/app/federation_reader.py10
-rw-r--r--synapse/app/federation_sender.py10
-rw-r--r--synapse/app/frontend_proxy.py10
-rwxr-xr-xsynapse/app/homeserver.py13
-rw-r--r--synapse/app/media_repository.py10
-rw-r--r--synapse/app/pusher.py10
-rw-r--r--synapse/app/synchrotron.py10
-rw-r--r--synapse/app/user_dir.py10
-rw-r--r--synapse/config/consent_config.py19
-rw-r--r--synapse/config/server.py10
-rw-r--r--synapse/config/server_notices_config.py15
-rw-r--r--synapse/event_auth.py4
-rw-r--r--synapse/events/__init__.py2
-rw-r--r--synapse/events/utils.py4
-rw-r--r--synapse/events/validator.py6
-rw-r--r--synapse/federation/federation_client.py21
-rw-r--r--synapse/federation/federation_server.py19
-rw-r--r--synapse/federation/send_queue.py13
-rw-r--r--synapse/federation/transaction_queue.py63
-rw-r--r--synapse/groups/groups_server.py4
-rw-r--r--synapse/handlers/_base.py4
-rw-r--r--synapse/handlers/appservice.py26
-rw-r--r--synapse/handlers/auth.py6
-rw-r--r--synapse/handlers/deactivate_account.py6
-rw-r--r--synapse/handlers/device.py18
-rw-r--r--synapse/handlers/e2e_keys.py13
-rw-r--r--synapse/handlers/federation.py61
-rw-r--r--synapse/handlers/groups_local.py3
-rw-r--r--synapse/handlers/message.py21
-rw-r--r--synapse/handlers/presence.py86
-rw-r--r--synapse/handlers/room.py2
-rw-r--r--synapse/handlers/room_list.py3
-rw-r--r--synapse/handlers/room_member.py23
-rw-r--r--synapse/handlers/search.py2
-rw-r--r--synapse/handlers/sync.py32
-rw-r--r--synapse/handlers/user_directory.py10
-rw-r--r--synapse/http/client.py21
-rw-r--r--synapse/http/matrixfederationclient.py24
-rw-r--r--synapse/http/request_metrics.py216
-rw-r--r--synapse/http/server.py4
-rw-r--r--synapse/http/site.py22
-rw-r--r--synapse/metrics/__init__.py238
-rw-r--r--synapse/metrics/metric.py328
-rw-r--r--synapse/metrics/process_collector.py122
-rw-r--r--synapse/metrics/resource.py23
-rw-r--r--synapse/notifier.py24
-rw-r--r--synapse/push/baserules.py2
-rw-r--r--synapse/push/bulk_push_rule_evaluator.py43
-rw-r--r--synapse/push/httppusher.py13
-rw-r--r--synapse/push/mailer.py3
-rw-r--r--synapse/push/presentable_names.py2
-rw-r--r--synapse/push/push_rule_evaluator.py6
-rw-r--r--synapse/python_dependencies.py1
-rw-r--r--synapse/replication/tcp/protocol.py101
-rw-r--r--synapse/replication/tcp/resource.py37
-rw-r--r--synapse/rest/client/transactions.py2
-rw-r--r--synapse/rest/client/v1/presence.py8
-rw-r--r--synapse/rest/media/v1/media_repository.py3
-rw-r--r--synapse/rest/media/v1/preview_url_resource.py8
-rw-r--r--synapse/server_notices/consent_server_notices.py46
-rw-r--r--synapse/server_notices/server_notices_manager.py23
-rw-r--r--synapse/server_notices/worker_server_notices_sender.py2
-rw-r--r--synapse/state.py51
-rw-r--r--synapse/storage/_base.py84
-rw-r--r--synapse/storage/client_ips.py6
-rw-r--r--synapse/storage/devices.py9
-rw-r--r--synapse/storage/end_to_end_keys.py6
-rw-r--r--synapse/storage/event_push_actions.py4
-rw-r--r--synapse/storage/events.py78
-rw-r--r--synapse/storage/events_worker.py2
-rw-r--r--synapse/storage/filtering.py2
-rw-r--r--synapse/storage/keys.py16
-rw-r--r--synapse/storage/presence.py7
-rw-r--r--synapse/storage/receipts.py59
-rw-r--r--synapse/storage/registration.py1
-rw-r--r--synapse/storage/roommember.py10
-rw-r--r--synapse/storage/search.py9
-rw-r--r--synapse/storage/signatures.py12
-rw-r--r--synapse/storage/state.py47
-rw-r--r--synapse/storage/stream.py15
-rw-r--r--synapse/storage/transactions.py10
-rw-r--r--synapse/storage/user_directory.py8
-rw-r--r--synapse/util/__init__.py18
-rw-r--r--synapse/util/caches/__init__.py87
-rw-r--r--synapse/util/caches/descriptors.py16
-rw-r--r--synapse/util/caches/dictionary_cache.py2
-rw-r--r--synapse/util/caches/expiringcache.py4
-rw-r--r--synapse/util/caches/response_cache.py11
-rw-r--r--synapse/util/caches/stream_change_cache.py2
-rw-r--r--synapse/util/caches/treecache.py6
-rw-r--r--synapse/util/frozenutils.py14
-rw-r--r--synapse/util/logcontext.py24
-rw-r--r--synapse/util/logutils.py6
-rw-r--r--synapse/util/metrics.py106
102 files changed, 1245 insertions, 1440 deletions
diff --git a/synapse/__init__.py b/synapse/__init__.py
index b11a1d3ea3..5bada5e290 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -16,4 +16,4 @@
 """ This is a reference implementation of a Matrix home server.
 """
 
-__version__ = "0.29.1"
+__version__ = "0.30.0"
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index f17fda6315..06fa38366d 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -15,6 +15,8 @@
 
 import logging
 
+from six import itervalues
+
 import pymacaroons
 from twisted.internet import defer
 
@@ -57,7 +59,7 @@ class Auth(object):
         self.TOKEN_NOT_FOUND_HTTP_STATUS = 401
 
         self.token_cache = LruCache(CACHE_SIZE_FACTOR * 10000)
-        register_cache("token_cache", self.token_cache)
+        register_cache("cache", "token_cache", self.token_cache)
 
     @defer.inlineCallbacks
     def check_from_context(self, event, context, do_sig_check=True):
@@ -66,7 +68,7 @@ class Auth(object):
         )
         auth_events = yield self.store.get_events(auth_events_ids)
         auth_events = {
-            (e.type, e.state_key): e for e in auth_events.values()
+            (e.type, e.state_key): e for e in itervalues(auth_events)
         }
         self.check(event, auth_events=auth_events, do_sig_check=do_sig_check)
 
diff --git a/synapse/api/errors.py b/synapse/api/errors.py
index aca804280c..e6ad3768f0 100644
--- a/synapse/api/errors.py
+++ b/synapse/api/errors.py
@@ -53,6 +53,7 @@ class Codes(object):
     INVALID_USERNAME = "M_INVALID_USERNAME"
     SERVER_NOT_TRUSTED = "M_SERVER_NOT_TRUSTED"
     CONSENT_NOT_GIVEN = "M_CONSENT_NOT_GIVEN"
+    CANNOT_LEAVE_SERVER_NOTICE_ROOM = "M_CANNOT_LEAVE_SERVER_NOTICE_ROOM"
 
 
 class CodeMessageException(RuntimeError):
diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index db43219d24..dbc0e7e445 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -411,7 +411,7 @@ class Filter(object):
         return room_ids
 
     def filter(self, events):
-        return filter(self.check, events)
+        return list(filter(self.check, events))
 
     def limit(self):
         return self.filter_json.get("limit", 10)
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index e4318cdfc3..a6925ab139 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -124,6 +124,19 @@ def quit_with_error(error_string):
     sys.exit(1)
 
 
+def listen_metrics(bind_addresses, port):
+    """
+    Start Prometheus metrics server.
+    """
+    from synapse.metrics import RegistryProxy
+    from prometheus_client import start_http_server
+
+    for host in bind_addresses:
+        reactor.callInThread(start_http_server, int(port),
+                             addr=host, registry=RegistryProxy)
+        logger.info("Metrics now reporting on %s:%d", host, port)
+
+
 def listen_tcp(bind_addresses, port, factory, backlog=50):
     """
     Create a TCP socket for a port and several addresses
diff --git a/synapse/app/appservice.py b/synapse/app/appservice.py
index b1efacc9f8..dd114dee07 100644
--- a/synapse/app/appservice.py
+++ b/synapse/app/appservice.py
@@ -94,6 +94,13 @@ class AppserviceServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/client_reader.py b/synapse/app/client_reader.py
index 38b98382c6..85dada7f9f 100644
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@@ -25,6 +25,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -77,7 +78,7 @@ class ClientReaderServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     PublicRoomListRestServlet(self).register(resource)
@@ -118,7 +119,13 @@ class ClientReaderServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
-
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/event_creator.py b/synapse/app/event_creator.py
index bd7f3d5679..5ca77c0f1a 100644
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@@ -25,6 +25,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
@@ -90,7 +91,7 @@ class EventCreatorServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     RoomSendEventRestServlet(self).register(resource)
@@ -134,6 +135,13 @@ class EventCreatorServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/federation_reader.py b/synapse/app/federation_reader.py
index 6e10b27b9e..2a1995d0cd 100644
--- a/synapse/app/federation_reader.py
+++ b/synapse/app/federation_reader.py
@@ -26,6 +26,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.federation.transport.server import TransportLayerServer
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.directory import DirectoryStore
@@ -71,7 +72,7 @@ class FederationReaderServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "federation":
                     resources.update({
                         FEDERATION_PREFIX: TransportLayerServer(self),
@@ -107,6 +108,13 @@ class FederationReaderServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py
index 6f24e32d6d..81ad574043 100644
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@@ -25,6 +25,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.federation import send_queue
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
 from synapse.replication.slave.storage.devices import SlavedDeviceStore
@@ -89,7 +90,7 @@ class FederationSenderServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
 
         root_resource = create_resource_tree(resources, NoResource())
 
@@ -121,6 +122,13 @@ class FederationSenderServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index 0f700ee786..5a164a7a95 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -29,6 +29,7 @@ from synapse.http.servlet import (
     RestServlet, parse_json_object_from_request,
 )
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -131,7 +132,7 @@ class FrontendProxyServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     KeyUploadServlet(self).register(resource)
@@ -172,6 +173,13 @@ class FrontendProxyServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 026422a023..714f98a3e0 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -34,7 +34,7 @@ from synapse.module_api import ModuleApi
 from synapse.http.additional_resource import AdditionalResource
 from synapse.http.server import RootRedirect
 from synapse.http.site import SynapseSite
-from synapse.metrics import register_memory_metrics
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.python_dependencies import CONDITIONAL_REQUIREMENTS, \
     check_requirements
@@ -230,7 +230,7 @@ class SynapseHomeServer(HomeServer):
             resources[WEB_CLIENT_PREFIX] = build_resource_for_web_client(self)
 
         if name == "metrics" and self.get_config().enable_metrics:
-            resources[METRICS_PREFIX] = MetricsResource(self)
+            resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
 
         if name == "replication":
             resources[REPLICATION_PREFIX] = ReplicationRestResource(self)
@@ -263,6 +263,13 @@ class SynapseHomeServer(HomeServer):
                     reactor.addSystemEventTrigger(
                         "before", "shutdown", server_listener.stopListening,
                     )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
@@ -362,8 +369,6 @@ def setup(config_options):
         hs.get_datastore().start_doing_background_updates()
         hs.get_federation_client().start_get_pdu_cache()
 
-        register_memory_metrics(hs)
-
     reactor.callWhenRunning(start)
 
     return hs
diff --git a/synapse/app/media_repository.py b/synapse/app/media_repository.py
index 9c93195f0a..006bba80a8 100644
--- a/synapse/app/media_repository.py
+++ b/synapse/app/media_repository.py
@@ -27,6 +27,7 @@ from synapse.config.homeserver import HomeServerConfig
 from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -73,7 +74,7 @@ class MediaRepositoryServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "media":
                     media_repo = self.get_media_repository_resource()
                     resources.update({
@@ -114,6 +115,13 @@ class MediaRepositoryServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index 3912eae48c..64df47f9cc 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -23,6 +23,7 @@ from synapse.config._base import ConfigError
 from synapse.config.homeserver import HomeServerConfig
 from synapse.config.logger import setup_logging
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
 from synapse.replication.slave.storage.events import SlavedEventStore
@@ -92,7 +93,7 @@ class PusherServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
 
         root_resource = create_resource_tree(resources, NoResource())
 
@@ -124,6 +125,13 @@ class PusherServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index c6294a7a0c..6808d6d3e0 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -26,6 +26,7 @@ from synapse.config.logger import setup_logging
 from synapse.handlers.presence import PresenceHandler, get_interested_parties
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
@@ -257,7 +258,7 @@ class SynchrotronServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     sync.register_servlets(self, resource)
@@ -301,6 +302,13 @@ class SynchrotronServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/app/user_dir.py b/synapse/app/user_dir.py
index 53eb3474da..ada1c13cec 100644
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@@ -26,6 +26,7 @@ from synapse.config.logger import setup_logging
 from synapse.crypto import context_factory
 from synapse.http.server import JsonResource
 from synapse.http.site import SynapseSite
+from synapse.metrics import RegistryProxy
 from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
@@ -105,7 +106,7 @@ class UserDirectoryServer(HomeServer):
         for res in listener_config["resources"]:
             for name in res["names"]:
                 if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(self)
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                 elif name == "client":
                     resource = JsonResource(self, canonical_json=False)
                     user_directory.register_servlets(self, resource)
@@ -146,6 +147,13 @@ class UserDirectoryServer(HomeServer):
                         globals={"hs": self},
                     )
                 )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warn(("Metrics listener configured, but "
+                                 "collect_metrics is not enabled!"))
+                else:
+                    _base.listen_metrics(listener["bind_addresses"],
+                                         listener["port"])
             else:
                 logger.warn("Unrecognized listener type: %s", listener["type"])
 
diff --git a/synapse/config/consent_config.py b/synapse/config/consent_config.py
index 44c4711e6c..8f6ed73328 100644
--- a/synapse/config/consent_config.py
+++ b/synapse/config/consent_config.py
@@ -32,7 +32,8 @@ DEFAULT_CONFIG = """\
 #
 # 'server_notice_content', if enabled, will send a user a "Server Notice"
 # asking them to consent to the privacy policy. The 'server_notices' section
-# must also be configured for this to work.
+# must also be configured for this to work. Notices will *not* be sent to
+# guest users unless 'send_server_notice_to_guests' is set to true.
 #
 # 'block_events_error', if set, will block any attempts to send events
 # until the user consents to the privacy policy. The value of the setting is
@@ -43,10 +44,14 @@ DEFAULT_CONFIG = """\
 #   version: 1.0
 #   server_notice_content:
 #     msgtype: m.text
-#     body: |
-#       Pls do consent kthx
-#   block_events_error: |
-#     You can't send any messages until you consent to the privacy policy.
+#     body: >-
+#       To continue using this homeserver you must review and agree to the
+#       terms and conditions at %(consent_uri)s
+#   send_server_notice_to_guests: True
+#   block_events_error: >-
+#     To continue using this homeserver you must review and agree to the
+#     terms and conditions at %(consent_uri)s
+#
 """
 
 
@@ -57,6 +62,7 @@ class ConsentConfig(Config):
         self.user_consent_version = None
         self.user_consent_template_dir = None
         self.user_consent_server_notice_content = None
+        self.user_consent_server_notice_to_guests = False
         self.block_events_without_consent_error = None
 
     def read_config(self, config):
@@ -71,6 +77,9 @@ class ConsentConfig(Config):
         self.block_events_without_consent_error = consent_config.get(
             "block_events_error",
         )
+        self.user_consent_server_notice_to_guests = bool(consent_config.get(
+            "send_server_notice_to_guests", False,
+        ))
 
     def default_config(self, **kwargs):
         return DEFAULT_CONFIG
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 8f0b6d1f28..968ecd9ea0 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -14,8 +14,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import logging
+
 from ._base import Config, ConfigError
 
+logger = logging.Logger(__name__)
+
 
 class ServerConfig(Config):
 
@@ -138,6 +142,12 @@ class ServerConfig(Config):
 
         metrics_port = config.get("metrics_port")
         if metrics_port:
+            logger.warn(
+                ("The metrics_port configuration option is deprecated in Synapse 0.31 "
+                 "in favour of a listener. Please see "
+                 "http://github.com/matrix-org/synapse/blob/master/docs/metrics-howto.rst"
+                 " on how to configure the new listener."))
+
             self.listeners.append({
                 "port": metrics_port,
                 "bind_addresses": [config.get("metrics_bind_host", "127.0.0.1")],
diff --git a/synapse/config/server_notices_config.py b/synapse/config/server_notices_config.py
index ccef8d2ec5..be1d1f762c 100644
--- a/synapse/config/server_notices_config.py
+++ b/synapse/config/server_notices_config.py
@@ -26,12 +26,13 @@ DEFAULT_CONFIG = """\
 # setting, which defines the id of the user which will be used to send the
 # notices.
 #
-# It's also possible to override the room name, or the display name of the
-# "notices" user.
+# It's also possible to override the room name, the display name of the
+# "notices" user, and the avatar for the user.
 #
 # server_notices:
 #   system_mxid_localpart: notices
 #   system_mxid_display_name: "Server Notices"
+#   system_mxid_avatar_url: "mxc://server.com/oumMVlgDnLYFaPVkExemNVVZ"
 #   room_name: "Server Notices"
 """
 
@@ -48,6 +49,10 @@ class ServerNoticesConfig(Config):
             The display name to use for the server notices user.
             None if server notices are not enabled.
 
+        server_notices_mxid_avatar_url (str|None):
+            The display name to use for the server notices user.
+            None if server notices are not enabled.
+
         server_notices_room_name (str|None):
             The name to use for the server notices room.
             None if server notices are not enabled.
@@ -56,6 +61,7 @@ class ServerNoticesConfig(Config):
         super(ServerNoticesConfig, self).__init__()
         self.server_notices_mxid = None
         self.server_notices_mxid_display_name = None
+        self.server_notices_mxid_avatar_url = None
         self.server_notices_room_name = None
 
     def read_config(self, config):
@@ -68,7 +74,10 @@ class ServerNoticesConfig(Config):
             mxid_localpart, self.server_name,
         ).to_string()
         self.server_notices_mxid_display_name = c.get(
-            'system_mxid_display_name', 'Server Notices',
+            'system_mxid_display_name', None,
+        )
+        self.server_notices_mxid_avatar_url = c.get(
+            'system_mxid_avatar_url', None,
         )
         # todo: i18n
         self.server_notices_room_name = c.get('room_name', "Server Notices")
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index cd5627e36a..eaf9cecde6 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -471,14 +471,14 @@ def _check_power_levels(event, auth_events):
     ]
 
     old_list = current_state.content.get("users", {})
-    for user in set(old_list.keys() + user_list.keys()):
+    for user in set(list(old_list) + list(user_list)):
         levels_to_check.append(
             (user, "users")
         )
 
     old_list = current_state.content.get("events", {})
     new_list = event.content.get("events", {})
-    for ev_id in set(old_list.keys() + new_list.keys()):
+    for ev_id in set(list(old_list) + list(new_list)):
         levels_to_check.append(
             (ev_id, "events")
         )
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index c3ff85c49a..cb08da4984 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -146,7 +146,7 @@ class EventBase(object):
         return field in self._event_dict
 
     def items(self):
-        return self._event_dict.items()
+        return list(self._event_dict.items())
 
 
 class FrozenEvent(EventBase):
diff --git a/synapse/events/utils.py b/synapse/events/utils.py
index 824f4a42e3..29ae086786 100644
--- a/synapse/events/utils.py
+++ b/synapse/events/utils.py
@@ -20,6 +20,8 @@ from frozendict import frozendict
 
 import re
 
+from six import string_types
+
 # Split strings on "." but not "\." This uses a negative lookbehind assertion for '\'
 # (?<!stuff) matches if the current position in the string is not preceded
 # by a match for 'stuff'.
@@ -277,7 +279,7 @@ def serialize_event(e, time_now_ms, as_client_event=True,
 
     if only_event_fields:
         if (not isinstance(only_event_fields, list) or
-                not all(isinstance(f, basestring) for f in only_event_fields)):
+                not all(isinstance(f, string_types) for f in only_event_fields)):
             raise TypeError("only_event_fields must be a list of strings")
         d = only_fields(d, only_event_fields)
 
diff --git a/synapse/events/validator.py b/synapse/events/validator.py
index 2f4c8a1018..e0e5bf818c 100644
--- a/synapse/events/validator.py
+++ b/synapse/events/validator.py
@@ -17,6 +17,8 @@ from synapse.types import EventID, RoomID, UserID
 from synapse.api.errors import SynapseError
 from synapse.api.constants import EventTypes, Membership
 
+from six import string_types
+
 
 class EventValidator(object):
 
@@ -49,7 +51,7 @@ class EventValidator(object):
             strings.append("state_key")
 
         for s in strings:
-            if not isinstance(getattr(event, s), basestring):
+            if not isinstance(getattr(event, s), string_types):
                 raise SynapseError(400, "Not '%s' a string type" % (s,))
 
         if event.type == EventTypes.Member:
@@ -88,5 +90,5 @@ class EventValidator(object):
         for s in keys:
             if s not in d:
                 raise SynapseError(400, "'%s' not in content" % (s,))
-            if not isinstance(d[s], basestring):
+            if not isinstance(d[s], string_types):
                 raise SynapseError(400, "Not '%s' a string type" % (s,))
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 6163f7c466..87a92f6ea9 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -32,20 +32,17 @@ from synapse.federation.federation_base import (
     FederationBase,
     event_from_pdu_json,
 )
-import synapse.metrics
 from synapse.util import logcontext, unwrapFirstError
 from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 from synapse.util.logutils import log_function
 from synapse.util.retryutils import NotRetryingDestination
 
-logger = logging.getLogger(__name__)
-
+from prometheus_client import Counter
 
-# synapse.federation.federation_client is a silly name
-metrics = synapse.metrics.get_metrics_for("synapse.federation.client")
+logger = logging.getLogger(__name__)
 
-sent_queries_counter = metrics.register_counter("sent_queries", labels=["type"])
+sent_queries_counter = Counter("synapse_federation_client_sent_queries", "", ["type"])
 
 
 PDU_RETRY_TIME_MS = 1 * 60 * 1000
@@ -108,7 +105,7 @@ class FederationClient(FederationBase):
             a Deferred which will eventually yield a JSON object from the
             response
         """
-        sent_queries_counter.inc(query_type)
+        sent_queries_counter.labels(query_type).inc()
 
         return self.transport_layer.make_query(
             destination, query_type, args, retry_on_dns_fail=retry_on_dns_fail,
@@ -127,7 +124,7 @@ class FederationClient(FederationBase):
             a Deferred which will eventually yield a JSON object from the
             response
         """
-        sent_queries_counter.inc("client_device_keys")
+        sent_queries_counter.labels("client_device_keys").inc()
         return self.transport_layer.query_client_keys(
             destination, content, timeout
         )
@@ -137,7 +134,7 @@ class FederationClient(FederationBase):
         """Query the device keys for a list of user ids hosted on a remote
         server.
         """
-        sent_queries_counter.inc("user_devices")
+        sent_queries_counter.labels("user_devices").inc()
         return self.transport_layer.query_user_devices(
             destination, user_id, timeout
         )
@@ -154,7 +151,7 @@ class FederationClient(FederationBase):
             a Deferred which will eventually yield a JSON object from the
             response
         """
-        sent_queries_counter.inc("client_one_time_keys")
+        sent_queries_counter.labels("client_one_time_keys").inc()
         return self.transport_layer.claim_client_keys(
             destination, content, timeout
         )
@@ -394,7 +391,7 @@ class FederationClient(FederationBase):
         """
         if return_local:
             seen_events = yield self.store.get_events(event_ids, allow_rejected=True)
-            signed_events = seen_events.values()
+            signed_events = list(seen_events.values())
         else:
             seen_events = yield self.store.have_seen_events(event_ids)
             signed_events = []
@@ -592,7 +589,7 @@ class FederationClient(FederationBase):
                 }
 
                 valid_pdus = yield self._check_sigs_and_hash_and_fetch(
-                    destination, pdus.values(),
+                    destination, list(pdus.values()),
                     outlier=True,
                 )
 
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 247ddc89d5..2d420a58a2 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -27,12 +27,13 @@ from synapse.federation.federation_base import (
 
 from synapse.federation.persistence import TransactionActions
 from synapse.federation.units import Edu, Transaction
-import synapse.metrics
 from synapse.types import get_domain_from_id
 from synapse.util import async
 from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.logutils import log_function
 
+from prometheus_client import Counter
+
 from six import iteritems
 
 # when processing incoming transactions, we try to handle multiple rooms in
@@ -41,17 +42,17 @@ TRANSACTION_CONCURRENCY_LIMIT = 10
 
 logger = logging.getLogger(__name__)
 
-# synapse.federation.federation_server is a silly name
-metrics = synapse.metrics.get_metrics_for("synapse.federation.server")
-
-received_pdus_counter = metrics.register_counter("received_pdus")
+received_pdus_counter = Counter("synapse_federation_server_received_pdus", "")
 
-received_edus_counter = metrics.register_counter("received_edus")
+received_edus_counter = Counter("synapse_federation_server_received_edus", "")
 
-received_queries_counter = metrics.register_counter("received_queries", labels=["type"])
+received_queries_counter = Counter(
+    "synapse_federation_server_received_queries", "", ["type"]
+)
 
 
 class FederationServer(FederationBase):
+
     def __init__(self, hs):
         super(FederationServer, self).__init__(hs)
 
@@ -131,7 +132,7 @@ class FederationServer(FederationBase):
 
         logger.debug("[%s] Transaction is new", transaction.transaction_id)
 
-        received_pdus_counter.inc_by(len(transaction.pdus))
+        received_pdus_counter.inc(len(transaction.pdus))
 
         pdus_by_room = {}
 
@@ -292,7 +293,7 @@ class FederationServer(FederationBase):
 
     @defer.inlineCallbacks
     def on_query_request(self, query_type, args):
-        received_queries_counter.inc(query_type)
+        received_queries_counter.labels(query_type).inc()
         resp = yield self.registry.on_query(query_type, args)
         defer.returnValue((200, resp))
 
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 0f0c687b37..3dcc629d44 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -33,7 +33,7 @@ from .units import Edu
 
 from synapse.storage.presence import UserPresenceState
 from synapse.util.metrics import Measure
-import synapse.metrics
+from synapse.metrics import LaterGauge
 
 from blist import sorteddict
 from collections import namedtuple
@@ -45,9 +45,6 @@ from six import itervalues, iteritems
 logger = logging.getLogger(__name__)
 
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-
-
 class FederationRemoteSendQueue(object):
     """A drop in replacement for TransactionQueue"""
 
@@ -77,10 +74,8 @@ class FederationRemoteSendQueue(object):
         # lambda binds to the queue rather than to the name of the queue which
         # changes. ARGH.
         def register(name, queue):
-            metrics.register_callback(
-                queue_name + "_size",
-                lambda: len(queue),
-            )
+            LaterGauge("synapse_federation_send_queue_%s_size" % (queue_name,),
+                       "", lambda: len(queue))
 
         for queue_name in [
             "presence_map", "presence_changed", "keyed_edu", "keyed_edu_changed",
@@ -202,7 +197,7 @@ class FederationRemoteSendQueue(object):
 
         # We only want to send presence for our own users, so lets always just
         # filter here just in case.
-        local_states = filter(lambda s: self.is_mine_id(s.user_id), states)
+        local_states = list(filter(lambda s: self.is_mine_id(s.user_id), states))
 
         self.presence_map.update({state.user_id: state for state in local_states})
         self.presence_changed[pos] = [state.user_id for state in local_states]
diff --git a/synapse/federation/transaction_queue.py b/synapse/federation/transaction_queue.py
index ded2b1871a..f0aeb5a0d3 100644
--- a/synapse/federation/transaction_queue.py
+++ b/synapse/federation/transaction_queue.py
@@ -26,23 +26,25 @@ from synapse.util.retryutils import NotRetryingDestination, get_retry_limiter
 from synapse.util.metrics import measure_func
 from synapse.handlers.presence import format_user_presence_state, get_interested_remotes
 import synapse.metrics
+from synapse.metrics import LaterGauge
+from synapse.metrics import (
+    sent_edus_counter,
+    sent_transactions_counter,
+    events_processed_counter,
+)
+
+from prometheus_client import Counter
+
+from six import itervalues
 
 import logging
 
 
 logger = logging.getLogger(__name__)
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-
-client_metrics = synapse.metrics.get_metrics_for("synapse.federation.client")
-sent_pdus_destination_dist = client_metrics.register_distribution(
-    "sent_pdu_destinations"
+sent_pdus_destination_dist = Counter(
+    "synapse_federation_transaction_queue_sent_pdu_destinations", ""
 )
-sent_edus_counter = client_metrics.register_counter("sent_edus")
-
-sent_transactions_counter = client_metrics.register_counter("sent_transactions")
-
-events_processed_counter = client_metrics.register_counter("events_processed")
 
 
 class TransactionQueue(object):
@@ -69,8 +71,10 @@ class TransactionQueue(object):
         # done
         self.pending_transactions = {}
 
-        metrics.register_callback(
-            "pending_destinations",
+        LaterGauge(
+            "synapse_federation_transaction_queue_pending_destinations",
+            "",
+            [],
             lambda: len(self.pending_transactions),
         )
 
@@ -94,12 +98,16 @@ class TransactionQueue(object):
         # Map of destination -> (edu_type, key) -> Edu
         self.pending_edus_keyed_by_dest = edus_keyed = {}
 
-        metrics.register_callback(
-            "pending_pdus",
+        LaterGauge(
+            "synapse_federation_transaction_queue_pending_pdus",
+            "",
+            [],
             lambda: sum(map(len, pdus.values())),
         )
-        metrics.register_callback(
-            "pending_edus",
+        LaterGauge(
+            "synapse_federation_transaction_queue_pending_edus",
+            "",
+            [],
             lambda: (
                 sum(map(len, edus.values()))
                 + sum(map(len, presence.values()))
@@ -228,7 +236,7 @@ class TransactionQueue(object):
                 yield logcontext.make_deferred_yieldable(defer.gatherResults(
                     [
                         logcontext.run_in_background(handle_room_events, evs)
-                        for evs in events_by_room.itervalues()
+                        for evs in itervalues(events_by_room)
                     ],
                     consumeErrors=True
                 ))
@@ -241,18 +249,15 @@ class TransactionQueue(object):
                     now = self.clock.time_msec()
                     ts = yield self.store.get_received_ts(events[-1].event_id)
 
-                    synapse.metrics.event_processing_lag.set(
-                        now - ts, "federation_sender",
-                    )
-                    synapse.metrics.event_processing_last_ts.set(
-                        ts, "federation_sender",
-                    )
+                    synapse.metrics.event_processing_lag.labels(
+                        "federation_sender").set(now - ts)
+                    synapse.metrics.event_processing_last_ts.labels(
+                        "federation_sender").set(ts)
 
-                events_processed_counter.inc_by(len(events))
+                events_processed_counter.inc(len(events))
 
-                synapse.metrics.event_processing_positions.set(
-                    next_token, "federation_sender",
-                )
+                synapse.metrics.event_processing_positions.labels(
+                    "federation_sender").set(next_token)
 
         finally:
             self._is_processing = False
@@ -275,7 +280,7 @@ class TransactionQueue(object):
         if not destinations:
             return
 
-        sent_pdus_destination_dist.inc_by(len(destinations))
+        sent_pdus_destination_dist.inc(len(destinations))
 
         for destination in destinations:
             self.pending_pdus_by_dest.setdefault(destination, []).append(
@@ -322,7 +327,7 @@ class TransactionQueue(object):
                 if not states_map:
                     break
 
-                yield self._process_presence_inner(states_map.values())
+                yield self._process_presence_inner(list(states_map.values()))
         except Exception:
             logger.exception("Error sending presence states to servers")
         finally:
diff --git a/synapse/groups/groups_server.py b/synapse/groups/groups_server.py
index 2d95b04e0c..62d20ad130 100644
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -20,6 +20,8 @@ from synapse.api.errors import SynapseError
 from synapse.types import GroupID, RoomID, UserID, get_domain_from_id
 from twisted.internet import defer
 
+from six import string_types
+
 logger = logging.getLogger(__name__)
 
 
@@ -431,7 +433,7 @@ class GroupsServerHandler(object):
                         "long_description"):
             if keyname in content:
                 value = content[keyname]
-                if not isinstance(value, basestring):
+                if not isinstance(value, string_types):
                     raise SynapseError(400, "%r value is not a string" % (keyname,))
                 profile[keyname] = value
 
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index e089e66fde..2d1db0c245 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -114,14 +114,14 @@ class BaseHandler(object):
             if guest_access != "can_join":
                 if context:
                     current_state = yield self.store.get_events(
-                        context.current_state_ids.values()
+                        list(context.current_state_ids.values())
                     )
                 else:
                     current_state = yield self.state_handler.get_current_state(
                         event.room_id
                     )
 
-                current_state = current_state.values()
+                current_state = list(current_state.values())
 
                 logger.info("maybe_kick_guest_users %r", current_state)
                 yield self.kick_guest_users(current_state)
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index b596f098fd..1c29c43a83 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -15,20 +15,21 @@
 
 from twisted.internet import defer
 
+from six import itervalues
+
 import synapse
 from synapse.api.constants import EventTypes
 from synapse.util.metrics import Measure
 from synapse.util.logcontext import (
     make_deferred_yieldable, run_in_background,
 )
+from prometheus_client import Counter
 
 import logging
 
 logger = logging.getLogger(__name__)
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-
-events_processed_counter = metrics.register_counter("events_processed")
+events_processed_counter = Counter("synapse_handlers_appservice_events_processed", "")
 
 
 def log_failure(failure):
@@ -120,7 +121,7 @@ class ApplicationServicesHandler(object):
 
                     yield make_deferred_yieldable(defer.gatherResults([
                         run_in_background(handle_room_events, evs)
-                        for evs in events_by_room.itervalues()
+                        for evs in itervalues(events_by_room)
                     ], consumeErrors=True))
 
                     yield self.store.set_appservice_last_pos(upper_bound)
@@ -128,18 +129,15 @@ class ApplicationServicesHandler(object):
                     now = self.clock.time_msec()
                     ts = yield self.store.get_received_ts(events[-1].event_id)
 
-                    synapse.metrics.event_processing_positions.set(
-                        upper_bound, "appservice_sender",
-                    )
+                    synapse.metrics.event_processing_positions.labels(
+                        "appservice_sender").set(upper_bound)
 
-                    events_processed_counter.inc_by(len(events))
+                    events_processed_counter.inc(len(events))
 
-                    synapse.metrics.event_processing_lag.set(
-                        now - ts, "appservice_sender",
-                    )
-                    synapse.metrics.event_processing_last_ts.set(
-                        ts, "appservice_sender",
-                    )
+                    synapse.metrics.event_processing_lag.labels(
+                        "appservice_sender").set(now - ts)
+                    synapse.metrics.event_processing_last_ts.labels(
+                        "appservice_sender").set(ts)
             finally:
                 self.is_processing = False
 
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index a5365c4fe4..3c0051586d 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -249,7 +249,7 @@ class AuthHandler(BaseHandler):
                 errordict = e.error_dict()
 
         for f in flows:
-            if len(set(f) - set(creds.keys())) == 0:
+            if len(set(f) - set(creds)) == 0:
                 # it's very useful to know what args are stored, but this can
                 # include the password in the case of registering, so only log
                 # the keys (confusingly, clientdict may contain a password
@@ -257,12 +257,12 @@ class AuthHandler(BaseHandler):
                 # and is not sensitive).
                 logger.info(
                     "Auth completed with creds: %r. Client dict has keys: %r",
-                    creds, clientdict.keys()
+                    creds, list(clientdict)
                 )
                 defer.returnValue((creds, clientdict, session['id']))
 
         ret = self._auth_dict_for_flows(flows, session)
-        ret['completed'] = creds.keys()
+        ret['completed'] = list(creds)
         ret.update(errordict)
         raise InteractiveAuthIncompleteError(
             ret,
diff --git a/synapse/handlers/deactivate_account.py b/synapse/handlers/deactivate_account.py
index 4eb18775e8..c5e92f6214 100644
--- a/synapse/handlers/deactivate_account.py
+++ b/synapse/handlers/deactivate_account.py
@@ -30,6 +30,7 @@ class DeactivateAccountHandler(BaseHandler):
         self._auth_handler = hs.get_auth_handler()
         self._device_handler = hs.get_device_handler()
         self._room_member_handler = hs.get_room_member_handler()
+        self.user_directory_handler = hs.get_user_directory_handler()
 
         # Flag that indicates whether the process to part users from rooms is running
         self._user_parter_running = False
@@ -61,10 +62,13 @@ class DeactivateAccountHandler(BaseHandler):
         yield self.store.user_delete_threepids(user_id)
         yield self.store.user_set_password_hash(user_id, None)
 
-        # Add the user to a table of users penpding deactivation (ie.
+        # Add the user to a table of users pending deactivation (ie.
         # removal from all the rooms they're a member of)
         yield self.store.add_user_pending_deactivation(user_id)
 
+        # delete from user directory
+        yield self.user_directory_handler.handle_user_deactivated(user_id)
+
         # Now start the process that goes through that list and
         # parts users from rooms (if it isn't already running)
         self._start_user_parting()
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index f7457a7082..11c6fb3657 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -26,6 +26,8 @@ from ._base import BaseHandler
 
 import logging
 
+from six import itervalues, iteritems
+
 logger = logging.getLogger(__name__)
 
 
@@ -112,7 +114,7 @@ class DeviceHandler(BaseHandler):
             user_id, device_id=None
         )
 
-        devices = device_map.values()
+        devices = list(device_map.values())
         for device in devices:
             _update_device_from_client_ips(device, ips)
 
@@ -185,7 +187,7 @@ class DeviceHandler(BaseHandler):
             defer.Deferred:
         """
         device_map = yield self.store.get_devices_by_user(user_id)
-        device_ids = device_map.keys()
+        device_ids = list(device_map)
         if except_device_id is not None:
             device_ids = [d for d in device_ids if d != except_device_id]
         yield self.delete_devices(user_id, device_ids)
@@ -318,7 +320,7 @@ class DeviceHandler(BaseHandler):
             # The user may have left the room
             # TODO: Check if they actually did or if we were just invited.
             if room_id not in room_ids:
-                for key, event_id in current_state_ids.iteritems():
+                for key, event_id in iteritems(current_state_ids):
                     etype, state_key = key
                     if etype != EventTypes.Member:
                         continue
@@ -338,7 +340,7 @@ class DeviceHandler(BaseHandler):
             # special-case for an empty prev state: include all members
             # in the changed list
             if not event_ids:
-                for key, event_id in current_state_ids.iteritems():
+                for key, event_id in iteritems(current_state_ids):
                     etype, state_key = key
                     if etype != EventTypes.Member:
                         continue
@@ -354,10 +356,10 @@ class DeviceHandler(BaseHandler):
 
             # Check if we've joined the room? If so we just blindly add all the users to
             # the "possibly changed" users.
-            for state_dict in prev_state_ids.itervalues():
+            for state_dict in itervalues(prev_state_ids):
                 member_event = state_dict.get((EventTypes.Member, user_id), None)
                 if not member_event or member_event != current_member_id:
-                    for key, event_id in current_state_ids.iteritems():
+                    for key, event_id in iteritems(current_state_ids):
                         etype, state_key = key
                         if etype != EventTypes.Member:
                             continue
@@ -367,14 +369,14 @@ class DeviceHandler(BaseHandler):
             # If there has been any change in membership, include them in the
             # possibly changed list. We'll check if they are joined below,
             # and we're not toooo worried about spuriously adding users.
-            for key, event_id in current_state_ids.iteritems():
+            for key, event_id in iteritems(current_state_ids):
                 etype, state_key = key
                 if etype != EventTypes.Member:
                     continue
 
                 # check if this member has changed since any of the extremities
                 # at the stream_ordering, and add them to the list if so.
-                for state_dict in prev_state_ids.itervalues():
+                for state_dict in itervalues(prev_state_ids):
                     prev_event_id = state_dict.get(key, None)
                     if not prev_event_id or prev_event_id != event_id:
                         if state_key != user_id:
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 25aec624af..8a2d177539 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -19,6 +19,7 @@ import logging
 
 from canonicaljson import encode_canonical_json
 from twisted.internet import defer
+from six import iteritems
 
 from synapse.api.errors import (
     SynapseError, CodeMessageException, FederationDeniedError,
@@ -92,7 +93,7 @@ class E2eKeysHandler(object):
         remote_queries_not_in_cache = {}
         if remote_queries:
             query_list = []
-            for user_id, device_ids in remote_queries.iteritems():
+            for user_id, device_ids in iteritems(remote_queries):
                 if device_ids:
                     query_list.extend((user_id, device_id) for device_id in device_ids)
                 else:
@@ -103,9 +104,9 @@ class E2eKeysHandler(object):
                     query_list
                 )
             )
-            for user_id, devices in remote_results.iteritems():
+            for user_id, devices in iteritems(remote_results):
                 user_devices = results.setdefault(user_id, {})
-                for device_id, device in devices.iteritems():
+                for device_id, device in iteritems(devices):
                     keys = device.get("keys", None)
                     device_display_name = device.get("device_display_name", None)
                     if keys:
@@ -250,9 +251,9 @@ class E2eKeysHandler(object):
             "Claimed one-time-keys: %s",
             ",".join((
                 "%s for %s:%s" % (key_id, user_id, device_id)
-                for user_id, user_keys in json_result.iteritems()
-                for device_id, device_keys in user_keys.iteritems()
-                for key_id, _ in device_keys.iteritems()
+                for user_id, user_keys in iteritems(json_result)
+                for device_id, device_keys in iteritems(user_keys)
+                for key_id, _ in iteritems(device_keys)
             )),
         )
 
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index ba3ede8024..fcf94befb7 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -24,6 +24,7 @@ from signedjson.key import decode_verify_key_bytes
 from signedjson.sign import verify_signed_json
 import six
 from six.moves import http_client
+from six import iteritems
 from twisted.internet import defer
 from unpaddedbase64 import decode_base64
 
@@ -51,7 +52,6 @@ from synapse.util.retryutils import NotRetryingDestination
 
 from synapse.util.distributor import user_joined_room
 
-
 logger = logging.getLogger(__name__)
 
 
@@ -479,7 +479,7 @@ class FederationHandler(BaseHandler):
         # to get all state ids that we're interested in.
         event_map = yield self.store.get_events([
             e_id
-            for key_to_eid in event_to_state_ids.values()
+            for key_to_eid in list(event_to_state_ids.values())
             for key, e_id in key_to_eid.items()
             if key[0] != EventTypes.Member or check_match(key[1])
         ])
@@ -487,10 +487,10 @@ class FederationHandler(BaseHandler):
         event_to_state = {
             e_id: {
                 key: event_map[inner_e_id]
-                for key, inner_e_id in key_to_eid.items()
+                for key, inner_e_id in key_to_eid.iteritems()
                 if inner_e_id in event_map
             }
-            for e_id, key_to_eid in event_to_state_ids.items()
+            for e_id, key_to_eid in event_to_state_ids.iteritems()
         }
 
         def redact_disallowed(event, state):
@@ -505,7 +505,7 @@ class FederationHandler(BaseHandler):
                     # membership states for the requesting server to determine
                     # if the server is either in the room or has been invited
                     # into the room.
-                    for ev in state.values():
+                    for ev in state.itervalues():
                         if ev.type != EventTypes.Member:
                             continue
                         try:
@@ -751,9 +751,19 @@ class FederationHandler(BaseHandler):
         curr_state = yield self.state_handler.get_current_state(room_id)
 
         def get_domains_from_state(state):
+            """Get joined domains from state
+
+            Args:
+                state (dict[tuple, FrozenEvent]): State map from type/state
+                    key to event.
+
+            Returns:
+                list[tuple[str, int]]: Returns a list of servers with the
+                lowest depth of their joins. Sorted by lowest depth first.
+            """
             joined_users = [
                 (state_key, int(event.depth))
-                for (e_type, state_key), event in state.items()
+                for (e_type, state_key), event in state.iteritems()
                 if e_type == EventTypes.Member
                 and event.membership == Membership.JOIN
             ]
@@ -770,7 +780,7 @@ class FederationHandler(BaseHandler):
                 except Exception:
                     pass
 
-            return sorted(joined_domains.items(), key=lambda d: d[1])
+            return sorted(joined_domains.iteritems(), key=lambda d: d[1])
 
         curr_domains = get_domains_from_state(curr_state)
 
@@ -787,7 +797,7 @@ class FederationHandler(BaseHandler):
                     yield self.backfill(
                         dom, room_id,
                         limit=100,
-                        extremities=[e for e in extremities.keys()]
+                        extremities=extremities,
                     )
                     # If this succeeded then we probably already have the
                     # appropriate stuff.
@@ -833,7 +843,7 @@ class FederationHandler(BaseHandler):
         tried_domains = set(likely_domains)
         tried_domains.add(self.server_name)
 
-        event_ids = list(extremities.keys())
+        event_ids = list(extremities.iterkeys())
 
         logger.debug("calling resolve_state_groups in _maybe_backfill")
         resolve = logcontext.preserve_fn(
@@ -843,31 +853,34 @@ class FederationHandler(BaseHandler):
             [resolve(room_id, [e]) for e in event_ids],
             consumeErrors=True,
         ))
+
+        # dict[str, dict[tuple, str]], a map from event_id to state map of
+        # event_ids.
         states = dict(zip(event_ids, [s.state for s in states]))
 
         state_map = yield self.store.get_events(
-            [e_id for ids in states.values() for e_id in ids],
+            [e_id for ids in states.itervalues() for e_id in ids.itervalues()],
             get_prev_content=False
         )
         states = {
             key: {
                 k: state_map[e_id]
-                for k, e_id in state_dict.items()
+                for k, e_id in state_dict.iteritems()
                 if e_id in state_map
-            } for key, state_dict in states.items()
+            } for key, state_dict in states.iteritems()
         }
 
         for e_id, _ in sorted_extremeties_tuple:
             likely_domains = get_domains_from_state(states[e_id])
 
             success = yield try_backfill([
-                dom for dom in likely_domains
+                dom for dom, _ in likely_domains
                 if dom not in tried_domains
             ])
             if success:
                 defer.returnValue(True)
 
-            tried_domains.update(likely_domains)
+            tried_domains.update(dom for dom, _ in likely_domains)
 
         defer.returnValue(False)
 
@@ -1135,13 +1148,13 @@ class FederationHandler(BaseHandler):
                 user = UserID.from_string(event.state_key)
                 yield user_joined_room(self.distributor, user, event.room_id)
 
-        state_ids = context.prev_state_ids.values()
+        state_ids = list(context.prev_state_ids.values())
         auth_chain = yield self.store.get_auth_chain(state_ids)
 
-        state = yield self.store.get_events(context.prev_state_ids.values())
+        state = yield self.store.get_events(list(context.prev_state_ids.values()))
 
         defer.returnValue({
-            "state": state.values(),
+            "state": list(state.values()),
             "auth_chain": auth_chain,
         })
 
@@ -1375,7 +1388,7 @@ class FederationHandler(BaseHandler):
         )
 
         if state_groups:
-            _, state = state_groups.items().pop()
+            _, state = list(iteritems(state_groups)).pop()
             results = {
                 (e.type, e.state_key): e for e in state
             }
@@ -1391,7 +1404,7 @@ class FederationHandler(BaseHandler):
                 else:
                     del results[(event.type, event.state_key)]
 
-            res = results.values()
+            res = list(results.values())
             for event in res:
                 # We sign these again because there was a bug where we
                 # incorrectly signed things the first time round
@@ -1432,7 +1445,7 @@ class FederationHandler(BaseHandler):
                 else:
                     results.pop((event.type, event.state_key), None)
 
-            defer.returnValue(results.values())
+            defer.returnValue(list(results.values()))
         else:
             defer.returnValue([])
 
@@ -1901,7 +1914,7 @@ class FederationHandler(BaseHandler):
                 })
 
                 new_state = self.state_handler.resolve_events(
-                    [local_view.values(), remote_view.values()],
+                    [list(local_view.values()), list(remote_view.values())],
                     event
                 )
 
@@ -2021,7 +2034,7 @@ class FederationHandler(BaseHandler):
                 this will not be included in the current_state in the context.
         """
         state_updates = {
-            k: a.event_id for k, a in auth_events.iteritems()
+            k: a.event_id for k, a in iteritems(auth_events)
             if k != event_key
         }
         context.current_state_ids = dict(context.current_state_ids)
@@ -2031,7 +2044,7 @@ class FederationHandler(BaseHandler):
             context.delta_ids.update(state_updates)
         context.prev_state_ids = dict(context.prev_state_ids)
         context.prev_state_ids.update({
-            k: a.event_id for k, a in auth_events.iteritems()
+            k: a.event_id for k, a in iteritems(auth_events)
         })
         context.state_group = yield self.store.store_state_group(
             event.event_id,
@@ -2083,7 +2096,7 @@ class FederationHandler(BaseHandler):
 
         def get_next(it, opt=None):
             try:
-                return it.next()
+                return next(it)
             except Exception:
                 return opt
 
diff --git a/synapse/handlers/groups_local.py b/synapse/handlers/groups_local.py
index 977993e7d4..dcae083734 100644
--- a/synapse/handlers/groups_local.py
+++ b/synapse/handlers/groups_local.py
@@ -15,6 +15,7 @@
 # limitations under the License.
 
 from twisted.internet import defer
+from six import iteritems
 
 from synapse.api.errors import SynapseError
 from synapse.types import get_domain_from_id
@@ -449,7 +450,7 @@ class GroupsLocalHandler(object):
 
         results = {}
         failed_results = []
-        for destination, dest_user_ids in destinations.iteritems():
+        for destination, dest_user_ids in iteritems(destinations):
             try:
                 r = yield self.transport_client.bulk_get_publicised_groups(
                     destination, list(dest_user_ids),
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index c3adbc6c95..1cb81b6cf8 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -19,6 +19,7 @@ import sys
 
 from canonicaljson import encode_canonical_json
 import six
+from six import string_types, itervalues, iteritems
 from twisted.internet import defer, reactor
 from twisted.internet.defer import succeed
 from twisted.python.failure import Failure
@@ -402,7 +403,7 @@ class MessageHandler(BaseHandler):
                 "avatar_url": profile.avatar_url,
                 "display_name": profile.display_name,
             }
-            for user_id, profile in users_with_profile.iteritems()
+            for user_id, profile in iteritems(users_with_profile)
         })
 
 
@@ -571,12 +572,20 @@ class EventCreationHandler(object):
 
         u = yield self.store.get_user_by_id(user_id)
         assert u is not None
+        if u["appservice_id"] is not None:
+            # users registered by an appservice are exempt
+            return
         if u["consent_version"] == self.config.user_consent_version:
             return
 
-        consent_uri = self._consent_uri_builder.build_user_consent_uri(user_id)
+        consent_uri = self._consent_uri_builder.build_user_consent_uri(
+            requester.user.localpart,
+        )
+        msg = self.config.block_events_without_consent_error % {
+            'consent_uri': consent_uri,
+        }
         raise ConsentNotGivenError(
-            msg=self.config.block_events_without_consent_error,
+            msg=msg,
             consent_uri=consent_uri,
         )
 
@@ -662,7 +671,7 @@ class EventCreationHandler(object):
 
             spam_error = self.spam_checker.check_event_for_spam(event)
             if spam_error:
-                if not isinstance(spam_error, basestring):
+                if not isinstance(spam_error, string_types):
                     spam_error = "Spam is not permitted here"
                 raise SynapseError(
                     403, spam_error, Codes.FORBIDDEN
@@ -876,7 +885,7 @@ class EventCreationHandler(object):
 
                 state_to_include_ids = [
                     e_id
-                    for k, e_id in context.current_state_ids.iteritems()
+                    for k, e_id in iteritems(context.current_state_ids)
                     if k[0] in self.hs.config.room_invite_state_types
                     or k == (EventTypes.Member, event.sender)
                 ]
@@ -890,7 +899,7 @@ class EventCreationHandler(object):
                         "content": e.content,
                         "sender": e.sender,
                     }
-                    for e in state_to_include.itervalues()
+                    for e in itervalues(state_to_include)
                 ]
 
                 invitee = UserID.from_string(event.state_key)
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 500a131874..7fe568132f 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -25,6 +25,8 @@ The methods that define policy are:
 from twisted.internet import defer, reactor
 from contextlib import contextmanager
 
+from six import itervalues, iteritems
+
 from synapse.api.errors import SynapseError
 from synapse.api.constants import PresenceState
 from synapse.storage.presence import UserPresenceState
@@ -36,27 +38,29 @@ from synapse.util.logutils import log_function
 from synapse.util.metrics import Measure
 from synapse.util.wheel_timer import WheelTimer
 from synapse.types import UserID, get_domain_from_id
-import synapse.metrics
+from synapse.metrics import LaterGauge
 
 import logging
 
+from prometheus_client import Counter
 
 logger = logging.getLogger(__name__)
 
-metrics = synapse.metrics.get_metrics_for(__name__)
 
-notified_presence_counter = metrics.register_counter("notified_presence")
-federation_presence_out_counter = metrics.register_counter("federation_presence_out")
-presence_updates_counter = metrics.register_counter("presence_updates")
-timers_fired_counter = metrics.register_counter("timers_fired")
-federation_presence_counter = metrics.register_counter("federation_presence")
-bump_active_time_counter = metrics.register_counter("bump_active_time")
+notified_presence_counter = Counter("synapse_handler_presence_notified_presence", "")
+federation_presence_out_counter = Counter(
+    "synapse_handler_presence_federation_presence_out", "")
+presence_updates_counter = Counter("synapse_handler_presence_presence_updates", "")
+timers_fired_counter = Counter("synapse_handler_presence_timers_fired", "")
+federation_presence_counter = Counter("synapse_handler_presence_federation_presence", "")
+bump_active_time_counter = Counter("synapse_handler_presence_bump_active_time", "")
 
-get_updates_counter = metrics.register_counter("get_updates", labels=["type"])
+get_updates_counter = Counter("synapse_handler_presence_get_updates", "", ["type"])
 
-notify_reason_counter = metrics.register_counter("notify_reason", labels=["reason"])
-state_transition_counter = metrics.register_counter(
-    "state_transition", labels=["from", "to"]
+notify_reason_counter = Counter(
+    "synapse_handler_presence_notify_reason", "", ["reason"])
+state_transition_counter = Counter(
+    "synapse_handler_presence_state_transition", "", ["from", "to"]
 )
 
 
@@ -141,8 +145,9 @@ class PresenceHandler(object):
             for state in active_presence
         }
 
-        metrics.register_callback(
-            "user_to_current_state_size", lambda: len(self.user_to_current_state)
+        LaterGauge(
+            "synapse_handlers_presence_user_to_current_state_size", "", [],
+            lambda: len(self.user_to_current_state)
         )
 
         now = self.clock.time_msec()
@@ -212,7 +217,8 @@ class PresenceHandler(object):
             60 * 1000,
         )
 
-        metrics.register_callback("wheel_timer_size", lambda: len(self.wheel_timer))
+        LaterGauge("synapse_handlers_presence_wheel_timer_size", "", [],
+                   lambda: len(self.wheel_timer))
 
     @defer.inlineCallbacks
     def _on_shutdown(self):
@@ -315,11 +321,11 @@ class PresenceHandler(object):
 
             # TODO: We should probably ensure there are no races hereafter
 
-            presence_updates_counter.inc_by(len(new_states))
+            presence_updates_counter.inc(len(new_states))
 
             if to_notify:
-                notified_presence_counter.inc_by(len(to_notify))
-                yield self._persist_and_notify(to_notify.values())
+                notified_presence_counter.inc(len(to_notify))
+                yield self._persist_and_notify(list(to_notify.values()))
 
             self.unpersisted_users_changes |= set(s.user_id for s in new_states)
             self.unpersisted_users_changes -= set(to_notify.keys())
@@ -329,7 +335,7 @@ class PresenceHandler(object):
                 if user_id not in to_notify
             }
             if to_federation_ping:
-                federation_presence_out_counter.inc_by(len(to_federation_ping))
+                federation_presence_out_counter.inc(len(to_federation_ping))
 
                 self._push_to_remotes(to_federation_ping.values())
 
@@ -367,7 +373,7 @@ class PresenceHandler(object):
                     for user_id in users_to_check
                 ]
 
-                timers_fired_counter.inc_by(len(states))
+                timers_fired_counter.inc(len(states))
 
                 changes = handle_timeouts(
                     states,
@@ -530,7 +536,7 @@ class PresenceHandler(object):
                 prev_state.copy_and_replace(
                     last_user_sync_ts=time_now_ms,
                 )
-                for prev_state in prev_states.itervalues()
+                for prev_state in itervalues(prev_states)
             ])
             self.external_process_last_updated_ms.pop(process_id, None)
 
@@ -553,14 +559,14 @@ class PresenceHandler(object):
             for user_id in user_ids
         }
 
-        missing = [user_id for user_id, state in states.iteritems() if not state]
+        missing = [user_id for user_id, state in iteritems(states) if not state]
         if missing:
             # There are things not in our in memory cache. Lets pull them out of
             # the database.
             res = yield self.store.get_presence_for_users(missing)
             states.update(res)
 
-            missing = [user_id for user_id, state in states.iteritems() if not state]
+            missing = [user_id for user_id, state in iteritems(states) if not state]
             if missing:
                 new = {
                     user_id: UserPresenceState.default(user_id)
@@ -656,7 +662,7 @@ class PresenceHandler(object):
             updates.append(prev_state.copy_and_replace(**new_fields))
 
         if updates:
-            federation_presence_counter.inc_by(len(updates))
+            federation_presence_counter.inc(len(updates))
             yield self._update_states(updates)
 
     @defer.inlineCallbacks
@@ -681,7 +687,7 @@ class PresenceHandler(object):
         """
 
         updates = yield self.current_state_for_users(target_user_ids)
-        updates = updates.values()
+        updates = list(updates.values())
 
         for user_id in set(target_user_ids) - set(u.user_id for u in updates):
             updates.append(UserPresenceState.default(user_id))
@@ -747,11 +753,11 @@ class PresenceHandler(object):
             self._push_to_remotes([state])
         else:
             user_ids = yield self.store.get_users_in_room(room_id)
-            user_ids = filter(self.is_mine_id, user_ids)
+            user_ids = list(filter(self.is_mine_id, user_ids))
 
             states = yield self.current_state_for_users(user_ids)
 
-            self._push_to_remotes(states.values())
+            self._push_to_remotes(list(states.values()))
 
     @defer.inlineCallbacks
     def get_presence_list(self, observer_user, accepted=None):
@@ -931,28 +937,28 @@ def should_notify(old_state, new_state):
         return False
 
     if old_state.status_msg != new_state.status_msg:
-        notify_reason_counter.inc("status_msg_change")
+        notify_reason_counter.labels("status_msg_change").inc()
         return True
 
     if old_state.state != new_state.state:
-        notify_reason_counter.inc("state_change")
-        state_transition_counter.inc(old_state.state, new_state.state)
+        notify_reason_counter.labels("state_change").inc()
+        state_transition_counter.labels(old_state.state, new_state.state).inc()
         return True
 
     if old_state.state == PresenceState.ONLINE:
         if new_state.currently_active != old_state.currently_active:
-            notify_reason_counter.inc("current_active_change")
+            notify_reason_counter.labels("current_active_change").inc()
             return True
 
         if new_state.last_active_ts - old_state.last_active_ts > LAST_ACTIVE_GRANULARITY:
             # Only notify about last active bumps if we're not currently acive
             if not new_state.currently_active:
-                notify_reason_counter.inc("last_active_change_online")
+                notify_reason_counter.labels("last_active_change_online").inc()
                 return True
 
     elif new_state.last_active_ts - old_state.last_active_ts > LAST_ACTIVE_GRANULARITY:
         # Always notify for a transition where last active gets bumped.
-        notify_reason_counter.inc("last_active_change_not_online")
+        notify_reason_counter.labels("last_active_change_not_online").inc()
         return True
 
     return False
@@ -1026,14 +1032,14 @@ class PresenceEventSource(object):
             if changed is not None and len(changed) < 500:
                 # For small deltas, its quicker to get all changes and then
                 # work out if we share a room or they're in our presence list
-                get_updates_counter.inc("stream")
+                get_updates_counter.labels("stream").inc()
                 for other_user_id in changed:
                     if other_user_id in users_interested_in:
                         user_ids_changed.add(other_user_id)
             else:
                 # Too many possible updates. Find all users we can see and check
                 # if any of them have changed.
-                get_updates_counter.inc("full")
+                get_updates_counter.labels("full").inc()
 
                 if from_key:
                     user_ids_changed = stream_change_cache.get_entities_changed(
@@ -1045,10 +1051,10 @@ class PresenceEventSource(object):
             updates = yield presence.current_state_for_users(user_ids_changed)
 
         if include_offline:
-            defer.returnValue((updates.values(), max_token))
+            defer.returnValue((list(updates.values()), max_token))
         else:
             defer.returnValue(([
-                s for s in updates.itervalues()
+                s for s in itervalues(updates)
                 if s.state != PresenceState.OFFLINE
             ], max_token))
 
@@ -1106,7 +1112,7 @@ def handle_timeouts(user_states, is_mine_fn, syncing_user_ids, now):
         if new_state:
             changes[state.user_id] = new_state
 
-    return changes.values()
+    return list(changes.values())
 
 
 def handle_timeout(state, is_mine, syncing_user_ids, now):
@@ -1305,11 +1311,11 @@ def get_interested_remotes(store, states, state_handler):
     # hosts in those rooms.
     room_ids_to_states, users_to_states = yield get_interested_parties(store, states)
 
-    for room_id, states in room_ids_to_states.iteritems():
+    for room_id, states in iteritems(room_ids_to_states):
         hosts = yield state_handler.get_current_hosts_in_room(room_id)
         hosts_and_states.append((hosts, states))
 
-    for user_id, states in users_to_states.iteritems():
+    for user_id, states in iteritems(users_to_states):
         host = get_domain_from_id(user_id)
         hosts_and_states.append(([host], states))
 
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index b5850db42f..2abd63ad05 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -455,7 +455,7 @@ class RoomContextHandler(BaseHandler):
         state = yield self.store.get_state_for_events(
             [last_event_id], None
         )
-        results["state"] = state[last_event_id].values()
+        results["state"] = list(state[last_event_id].values())
 
         results["start"] = now_token.copy_and_replace(
             "room_key", results["start"]
diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py
index 5757bb7f8a..fc507cef36 100644
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@@ -15,6 +15,7 @@
 
 from twisted.internet import defer
 
+from six import iteritems
 from six.moves import range
 
 from ._base import BaseHandler
@@ -307,7 +308,7 @@ class RoomListHandler(BaseHandler):
         )
 
         event_map = yield self.store.get_events([
-            event_id for key, event_id in current_state_ids.iteritems()
+            event_id for key, event_id in iteritems(current_state_ids)
             if key[0] in (
                 EventTypes.JoinRules,
                 EventTypes.Name,
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 5263f09aaa..f930e939e8 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -298,15 +298,6 @@ class RoomMemberHandler(object):
             is_blocked = yield self.store.is_room_blocked(room_id)
             if is_blocked:
                 raise SynapseError(403, "This room has been blocked on this server")
-        else:
-            # we don't allow people to reject invites to, or leave, the
-            # server notice room.
-            is_blocked = yield self._is_server_notice_room(room_id)
-            if is_blocked:
-                raise SynapseError(
-                    http_client.FORBIDDEN,
-                    "You cannot leave this room",
-                )
 
         if effective_membership_state == Membership.INVITE:
             # block any attempts to invite the server notices mxid
@@ -382,6 +373,20 @@ class RoomMemberHandler(object):
                 if same_sender and same_membership and same_content:
                     defer.returnValue(old_state)
 
+            # we don't allow people to reject invites to the server notice
+            # room, but they can leave it once they are joined.
+            if (
+                old_membership == Membership.INVITE and
+                effective_membership_state == Membership.LEAVE
+            ):
+                is_blocked = yield self._is_server_notice_room(room_id)
+                if is_blocked:
+                    raise SynapseError(
+                        http_client.FORBIDDEN,
+                        "You cannot reject this invite",
+                        errcode=Codes.CANNOT_LEAVE_SERVER_NOTICE_ROOM,
+                    )
+
         is_host_in_room = yield self._is_host_in_room(current_state_ids)
 
         if effective_membership_state == Membership.JOIN:
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index 9772ed1a0e..1eca26aa1e 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -348,7 +348,7 @@ class SearchHandler(BaseHandler):
             rooms = set(e.room_id for e in allowed_events)
             for room_id in rooms:
                 state = yield self.state_handler.get_current_state(room_id)
-                state_results[room_id] = state.values()
+                state_results[room_id] = list(state.values())
 
             state_results.values()
 
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 263e42dded..51ec727df0 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -28,6 +28,8 @@ import collections
 import logging
 import itertools
 
+from six import itervalues, iteritems
+
 logger = logging.getLogger(__name__)
 
 
@@ -275,7 +277,7 @@ class SyncHandler(object):
                 # result returned by the event source is poor form (it might cache
                 # the object)
                 room_id = event["room_id"]
-                event_copy = {k: v for (k, v) in event.iteritems()
+                event_copy = {k: v for (k, v) in iteritems(event)
                               if k != "room_id"}
                 ephemeral_by_room.setdefault(room_id, []).append(event_copy)
 
@@ -294,7 +296,7 @@ class SyncHandler(object):
             for event in receipts:
                 room_id = event["room_id"]
                 # exclude room id, as above
-                event_copy = {k: v for (k, v) in event.iteritems()
+                event_copy = {k: v for (k, v) in iteritems(event)
                               if k != "room_id"}
                 ephemeral_by_room.setdefault(room_id, []).append(event_copy)
 
@@ -325,7 +327,7 @@ class SyncHandler(object):
                 current_state_ids = frozenset()
                 if any(e.is_state() for e in recents):
                     current_state_ids = yield self.state.get_current_state_ids(room_id)
-                    current_state_ids = frozenset(current_state_ids.itervalues())
+                    current_state_ids = frozenset(itervalues(current_state_ids))
 
                 recents = yield filter_events_for_client(
                     self.store,
@@ -382,7 +384,7 @@ class SyncHandler(object):
                 current_state_ids = frozenset()
                 if any(e.is_state() for e in loaded_recents):
                     current_state_ids = yield self.state.get_current_state_ids(room_id)
-                    current_state_ids = frozenset(current_state_ids.itervalues())
+                    current_state_ids = frozenset(itervalues(current_state_ids))
 
                 loaded_recents = yield filter_events_for_client(
                     self.store,
@@ -441,6 +443,10 @@ class SyncHandler(object):
         Returns:
             A Deferred map from ((type, state_key)->Event)
         """
+        # FIXME this claims to get the state at a stream position, but
+        # get_recent_events_for_room operates by topo ordering. This therefore
+        # does not reliably give you the state at the given stream position.
+        # (https://github.com/matrix-org/synapse/issues/3305)
         last_events, _ = yield self.store.get_recent_events_for_room(
             room_id, end_token=stream_position.room_key, limit=1,
         )
@@ -535,11 +541,11 @@ class SyncHandler(object):
 
         state = {}
         if state_ids:
-            state = yield self.store.get_events(state_ids.values())
+            state = yield self.store.get_events(list(state_ids.values()))
 
         defer.returnValue({
             (e.type, e.state_key): e
-            for e in sync_config.filter_collection.filter_room_state(state.values())
+            for e in sync_config.filter_collection.filter_room_state(list(state.values()))
         })
 
     @defer.inlineCallbacks
@@ -888,7 +894,7 @@ class SyncHandler(object):
             presence.extend(states)
 
             # Deduplicate the presence entries so that there's at most one per user
-            presence = {p.user_id: p for p in presence}.values()
+            presence = list({p.user_id: p for p in presence}.values())
 
         presence = sync_config.filter_collection.filter_presence(
             presence
@@ -984,7 +990,7 @@ class SyncHandler(object):
         if since_token:
             for joined_sync in sync_result_builder.joined:
                 it = itertools.chain(
-                    joined_sync.timeline.events, joined_sync.state.itervalues()
+                    joined_sync.timeline.events, itervalues(joined_sync.state)
                 )
                 for event in it:
                     if event.type == EventTypes.Member:
@@ -1040,7 +1046,13 @@ class SyncHandler(object):
 
         Returns:
             Deferred(tuple): Returns a tuple of the form:
-            `([RoomSyncResultBuilder], [InvitedSyncResult], newly_joined_rooms)`
+            `(room_entries, invited_rooms, newly_joined_rooms, newly_left_rooms)`
+
+            where:
+                room_entries is a list [RoomSyncResultBuilder]
+                invited_rooms is a list [InvitedSyncResult]
+                newly_joined rooms is a list[str] of room ids
+                newly_left_rooms is a list[str] of room ids
         """
         user_id = sync_result_builder.sync_config.user.to_string()
         since_token = sync_result_builder.since_token
@@ -1062,7 +1074,7 @@ class SyncHandler(object):
         newly_left_rooms = []
         room_entries = []
         invited = []
-        for room_id, events in mem_change_events_by_room_id.iteritems():
+        for room_id, events in iteritems(mem_change_events_by_room_id):
             non_joins = [e for e in events if e.membership != Membership.JOIN]
             has_join = len(non_joins) != len(events)
 
diff --git a/synapse/handlers/user_directory.py b/synapse/handlers/user_directory.py
index 714f0195c8..a39f0f7343 100644
--- a/synapse/handlers/user_directory.py
+++ b/synapse/handlers/user_directory.py
@@ -22,6 +22,7 @@ from synapse.util.metrics import Measure
 from synapse.util.async import sleep
 from synapse.types import get_localpart_from_id
 
+from six import iteritems
 
 logger = logging.getLogger(__name__)
 
@@ -123,6 +124,13 @@ class UserDirectoryHandler(object):
         )
 
     @defer.inlineCallbacks
+    def handle_user_deactivated(self, user_id):
+        """Called when a user ID is deactivated
+        """
+        yield self.store.remove_from_user_dir(user_id)
+        yield self.store.remove_from_user_in_public_room(user_id)
+
+    @defer.inlineCallbacks
     def _unsafe_process(self):
         # If self.pos is None then means we haven't fetched it from DB
         if self.pos is None:
@@ -403,7 +411,7 @@ class UserDirectoryHandler(object):
 
         if change:
             users_with_profile = yield self.state.get_current_user_in_room(room_id)
-            for user_id, profile in users_with_profile.iteritems():
+            for user_id, profile in iteritems(users_with_profile):
                 yield self._handle_new_user(room_id, user_id, profile)
         else:
             users = yield self.store.get_users_in_public_due_to_room(room_id)
diff --git a/synapse/http/client.py b/synapse/http/client.py
index 70a19d9b74..4d4eee3d64 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -23,7 +23,6 @@ from synapse.http import cancelled_to_request_timed_out_error
 from synapse.util.async import add_timeout_to_deferred
 from synapse.util.caches import CACHE_SIZE_FACTOR
 from synapse.util.logcontext import make_deferred_yieldable
-import synapse.metrics
 from synapse.http.endpoint import SpiderEndpoint
 
 from canonicaljson import encode_canonical_json
@@ -42,6 +41,7 @@ from twisted.web._newclient import ResponseDone
 
 from six import StringIO
 
+from prometheus_client import Counter
 import simplejson as json
 import logging
 import urllib
@@ -49,16 +49,9 @@ import urllib
 
 logger = logging.getLogger(__name__)
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-
-outgoing_requests_counter = metrics.register_counter(
-    "requests",
-    labels=["method"],
-)
-incoming_responses_counter = metrics.register_counter(
-    "responses",
-    labels=["method", "code"],
-)
+outgoing_requests_counter = Counter("synapse_http_client_requests", "", ["method"])
+incoming_responses_counter = Counter("synapse_http_client_responses", "",
+                                     ["method", "code"])
 
 
 class SimpleHttpClient(object):
@@ -95,7 +88,7 @@ class SimpleHttpClient(object):
     def request(self, method, uri, *args, **kwargs):
         # A small wrapper around self.agent.request() so we can easily attach
         # counters to it
-        outgoing_requests_counter.inc(method)
+        outgoing_requests_counter.labels(method).inc()
 
         logger.info("Sending request %s %s", method, uri)
 
@@ -109,14 +102,14 @@ class SimpleHttpClient(object):
             )
             response = yield make_deferred_yieldable(request_deferred)
 
-            incoming_responses_counter.inc(method, response.code)
+            incoming_responses_counter.labels(method, response.code).inc()
             logger.info(
                 "Received response to  %s %s: %s",
                 method, uri, response.code
             )
             defer.returnValue(response)
         except Exception as e:
-            incoming_responses_counter.inc(method, "ERR")
+            incoming_responses_counter.labels(method, "ERR").inc()
             logger.info(
                 "Error sending request to  %s %s: %s %s",
                 method, uri, type(e).__name__, e.message
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 4b2b85464d..821aed362b 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -42,20 +42,18 @@ import random
 import sys
 import urllib
 from six.moves.urllib import parse as urlparse
+from six import string_types
+
+
+from prometheus_client import Counter
 
 logger = logging.getLogger(__name__)
 outbound_logger = logging.getLogger("synapse.http.outbound")
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-
-outgoing_requests_counter = metrics.register_counter(
-    "requests",
-    labels=["method"],
-)
-incoming_responses_counter = metrics.register_counter(
-    "responses",
-    labels=["method", "code"],
-)
+outgoing_requests_counter = Counter("synapse_http_matrixfederationclient_requests",
+                                    "", ["method"])
+incoming_responses_counter = Counter("synapse_http_matrixfederationclient_responses",
+                                     "", ["method", "code"])
 
 
 MAX_LONG_RETRIES = 10
@@ -553,7 +551,7 @@ class MatrixFederationHttpClient(object):
 
         encoded_args = {}
         for k, vs in args.items():
-            if isinstance(vs, basestring):
+            if isinstance(vs, string_types):
                 vs = [vs]
             encoded_args[k] = [v.encode("UTF-8") for v in vs]
 
@@ -668,7 +666,7 @@ def check_content_type_is_json(headers):
         RuntimeError if the
 
     """
-    c_type = headers.getRawHeaders("Content-Type")
+    c_type = headers.getRawHeaders(b"Content-Type")
     if c_type is None:
         raise RuntimeError(
             "No Content-Type header"
@@ -685,7 +683,7 @@ def check_content_type_is_json(headers):
 def encode_query_args(args):
     encoded_args = {}
     for k, vs in args.items():
-        if isinstance(vs, basestring):
+        if isinstance(vs, string_types):
             vs = [vs]
         encoded_args[k] = [v.encode("UTF-8") for v in vs]
 
diff --git a/synapse/http/request_metrics.py b/synapse/http/request_metrics.py
index 5917c83958..dc06f6c443 100644
--- a/synapse/http/request_metrics.py
+++ b/synapse/http/request_metrics.py
@@ -16,137 +16,109 @@
 
 import logging
 
-import synapse.metrics
+from prometheus_client.core import Counter, Histogram
+from synapse.metrics import LaterGauge
+
 from synapse.util.logcontext import LoggingContext
 
 logger = logging.getLogger(__name__)
 
-metrics = synapse.metrics.get_metrics_for("synapse.http.server")
 
 # total number of responses served, split by method/servlet/tag
-response_count = metrics.register_counter(
-    "response_count",
-    labels=["method", "servlet", "tag"],
-    alternative_names=(
-        # the following are all deprecated aliases for the same metric
-        metrics.name_prefix + x for x in (
-            "_requests",
-            "_response_time:count",
-            "_response_ru_utime:count",
-            "_response_ru_stime:count",
-            "_response_db_txn_count:count",
-            "_response_db_txn_duration:count",
-        )
-    )
+response_count = Counter(
+    "synapse_http_server_response_count", "", ["method", "servlet", "tag"]
 )
 
-requests_counter = metrics.register_counter(
-    "requests_received",
-    labels=["method", "servlet", ],
+requests_counter = Counter(
+    "synapse_http_server_requests_received", "", ["method", "servlet"]
 )
 
-outgoing_responses_counter = metrics.register_counter(
-    "responses",
-    labels=["method", "code"],
+outgoing_responses_counter = Counter(
+    "synapse_http_server_responses", "", ["method", "code"]
 )
 
-response_timer = metrics.register_counter(
-    "response_time_seconds",
-    labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_time:total",
-    ),
+response_timer = Histogram(
+    "synapse_http_server_response_time_seconds", "sec", ["method", "servlet", "tag"]
 )
 
-response_ru_utime = metrics.register_counter(
-    "response_ru_utime_seconds", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_ru_utime:total",
-    ),
+response_ru_utime = Counter(
+    "synapse_http_server_response_ru_utime_seconds", "sec", ["method", "servlet", "tag"]
 )
 
-response_ru_stime = metrics.register_counter(
-    "response_ru_stime_seconds", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_ru_stime:total",
-    ),
+response_ru_stime = Counter(
+    "synapse_http_server_response_ru_stime_seconds", "sec", ["method", "servlet", "tag"]
 )
 
-response_db_txn_count = metrics.register_counter(
-    "response_db_txn_count", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_db_txn_count:total",
-    ),
+response_db_txn_count = Counter(
+    "synapse_http_server_response_db_txn_count", "", ["method", "servlet", "tag"]
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, when processing
 # this request
-response_db_txn_duration = metrics.register_counter(
-    "response_db_txn_duration_seconds", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_db_txn_duration:total",
-    ),
+response_db_txn_duration = Counter(
+    "synapse_http_server_response_db_txn_duration_seconds",
+    "",
+    ["method", "servlet", "tag"],
 )
 
 # seconds spent waiting for a db connection, when processing this request
-response_db_sched_duration = metrics.register_counter(
-    "response_db_sched_duration_seconds", labels=["method", "servlet", "tag"]
+response_db_sched_duration = Counter(
+    "synapse_http_server_response_db_sched_duration_seconds",
+    "",
+    ["method", "servlet", "tag"],
 )
 
 # size in bytes of the response written
-response_size = metrics.register_counter(
-    "response_size", labels=["method", "servlet", "tag"]
+response_size = Counter(
+    "synapse_http_server_response_size", "", ["method", "servlet", "tag"]
 )
 
 # In flight metrics are incremented while the requests are in flight, rather
 # than when the response was written.
 
-in_flight_requests_ru_utime = metrics.register_counter(
-    "in_flight_requests_ru_utime_seconds", labels=["method", "servlet"],
+in_flight_requests_ru_utime = Counter(
+    "synapse_http_server_in_flight_requests_ru_utime_seconds",
+    "",
+    ["method", "servlet"],
 )
 
-in_flight_requests_ru_stime = metrics.register_counter(
-    "in_flight_requests_ru_stime_seconds", labels=["method", "servlet"],
+in_flight_requests_ru_stime = Counter(
+    "synapse_http_server_in_flight_requests_ru_stime_seconds",
+    "",
+    ["method", "servlet"],
 )
 
-in_flight_requests_db_txn_count = metrics.register_counter(
-    "in_flight_requests_db_txn_count", labels=["method", "servlet"],
+in_flight_requests_db_txn_count = Counter(
+    "synapse_http_server_in_flight_requests_db_txn_count", "", ["method", "servlet"]
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, when processing
 # this request
-in_flight_requests_db_txn_duration = metrics.register_counter(
-    "in_flight_requests_db_txn_duration_seconds", labels=["method", "servlet"],
+in_flight_requests_db_txn_duration = Counter(
+    "synapse_http_server_in_flight_requests_db_txn_duration_seconds",
+    "",
+    ["method", "servlet"],
 )
 
 # seconds spent waiting for a db connection, when processing this request
-in_flight_requests_db_sched_duration = metrics.register_counter(
-    "in_flight_requests_db_sched_duration_seconds", labels=["method", "servlet"]
+in_flight_requests_db_sched_duration = Counter(
+    "synapse_http_server_in_flight_requests_db_sched_duration_seconds",
+    "",
+    ["method", "servlet"],
 )
 
-
 # The set of all in flight requests, set[RequestMetrics]
 _in_flight_requests = set()
 
 
-def _collect_in_flight():
-    """Called just before metrics are collected, so we use it to update all
-    the in flight request metrics
-    """
-
-    for rm in _in_flight_requests:
-        rm.update_metrics()
-
-
-metrics.register_collector(_collect_in_flight)
-
-
 def _get_in_flight_counts():
     """Returns a count of all in flight requests by (method, server_name)
 
     Returns:
         dict[tuple[str, str], int]
     """
+    for rm in _in_flight_requests:
+        rm.update_metrics()
 
     # Map from (method, name) -> int, the number of in flight requests of that
     # type
@@ -158,16 +130,17 @@ def _get_in_flight_counts():
     return counts
 
 
-metrics.register_callback(
-    "in_flight_requests_count",
+LaterGauge(
+    "synapse_http_request_metrics_in_flight_requests_count",
+    "",
+    ["method", "servlet"],
     _get_in_flight_counts,
-    labels=["method", "servlet"]
 )
 
 
 class RequestMetrics(object):
-    def start(self, time_msec, name, method):
-        self.start = time_msec
+    def start(self, time_sec, name, method):
+        self.start = time_sec
         self.start_context = LoggingContext.current_context()
         self.name = name
         self.method = method
@@ -176,7 +149,7 @@ class RequestMetrics(object):
 
         _in_flight_requests.add(self)
 
-    def stop(self, time_msec, request):
+    def stop(self, time_sec, request):
         _in_flight_requests.discard(self)
 
         context = LoggingContext.current_context()
@@ -192,34 +165,29 @@ class RequestMetrics(object):
                 )
                 return
 
-        outgoing_responses_counter.inc(request.method, str(request.code))
+        outgoing_responses_counter.labels(request.method, str(request.code)).inc()
 
-        response_count.inc(request.method, self.name, tag)
+        response_count.labels(request.method, self.name, tag).inc()
 
-        response_timer.inc_by(
-            time_msec - self.start, request.method,
-            self.name, tag
+        response_timer.labels(request.method, self.name, tag).observe(
+            time_sec - self.start
         )
 
         ru_utime, ru_stime = context.get_resource_usage()
 
-        response_ru_utime.inc_by(
-            ru_utime, request.method, self.name, tag
-        )
-        response_ru_stime.inc_by(
-            ru_stime, request.method, self.name, tag
-        )
-        response_db_txn_count.inc_by(
-            context.db_txn_count, request.method, self.name, tag
+        response_ru_utime.labels(request.method, self.name, tag).inc(ru_utime)
+        response_ru_stime.labels(request.method, self.name, tag).inc(ru_stime)
+        response_db_txn_count.labels(request.method, self.name, tag).inc(
+            context.db_txn_count
         )
-        response_db_txn_duration.inc_by(
-            context.db_txn_duration_ms / 1000., request.method, self.name, tag
+        response_db_txn_duration.labels(request.method, self.name, tag).inc(
+            context.db_txn_duration_sec
         )
-        response_db_sched_duration.inc_by(
-            context.db_sched_duration_ms / 1000., request.method, self.name, tag
+        response_db_sched_duration.labels(request.method, self.name, tag).inc(
+            context.db_sched_duration_sec
         )
 
-        response_size.inc_by(request.sentLength, request.method, self.name, tag)
+        response_size.labels(request.method, self.name, tag).inc(request.sentLength)
 
         # We always call this at the end to ensure that we update the metrics
         # regardless of whether a call to /metrics while the request was in
@@ -229,27 +197,21 @@ class RequestMetrics(object):
     def update_metrics(self):
         """Updates the in flight metrics with values from this request.
         """
-
         diff = self._request_stats.update(self.start_context)
 
-        in_flight_requests_ru_utime.inc_by(
-            diff.ru_utime, self.method, self.name,
-        )
-
-        in_flight_requests_ru_stime.inc_by(
-            diff.ru_stime, self.method, self.name,
-        )
+        in_flight_requests_ru_utime.labels(self.method, self.name).inc(diff.ru_utime)
+        in_flight_requests_ru_stime.labels(self.method, self.name).inc(diff.ru_stime)
 
-        in_flight_requests_db_txn_count.inc_by(
-            diff.db_txn_count, self.method, self.name,
+        in_flight_requests_db_txn_count.labels(self.method, self.name).inc(
+            diff.db_txn_count
         )
 
-        in_flight_requests_db_txn_duration.inc_by(
-            diff.db_txn_duration_ms / 1000., self.method, self.name,
+        in_flight_requests_db_txn_duration.labels(self.method, self.name).inc(
+            diff.db_txn_duration_sec
         )
 
-        in_flight_requests_db_sched_duration.inc_by(
-            diff.db_sched_duration_ms / 1000., self.method, self.name,
+        in_flight_requests_db_sched_duration.labels(self.method, self.name).inc(
+            diff.db_sched_duration_sec
         )
 
 
@@ -258,17 +220,21 @@ class _RequestStats(object):
     """
 
     __slots__ = [
-        "ru_utime", "ru_stime",
-        "db_txn_count", "db_txn_duration_ms", "db_sched_duration_ms",
+        "ru_utime",
+        "ru_stime",
+        "db_txn_count",
+        "db_txn_duration_sec",
+        "db_sched_duration_sec",
     ]
 
-    def __init__(self, ru_utime, ru_stime, db_txn_count,
-                 db_txn_duration_ms, db_sched_duration_ms):
+    def __init__(
+        self, ru_utime, ru_stime, db_txn_count, db_txn_duration_sec, db_sched_duration_sec
+    ):
         self.ru_utime = ru_utime
         self.ru_stime = ru_stime
         self.db_txn_count = db_txn_count
-        self.db_txn_duration_ms = db_txn_duration_ms
-        self.db_sched_duration_ms = db_sched_duration_ms
+        self.db_txn_duration_sec = db_txn_duration_sec
+        self.db_sched_duration_sec = db_sched_duration_sec
 
     @staticmethod
     def from_context(context):
@@ -277,8 +243,8 @@ class _RequestStats(object):
         return _RequestStats(
             ru_utime, ru_stime,
             context.db_txn_count,
-            context.db_txn_duration_ms,
-            context.db_sched_duration_ms,
+            context.db_txn_duration_sec,
+            context.db_sched_duration_sec,
         )
 
     def update(self, context):
@@ -294,14 +260,14 @@ class _RequestStats(object):
             new.ru_utime - self.ru_utime,
             new.ru_stime - self.ru_stime,
             new.db_txn_count - self.db_txn_count,
-            new.db_txn_duration_ms - self.db_txn_duration_ms,
-            new.db_sched_duration_ms - self.db_sched_duration_ms,
+            new.db_txn_duration_sec - self.db_txn_duration_sec,
+            new.db_sched_duration_sec - self.db_sched_duration_sec,
         )
 
         self.ru_utime = new.ru_utime
         self.ru_stime = new.ru_stime
         self.db_txn_count = new.db_txn_count
-        self.db_txn_duration_ms = new.db_txn_duration_ms
-        self.db_sched_duration_ms = new.db_sched_duration_ms
+        self.db_txn_duration_sec = new.db_txn_duration_sec
+        self.db_sched_duration_sec = new.db_sched_duration_sec
 
         return diff
diff --git a/synapse/http/server.py b/synapse/http/server.py
index faf700851a..bc09b8b2be 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -210,8 +210,8 @@ def wrap_request_handler_with_logging(h):
                         # dispatching to the handler, so that the handler
                         # can update the servlet name in the request
                         # metrics
-                        requests_counter.inc(request.method,
-                                             request.request_metrics.name)
+                        requests_counter.labels(request.method,
+                                                request.request_metrics.name).inc()
                         yield d
     return wrapped_request_handler
 
diff --git a/synapse/http/site.py b/synapse/http/site.py
index b608504225..60299657b9 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -56,7 +56,7 @@ class SynapseRequest(Request):
 
     def __repr__(self):
         # We overwrite this so that we don't log ``access_token``
-        return '<%s at 0x%x method=%s uri=%s clientproto=%s site=%s>' % (
+        return '<%s at 0x%x method=%r uri=%r clientproto=%r site=%r>' % (
             self.__class__.__name__,
             id(self),
             self.method,
@@ -83,7 +83,7 @@ class SynapseRequest(Request):
         return Request.render(self, resrc)
 
     def _started_processing(self, servlet_name):
-        self.start_time = int(time.time() * 1000)
+        self.start_time = time.time()
         self.request_metrics = RequestMetrics()
         self.request_metrics.start(
             self.start_time, name=servlet_name, method=self.method,
@@ -102,26 +102,26 @@ class SynapseRequest(Request):
             context = LoggingContext.current_context()
             ru_utime, ru_stime = context.get_resource_usage()
             db_txn_count = context.db_txn_count
-            db_txn_duration_ms = context.db_txn_duration_ms
-            db_sched_duration_ms = context.db_sched_duration_ms
+            db_txn_duration_sec = context.db_txn_duration_sec
+            db_sched_duration_sec = context.db_sched_duration_sec
         except Exception:
             ru_utime, ru_stime = (0, 0)
-            db_txn_count, db_txn_duration_ms = (0, 0)
+            db_txn_count, db_txn_duration_sec = (0, 0)
 
-        end_time = int(time.time() * 1000)
+        end_time = time.time()
 
         self.site.access_logger.info(
             "%s - %s - {%s}"
-            " Processed request: %dms (%dms, %dms) (%dms/%dms/%d)"
+            " Processed request: %.3fsec (%.3fsec, %.3fsec) (%.3fsec/%.3fsec/%d)"
             " %sB %s \"%s %s %s\" \"%s\"",
             self.getClientIP(),
             self.site.site_tag,
             self.authenticated_entity,
             end_time - self.start_time,
-            int(ru_utime * 1000),
-            int(ru_stime * 1000),
-            db_sched_duration_ms,
-            db_txn_duration_ms,
+            ru_utime,
+            ru_stime,
+            db_sched_duration_sec,
+            db_txn_duration_sec,
             int(db_txn_count),
             self.sentLength,
             self.code,
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index e3b831db67..56c0032f91 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -17,165 +17,175 @@ import logging
 import functools
 import time
 import gc
+import os
 import platform
+import attr
 
-from twisted.internet import reactor
+from prometheus_client import Gauge, Histogram, Counter
+from prometheus_client.core import GaugeMetricFamily, REGISTRY
 
-from .metric import (
-    CounterMetric, CallbackMetric, DistributionMetric, CacheMetric,
-    MemoryUsageMetric, GaugeMetric,
-)
-from .process_collector import register_process_collector
+from twisted.internet import reactor
 
 
 logger = logging.getLogger(__name__)
 
-
-running_on_pypy = platform.python_implementation() == 'PyPy'
+running_on_pypy = platform.python_implementation() == "PyPy"
 all_metrics = []
 all_collectors = []
+all_gauges = {}
 
+HAVE_PROC_SELF_STAT = os.path.exists("/proc/self/stat")
 
-class Metrics(object):
-    """ A single Metrics object gives a (mutable) slice view of the all_metrics
-    dict, allowing callers to easily register new metrics that are namespaced
-    nicely."""
 
-    def __init__(self, name):
-        self.name_prefix = name
+class RegistryProxy(object):
 
-    def make_subspace(self, name):
-        return Metrics("%s_%s" % (self.name_prefix, name))
+    @staticmethod
+    def collect():
+        for metric in REGISTRY.collect():
+            if not metric.name.startswith("__"):
+                yield metric
 
-    def register_collector(self, func):
-        all_collectors.append(func)
 
-    def _register(self, metric_class, name, *args, **kwargs):
-        full_name = "%s_%s" % (self.name_prefix, name)
+@attr.s(hash=True)
+class LaterGauge(object):
 
-        metric = metric_class(full_name, *args, **kwargs)
+    name = attr.ib()
+    desc = attr.ib()
+    labels = attr.ib(hash=False)
+    caller = attr.ib()
 
-        all_metrics.append(metric)
-        return metric
+    def collect(self):
 
-    def register_counter(self, *args, **kwargs):
-        """
-        Returns:
-            CounterMetric
-        """
-        return self._register(CounterMetric, *args, **kwargs)
+        g = GaugeMetricFamily(self.name, self.desc, labels=self.labels)
 
-    def register_gauge(self, *args, **kwargs):
-        """
-        Returns:
-            GaugeMetric
-        """
-        return self._register(GaugeMetric, *args, **kwargs)
+        try:
+            calls = self.caller()
+        except Exception as e:
+            print(e)
+            logger.err()
+            yield g
 
-    def register_callback(self, *args, **kwargs):
-        """
-        Returns:
-            CallbackMetric
-        """
-        return self._register(CallbackMetric, *args, **kwargs)
+        if isinstance(calls, dict):
+            for k, v in calls.items():
+                g.add_metric(k, v)
+        else:
+            g.add_metric([], calls)
 
-    def register_distribution(self, *args, **kwargs):
-        """
-        Returns:
-            DistributionMetric
-        """
-        return self._register(DistributionMetric, *args, **kwargs)
+        yield g
 
-    def register_cache(self, *args, **kwargs):
-        """
-        Returns:
-            CacheMetric
-        """
-        return self._register(CacheMetric, *args, **kwargs)
+    def __attrs_post_init__(self):
+        self._register()
 
+    def _register(self):
+        if self.name in all_gauges.keys():
+            logger.warning("%s already registered, reregistering" % (self.name,))
+            REGISTRY.unregister(all_gauges.pop(self.name))
 
-def register_memory_metrics(hs):
-    try:
-        import psutil
-        process = psutil.Process()
-        process.memory_info().rss
-    except (ImportError, AttributeError):
-        logger.warn(
-            "psutil is not installed or incorrect version."
-            " Disabling memory metrics."
-        )
-        return
-    metric = MemoryUsageMetric(hs, psutil)
-    all_metrics.append(metric)
+        REGISTRY.register(self)
+        all_gauges[self.name] = self
 
 
-def get_metrics_for(pkg_name):
-    """ Returns a Metrics instance for conveniently creating metrics
-    namespaced with the given name prefix. """
+#
+# Detailed CPU metrics
+#
 
-    # Convert a "package.name" to "package_name" because Prometheus doesn't
-    # let us use . in metric names
-    return Metrics(pkg_name.replace(".", "_"))
+class CPUMetrics(object):
 
+    def __init__(self):
+        ticks_per_sec = 100
+        try:
+            # Try and get the system config
+            ticks_per_sec = os.sysconf('SC_CLK_TCK')
+        except (ValueError, TypeError, AttributeError):
+            pass
 
-def render_all():
-    strs = []
+        self.ticks_per_sec = ticks_per_sec
 
-    for collector in all_collectors:
-        collector()
+    def collect(self):
+        if not HAVE_PROC_SELF_STAT:
+            return
+
+        with open("/proc/self/stat") as s:
+            line = s.read()
+            raw_stats = line.split(") ", 1)[1].split(" ")
+
+            user = GaugeMetricFamily("process_cpu_user_seconds_total", "")
+            user.add_metric([], float(raw_stats[11]) / self.ticks_per_sec)
+            yield user
+
+            sys = GaugeMetricFamily("process_cpu_system_seconds_total", "")
+            sys.add_metric([], float(raw_stats[12]) / self.ticks_per_sec)
+            yield sys
+
+
+REGISTRY.register(CPUMetrics())
+
+#
+# Python GC metrics
+#
+
+gc_unreachable = Gauge("python_gc_unreachable_total", "Unreachable GC objects", ["gen"])
+gc_time = Histogram(
+    "python_gc_time",
+    "Time taken to GC (sec)",
+    ["gen"],
+    buckets=[0.0025, 0.005, 0.01, 0.025, 0.05, 0.10, 0.25, 0.50, 1.00, 2.50,
+             5.00, 7.50, 15.00, 30.00, 45.00, 60.00],
+)
 
-    for metric in all_metrics:
-        try:
-            strs += metric.render()
-        except Exception:
-            strs += ["# FAILED to render"]
-            logger.exception("Failed to render metric")
 
-    strs.append("")  # to generate a final CRLF
+class GCCounts(object):
 
-    return "\n".join(strs)
+    def collect(self):
+        cm = GaugeMetricFamily("python_gc_counts", "GC cycle counts", labels=["gen"])
+        for n, m in enumerate(gc.get_count()):
+            cm.add_metric([str(n)], m)
 
+        yield cm
 
-register_process_collector(get_metrics_for("process"))
 
+REGISTRY.register(GCCounts())
 
-python_metrics = get_metrics_for("python")
+#
+# Twisted reactor metrics
+#
 
-gc_time = python_metrics.register_distribution("gc_time", labels=["gen"])
-gc_unreachable = python_metrics.register_counter("gc_unreachable_total", labels=["gen"])
-python_metrics.register_callback(
-    "gc_counts", lambda: {(i,): v for i, v in enumerate(gc.get_count())}, labels=["gen"]
+tick_time = Histogram(
+    "python_twisted_reactor_tick_time",
+    "Tick time of the Twisted reactor (sec)",
+    buckets=[0.001, 0.002, 0.005, 0.01, 0.025, 0.05, 0.1, 0.2, 0.5, 1, 2, 5],
+)
+pending_calls_metric = Histogram(
+    "python_twisted_reactor_pending_calls",
+    "Pending calls",
+    buckets=[1, 2, 5, 10, 25, 50, 100, 250, 500, 1000],
 )
 
-reactor_metrics = get_metrics_for("python.twisted.reactor")
-tick_time = reactor_metrics.register_distribution("tick_time")
-pending_calls_metric = reactor_metrics.register_distribution("pending_calls")
+#
+# Federation Metrics
+#
+
+sent_edus_counter = Counter("synapse_federation_client_sent_edus", "")
 
-synapse_metrics = get_metrics_for("synapse")
+sent_transactions_counter = Counter("synapse_federation_client_sent_transactions", "")
+
+events_processed_counter = Counter("synapse_federation_client_events_processed", "")
 
 # Used to track where various components have processed in the event stream,
 # e.g. federation sending, appservice sending, etc.
-event_processing_positions = synapse_metrics.register_gauge(
-    "event_processing_positions", labels=["name"],
-)
+event_processing_positions = Gauge("synapse_event_processing_positions", "", ["name"])
 
 # Used to track the current max events stream position
-event_persisted_position = synapse_metrics.register_gauge(
-    "event_persisted_position",
-)
+event_persisted_position = Gauge("synapse_event_persisted_position", "")
 
 # Used to track the received_ts of the last event processed by various
 # components
-event_processing_last_ts = synapse_metrics.register_gauge(
-    "event_processing_last_ts", labels=["name"],
-)
+event_processing_last_ts = Gauge("synapse_event_processing_last_ts", "", ["name"])
 
 # Used to track the lag processing events. This is the time difference
 # between the last processed event's received_ts and the time it was
 # finished being processed.
-event_processing_lag = synapse_metrics.register_gauge(
-    "event_processing_lag", labels=["name"],
-)
+event_processing_lag = Gauge("synapse_event_processing_lag", "", ["name"])
 
 
 def runUntilCurrentTimer(func):
@@ -197,17 +207,17 @@ def runUntilCurrentTimer(func):
             num_pending += 1
 
         num_pending += len(reactor.threadCallQueue)
-        start = time.time() * 1000
+        start = time.time()
         ret = func(*args, **kwargs)
-        end = time.time() * 1000
+        end = time.time()
 
         # record the amount of wallclock time spent running pending calls.
         # This is a proxy for the actual amount of time between reactor polls,
         # since about 25% of time is actually spent running things triggered by
         # I/O events, but that is harder to capture without rewriting half the
         # reactor.
-        tick_time.inc_by(end - start)
-        pending_calls_metric.inc_by(num_pending)
+        tick_time.observe(end - start)
+        pending_calls_metric.observe(num_pending)
 
         if running_on_pypy:
             return ret
@@ -220,12 +230,12 @@ def runUntilCurrentTimer(func):
             if threshold[i] < counts[i]:
                 logger.info("Collecting gc %d", i)
 
-                start = time.time() * 1000
+                start = time.time()
                 unreachable = gc.collect(i)
-                end = time.time() * 1000
+                end = time.time()
 
-                gc_time.inc_by(end - start, i)
-                gc_unreachable.inc_by(unreachable, i)
+                gc_time.labels(i).observe(end - start)
+                gc_unreachable.labels(i).set(unreachable)
 
         return ret
 
diff --git a/synapse/metrics/metric.py b/synapse/metrics/metric.py
deleted file mode 100644
index f421e7a93f..0000000000
--- a/synapse/metrics/metric.py
+++ /dev/null
@@ -1,328 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2015, 2016 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-
-from itertools import chain
-import logging
-import re
-
-logger = logging.getLogger(__name__)
-
-
-def flatten(items):
-    """Flatten a list of lists
-
-    Args:
-        items: iterable[iterable[X]]
-
-    Returns:
-        list[X]: flattened list
-    """
-    return list(chain.from_iterable(items))
-
-
-class BaseMetric(object):
-    """Base class for metrics which report a single value per label set
-    """
-
-    def __init__(self, name, labels=[], alternative_names=[]):
-        """
-        Args:
-            name (str): principal name for this metric
-            labels (list(str)): names of the labels which will be reported
-                for this metric
-            alternative_names (iterable(str)): list of alternative names for
-                 this metric. This can be useful to provide a migration path
-                when renaming metrics.
-        """
-        self._names = [name] + list(alternative_names)
-        self.labels = labels  # OK not to clone as we never write it
-
-    def dimension(self):
-        return len(self.labels)
-
-    def is_scalar(self):
-        return not len(self.labels)
-
-    def _render_labelvalue(self, value):
-        return '"%s"' % (_escape_label_value(value),)
-
-    def _render_key(self, values):
-        if self.is_scalar():
-            return ""
-        return "{%s}" % (
-            ",".join(["%s=%s" % (k, self._render_labelvalue(v))
-                      for k, v in zip(self.labels, values)])
-        )
-
-    def _render_for_labels(self, label_values, value):
-        """Render this metric for a single set of labels
-
-        Args:
-            label_values (list[object]): values for each of the labels,
-                (which get stringified).
-            value: value of the metric at with these labels
-
-        Returns:
-            iterable[str]: rendered metric
-        """
-        rendered_labels = self._render_key(label_values)
-        return (
-            "%s%s %.12g" % (name, rendered_labels, value)
-            for name in self._names
-        )
-
-    def render(self):
-        """Render this metric
-
-        Each metric is rendered as:
-
-            name{label1="val1",label2="val2"} value
-
-        https://prometheus.io/docs/instrumenting/exposition_formats/#text-format-details
-
-        Returns:
-            iterable[str]: rendered metrics
-        """
-        raise NotImplementedError()
-
-
-class CounterMetric(BaseMetric):
-    """The simplest kind of metric; one that stores a monotonically-increasing
-    value that counts events or running totals.
-
-    Example use cases for Counters:
-    - Number of requests processed
-    - Number of items that were inserted into a queue
-    - Total amount of data that a system has processed
-    Counters can only go up (and be reset when the process restarts).
-    """
-
-    def __init__(self, *args, **kwargs):
-        super(CounterMetric, self).__init__(*args, **kwargs)
-
-        # dict[list[str]]: value for each set of label values. the keys are the
-        # label values, in the same order as the labels in self.labels.
-        #
-        # (if the metric is a scalar, the (single) key is the empty tuple).
-        self.counts = {}
-
-        # Scalar metrics are never empty
-        if self.is_scalar():
-            self.counts[()] = 0.
-
-    def inc_by(self, incr, *values):
-        if len(values) != self.dimension():
-            raise ValueError(
-                "Expected as many values to inc() as labels (%d)" % (self.dimension())
-            )
-
-        # TODO: should assert that the tag values are all strings
-
-        if values not in self.counts:
-            self.counts[values] = incr
-        else:
-            self.counts[values] += incr
-
-    def inc(self, *values):
-        self.inc_by(1, *values)
-
-    def render(self):
-        return flatten(
-            self._render_for_labels(k, self.counts[k])
-            for k in sorted(self.counts.keys())
-        )
-
-
-class GaugeMetric(BaseMetric):
-    """A metric that can go up or down
-    """
-
-    def __init__(self, *args, **kwargs):
-        super(GaugeMetric, self).__init__(*args, **kwargs)
-
-        # dict[list[str]]: value for each set of label values. the keys are the
-        # label values, in the same order as the labels in self.labels.
-        #
-        # (if the metric is a scalar, the (single) key is the empty tuple).
-        self.guages = {}
-
-    def set(self, v, *values):
-        if len(values) != self.dimension():
-            raise ValueError(
-                "Expected as many values to inc() as labels (%d)" % (self.dimension())
-            )
-
-        # TODO: should assert that the tag values are all strings
-
-        self.guages[values] = v
-
-    def render(self):
-        return flatten(
-            self._render_for_labels(k, self.guages[k])
-            for k in sorted(self.guages.keys())
-        )
-
-
-class CallbackMetric(BaseMetric):
-    """A metric that returns the numeric value returned by a callback whenever
-    it is rendered. Typically this is used to implement gauges that yield the
-    size or other state of some in-memory object by actively querying it."""
-
-    def __init__(self, name, callback, labels=[]):
-        super(CallbackMetric, self).__init__(name, labels=labels)
-
-        self.callback = callback
-
-    def render(self):
-        try:
-            value = self.callback()
-        except Exception:
-            logger.exception("Failed to render %s", self.name)
-            return ["# FAILED to render " + self.name]
-
-        if self.is_scalar():
-            return list(self._render_for_labels([], value))
-
-        return flatten(
-            self._render_for_labels(k, value[k])
-            for k in sorted(value.keys())
-        )
-
-
-class DistributionMetric(object):
-    """A combination of an event counter and an accumulator, which counts
-    both the number of events and accumulates the total value. Typically this
-    could be used to keep track of method-running times, or other distributions
-    of values that occur in discrete occurances.
-
-    TODO(paul): Try to export some heatmap-style stats?
-    """
-
-    def __init__(self, name, *args, **kwargs):
-        self.counts = CounterMetric(name + ":count", **kwargs)
-        self.totals = CounterMetric(name + ":total", **kwargs)
-
-    def inc_by(self, inc, *values):
-        self.counts.inc(*values)
-        self.totals.inc_by(inc, *values)
-
-    def render(self):
-        return self.counts.render() + self.totals.render()
-
-
-class CacheMetric(object):
-    __slots__ = (
-        "name", "cache_name", "hits", "misses", "evicted_size", "size_callback",
-    )
-
-    def __init__(self, name, size_callback, cache_name):
-        self.name = name
-        self.cache_name = cache_name
-
-        self.hits = 0
-        self.misses = 0
-        self.evicted_size = 0
-
-        self.size_callback = size_callback
-
-    def inc_hits(self):
-        self.hits += 1
-
-    def inc_misses(self):
-        self.misses += 1
-
-    def inc_evictions(self, size=1):
-        self.evicted_size += size
-
-    def render(self):
-        size = self.size_callback()
-        hits = self.hits
-        total = self.misses + self.hits
-
-        return [
-            """%s:hits{name="%s"} %d""" % (self.name, self.cache_name, hits),
-            """%s:total{name="%s"} %d""" % (self.name, self.cache_name, total),
-            """%s:size{name="%s"} %d""" % (self.name, self.cache_name, size),
-            """%s:evicted_size{name="%s"} %d""" % (
-                self.name, self.cache_name, self.evicted_size
-            ),
-        ]
-
-
-class MemoryUsageMetric(object):
-    """Keeps track of the current memory usage, using psutil.
-
-    The class will keep the current min/max/sum/counts of rss over the last
-    WINDOW_SIZE_SEC, by polling UPDATE_HZ times per second
-    """
-
-    UPDATE_HZ = 2  # number of times to get memory per second
-    WINDOW_SIZE_SEC = 30  # the size of the window in seconds
-
-    def __init__(self, hs, psutil):
-        clock = hs.get_clock()
-        self.memory_snapshots = []
-
-        self.process = psutil.Process()
-
-        clock.looping_call(self._update_curr_values, 1000 / self.UPDATE_HZ)
-
-    def _update_curr_values(self):
-        max_size = self.UPDATE_HZ * self.WINDOW_SIZE_SEC
-        self.memory_snapshots.append(self.process.memory_info().rss)
-        self.memory_snapshots[:] = self.memory_snapshots[-max_size:]
-
-    def render(self):
-        if not self.memory_snapshots:
-            return []
-
-        max_rss = max(self.memory_snapshots)
-        min_rss = min(self.memory_snapshots)
-        sum_rss = sum(self.memory_snapshots)
-        len_rss = len(self.memory_snapshots)
-
-        return [
-            "process_psutil_rss:max %d" % max_rss,
-            "process_psutil_rss:min %d" % min_rss,
-            "process_psutil_rss:total %d" % sum_rss,
-            "process_psutil_rss:count %d" % len_rss,
-        ]
-
-
-def _escape_character(m):
-    """Replaces a single character with its escape sequence.
-
-    Args:
-        m (re.MatchObject): A match object whose first group is the single
-            character to replace
-
-    Returns:
-        str
-    """
-    c = m.group(1)
-    if c == "\\":
-        return "\\\\"
-    elif c == "\"":
-        return "\\\""
-    elif c == "\n":
-        return "\\n"
-    return c
-
-
-def _escape_label_value(value):
-    """Takes a label value and escapes quotes, newlines and backslashes
-    """
-    return re.sub(r"([\n\"\\])", _escape_character, str(value))
diff --git a/synapse/metrics/process_collector.py b/synapse/metrics/process_collector.py
deleted file mode 100644
index 6fec3de399..0000000000
--- a/synapse/metrics/process_collector.py
+++ /dev/null
@@ -1,122 +0,0 @@
-# -*- coding: utf-8 -*-
-# Copyright 2015, 2016 OpenMarket Ltd
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-
-import os
-
-
-TICKS_PER_SEC = 100
-BYTES_PER_PAGE = 4096
-
-HAVE_PROC_STAT = os.path.exists("/proc/stat")
-HAVE_PROC_SELF_STAT = os.path.exists("/proc/self/stat")
-HAVE_PROC_SELF_LIMITS = os.path.exists("/proc/self/limits")
-HAVE_PROC_SELF_FD = os.path.exists("/proc/self/fd")
-
-# Field indexes from /proc/self/stat, taken from the proc(5) manpage
-STAT_FIELDS = {
-    "utime": 14,
-    "stime": 15,
-    "starttime": 22,
-    "vsize": 23,
-    "rss": 24,
-}
-
-
-stats = {}
-
-# In order to report process_start_time_seconds we need to know the
-# machine's boot time, because the value in /proc/self/stat is relative to
-# this
-boot_time = None
-if HAVE_PROC_STAT:
-    with open("/proc/stat") as _procstat:
-        for line in _procstat:
-            if line.startswith("btime "):
-                boot_time = int(line.split()[1])
-
-
-def update_resource_metrics():
-    if HAVE_PROC_SELF_STAT:
-        global stats
-        with open("/proc/self/stat") as s:
-            line = s.read()
-            # line is PID (command) more stats go here ...
-            raw_stats = line.split(") ", 1)[1].split(" ")
-
-            for (name, index) in STAT_FIELDS.iteritems():
-                # subtract 3 from the index, because proc(5) is 1-based, and
-                # we've lost the first two fields in PID and COMMAND above
-                stats[name] = int(raw_stats[index - 3])
-
-
-def _count_fds():
-    # Not every OS will have a /proc/self/fd directory
-    if not HAVE_PROC_SELF_FD:
-        return 0
-
-    return len(os.listdir("/proc/self/fd"))
-
-
-def register_process_collector(process_metrics):
-    process_metrics.register_collector(update_resource_metrics)
-
-    if HAVE_PROC_SELF_STAT:
-        process_metrics.register_callback(
-            "cpu_user_seconds_total",
-            lambda: float(stats["utime"]) / TICKS_PER_SEC
-        )
-        process_metrics.register_callback(
-            "cpu_system_seconds_total",
-            lambda: float(stats["stime"]) / TICKS_PER_SEC
-        )
-        process_metrics.register_callback(
-            "cpu_seconds_total",
-            lambda: (float(stats["utime"] + stats["stime"])) / TICKS_PER_SEC
-        )
-
-        process_metrics.register_callback(
-            "virtual_memory_bytes",
-            lambda: int(stats["vsize"])
-        )
-        process_metrics.register_callback(
-            "resident_memory_bytes",
-            lambda: int(stats["rss"]) * BYTES_PER_PAGE
-        )
-
-        process_metrics.register_callback(
-            "start_time_seconds",
-            lambda: boot_time + int(stats["starttime"]) / TICKS_PER_SEC
-        )
-
-    if HAVE_PROC_SELF_FD:
-        process_metrics.register_callback(
-            "open_fds",
-            lambda: _count_fds()
-        )
-
-    if HAVE_PROC_SELF_LIMITS:
-        def _get_max_fds():
-            with open("/proc/self/limits") as limits:
-                for line in limits:
-                    if not line.startswith("Max open files "):
-                        continue
-                    # Line is  Max open files  $SOFT  $HARD
-                    return int(line.split()[3])
-            return None
-
-        process_metrics.register_callback(
-            "max_fds",
-            lambda: _get_max_fds()
-        )
diff --git a/synapse/metrics/resource.py b/synapse/metrics/resource.py
index 870f400600..9789359077 100644
--- a/synapse/metrics/resource.py
+++ b/synapse/metrics/resource.py
@@ -13,27 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.web.resource import Resource
-
-import synapse.metrics
-
+from prometheus_client.twisted import MetricsResource
 
 METRICS_PREFIX = "/_synapse/metrics"
 
-
-class MetricsResource(Resource):
-    isLeaf = True
-
-    def __init__(self, hs):
-        Resource.__init__(self)  # Resource is old-style, so no super()
-
-        self.hs = hs
-
-    def render_GET(self, request):
-        response = synapse.metrics.render_all()
-
-        request.setHeader("Content-Type", "text/plain")
-        request.setHeader("Content-Length", str(len(response)))
-
-        # Encode as UTF-8 (default)
-        return response.encode()
+__all__ = ["MetricsResource", "METRICS_PREFIX"]
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 8355c7d621..6dce20a284 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -28,22 +28,20 @@ from synapse.util.logcontext import PreserveLoggingContext, run_in_background
 from synapse.util.metrics import Measure
 from synapse.types import StreamToken
 from synapse.visibility import filter_events_for_client
-import synapse.metrics
+from synapse.metrics import LaterGauge
 
 from collections import namedtuple
+from prometheus_client import Counter
 
 import logging
 
 
 logger = logging.getLogger(__name__)
 
-metrics = synapse.metrics.get_metrics_for(__name__)
+notified_events_counter = Counter("synapse_notifier_notified_events", "")
 
-notified_events_counter = metrics.register_counter("notified_events")
-
-users_woken_by_stream_counter = metrics.register_counter(
-    "users_woken_by_stream", labels=["stream"]
-)
+users_woken_by_stream_counter = Counter(
+    "synapse_notifier_users_woken_by_stream", "", ["stream"])
 
 
 # TODO(paul): Should be shared somewhere
@@ -108,7 +106,7 @@ class _NotifierUserStream(object):
         self.last_notified_ms = time_now_ms
         noify_deferred = self.notify_deferred
 
-        users_woken_by_stream_counter.inc(stream_key)
+        users_woken_by_stream_counter.labels(stream_key).inc()
 
         with PreserveLoggingContext():
             self.notify_deferred = ObservableDeferred(defer.Deferred())
@@ -197,14 +195,14 @@ class Notifier(object):
                 all_user_streams.add(x)
 
             return sum(stream.count_listeners() for stream in all_user_streams)
-        metrics.register_callback("listeners", count_listeners)
+        LaterGauge("synapse_notifier_listeners", "", [], count_listeners)
 
-        metrics.register_callback(
-            "rooms",
+        LaterGauge(
+            "synapse_notifier_rooms", "", [],
             lambda: count(bool, self.room_to_user_streams.values()),
         )
-        metrics.register_callback(
-            "users",
+        LaterGauge(
+            "synapse_notifier_users", "", [],
             lambda: len(self.user_to_user_stream),
         )
 
diff --git a/synapse/push/baserules.py b/synapse/push/baserules.py
index 7a18afe5f9..a8ae7bcd6c 100644
--- a/synapse/push/baserules.py
+++ b/synapse/push/baserules.py
@@ -39,7 +39,7 @@ def list_with_base_rules(rawrules):
     rawrules = [r for r in rawrules if r['priority_class'] >= 0]
 
     # shove the server default rules for each kind onto the end of each
-    current_prio_class = PRIORITY_CLASS_INVERSE_MAP.keys()[-1]
+    current_prio_class = list(PRIORITY_CLASS_INVERSE_MAP)[-1]
 
     ruleslist.extend(make_base_prepend_rules(
         PRIORITY_CLASS_INVERSE_MAP[current_prio_class], modified_base_rules
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 7c680659b6..a5cab1f043 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -22,35 +22,32 @@ from .push_rule_evaluator import PushRuleEvaluatorForEvent
 
 from synapse.event_auth import get_user_power_level
 from synapse.api.constants import EventTypes, Membership
-from synapse.metrics import get_metrics_for
-from synapse.util.caches import metrics as cache_metrics
+from synapse.util.caches import register_cache
 from synapse.util.caches.descriptors import cached
 from synapse.util.async import Linearizer
 from synapse.state import POWER_KEY
 
 from collections import namedtuple
-
+from prometheus_client import Counter
+from six import itervalues, iteritems
 
 logger = logging.getLogger(__name__)
 
 
 rules_by_room = {}
 
-push_metrics = get_metrics_for(__name__)
 
-push_rules_invalidation_counter = push_metrics.register_counter(
-    "push_rules_invalidation_counter"
-)
-push_rules_state_size_counter = push_metrics.register_counter(
-    "push_rules_state_size_counter"
-)
+push_rules_invalidation_counter = Counter(
+    "synapse_push_bulk_push_rule_evaluator_push_rules_invalidation_counter", "")
+push_rules_state_size_counter = Counter(
+    "synapse_push_bulk_push_rule_evaluator_push_rules_state_size_counter", "")
 
 # Measures whether we use the fast path of using state deltas, or if we have to
 # recalculate from scratch
-push_rules_delta_state_cache_metric = cache_metrics.register_cache(
+push_rules_delta_state_cache_metric = register_cache(
     "cache",
-    size_callback=lambda: 0,  # Meaningless size, as this isn't a cache that stores values
-    cache_name="push_rules_delta_state_cache_metric",
+    "push_rules_delta_state_cache_metric",
+    cache=[],  # Meaningless size, as this isn't a cache that stores values
 )
 
 
@@ -64,10 +61,10 @@ class BulkPushRuleEvaluator(object):
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
 
-        self.room_push_rule_cache_metrics = cache_metrics.register_cache(
+        self.room_push_rule_cache_metrics = register_cache(
             "cache",
-            size_callback=lambda: 0,  # There's not good value for this
-            cache_name="room_push_rule_cache",
+            "room_push_rule_cache",
+            cache=[],  # Meaningless size, as this isn't a cache that stores values
         )
 
     @defer.inlineCallbacks
@@ -126,7 +123,7 @@ class BulkPushRuleEvaluator(object):
             )
             auth_events = yield self.store.get_events(auth_events_ids)
             auth_events = {
-                (e.type, e.state_key): e for e in auth_events.itervalues()
+                (e.type, e.state_key): e for e in itervalues(auth_events)
             }
 
         sender_level = get_user_power_level(event.sender, auth_events)
@@ -160,7 +157,7 @@ class BulkPushRuleEvaluator(object):
 
         condition_cache = {}
 
-        for uid, rules in rules_by_user.iteritems():
+        for uid, rules in iteritems(rules_by_user):
             if event.sender == uid:
                 continue
 
@@ -309,7 +306,7 @@ class RulesForRoom(object):
                 current_state_ids = context.current_state_ids
                 push_rules_delta_state_cache_metric.inc_misses()
 
-            push_rules_state_size_counter.inc_by(len(current_state_ids))
+            push_rules_state_size_counter.inc(len(current_state_ids))
 
             logger.debug(
                 "Looking for member changes in %r %r", state_group, current_state_ids
@@ -406,7 +403,7 @@ class RulesForRoom(object):
         # If the event is a join event then it will be in current state evnts
         # map but not in the DB, so we have to explicitly insert it.
         if event.type == EventTypes.Member:
-            for event_id in member_event_ids.itervalues():
+            for event_id in itervalues(member_event_ids):
                 if event_id == event.event_id:
                     members[event_id] = (event.state_key, event.membership)
 
@@ -414,7 +411,7 @@ class RulesForRoom(object):
             logger.debug("Found members %r: %r", self.room_id, members.values())
 
         interested_in_user_ids = set(
-            user_id for user_id, membership in members.itervalues()
+            user_id for user_id, membership in itervalues(members)
             if membership == Membership.JOIN
         )
 
@@ -426,7 +423,7 @@ class RulesForRoom(object):
         )
 
         user_ids = set(
-            uid for uid, have_pusher in if_users_with_pushers.iteritems() if have_pusher
+            uid for uid, have_pusher in iteritems(if_users_with_pushers) if have_pusher
         )
 
         logger.debug("With pushers: %r", user_ids)
@@ -447,7 +444,7 @@ class RulesForRoom(object):
         )
 
         ret_rules_by_user.update(
-            item for item in rules_by_user.iteritems() if item[0] is not None
+            item for item in iteritems(rules_by_user) if item[0] is not None
         )
 
         self.update_cache(sequence, members, ret_rules_by_user, state_group)
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index b077e1a446..bf7ff74a1a 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -20,22 +20,17 @@ from twisted.internet.error import AlreadyCalled, AlreadyCancelled
 
 from . import push_rule_evaluator
 from . import push_tools
-import synapse
 from synapse.push import PusherConfigException
 from synapse.util.logcontext import LoggingContext
 from synapse.util.metrics import Measure
 
-logger = logging.getLogger(__name__)
+from prometheus_client import Counter
 
-metrics = synapse.metrics.get_metrics_for(__name__)
+logger = logging.getLogger(__name__)
 
-http_push_processed_counter = metrics.register_counter(
-    "http_pushes_processed",
-)
+http_push_processed_counter = Counter("synapse_http_httppusher_http_pushes_processed", "")
 
-http_push_failed_counter = metrics.register_counter(
-    "http_pushes_failed",
-)
+http_push_failed_counter = Counter("synapse_http_httppusher_http_pushes_failed", "")
 
 
 class HttpPusher(object):
diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py
index b5cd9b426a..d4be800e5e 100644
--- a/synapse/push/mailer.py
+++ b/synapse/push/mailer.py
@@ -229,7 +229,8 @@ class Mailer(object):
                 if room_vars['notifs'] and 'messages' in room_vars['notifs'][-1]:
                     prev_messages = room_vars['notifs'][-1]['messages']
                     for message in notifvars['messages']:
-                        pm = filter(lambda pm: pm['id'] == message['id'], prev_messages)
+                        pm = list(filter(lambda pm: pm['id'] == message['id'],
+                                         prev_messages))
                         if pm:
                             if not message["is_historical"]:
                                 pm[0]["is_historical"] = False
diff --git a/synapse/push/presentable_names.py b/synapse/push/presentable_names.py
index 277da3cd35..43f0c74ff3 100644
--- a/synapse/push/presentable_names.py
+++ b/synapse/push/presentable_names.py
@@ -113,7 +113,7 @@ def calculate_room_name(store, room_state_ids, user_id, fallback_to_members=True
     # so find out who is in the room that isn't the user.
     if "m.room.member" in room_state_bytype_ids:
         member_events = yield store.get_events(
-            room_state_bytype_ids["m.room.member"].values()
+            list(room_state_bytype_ids["m.room.member"].values())
         )
         all_members = [
             ev for ev in member_events.values()
diff --git a/synapse/push/push_rule_evaluator.py b/synapse/push/push_rule_evaluator.py
index 3601f2d365..cf735f7468 100644
--- a/synapse/push/push_rule_evaluator.py
+++ b/synapse/push/push_rule_evaluator.py
@@ -21,6 +21,8 @@ from synapse.types import UserID
 from synapse.util.caches import CACHE_SIZE_FACTOR, register_cache
 from synapse.util.caches.lrucache import LruCache
 
+from six import string_types
+
 logger = logging.getLogger(__name__)
 
 
@@ -150,7 +152,7 @@ class PushRuleEvaluatorForEvent(object):
 
 # Caches (glob, word_boundary) -> regex for push. See _glob_matches
 regex_cache = LruCache(50000 * CACHE_SIZE_FACTOR)
-register_cache("regex_push_cache", regex_cache)
+register_cache("cache", "regex_push_cache", regex_cache)
 
 
 def _glob_matches(glob, value, word_boundary=False):
@@ -238,7 +240,7 @@ def _flatten_dict(d, prefix=[], result=None):
     if result is None:
         result = {}
     for key, value in d.items():
-        if isinstance(value, basestring):
+        if isinstance(value, string_types):
             result[".".join(prefix + [key])] = value.lower()
         elif hasattr(value, "items"):
             _flatten_dict(value, prefix=(prefix + [key]), result=result)
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 216db4d164..478c497722 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -56,6 +56,7 @@ REQUIREMENTS = {
     "msgpack-python>=0.3.0": ["msgpack"],
     "phonenumbers>=8.2.0": ["phonenumbers"],
     "six": ["six"],
+    "prometheus_client": ["prometheus_client"],
 }
 CONDITIONAL_REQUIREMENTS = {
     "web_client": {
diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index d7d38464b2..a6280aae70 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -60,21 +60,21 @@ from .commands import (
 )
 from .streams import STREAMS_MAP
 
+from synapse.metrics import LaterGauge
 from synapse.util.stringutils import random_string
-from synapse.metrics.metric import CounterMetric
 
-import logging
-import synapse.metrics
-import struct
-import fcntl
+from prometheus_client import Counter
 
+from collections import defaultdict
 
-metrics = synapse.metrics.get_metrics_for(__name__)
+from six import iterkeys, iteritems
 
-connection_close_counter = metrics.register_counter(
-    "close_reason", labels=["reason_type"],
-)
+import logging
+import struct
+import fcntl
 
+connection_close_counter = Counter(
+    "synapse_replication_tcp_protocol_close_reason", "", ["reason_type"])
 
 # A list of all connected protocols. This allows us to send metrics about the
 # connections.
@@ -136,12 +136,8 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
         # The LoopingCall for sending pings.
         self._send_ping_loop = None
 
-        self.inbound_commands_counter = CounterMetric(
-            "inbound_commands", labels=["command"],
-        )
-        self.outbound_commands_counter = CounterMetric(
-            "outbound_commands", labels=["command"],
-        )
+        self.inbound_commands_counter = defaultdict(int)
+        self.outbound_commands_counter = defaultdict(int)
 
     def connectionMade(self):
         logger.info("[%s] Connection established", self.id())
@@ -201,7 +197,8 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
 
         self.last_received_command = self.clock.time_msec()
 
-        self.inbound_commands_counter.inc(cmd_name)
+        self.inbound_commands_counter[cmd_name] = (
+            self.inbound_commands_counter[cmd_name] + 1)
 
         cmd_cls = COMMAND_MAP[cmd_name]
         try:
@@ -251,8 +248,8 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
             self._queue_command(cmd)
             return
 
-        self.outbound_commands_counter.inc(cmd.NAME)
-
+        self.outbound_commands_counter[cmd.NAME] = (
+            self.outbound_commands_counter[cmd.NAME] + 1)
         string = "%s %s" % (cmd.NAME, cmd.to_line(),)
         if "\n" in string:
             raise Exception("Unexpected newline in command: %r", string)
@@ -317,9 +314,9 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
     def connectionLost(self, reason):
         logger.info("[%s] Replication connection closed: %r", self.id(), reason)
         if isinstance(reason, Failure):
-            connection_close_counter.inc(reason.type.__name__)
+            connection_close_counter.labels(reason.type.__name__).inc()
         else:
-            connection_close_counter.inc(reason.__class__.__name__)
+            connection_close_counter.labels(reason.__class__.__name__).inc()
 
         try:
             # Remove us from list of connections to be monitored
@@ -392,7 +389,7 @@ class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
 
         if stream_name == "ALL":
             # Subscribe to all streams we're publishing to.
-            for stream in self.streamer.streams_by_name.iterkeys():
+            for stream in iterkeys(self.streamer.streams_by_name):
                 self.subscribe_to_stream(stream, token)
         else:
             self.subscribe_to_stream(stream_name, token)
@@ -498,7 +495,7 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
         BaseReplicationStreamProtocol.connectionMade(self)
 
         # Once we've connected subscribe to the necessary streams
-        for stream_name, token in self.handler.get_streams_to_replicate().iteritems():
+        for stream_name, token in iteritems(self.handler.get_streams_to_replicate()):
             self.replicate(stream_name, token)
 
         # Tell the server if we have any users currently syncing (should only
@@ -518,7 +515,7 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
 
     def on_RDATA(self, cmd):
         stream_name = cmd.stream_name
-        inbound_rdata_count.inc(stream_name)
+        inbound_rdata_count.labels(stream_name).inc()
 
         try:
             row = STREAMS_MAP[stream_name].ROW_TYPE(*cmd.row)
@@ -566,14 +563,12 @@ class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
 
 # The following simply registers metrics for the replication connections
 
-metrics.register_callback(
-    "pending_commands",
+pending_commands = LaterGauge(
+    "pending_commands", "", ["name", "conn_id"],
     lambda: {
         (p.name, p.conn_id): len(p.pending_commands)
         for p in connected_connections
-    },
-    labels=["name", "conn_id"],
-)
+    })
 
 
 def transport_buffer_size(protocol):
@@ -583,14 +578,12 @@ def transport_buffer_size(protocol):
     return 0
 
 
-metrics.register_callback(
-    "transport_send_buffer",
+transport_send_buffer = LaterGauge(
+    "synapse_replication_tcp_transport_send_buffer", "", ["name", "conn_id"],
     lambda: {
         (p.name, p.conn_id): transport_buffer_size(p)
         for p in connected_connections
-    },
-    labels=["name", "conn_id"],
-)
+    })
 
 
 def transport_kernel_read_buffer_size(protocol, read=True):
@@ -608,48 +601,38 @@ def transport_kernel_read_buffer_size(protocol, read=True):
     return 0
 
 
-metrics.register_callback(
-    "transport_kernel_send_buffer",
+tcp_transport_kernel_send_buffer = LaterGauge(
+    "synapse_replication_tcp_transport_kernel_send_buffer", "", ["name", "conn_id"],
     lambda: {
         (p.name, p.conn_id): transport_kernel_read_buffer_size(p, False)
         for p in connected_connections
-    },
-    labels=["name", "conn_id"],
-)
+    })
 
 
-metrics.register_callback(
-    "transport_kernel_read_buffer",
+tcp_transport_kernel_read_buffer = LaterGauge(
+    "synapse_replication_tcp_transport_kernel_read_buffer", "", ["name", "conn_id"],
     lambda: {
         (p.name, p.conn_id): transport_kernel_read_buffer_size(p, True)
         for p in connected_connections
-    },
-    labels=["name", "conn_id"],
-)
+    })
 
 
-metrics.register_callback(
-    "inbound_commands",
+tcp_inbound_commands = LaterGauge(
+    "synapse_replication_tcp_inbound_commands", "", ["command", "name", "conn_id"],
     lambda: {
         (k[0], p.name, p.conn_id): count
         for p in connected_connections
-        for k, count in p.inbound_commands_counter.counts.iteritems()
-    },
-    labels=["command", "name", "conn_id"],
-)
+        for k, count in iteritems(p.inbound_commands_counter.counts)
+    })
 
-metrics.register_callback(
-    "outbound_commands",
+tcp_outbound_commands = LaterGauge(
+    "synapse_replication_tcp_outbound_commands", "", ["command", "name", "conn_id"],
     lambda: {
         (k[0], p.name, p.conn_id): count
         for p in connected_connections
-        for k, count in p.outbound_commands_counter.counts.iteritems()
-    },
-    labels=["command", "name", "conn_id"],
-)
+        for k, count in iteritems(p.outbound_commands_counter.counts)
+    })
 
 # number of updates received for each RDATA stream
-inbound_rdata_count = metrics.register_counter(
-    "inbound_rdata_count",
-    labels=["stream_name"],
-)
+inbound_rdata_count = Counter("synapse_replication_tcp_inbound_rdata_count", "",
+                              ["stream_name"])
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index a603c520ea..63bd6d2652 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -22,20 +22,21 @@ from .streams import STREAMS_MAP, FederationStream
 from .protocol import ServerReplicationStreamProtocol
 
 from synapse.util.metrics import Measure, measure_func
+from synapse.metrics import LaterGauge
 
 import logging
-import synapse.metrics
 
+from prometheus_client import Counter
+from six import itervalues
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-stream_updates_counter = metrics.register_counter(
-    "stream_updates", labels=["stream_name"]
-)
-user_sync_counter = metrics.register_counter("user_sync")
-federation_ack_counter = metrics.register_counter("federation_ack")
-remove_pusher_counter = metrics.register_counter("remove_pusher")
-invalidate_cache_counter = metrics.register_counter("invalidate_cache")
-user_ip_cache_counter = metrics.register_counter("user_ip_cache")
+stream_updates_counter = Counter("synapse_replication_tcp_resource_stream_updates",
+                                 "", ["stream_name"])
+user_sync_counter = Counter("synapse_replication_tcp_resource_user_sync", "")
+federation_ack_counter = Counter("synapse_replication_tcp_resource_federation_ack", "")
+remove_pusher_counter = Counter("synapse_replication_tcp_resource_remove_pusher", "")
+invalidate_cache_counter = Counter("synapse_replication_tcp_resource_invalidate_cache",
+                                   "")
+user_ip_cache_counter = Counter("synapse_replication_tcp_resource_user_ip_cache", "")
 
 logger = logging.getLogger(__name__)
 
@@ -74,29 +75,29 @@ class ReplicationStreamer(object):
         # Current connections.
         self.connections = []
 
-        metrics.register_callback("total_connections", lambda: len(self.connections))
+        LaterGauge("synapse_replication_tcp_resource_total_connections", "", [],
+                   lambda: len(self.connections))
 
         # List of streams that clients can subscribe to.
         # We only support federation stream if federation sending hase been
         # disabled on the master.
         self.streams = [
-            stream(hs) for stream in STREAMS_MAP.itervalues()
+            stream(hs) for stream in itervalues(STREAMS_MAP)
             if stream != FederationStream or not hs.config.send_federation
         ]
 
         self.streams_by_name = {stream.NAME: stream for stream in self.streams}
 
-        metrics.register_callback(
-            "connections_per_stream",
+        LaterGauge(
+            "synapse_replication_tcp_resource_connections_per_stream", "",
+            ["stream_name"],
             lambda: {
                 (stream_name,): len([
                     conn for conn in self.connections
                     if stream_name in conn.replication_streams
                 ])
                 for stream_name in self.streams_by_name
-            },
-            labels=["stream_name"],
-        )
+            })
 
         self.federation_sender = None
         if not hs.config.send_federation:
@@ -176,7 +177,7 @@ class ReplicationStreamer(object):
                             logger.info(
                                 "Streaming: %s -> %s", stream.NAME, updates[-1][0]
                             )
-                            stream_updates_counter.inc_by(len(updates), stream.NAME)
+                            stream_updates_counter.labels(stream.NAME).inc(len(updates))
 
                         # Some streams return multiple rows with the same stream IDs,
                         # we need to make sure they get sent out in batches. We do
diff --git a/synapse/rest/client/transactions.py b/synapse/rest/client/transactions.py
index 20fa6678ef..7c01b438cb 100644
--- a/synapse/rest/client/transactions.py
+++ b/synapse/rest/client/transactions.py
@@ -104,7 +104,7 @@ class HttpTransactionCache(object):
 
     def _cleanup(self):
         now = self.clock.time_msec()
-        for key in self.transactions.keys():
+        for key in list(self.transactions):
             ts = self.transactions[key][1]
             if now > (ts + CLEANUP_PERIOD_MS):  # after cleanup period
                 del self.transactions[key]
diff --git a/synapse/rest/client/v1/presence.py b/synapse/rest/client/v1/presence.py
index 4a73813c58..647994bd53 100644
--- a/synapse/rest/client/v1/presence.py
+++ b/synapse/rest/client/v1/presence.py
@@ -23,6 +23,8 @@ from synapse.handlers.presence import format_user_presence_state
 from synapse.http.servlet import parse_json_object_from_request
 from .base import ClientV1RestServlet, client_path_patterns
 
+from six import string_types
+
 import logging
 
 logger = logging.getLogger(__name__)
@@ -71,7 +73,7 @@ class PresenceStatusRestServlet(ClientV1RestServlet):
 
             if "status_msg" in content:
                 state["status_msg"] = content.pop("status_msg")
-                if not isinstance(state["status_msg"], basestring):
+                if not isinstance(state["status_msg"], string_types):
                     raise SynapseError(400, "status_msg must be a string.")
 
             if content:
@@ -129,7 +131,7 @@ class PresenceListRestServlet(ClientV1RestServlet):
 
         if "invite" in content:
             for u in content["invite"]:
-                if not isinstance(u, basestring):
+                if not isinstance(u, string_types):
                     raise SynapseError(400, "Bad invite value.")
                 if len(u) == 0:
                     continue
@@ -140,7 +142,7 @@ class PresenceListRestServlet(ClientV1RestServlet):
 
         if "drop" in content:
             for u in content["drop"]:
-                if not isinstance(u, basestring):
+                if not isinstance(u, string_types):
                     raise SynapseError(400, "Bad drop value.")
                 if len(u) == 0:
                     continue
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index 9800ce7581..2ac767d2dc 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -48,6 +48,7 @@ import shutil
 import cgi
 import logging
 from six.moves.urllib import parse as urlparse
+from six import iteritems
 
 logger = logging.getLogger(__name__)
 
@@ -603,7 +604,7 @@ class MediaRepository(object):
                 thumbnails[(t_width, t_height, r_type)] = r_method
 
         # Now we generate the thumbnails for each dimension, store it
-        for (t_width, t_height, t_type), t_method in thumbnails.iteritems():
+        for (t_width, t_height, t_type), t_method in iteritems(thumbnails):
             # Generate the thumbnail
             if t_method == "crop":
                 t_byte_source = yield make_deferred_yieldable(threads.deferToThread(
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 2839207abc..565cef2b8d 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -24,7 +24,9 @@ import shutil
 import sys
 import traceback
 import simplejson as json
-import urlparse
+
+from six.moves import urllib_parse as urlparse
+from six import string_types
 
 from twisted.web.server import NOT_DONE_YET
 from twisted.internet import defer
@@ -590,8 +592,8 @@ def _iterate_over_text(tree, *tags_to_ignore):
     # to be returned.
     elements = iter([tree])
     while True:
-        el = elements.next()
-        if isinstance(el, basestring):
+        el = next(elements)
+        if isinstance(el, string_types):
             yield el
         elif el is not None and el.tag not in tags_to_ignore:
             # el.text is the text before the first child, so we can immediately
diff --git a/synapse/server_notices/consent_server_notices.py b/synapse/server_notices/consent_server_notices.py
index 440f6b1cd4..bb74af1af5 100644
--- a/synapse/server_notices/consent_server_notices.py
+++ b/synapse/server_notices/consent_server_notices.py
@@ -14,10 +14,13 @@
 # limitations under the License.
 import logging
 
+from six import (iteritems, string_types)
 from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
+from synapse.api.urls import ConsentURIBuilder
 from synapse.config import ConfigError
+from synapse.types import get_localpart_from_id
 
 logger = logging.getLogger(__name__)
 
@@ -39,6 +42,7 @@ class ConsentServerNotices(object):
 
         self._current_consent_version = hs.config.user_consent_version
         self._server_notice_content = hs.config.user_consent_server_notice_content
+        self._send_to_guests = hs.config.user_consent_server_notice_to_guests
 
         if self._server_notice_content is not None:
             if not self._server_notices_manager.is_enabled():
@@ -52,6 +56,8 @@ class ConsentServerNotices(object):
                     "key.",
                 )
 
+            self._consent_uri_builder = ConsentURIBuilder(hs.config)
+
     @defer.inlineCallbacks
     def maybe_send_server_notice_to_user(self, user_id):
         """Check if we need to send a notice to this user, and does so if so
@@ -73,6 +79,10 @@ class ConsentServerNotices(object):
         try:
             u = yield self._store.get_user_by_id(user_id)
 
+            if u["is_guest"] and not self._send_to_guests:
+                # don't send to guests
+                return
+
             if u["consent_version"] == self._current_consent_version:
                 # user has already consented
                 return
@@ -81,10 +91,18 @@ class ConsentServerNotices(object):
                 # we've already sent a notice to the user
                 return
 
-            # need to send a message
+            # need to send a message.
             try:
+                consent_uri = self._consent_uri_builder.build_user_consent_uri(
+                    get_localpart_from_id(user_id),
+                )
+                content = copy_with_str_subst(
+                    self._server_notice_content, {
+                        'consent_uri': consent_uri,
+                    },
+                )
                 yield self._server_notices_manager.send_notice(
-                    user_id, self._server_notice_content,
+                    user_id, content,
                 )
                 yield self._store.user_set_consent_server_notice_sent(
                     user_id, self._current_consent_version,
@@ -93,3 +111,27 @@ class ConsentServerNotices(object):
                 logger.error("Error sending server notice about user consent: %s", e)
         finally:
             self._users_in_progress.remove(user_id)
+
+
+def copy_with_str_subst(x, substitutions):
+    """Deep-copy a structure, carrying out string substitions on any strings
+
+    Args:
+        x (object): structure to be copied
+        substitutions (object): substitutions to be made - passed into the
+            string '%' operator
+
+    Returns:
+        copy of x
+    """
+    if isinstance(x, string_types):
+        return x % substitutions
+    if isinstance(x, dict):
+        return {
+            k: copy_with_str_subst(v, substitutions) for (k, v) in iteritems(x)
+        }
+    if isinstance(x, (list, tuple)):
+        return [copy_with_str_subst(y) for y in x]
+
+    # assume it's uninterested and can be shallow-copied.
+    return x
diff --git a/synapse/server_notices/server_notices_manager.py b/synapse/server_notices/server_notices_manager.py
index f535b9c9da..a26deace53 100644
--- a/synapse/server_notices/server_notices_manager.py
+++ b/synapse/server_notices/server_notices_manager.py
@@ -35,6 +35,7 @@ class ServerNoticesManager(object):
         self._config = hs.config
         self._room_creation_handler = hs.get_room_creation_handler()
         self._event_creation_handler = hs.get_event_creation_handler()
+        self._is_mine_id = hs.is_mine_id
 
     def is_enabled(self):
         """Checks if server notices are enabled on this server.
@@ -55,7 +56,7 @@ class ServerNoticesManager(object):
             event_content (dict): content of event to send
 
         Returns:
-            Deferrred[None]
+            Deferred[None]
         """
         room_id = yield self.get_notice_room_for_user(user_id)
 
@@ -89,6 +90,9 @@ class ServerNoticesManager(object):
         if not self.is_enabled():
             raise Exception("Server notices not enabled")
 
+        assert self._is_mine_id(user_id), \
+            "Cannot send server notices to remote users"
+
         rooms = yield self._store.get_rooms_for_user_where_membership_is(
             user_id, [Membership.INVITE, Membership.JOIN],
         )
@@ -109,6 +113,19 @@ class ServerNoticesManager(object):
         # apparently no existing notice room: create a new one
         logger.info("Creating server notices room for %s", user_id)
 
+        # see if we want to override the profile info for the server user.
+        # note that if we want to override either the display name or the
+        # avatar, we have to use both.
+        join_profile = None
+        if (
+            self._config.server_notices_mxid_display_name is not None or
+            self._config.server_notices_mxid_avatar_url is not None
+        ):
+            join_profile = {
+                "displayname": self._config.server_notices_mxid_display_name,
+                "avatar_url": self._config.server_notices_mxid_avatar_url,
+            }
+
         requester = create_requester(system_mxid)
         info = yield self._room_creation_handler.create_room(
             requester,
@@ -121,9 +138,7 @@ class ServerNoticesManager(object):
                 "invite": (user_id,)
             },
             ratelimit=False,
-            creator_join_profile={
-                "displayname": self._config.server_notices_mxid_display_name,
-            },
+            creator_join_profile=join_profile,
         )
         room_id = info['room_id']
 
diff --git a/synapse/server_notices/worker_server_notices_sender.py b/synapse/server_notices/worker_server_notices_sender.py
index 25abb4ccf5..4a133026c3 100644
--- a/synapse/server_notices/worker_server_notices_sender.py
+++ b/synapse/server_notices/worker_server_notices_sender.py
@@ -32,7 +32,7 @@ class WorkerServerNoticesSender(object):
         Returns:
             Deferred
         """
-        return defer.succeed()
+        return defer.succeed(None)
 
     def on_user_ip(self, user_id):
         """Called on the master when a worker process saw a client request.
diff --git a/synapse/state.py b/synapse/state.py
index 26093c8434..216418f58d 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -32,6 +32,8 @@ from frozendict import frozendict
 import logging
 import hashlib
 
+from six import iteritems, itervalues
+
 logger = logging.getLogger(__name__)
 
 
@@ -130,9 +132,10 @@ class StateHandler(object):
             defer.returnValue(event)
             return
 
-        state_map = yield self.store.get_events(state.values(), get_prev_content=False)
+        state_map = yield self.store.get_events(list(state.values()),
+                                                get_prev_content=False)
         state = {
-            key: state_map[e_id] for key, e_id in state.iteritems() if e_id in state_map
+            key: state_map[e_id] for key, e_id in iteritems(state) if e_id in state_map
         }
 
         defer.returnValue(state)
@@ -338,7 +341,7 @@ class StateHandler(object):
         )
 
         if len(state_groups_ids) == 1:
-            name, state_list = state_groups_ids.items().pop()
+            name, state_list = list(state_groups_ids.items()).pop()
 
             prev_group, delta_ids = yield self.store.get_state_group_delta(name)
 
@@ -378,7 +381,7 @@ class StateHandler(object):
             new_state = resolve_events_with_state_map(state_set_ids, state_map)
 
         new_state = {
-            key: state_map[ev_id] for key, ev_id in new_state.iteritems()
+            key: state_map[ev_id] for key, ev_id in iteritems(new_state)
         }
 
         return new_state
@@ -458,15 +461,15 @@ class StateResolutionHandler(object):
             # build a map from state key to the event_ids which set that state.
             # dict[(str, str), set[str])
             state = {}
-            for st in state_groups_ids.itervalues():
-                for key, e_id in st.iteritems():
+            for st in itervalues(state_groups_ids):
+                for key, e_id in iteritems(st):
                     state.setdefault(key, set()).add(e_id)
 
             # build a map from state key to the event_ids which set that state,
             # including only those where there are state keys in conflict.
             conflicted_state = {
                 k: list(v)
-                for k, v in state.iteritems()
+                for k, v in iteritems(state)
                 if len(v) > 1
             }
 
@@ -474,13 +477,13 @@ class StateResolutionHandler(object):
                 logger.info("Resolving conflicted state for %r", room_id)
                 with Measure(self.clock, "state._resolve_events"):
                     new_state = yield resolve_events_with_factory(
-                        state_groups_ids.values(),
+                        list(state_groups_ids.values()),
                         event_map=event_map,
                         state_map_factory=state_map_factory,
                     )
             else:
                 new_state = {
-                    key: e_ids.pop() for key, e_ids in state.iteritems()
+                    key: e_ids.pop() for key, e_ids in iteritems(state)
                 }
 
             with Measure(self.clock, "state.create_group_ids"):
@@ -489,8 +492,8 @@ class StateResolutionHandler(object):
                 # which will be used as a cache key for future resolutions, but
                 # not get persisted.
                 state_group = None
-                new_state_event_ids = frozenset(new_state.itervalues())
-                for sg, events in state_groups_ids.iteritems():
+                new_state_event_ids = frozenset(itervalues(new_state))
+                for sg, events in iteritems(state_groups_ids):
                     if new_state_event_ids == frozenset(e_id for e_id in events):
                         state_group = sg
                         break
@@ -501,11 +504,11 @@ class StateResolutionHandler(object):
 
                 prev_group = None
                 delta_ids = None
-                for old_group, old_ids in state_groups_ids.iteritems():
+                for old_group, old_ids in iteritems(state_groups_ids):
                     if not set(new_state) - set(old_ids):
                         n_delta_ids = {
                             k: v
-                            for k, v in new_state.iteritems()
+                            for k, v in iteritems(new_state)
                             if old_ids.get(k) != v
                         }
                         if not delta_ids or len(n_delta_ids) < len(delta_ids):
@@ -527,7 +530,7 @@ class StateResolutionHandler(object):
 
 def _ordered_events(events):
     def key_func(e):
-        return -int(e.depth), hashlib.sha1(e.event_id).hexdigest()
+        return -int(e.depth), hashlib.sha1(e.event_id.encode()).hexdigest()
 
     return sorted(events, key=key_func)
 
@@ -584,7 +587,7 @@ def _seperate(state_sets):
     conflicted_state = {}
 
     for state_set in state_sets[1:]:
-        for key, value in state_set.iteritems():
+        for key, value in iteritems(state_set):
             # Check if there is an unconflicted entry for the state key.
             unconflicted_value = unconflicted_state.get(key)
             if unconflicted_value is None:
@@ -640,7 +643,7 @@ def resolve_events_with_factory(state_sets, event_map, state_map_factory):
 
     needed_events = set(
         event_id
-        for event_ids in conflicted_state.itervalues()
+        for event_ids in itervalues(conflicted_state)
         for event_id in event_ids
     )
     if event_map is not None:
@@ -662,7 +665,7 @@ def resolve_events_with_factory(state_sets, event_map, state_map_factory):
         unconflicted_state, conflicted_state, state_map
     )
 
-    new_needed_events = set(auth_events.itervalues())
+    new_needed_events = set(itervalues(auth_events))
     new_needed_events -= needed_events
     if event_map is not None:
         new_needed_events -= set(event_map.iterkeys())
@@ -679,7 +682,7 @@ def resolve_events_with_factory(state_sets, event_map, state_map_factory):
 
 def _create_auth_events_from_maps(unconflicted_state, conflicted_state, state_map):
     auth_events = {}
-    for event_ids in conflicted_state.itervalues():
+    for event_ids in itervalues(conflicted_state):
         for event_id in event_ids:
             if event_id in state_map:
                 keys = event_auth.auth_types_for_event(state_map[event_id])
@@ -694,7 +697,7 @@ def _create_auth_events_from_maps(unconflicted_state, conflicted_state, state_ma
 def _resolve_with_state(unconflicted_state_ids, conflicted_state_ds, auth_event_ids,
                         state_map):
     conflicted_state = {}
-    for key, event_ids in conflicted_state_ds.iteritems():
+    for key, event_ids in iteritems(conflicted_state_ds):
         events = [state_map[ev_id] for ev_id in event_ids if ev_id in state_map]
         if len(events) > 1:
             conflicted_state[key] = events
@@ -703,7 +706,7 @@ def _resolve_with_state(unconflicted_state_ids, conflicted_state_ds, auth_event_
 
     auth_events = {
         key: state_map[ev_id]
-        for key, ev_id in auth_event_ids.iteritems()
+        for key, ev_id in iteritems(auth_event_ids)
         if ev_id in state_map
     }
 
@@ -716,7 +719,7 @@ def _resolve_with_state(unconflicted_state_ids, conflicted_state_ds, auth_event_
         raise
 
     new_state = unconflicted_state_ids
-    for key, event in resolved_state.iteritems():
+    for key, event in iteritems(resolved_state):
         new_state[key] = event.event_id
 
     return new_state
@@ -741,7 +744,7 @@ def _resolve_state_events(conflicted_state, auth_events):
 
     auth_events.update(resolved_state)
 
-    for key, events in conflicted_state.iteritems():
+    for key, events in iteritems(conflicted_state):
         if key[0] == EventTypes.JoinRules:
             logger.debug("Resolving conflicted join rules %r", events)
             resolved_state[key] = _resolve_auth_events(
@@ -751,7 +754,7 @@ def _resolve_state_events(conflicted_state, auth_events):
 
     auth_events.update(resolved_state)
 
-    for key, events in conflicted_state.iteritems():
+    for key, events in iteritems(conflicted_state):
         if key[0] == EventTypes.Member:
             logger.debug("Resolving conflicted member lists %r", events)
             resolved_state[key] = _resolve_auth_events(
@@ -761,7 +764,7 @@ def _resolve_state_events(conflicted_state, auth_events):
 
     auth_events.update(resolved_state)
 
-    for key, events in conflicted_state.iteritems():
+    for key, events in iteritems(conflicted_state):
         if key not in resolved_state:
             logger.debug("Resolving conflicted state %r:%r", key, events)
             resolved_state[key] = _resolve_normal_events(
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 2262776ab2..22d6257a9f 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -18,8 +18,8 @@ from synapse.api.errors import StoreError
 from synapse.util.logcontext import LoggingContext, PreserveLoggingContext
 from synapse.util.caches.descriptors import Cache
 from synapse.storage.engines import PostgresEngine
-import synapse.metrics
 
+from prometheus_client import Histogram
 
 from twisted.internet import defer
 
@@ -27,20 +27,25 @@ import sys
 import time
 import threading
 
+from six import itervalues, iterkeys, iteritems
+from six.moves import intern, range
 
 logger = logging.getLogger(__name__)
 
+try:
+    MAX_TXN_ID = sys.maxint - 1
+except AttributeError:
+    # python 3 does not have a maximum int value
+    MAX_TXN_ID = 2**63 - 1
+
 sql_logger = logging.getLogger("synapse.storage.SQL")
 transaction_logger = logging.getLogger("synapse.storage.txn")
 perf_logger = logging.getLogger("synapse.storage.TIME")
 
+sql_scheduling_timer = Histogram("synapse_storage_schedule_time", "sec")
 
-metrics = synapse.metrics.get_metrics_for("synapse.storage")
-
-sql_scheduling_timer = metrics.register_distribution("schedule_time")
-
-sql_query_timer = metrics.register_distribution("query_time", labels=["verb"])
-sql_txn_timer = metrics.register_distribution("transaction_time", labels=["desc"])
+sql_query_timer = Histogram("synapse_storage_query_time", "sec", ["verb"])
+sql_txn_timer = Histogram("synapse_storage_transaction_time", "sec", ["desc"])
 
 
 class LoggingTransaction(object):
@@ -105,7 +110,7 @@ class LoggingTransaction(object):
                 # Don't let logging failures stop SQL from working
                 pass
 
-        start = time.time() * 1000
+        start = time.time()
 
         try:
             return func(
@@ -115,9 +120,9 @@ class LoggingTransaction(object):
             logger.debug("[SQL FAIL] {%s} %s", self.name, e)
             raise
         finally:
-            msecs = (time.time() * 1000) - start
-            sql_logger.debug("[SQL time] {%s} %f", self.name, msecs)
-            sql_query_timer.inc_by(msecs, sql.split()[0])
+            secs = time.time() - start
+            sql_logger.debug("[SQL time] {%s} %f sec", self.name, secs)
+            sql_query_timer.labels(sql.split()[0]).observe(secs)
 
 
 class PerformanceCounters(object):
@@ -127,7 +132,7 @@ class PerformanceCounters(object):
 
     def update(self, key, start_time, end_time=None):
         if end_time is None:
-            end_time = time.time() * 1000
+            end_time = time.time()
         duration = end_time - start_time
         count, cum_time = self.current_counters.get(key, (0, 0))
         count += 1
@@ -137,7 +142,7 @@ class PerformanceCounters(object):
 
     def interval(self, interval_duration, limit=3):
         counters = []
-        for name, (count, cum_time) in self.current_counters.iteritems():
+        for name, (count, cum_time) in iteritems(self.current_counters):
             prev_count, prev_time = self.previous_counters.get(name, (0, 0))
             counters.append((
                 (cum_time - prev_time) / interval_duration,
@@ -217,12 +222,12 @@ class SQLBaseStore(object):
 
     def _new_transaction(self, conn, desc, after_callbacks, exception_callbacks,
                          logging_context, func, *args, **kwargs):
-        start = time.time() * 1000
+        start = time.time()
         txn_id = self._TXN_ID
 
         # We don't really need these to be unique, so lets stop it from
         # growing really large.
-        self._TXN_ID = (self._TXN_ID + 1) % (sys.maxint - 1)
+        self._TXN_ID = (self._TXN_ID + 1) % (MAX_TXN_ID)
 
         name = "%s-%x" % (desc, txn_id, )
 
@@ -277,17 +282,17 @@ class SQLBaseStore(object):
             logger.debug("[TXN FAIL] {%s} %s", name, e)
             raise
         finally:
-            end = time.time() * 1000
+            end = time.time()
             duration = end - start
 
             if logging_context is not None:
                 logging_context.add_database_transaction(duration)
 
-            transaction_logger.debug("[TXN END] {%s} %f", name, duration)
+            transaction_logger.debug("[TXN END] {%s} %f sec", name, duration)
 
             self._current_txn_total_time += duration
             self._txn_perf_counters.update(desc, start, end)
-            sql_txn_timer.inc_by(duration, desc)
+            sql_txn_timer.labels(desc).observe(duration)
 
     @defer.inlineCallbacks
     def runInteraction(self, desc, func, *args, **kwargs):
@@ -344,13 +349,13 @@ class SQLBaseStore(object):
         """
         current_context = LoggingContext.current_context()
 
-        start_time = time.time() * 1000
+        start_time = time.time()
 
         def inner_func(conn, *args, **kwargs):
             with LoggingContext("runWithConnection") as context:
-                sched_duration_ms = time.time() * 1000 - start_time
-                sql_scheduling_timer.inc_by(sched_duration_ms)
-                current_context.add_database_scheduled(sched_duration_ms)
+                sched_duration_sec = time.time() - start_time
+                sql_scheduling_timer.observe(sched_duration_sec)
+                current_context.add_database_scheduled(sched_duration_sec)
 
                 if self.database_engine.is_connection_closed(conn):
                     logger.debug("Reconnecting closed database connection")
@@ -543,7 +548,7 @@ class SQLBaseStore(object):
             ", ".join("%s = ?" % (k,) for k in values),
             " AND ".join("%s = ?" % (k,) for k in keyvalues)
         )
-        sqlargs = values.values() + keyvalues.values()
+        sqlargs = list(values.values()) + list(keyvalues.values())
 
         txn.execute(sql, sqlargs)
         if txn.rowcount > 0:
@@ -561,7 +566,7 @@ class SQLBaseStore(object):
             ", ".join(k for k in allvalues),
             ", ".join("?" for _ in allvalues)
         )
-        txn.execute(sql, allvalues.values())
+        txn.execute(sql, list(allvalues.values()))
         # successfully inserted
         return True
 
@@ -629,8 +634,8 @@ class SQLBaseStore(object):
         }
 
         if keyvalues:
-            sql += " WHERE %s" % " AND ".join("%s = ?" % k for k in keyvalues.iterkeys())
-            txn.execute(sql, keyvalues.values())
+            sql += " WHERE %s" % " AND ".join("%s = ?" % k for k in iterkeys(keyvalues))
+            txn.execute(sql, list(keyvalues.values()))
         else:
             txn.execute(sql)
 
@@ -694,7 +699,7 @@ class SQLBaseStore(object):
                 table,
                 " AND ".join("%s = ?" % (k, ) for k in keyvalues)
             )
-            txn.execute(sql, keyvalues.values())
+            txn.execute(sql, list(keyvalues.values()))
         else:
             sql = "SELECT %s FROM %s" % (
                 ", ".join(retcols),
@@ -725,9 +730,12 @@ class SQLBaseStore(object):
         if not iterable:
             defer.returnValue(results)
 
+        # iterables can not be sliced, so convert it to a list first
+        it_list = list(iterable)
+
         chunks = [
-            iterable[i:i + batch_size]
-            for i in xrange(0, len(iterable), batch_size)
+            it_list[i:i + batch_size]
+            for i in range(0, len(it_list), batch_size)
         ]
         for chunk in chunks:
             rows = yield self.runInteraction(
@@ -767,7 +775,7 @@ class SQLBaseStore(object):
         )
         values.extend(iterable)
 
-        for key, value in keyvalues.iteritems():
+        for key, value in iteritems(keyvalues):
             clauses.append("%s = ?" % (key,))
             values.append(value)
 
@@ -790,7 +798,7 @@ class SQLBaseStore(object):
     @staticmethod
     def _simple_update_txn(txn, table, keyvalues, updatevalues):
         if keyvalues:
-            where = "WHERE %s" % " AND ".join("%s = ?" % k for k in keyvalues.iterkeys())
+            where = "WHERE %s" % " AND ".join("%s = ?" % k for k in iterkeys(keyvalues))
         else:
             where = ""
 
@@ -802,7 +810,7 @@ class SQLBaseStore(object):
 
         txn.execute(
             update_sql,
-            updatevalues.values() + keyvalues.values()
+            list(updatevalues.values()) + list(keyvalues.values())
         )
 
         return txn.rowcount
@@ -850,7 +858,7 @@ class SQLBaseStore(object):
             " AND ".join("%s = ?" % (k,) for k in keyvalues)
         )
 
-        txn.execute(select_sql, keyvalues.values())
+        txn.execute(select_sql, list(keyvalues.values()))
 
         row = txn.fetchone()
         if not row:
@@ -888,7 +896,7 @@ class SQLBaseStore(object):
             " AND ".join("%s = ?" % (k, ) for k in keyvalues)
         )
 
-        txn.execute(sql, keyvalues.values())
+        txn.execute(sql, list(keyvalues.values()))
         if txn.rowcount == 0:
             raise StoreError(404, "No row found")
         if txn.rowcount > 1:
@@ -906,7 +914,7 @@ class SQLBaseStore(object):
             " AND ".join("%s = ?" % (k, ) for k in keyvalues)
         )
 
-        return txn.execute(sql, keyvalues.values())
+        return txn.execute(sql, list(keyvalues.values()))
 
     def _simple_delete_many(self, table, column, iterable, keyvalues, desc):
         return self.runInteraction(
@@ -938,7 +946,7 @@ class SQLBaseStore(object):
         )
         values.extend(iterable)
 
-        for key, value in keyvalues.iteritems():
+        for key, value in iteritems(keyvalues):
             clauses.append("%s = ?" % (key,))
             values.append(value)
 
@@ -978,7 +986,7 @@ class SQLBaseStore(object):
         txn.close()
 
         if cache:
-            min_val = min(cache.itervalues())
+            min_val = min(itervalues(cache))
         else:
             min_val = max_value
 
@@ -1093,7 +1101,7 @@ class SQLBaseStore(object):
                 " AND ".join("%s = ?" % (k,) for k in keyvalues),
                 " ? ASC LIMIT ? OFFSET ?"
             )
-            txn.execute(sql, keyvalues.values() + pagevalues)
+            txn.execute(sql, list(keyvalues.values()) + list(pagevalues))
         else:
             sql = "SELECT %s FROM %s ORDER BY %s" % (
                 ", ".join(retcols),
diff --git a/synapse/storage/client_ips.py b/synapse/storage/client_ips.py
index ba46907737..ce338514e8 100644
--- a/synapse/storage/client_ips.py
+++ b/synapse/storage/client_ips.py
@@ -22,6 +22,8 @@ from . import background_updates
 
 from synapse.util.caches import CACHE_SIZE_FACTOR
 
+from six import iteritems
+
 
 logger = logging.getLogger(__name__)
 
@@ -99,7 +101,7 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
     def _update_client_ips_batch_txn(self, txn, to_update):
         self.database_engine.lock_table(txn, "user_ips")
 
-        for entry in to_update.iteritems():
+        for entry in iteritems(to_update):
             (user_id, access_token, ip), (user_agent, device_id, last_seen) = entry
 
             self._simple_upsert_txn(
@@ -231,5 +233,5 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
                 "user_agent": user_agent,
                 "last_seen": last_seen,
             }
-            for (access_token, ip), (user_agent, last_seen) in results.iteritems()
+            for (access_token, ip), (user_agent, last_seen) in iteritems(results)
         ))
diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py
index 712106b83a..d149d8392e 100644
--- a/synapse/storage/devices.py
+++ b/synapse/storage/devices.py
@@ -21,6 +21,7 @@ from synapse.api.errors import StoreError
 from ._base import SQLBaseStore, Cache
 from synapse.util.caches.descriptors import cached, cachedList, cachedInlineCallbacks
 
+from six import itervalues, iteritems
 
 logger = logging.getLogger(__name__)
 
@@ -360,7 +361,7 @@ class DeviceStore(SQLBaseStore):
             return (now_stream_id, [])
 
         if len(query_map) >= 20:
-            now_stream_id = max(stream_id for stream_id in query_map.itervalues())
+            now_stream_id = max(stream_id for stream_id in itervalues(query_map))
 
         devices = self._get_e2e_device_keys_txn(
             txn, query_map.keys(), include_all_devices=True
@@ -373,13 +374,13 @@ class DeviceStore(SQLBaseStore):
         """
 
         results = []
-        for user_id, user_devices in devices.iteritems():
+        for user_id, user_devices in iteritems(devices):
             # The prev_id for the first row is always the last row before
             # `from_stream_id`
             txn.execute(prev_sent_id_sql, (destination, user_id, from_stream_id))
             rows = txn.fetchall()
             prev_id = rows[0][0]
-            for device_id, device in user_devices.iteritems():
+            for device_id, device in iteritems(user_devices):
                 stream_id = query_map[(user_id, device_id)]
                 result = {
                     "user_id": user_id,
@@ -483,7 +484,7 @@ class DeviceStore(SQLBaseStore):
         if devices:
             user_devices = devices[user_id]
             results = []
-            for device_id, device in user_devices.iteritems():
+            for device_id, device in iteritems(user_devices):
                 result = {
                     "device_id": device_id,
                 }
diff --git a/synapse/storage/end_to_end_keys.py b/synapse/storage/end_to_end_keys.py
index ff8538ddf8..b146487943 100644
--- a/synapse/storage/end_to_end_keys.py
+++ b/synapse/storage/end_to_end_keys.py
@@ -21,6 +21,8 @@ import simplejson as json
 
 from ._base import SQLBaseStore
 
+from six import iteritems
+
 
 class EndToEndKeyStore(SQLBaseStore):
     def set_e2e_device_keys(self, user_id, device_id, time_now, device_keys):
@@ -81,8 +83,8 @@ class EndToEndKeyStore(SQLBaseStore):
             query_list, include_all_devices,
         )
 
-        for user_id, device_keys in results.iteritems():
-            for device_id, device_info in device_keys.iteritems():
+        for user_id, device_keys in iteritems(results):
+            for device_id, device_info in iteritems(device_keys):
                 device_info["keys"] = json.loads(device_info.pop("key_json"))
 
         defer.returnValue(results)
diff --git a/synapse/storage/event_push_actions.py b/synapse/storage/event_push_actions.py
index f084a5f54b..d0350ee5fe 100644
--- a/synapse/storage/event_push_actions.py
+++ b/synapse/storage/event_push_actions.py
@@ -22,6 +22,8 @@ from synapse.util.caches.descriptors import cachedInlineCallbacks
 import logging
 import simplejson as json
 
+from six import iteritems
+
 logger = logging.getLogger(__name__)
 
 
@@ -420,7 +422,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
 
             txn.executemany(sql, (
                 _gen_entry(user_id, actions)
-                for user_id, actions in user_id_actions.iteritems()
+                for user_id, actions in iteritems(user_id_actions)
             ))
 
         return self.runInteraction(
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 5ebef98c4f..cb1082e864 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -40,30 +40,30 @@ import synapse.metrics
 from synapse.events import EventBase    # noqa: F401
 from synapse.events.snapshot import EventContext   # noqa: F401
 
-logger = logging.getLogger(__name__)
+from six.moves import range
+from six import itervalues, iteritems
 
+from prometheus_client import Counter
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-persist_event_counter = metrics.register_counter("persisted_events")
-event_counter = metrics.register_counter(
-    "persisted_events_sep", labels=["type", "origin_type", "origin_entity"]
-)
+logger = logging.getLogger(__name__)
+
+persist_event_counter = Counter("synapse_storage_events_persisted_events", "")
+event_counter = Counter("synapse_storage_events_persisted_events_sep", "",
+                        ["type", "origin_type", "origin_entity"])
 
 # The number of times we are recalculating the current state
-state_delta_counter = metrics.register_counter(
-    "state_delta",
-)
+state_delta_counter = Counter("synapse_storage_events_state_delta", "")
+
 # The number of times we are recalculating state when there is only a
 # single forward extremity
-state_delta_single_event_counter = metrics.register_counter(
-    "state_delta_single_event",
-)
+state_delta_single_event_counter = Counter(
+    "synapse_storage_events_state_delta_single_event", "")
+
 # The number of times we are reculating state when we could have resonably
 # calculated the delta when we calculated the state for an event we were
 # persisting.
-state_delta_reuse_delta_counter = metrics.register_counter(
-    "state_delta_reuse_delta",
-)
+state_delta_reuse_delta_counter = Counter(
+    "synapse_storage_events_state_delta_reuse_delta", "")
 
 
 def encode_json(json_object):
@@ -248,7 +248,7 @@ class EventsStore(EventsWorkerStore):
             partitioned.setdefault(event.room_id, []).append((event, ctx))
 
         deferreds = []
-        for room_id, evs_ctxs in partitioned.iteritems():
+        for room_id, evs_ctxs in iteritems(partitioned):
             d = self._event_persist_queue.add_to_queue(
                 room_id, evs_ctxs,
                 backfilled=backfilled,
@@ -333,7 +333,7 @@ class EventsStore(EventsWorkerStore):
 
             chunks = [
                 events_and_contexts[x:x + 100]
-                for x in xrange(0, len(events_and_contexts), 100)
+                for x in range(0, len(events_and_contexts), 100)
             ]
 
             for chunk in chunks:
@@ -367,7 +367,7 @@ class EventsStore(EventsWorkerStore):
                                 (event, context)
                             )
 
-                        for room_id, ev_ctx_rm in events_by_room.iteritems():
+                        for room_id, ev_ctx_rm in iteritems(events_by_room):
                             # Work out new extremities by recursively adding and removing
                             # the new events.
                             latest_event_ids = yield self.get_latest_event_ids_in_room(
@@ -445,7 +445,7 @@ class EventsStore(EventsWorkerStore):
                     state_delta_for_room=state_delta_for_room,
                     new_forward_extremeties=new_forward_extremeties,
                 )
-                persist_event_counter.inc_by(len(chunk))
+                persist_event_counter.inc(len(chunk))
                 synapse.metrics.event_persisted_position.set(
                     chunk[-1][0].internal_metadata.stream_ordering,
                 )
@@ -460,14 +460,14 @@ class EventsStore(EventsWorkerStore):
                         origin_type = "remote"
                         origin_entity = get_domain_from_id(event.sender)
 
-                    event_counter.inc(event.type, origin_type, origin_entity)
+                    event_counter.labels(event.type, origin_type, origin_entity).inc()
 
-                for room_id, new_state in current_state_for_room.iteritems():
+                for room_id, new_state in iteritems(current_state_for_room):
                     self.get_current_state_ids.prefill(
                         (room_id, ), new_state
                     )
 
-                for room_id, latest_event_ids in new_forward_extremeties.iteritems():
+                for room_id, latest_event_ids in iteritems(new_forward_extremeties):
                     self.get_latest_event_ids_in_room.prefill(
                         (room_id,), list(latest_event_ids)
                     )
@@ -644,20 +644,20 @@ class EventsStore(EventsWorkerStore):
         """
         existing_state = yield self.get_current_state_ids(room_id)
 
-        existing_events = set(existing_state.itervalues())
-        new_events = set(ev_id for ev_id in current_state.itervalues())
+        existing_events = set(itervalues(existing_state))
+        new_events = set(ev_id for ev_id in itervalues(current_state))
         changed_events = existing_events ^ new_events
 
         if not changed_events:
             return
 
         to_delete = {
-            key: ev_id for key, ev_id in existing_state.iteritems()
+            key: ev_id for key, ev_id in iteritems(existing_state)
             if ev_id in changed_events
         }
         events_to_insert = (new_events - existing_events)
         to_insert = {
-            key: ev_id for key, ev_id in current_state.iteritems()
+            key: ev_id for key, ev_id in iteritems(current_state)
             if ev_id in events_to_insert
         }
 
@@ -760,11 +760,11 @@ class EventsStore(EventsWorkerStore):
         )
 
     def _update_current_state_txn(self, txn, state_delta_by_room, max_stream_order):
-        for room_id, current_state_tuple in state_delta_by_room.iteritems():
+        for room_id, current_state_tuple in iteritems(state_delta_by_room):
                 to_delete, to_insert = current_state_tuple
                 txn.executemany(
                     "DELETE FROM current_state_events WHERE event_id = ?",
-                    [(ev_id,) for ev_id in to_delete.itervalues()],
+                    [(ev_id,) for ev_id in itervalues(to_delete)],
                 )
 
                 self._simple_insert_many_txn(
@@ -777,7 +777,7 @@ class EventsStore(EventsWorkerStore):
                             "type": key[0],
                             "state_key": key[1],
                         }
-                        for key, ev_id in to_insert.iteritems()
+                        for key, ev_id in iteritems(to_insert)
                     ],
                 )
 
@@ -796,7 +796,7 @@ class EventsStore(EventsWorkerStore):
                             "event_id": ev_id,
                             "prev_event_id": to_delete.get(key, None),
                         }
-                        for key, ev_id in state_deltas.iteritems()
+                        for key, ev_id in iteritems(state_deltas)
                     ]
                 )
 
@@ -839,7 +839,7 @@ class EventsStore(EventsWorkerStore):
 
     def _update_forward_extremities_txn(self, txn, new_forward_extremities,
                                         max_stream_order):
-        for room_id, new_extrem in new_forward_extremities.iteritems():
+        for room_id, new_extrem in iteritems(new_forward_extremities):
             self._simple_delete_txn(
                 txn,
                 table="event_forward_extremities",
@@ -857,7 +857,7 @@ class EventsStore(EventsWorkerStore):
                     "event_id": ev_id,
                     "room_id": room_id,
                 }
-                for room_id, new_extrem in new_forward_extremities.iteritems()
+                for room_id, new_extrem in iteritems(new_forward_extremities)
                 for ev_id in new_extrem
             ],
         )
@@ -874,7 +874,7 @@ class EventsStore(EventsWorkerStore):
                     "event_id": event_id,
                     "stream_ordering": max_stream_order,
                 }
-                for room_id, new_extrem in new_forward_extremities.iteritems()
+                for room_id, new_extrem in iteritems(new_forward_extremities)
                 for event_id in new_extrem
             ]
         )
@@ -902,7 +902,7 @@ class EventsStore(EventsWorkerStore):
                         new_events_and_contexts[event.event_id] = (event, context)
             else:
                 new_events_and_contexts[event.event_id] = (event, context)
-        return new_events_and_contexts.values()
+        return list(new_events_and_contexts.values())
 
     def _update_room_depths_txn(self, txn, events_and_contexts, backfilled):
         """Update min_depth for each room
@@ -928,7 +928,7 @@ class EventsStore(EventsWorkerStore):
                     event.depth, depth_updates.get(event.room_id, event.depth)
                 )
 
-        for room_id, depth in depth_updates.iteritems():
+        for room_id, depth in iteritems(depth_updates):
             self._update_min_depth_for_room_txn(txn, room_id, depth)
 
     def _update_outliers_txn(self, txn, events_and_contexts):
@@ -1312,7 +1312,7 @@ class EventsStore(EventsWorkerStore):
                 " WHERE e.event_id IN (%s)"
             ) % (",".join(["?"] * len(ev_map)),)
 
-            txn.execute(sql, ev_map.keys())
+            txn.execute(sql, list(ev_map))
             rows = self.cursor_to_dict(txn)
             for row in rows:
                 event = ev_map[row["event_id"]]
@@ -1575,7 +1575,7 @@ class EventsStore(EventsWorkerStore):
 
             chunks = [
                 event_ids[i:i + 100]
-                for i in xrange(0, len(event_ids), 100)
+                for i in range(0, len(event_ids), 100)
             ]
             for chunk in chunks:
                 ev_rows = self._simple_select_many_txn(
@@ -1989,7 +1989,7 @@ class EventsStore(EventsWorkerStore):
         logger.info("[purge] finding state groups which depend on redundant"
                     " state groups")
         remaining_state_groups = []
-        for i in xrange(0, len(state_rows), 100):
+        for i in range(0, len(state_rows), 100):
             chunk = [sg for sg, in state_rows[i:i + 100]]
             # look for state groups whose prev_state_group is one we are about
             # to delete
@@ -2045,7 +2045,7 @@ class EventsStore(EventsWorkerStore):
                         "state_key": key[1],
                         "event_id": state_id,
                     }
-                    for key, state_id in curr_state.iteritems()
+                    for key, state_id in iteritems(curr_state)
                 ],
             )
 
diff --git a/synapse/storage/events_worker.py b/synapse/storage/events_worker.py
index ba834854e1..32d9d00ffb 100644
--- a/synapse/storage/events_worker.py
+++ b/synapse/storage/events_worker.py
@@ -337,7 +337,7 @@ class EventsWorkerStore(SQLBaseStore):
     def _fetch_event_rows(self, txn, events):
         rows = []
         N = 200
-        for i in range(1 + len(events) / N):
+        for i in range(1 + len(events) // N):
             evs = events[i * N:(i + 1) * N]
             if not evs:
                 break
diff --git a/synapse/storage/filtering.py b/synapse/storage/filtering.py
index 78b1e30945..2e2763126d 100644
--- a/synapse/storage/filtering.py
+++ b/synapse/storage/filtering.py
@@ -44,7 +44,7 @@ class FilteringStore(SQLBaseStore):
             desc="get_user_filter",
         )
 
-        defer.returnValue(json.loads(str(def_json).decode("utf-8")))
+        defer.returnValue(json.loads(bytes(def_json).decode("utf-8")))
 
     def add_user_filter(self, user_localpart, user_filter):
         def_json = encode_canonical_json(user_filter)
diff --git a/synapse/storage/keys.py b/synapse/storage/keys.py
index 87aeaf71d6..0f13b61da8 100644
--- a/synapse/storage/keys.py
+++ b/synapse/storage/keys.py
@@ -17,6 +17,7 @@ from ._base import SQLBaseStore
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 
 from twisted.internet import defer
+import six
 
 import OpenSSL
 from signedjson.key import decode_verify_key_bytes
@@ -26,6 +27,13 @@ import logging
 
 logger = logging.getLogger(__name__)
 
+# py2 sqlite has buffer hardcoded as only binary type, so we must use it,
+# despite being deprecated and removed in favor of memoryview
+if six.PY2:
+    db_binary_type = buffer
+else:
+    db_binary_type = memoryview
+
 
 class KeyStore(SQLBaseStore):
     """Persistence for signature verification keys and tls X.509 certificates
@@ -72,7 +80,7 @@ class KeyStore(SQLBaseStore):
             values={
                 "from_server": from_server,
                 "ts_added_ms": time_now_ms,
-                "tls_certificate": buffer(tls_certificate_bytes),
+                "tls_certificate": db_binary_type(tls_certificate_bytes),
             },
             desc="store_server_certificate",
         )
@@ -92,7 +100,7 @@ class KeyStore(SQLBaseStore):
 
         if verify_key_bytes:
             defer.returnValue(decode_verify_key_bytes(
-                key_id, str(verify_key_bytes)
+                key_id, bytes(verify_key_bytes)
             ))
 
     @defer.inlineCallbacks
@@ -135,7 +143,7 @@ class KeyStore(SQLBaseStore):
                 values={
                     "from_server": from_server,
                     "ts_added_ms": time_now_ms,
-                    "verify_key": buffer(verify_key.encode()),
+                    "verify_key": db_binary_type(verify_key.encode()),
                 },
             )
             txn.call_after(
@@ -172,7 +180,7 @@ class KeyStore(SQLBaseStore):
                 "from_server": from_server,
                 "ts_added_ms": ts_now_ms,
                 "ts_valid_until_ms": ts_expires_ms,
-                "key_json": buffer(key_json_bytes),
+                "key_json": db_binary_type(key_json_bytes),
             },
             desc="store_server_keys_json",
         )
diff --git a/synapse/storage/presence.py b/synapse/storage/presence.py
index 9e9d3c2591..f05d91cc58 100644
--- a/synapse/storage/presence.py
+++ b/synapse/storage/presence.py
@@ -16,6 +16,7 @@
 from ._base import SQLBaseStore
 from synapse.api.constants import PresenceState
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
+from synapse.util import batch_iter
 
 from collections import namedtuple
 from twisted.internet import defer
@@ -115,11 +116,7 @@ class PresenceStore(SQLBaseStore):
             " AND user_id IN (%s)"
         )
 
-        batches = (
-            presence_states[i:i + 50]
-            for i in xrange(0, len(presence_states), 50)
-        )
-        for states in batches:
+        for states in batch_iter(presence_states, 50):
             args = [stream_id]
             args.extend(s.user_id for s in states)
             txn.execute(
diff --git a/synapse/storage/receipts.py b/synapse/storage/receipts.py
index 709c69a926..c93c228f6e 100644
--- a/synapse/storage/receipts.py
+++ b/synapse/storage/receipts.py
@@ -332,6 +332,35 @@ class ReceiptsStore(ReceiptsWorkerStore):
 
     def insert_linearized_receipt_txn(self, txn, room_id, receipt_type,
                                       user_id, event_id, data, stream_id):
+        res = self._simple_select_one_txn(
+            txn,
+            table="events",
+            retcols=["topological_ordering", "stream_ordering"],
+            keyvalues={"event_id": event_id},
+            allow_none=True
+        )
+
+        stream_ordering = int(res["stream_ordering"]) if res else None
+
+        # We don't want to clobber receipts for more recent events, so we
+        # have to compare orderings of existing receipts
+        if stream_ordering is not None:
+            sql = (
+                "SELECT stream_ordering, event_id FROM events"
+                " INNER JOIN receipts_linearized as r USING (event_id, room_id)"
+                " WHERE r.room_id = ? AND r.receipt_type = ? AND r.user_id = ?"
+            )
+            txn.execute(sql, (room_id, receipt_type, user_id))
+
+            for so, eid in txn:
+                if int(so) >= stream_ordering:
+                    logger.debug(
+                        "Ignoring new receipt for %s in favour of existing "
+                        "one for later event %s",
+                        event_id, eid,
+                    )
+                    return False
+
         txn.call_after(
             self.get_receipts_for_room.invalidate, (room_id, receipt_type)
         )
@@ -355,34 +384,6 @@ class ReceiptsStore(ReceiptsWorkerStore):
             (user_id, room_id, receipt_type)
         )
 
-        res = self._simple_select_one_txn(
-            txn,
-            table="events",
-            retcols=["topological_ordering", "stream_ordering"],
-            keyvalues={"event_id": event_id},
-            allow_none=True
-        )
-
-        topological_ordering = int(res["topological_ordering"]) if res else None
-        stream_ordering = int(res["stream_ordering"]) if res else None
-
-        # We don't want to clobber receipts for more recent events, so we
-        # have to compare orderings of existing receipts
-        sql = (
-            "SELECT topological_ordering, stream_ordering, event_id FROM events"
-            " INNER JOIN receipts_linearized as r USING (event_id, room_id)"
-            " WHERE r.room_id = ? AND r.receipt_type = ? AND r.user_id = ?"
-        )
-
-        txn.execute(sql, (room_id, receipt_type, user_id))
-
-        if topological_ordering:
-            for to, so, _ in txn:
-                if int(to) > topological_ordering:
-                    return False
-                elif int(to) == topological_ordering and int(so) >= stream_ordering:
-                    return False
-
         self._simple_delete_txn(
             txn,
             table="receipts_linearized",
@@ -406,7 +407,7 @@ class ReceiptsStore(ReceiptsWorkerStore):
             }
         )
 
-        if receipt_type == "m.read" and topological_ordering:
+        if receipt_type == "m.read" and stream_ordering is not None:
             self._remove_old_push_actions_before_txn(
                 txn,
                 room_id=room_id,
diff --git a/synapse/storage/registration.py b/synapse/storage/registration.py
index c0bf5e9ed6..c241167fbe 100644
--- a/synapse/storage/registration.py
+++ b/synapse/storage/registration.py
@@ -36,6 +36,7 @@ class RegistrationWorkerStore(SQLBaseStore):
             retcols=[
                 "name", "password_hash", "is_guest",
                 "consent_version", "consent_server_notice_sent",
+                "appservice_id",
             ],
             allow_none=True,
             desc="get_user_by_id",
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index 6a861943a2..7bfc3d91b5 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -30,6 +30,8 @@ from synapse.types import get_domain_from_id
 import logging
 import simplejson as json
 
+from six import itervalues, iteritems
+
 logger = logging.getLogger(__name__)
 
 
@@ -272,7 +274,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         users_in_room = {}
         member_event_ids = [
             e_id
-            for key, e_id in current_state_ids.iteritems()
+            for key, e_id in iteritems(current_state_ids)
             if key[0] == EventTypes.Member
         ]
 
@@ -289,7 +291,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
                     users_in_room = dict(prev_res)
                     member_event_ids = [
                         e_id
-                        for key, e_id in context.delta_ids.iteritems()
+                        for key, e_id in iteritems(context.delta_ids)
                         if key[0] == EventTypes.Member
                     ]
                     for etype, state_key in context.delta_ids:
@@ -741,7 +743,7 @@ class _JoinedHostsCache(object):
             if state_entry.state_group == self.state_group:
                 pass
             elif state_entry.prev_group == self.state_group:
-                for (typ, state_key), event_id in state_entry.delta_ids.iteritems():
+                for (typ, state_key), event_id in iteritems(state_entry.delta_ids):
                     if typ != EventTypes.Member:
                         continue
 
@@ -771,7 +773,7 @@ class _JoinedHostsCache(object):
                 self.state_group = state_entry.state_group
             else:
                 self.state_group = object()
-            self._len = sum(len(v) for v in self.hosts_to_joined_users.itervalues())
+            self._len = sum(len(v) for v in itervalues(self.hosts_to_joined_users))
         defer.returnValue(frozenset(self.hosts_to_joined_users))
 
     def __len__(self):
diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index 6ba3e59889..f0fa5d7631 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -18,13 +18,14 @@ import logging
 import re
 import simplejson as json
 
+from six import string_types
+
 from twisted.internet import defer
 
 from .background_updates import BackgroundUpdateStore
 from synapse.api.errors import SynapseError
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 
-
 logger = logging.getLogger(__name__)
 
 SearchEntry = namedtuple('SearchEntry', [
@@ -126,7 +127,7 @@ class SearchStore(BackgroundUpdateStore):
                     # skip over it.
                     continue
 
-                if not isinstance(value, basestring):
+                if not isinstance(value, string_types):
                     # If the event body, name or topic isn't a string
                     # then skip over it
                     continue
@@ -447,7 +448,7 @@ class SearchStore(BackgroundUpdateStore):
             "search_msgs", self.cursor_to_dict, sql, *args
         )
 
-        results = filter(lambda row: row["room_id"] in room_ids, results)
+        results = list(filter(lambda row: row["room_id"] in room_ids, results))
 
         events = yield self._get_events([r["event_id"] for r in results])
 
@@ -602,7 +603,7 @@ class SearchStore(BackgroundUpdateStore):
             "search_rooms", self.cursor_to_dict, sql, *args
         )
 
-        results = filter(lambda row: row["room_id"] in room_ids, results)
+        results = list(filter(lambda row: row["room_id"] in room_ids, results))
 
         events = yield self._get_events([r["event_id"] for r in results])
 
diff --git a/synapse/storage/signatures.py b/synapse/storage/signatures.py
index 9e6eaaa532..25922e5a9c 100644
--- a/synapse/storage/signatures.py
+++ b/synapse/storage/signatures.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 from twisted.internet import defer
+import six
 
 from ._base import SQLBaseStore
 
@@ -21,6 +22,13 @@ from unpaddedbase64 import encode_base64
 from synapse.crypto.event_signing import compute_event_reference_hash
 from synapse.util.caches.descriptors import cached, cachedList
 
+# py2 sqlite has buffer hardcoded as only binary type, so we must use it,
+# despite being deprecated and removed in favor of memoryview
+if six.PY2:
+    db_binary_type = buffer
+else:
+    db_binary_type = memoryview
+
 
 class SignatureWorkerStore(SQLBaseStore):
     @cached()
@@ -56,7 +64,7 @@ class SignatureWorkerStore(SQLBaseStore):
             for e_id, h in hashes.items()
         }
 
-        defer.returnValue(hashes.items())
+        defer.returnValue(list(hashes.items()))
 
     def _get_event_reference_hashes_txn(self, txn, event_id):
         """Get all the hashes for a given PDU.
@@ -91,7 +99,7 @@ class SignatureStore(SignatureWorkerStore):
             vals.append({
                 "event_id": event.event_id,
                 "algorithm": ref_alg,
-                "hash": buffer(ref_hash_bytes),
+                "hash": db_binary_type(ref_hash_bytes),
             })
 
         self._simple_insert_many_txn(
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index ffa4246031..bdee14a8eb 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -16,6 +16,9 @@
 from collections import namedtuple
 import logging
 
+from six import iteritems, itervalues
+from six.moves import range
+
 from twisted.internet import defer
 
 from synapse.storage.background_updates import BackgroundUpdateStore
@@ -134,7 +137,7 @@ class StateGroupWorkerStore(SQLBaseStore):
             event_ids,
         )
 
-        groups = set(event_to_groups.itervalues())
+        groups = set(itervalues(event_to_groups))
         group_to_state = yield self._get_state_for_groups(groups)
 
         defer.returnValue(group_to_state)
@@ -166,18 +169,18 @@ class StateGroupWorkerStore(SQLBaseStore):
 
         state_event_map = yield self.get_events(
             [
-                ev_id for group_ids in group_to_ids.itervalues()
-                for ev_id in group_ids.itervalues()
+                ev_id for group_ids in itervalues(group_to_ids)
+                for ev_id in itervalues(group_ids)
             ],
             get_prev_content=False
         )
 
         defer.returnValue({
             group: [
-                state_event_map[v] for v in event_id_map.itervalues()
+                state_event_map[v] for v in itervalues(event_id_map)
                 if v in state_event_map
             ]
-            for group, event_id_map in group_to_ids.iteritems()
+            for group, event_id_map in iteritems(group_to_ids)
         })
 
     @defer.inlineCallbacks
@@ -186,7 +189,7 @@ class StateGroupWorkerStore(SQLBaseStore):
         """
         results = {}
 
-        chunks = [groups[i:i + 100] for i in xrange(0, len(groups), 100)]
+        chunks = [groups[i:i + 100] for i in range(0, len(groups), 100)]
         for chunk in chunks:
             res = yield self.runInteraction(
                 "_get_state_groups_from_groups",
@@ -347,21 +350,21 @@ class StateGroupWorkerStore(SQLBaseStore):
             event_ids,
         )
 
-        groups = set(event_to_groups.itervalues())
+        groups = set(itervalues(event_to_groups))
         group_to_state = yield self._get_state_for_groups(groups, types)
 
         state_event_map = yield self.get_events(
-            [ev_id for sd in group_to_state.itervalues() for ev_id in sd.itervalues()],
+            [ev_id for sd in itervalues(group_to_state) for ev_id in itervalues(sd)],
             get_prev_content=False
         )
 
         event_to_state = {
             event_id: {
                 k: state_event_map[v]
-                for k, v in group_to_state[group].iteritems()
+                for k, v in iteritems(group_to_state[group])
                 if v in state_event_map
             }
-            for event_id, group in event_to_groups.iteritems()
+            for event_id, group in iteritems(event_to_groups)
         }
 
         defer.returnValue({event: event_to_state[event] for event in event_ids})
@@ -384,12 +387,12 @@ class StateGroupWorkerStore(SQLBaseStore):
             event_ids,
         )
 
-        groups = set(event_to_groups.itervalues())
+        groups = set(itervalues(event_to_groups))
         group_to_state = yield self._get_state_for_groups(groups, types)
 
         event_to_state = {
             event_id: group_to_state[group]
-            for event_id, group in event_to_groups.iteritems()
+            for event_id, group in iteritems(event_to_groups)
         }
 
         defer.returnValue({event: event_to_state[event] for event in event_ids})
@@ -503,7 +506,7 @@ class StateGroupWorkerStore(SQLBaseStore):
         got_all = is_all or not missing_types
 
         return {
-            k: v for k, v in state_dict_ids.iteritems()
+            k: v for k, v in iteritems(state_dict_ids)
             if include(k[0], k[1])
         }, missing_types, got_all
 
@@ -562,12 +565,12 @@ class StateGroupWorkerStore(SQLBaseStore):
 
             # Now we want to update the cache with all the things we fetched
             # from the database.
-            for group, group_state_dict in group_to_state_dict.iteritems():
+            for group, group_state_dict in iteritems(group_to_state_dict):
                 state_dict = results[group]
 
                 state_dict.update(
                     ((intern_string(k[0]), intern_string(k[1])), to_ascii(v))
-                    for k, v in group_state_dict.iteritems()
+                    for k, v in iteritems(group_state_dict)
                 )
 
                 self._state_group_cache.update(
@@ -654,7 +657,7 @@ class StateGroupWorkerStore(SQLBaseStore):
                             "state_key": key[1],
                             "event_id": state_id,
                         }
-                        for key, state_id in delta_ids.iteritems()
+                        for key, state_id in iteritems(delta_ids)
                     ],
                 )
             else:
@@ -669,7 +672,7 @@ class StateGroupWorkerStore(SQLBaseStore):
                             "state_key": key[1],
                             "event_id": state_id,
                         }
-                        for key, state_id in current_state_ids.iteritems()
+                        for key, state_id in iteritems(current_state_ids)
                     ],
                 )
 
@@ -794,11 +797,11 @@ class StateStore(StateGroupWorkerStore, BackgroundUpdateStore):
                     "state_group": state_group_id,
                     "event_id": event_id,
                 }
-                for event_id, state_group_id in state_groups.iteritems()
+                for event_id, state_group_id in iteritems(state_groups)
             ],
         )
 
-        for event_id, state_group_id in state_groups.iteritems():
+        for event_id, state_group_id in iteritems(state_groups):
             txn.call_after(
                 self._get_state_group_for_event.prefill,
                 (event_id,), state_group_id
@@ -826,7 +829,7 @@ class StateStore(StateGroupWorkerStore, BackgroundUpdateStore):
 
         def reindex_txn(txn):
             new_last_state_group = last_state_group
-            for count in xrange(batch_size):
+            for count in range(batch_size):
                 txn.execute(
                     "SELECT id, room_id FROM state_groups"
                     " WHERE ? < id AND id <= ?"
@@ -884,7 +887,7 @@ class StateStore(StateGroupWorkerStore, BackgroundUpdateStore):
                         # of keys
 
                         delta_state = {
-                            key: value for key, value in curr_state.iteritems()
+                            key: value for key, value in iteritems(curr_state)
                             if prev_state.get(key, None) != value
                         }
 
@@ -924,7 +927,7 @@ class StateStore(StateGroupWorkerStore, BackgroundUpdateStore):
                                     "state_key": key[1],
                                     "event_id": state_id,
                                 }
-                                for key, state_id in delta_state.iteritems()
+                                for key, state_id in iteritems(delta_state)
                             ],
                         )
 
diff --git a/synapse/storage/stream.py b/synapse/storage/stream.py
index ea24710ad8..fb463c525a 100644
--- a/synapse/storage/stream.py
+++ b/synapse/storage/stream.py
@@ -684,8 +684,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
                 results to only those before
             direction(char): Either 'b' or 'f' to indicate whether we are
                 paginating forwards or backwards from `from_key`.
-            limit (int): The maximum number of events to return. Zero or less
-                means no limit.
+            limit (int): The maximum number of events to return.
             event_filter (Filter|None): If provided filters the events to
                 those that match the filter.
 
@@ -694,6 +693,9 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             as a list of _EventDictReturn and a token that points to the end
             of the result set.
         """
+
+        assert int(limit) >= 0
+
         # Tokens really represent positions between elements, but we use
         # the convention of pointing to the event before the gap. Hence
         # we have a bit of asymmetry when it comes to equalities.
@@ -723,22 +725,17 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             bounds += " AND " + filter_clause
             args.extend(filter_args)
 
-        if int(limit) > 0:
-            args.append(int(limit))
-            limit_str = " LIMIT ?"
-        else:
-            limit_str = ""
+        args.append(int(limit))
 
         sql = (
             "SELECT event_id, topological_ordering, stream_ordering"
             " FROM events"
             " WHERE outlier = ? AND room_id = ? AND %(bounds)s"
             " ORDER BY topological_ordering %(order)s,"
-            " stream_ordering %(order)s %(limit)s"
+            " stream_ordering %(order)s LIMIT ?"
         ) % {
             "bounds": bounds,
             "order": order,
-            "limit": limit_str
         }
 
         txn.execute(sql, args)
diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py
index f825264ea9..e485d19b84 100644
--- a/synapse/storage/transactions.py
+++ b/synapse/storage/transactions.py
@@ -17,6 +17,7 @@ from ._base import SQLBaseStore
 from synapse.util.caches.descriptors import cached
 
 from twisted.internet import defer
+import six
 
 from canonicaljson import encode_canonical_json
 
@@ -25,6 +26,13 @@ from collections import namedtuple
 import logging
 import simplejson as json
 
+# py2 sqlite has buffer hardcoded as only binary type, so we must use it,
+# despite being deprecated and removed in favor of memoryview
+if six.PY2:
+    db_binary_type = buffer
+else:
+    db_binary_type = memoryview
+
 logger = logging.getLogger(__name__)
 
 
@@ -110,7 +118,7 @@ class TransactionStore(SQLBaseStore):
                 "transaction_id": transaction_id,
                 "origin": origin,
                 "response_code": code,
-                "response_json": buffer(encode_canonical_json(response_dict)),
+                "response_json": db_binary_type(encode_canonical_json(response_dict)),
                 "ts": self._clock.time_msec(),
             },
             or_ignore=True,
diff --git a/synapse/storage/user_directory.py b/synapse/storage/user_directory.py
index d6e289ffbe..275c299998 100644
--- a/synapse/storage/user_directory.py
+++ b/synapse/storage/user_directory.py
@@ -22,6 +22,8 @@ from synapse.api.constants import EventTypes, JoinRules
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.types import get_domain_from_id, get_localpart_from_id
 
+from six import iteritems
+
 import re
 import logging
 
@@ -100,7 +102,7 @@ class UserDirectoryStore(SQLBaseStore):
                     user_id, get_localpart_from_id(user_id), get_domain_from_id(user_id),
                     profile.display_name,
                 )
-                for user_id, profile in users_with_profile.iteritems()
+                for user_id, profile in iteritems(users_with_profile)
             )
         elif isinstance(self.database_engine, Sqlite3Engine):
             sql = """
@@ -112,7 +114,7 @@ class UserDirectoryStore(SQLBaseStore):
                     user_id,
                     "%s %s" % (user_id, p.display_name,) if p.display_name else user_id
                 )
-                for user_id, p in users_with_profile.iteritems()
+                for user_id, p in iteritems(users_with_profile)
             )
         else:
             # This should be unreachable.
@@ -130,7 +132,7 @@ class UserDirectoryStore(SQLBaseStore):
                         "display_name": profile.display_name,
                         "avatar_url": profile.avatar_url,
                     }
-                    for user_id, profile in users_with_profile.iteritems()
+                    for user_id, profile in iteritems(users_with_profile)
                 ]
             )
             for user_id in users_with_profile:
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index 814a7bf71b..fc11e26623 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -20,6 +20,8 @@ from twisted.internet import defer, reactor, task
 import time
 import logging
 
+from itertools import islice
+
 logger = logging.getLogger(__name__)
 
 
@@ -79,3 +81,19 @@ class Clock(object):
         except Exception:
             if not ignore_errs:
                 raise
+
+
+def batch_iter(iterable, size):
+    """batch an iterable up into tuples with a maximum size
+
+    Args:
+        iterable (iterable): the iterable to slice
+        size (int): the maximum batch size
+
+    Returns:
+        an iterator over the chunks
+    """
+    # make sure we can deal with iterables like lists too
+    sourceiter = iter(iterable)
+    # call islice until it returns an empty tuple
+    return iter(lambda: tuple(islice(sourceiter, size)), ())
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index 4adae96681..183faf75a1 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -13,28 +13,77 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import synapse.metrics
+from prometheus_client.core import Gauge, REGISTRY, GaugeMetricFamily
+
 import os
 
-CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.5))
+from six.moves import intern
+import six
 
-metrics = synapse.metrics.get_metrics_for("synapse.util.caches")
+CACHE_SIZE_FACTOR = float(os.environ.get("SYNAPSE_CACHE_FACTOR", 0.5))
 
 caches_by_name = {}
-# cache_counter = metrics.register_cache(
-#     "cache",
-#     lambda: {(name,): len(caches_by_name[name]) for name in caches_by_name.keys()},
-#     labels=["name"],
-# )
-
-
-def register_cache(name, cache):
-    caches_by_name[name] = cache
-    return metrics.register_cache(
-        "cache",
-        lambda: len(cache),
-        name,
-    )
+collectors_by_name = {}
+
+cache_size = Gauge("synapse_util_caches_cache:size", "", ["name"])
+cache_hits = Gauge("synapse_util_caches_cache:hits", "", ["name"])
+cache_evicted = Gauge("synapse_util_caches_cache:evicted_size", "", ["name"])
+cache_total = Gauge("synapse_util_caches_cache:total", "", ["name"])
+
+response_cache_size = Gauge("synapse_util_caches_response_cache:size", "", ["name"])
+response_cache_hits = Gauge("synapse_util_caches_response_cache:hits", "", ["name"])
+response_cache_evicted = Gauge(
+    "synapse_util_caches_response_cache:evicted_size", "", ["name"]
+)
+response_cache_total = Gauge("synapse_util_caches_response_cache:total", "", ["name"])
+
+
+def register_cache(cache_type, cache_name, cache):
+
+    # Check if the metric is already registered. Unregister it, if so.
+    # This usually happens during tests, as at runtime these caches are
+    # effectively singletons.
+    metric_name = "cache_%s_%s" % (cache_type, cache_name)
+    if metric_name in collectors_by_name.keys():
+        REGISTRY.unregister(collectors_by_name[metric_name])
+
+    class CacheMetric(object):
+
+        hits = 0
+        misses = 0
+        evicted_size = 0
+
+        def inc_hits(self):
+            self.hits += 1
+
+        def inc_misses(self):
+            self.misses += 1
+
+        def inc_evictions(self, size=1):
+            self.evicted_size += size
+
+        def describe(self):
+            return []
+
+        def collect(self):
+            if cache_type == "response_cache":
+                response_cache_size.labels(cache_name).set(len(cache))
+                response_cache_hits.labels(cache_name).set(self.hits)
+                response_cache_evicted.labels(cache_name).set(self.evicted_size)
+                response_cache_total.labels(cache_name).set(self.hits + self.misses)
+            else:
+                cache_size.labels(cache_name).set(len(cache))
+                cache_hits.labels(cache_name).set(self.hits)
+                cache_evicted.labels(cache_name).set(self.evicted_size)
+                cache_total.labels(cache_name).set(self.hits + self.misses)
+
+            yield GaugeMetricFamily("__unused", "")
+
+    metric = CacheMetric()
+    REGISTRY.register(metric)
+    caches_by_name[cache_name] = cache
+    collectors_by_name[metric_name] = metric
+    return metric
 
 
 KNOWN_KEYS = {
@@ -66,7 +115,9 @@ def intern_string(string):
         return None
 
     try:
-        string = string.encode("ascii")
+        if six.PY2:
+            string = string.encode("ascii")
+
         return intern(string)
     except UnicodeEncodeError:
         return string
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 68285a7594..fc1874b65b 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -31,6 +31,9 @@ import functools
 import inspect
 import threading
 
+from six import string_types, itervalues
+import six
+
 
 logger = logging.getLogger(__name__)
 
@@ -80,7 +83,7 @@ class Cache(object):
         self.name = name
         self.keylen = keylen
         self.thread = None
-        self.metrics = register_cache(name, self.cache)
+        self.metrics = register_cache("cache", name, self.cache)
 
     def _on_evicted(self, evicted_count):
         self.metrics.inc_evictions(evicted_count)
@@ -205,7 +208,7 @@ class Cache(object):
     def invalidate_all(self):
         self.check_thread()
         self.cache.clear()
-        for entry in self._pending_deferred_cache.itervalues():
+        for entry in itervalues(self._pending_deferred_cache):
             entry.invalidate()
         self._pending_deferred_cache.clear()
 
@@ -392,9 +395,10 @@ class CacheDescriptor(_CacheDescriptorBase):
 
                 ret.addErrback(onErr)
 
-                # If our cache_key is a string, try to convert to ascii to save
-                # a bit of space in large caches
-                if isinstance(cache_key, basestring):
+                # If our cache_key is a string on py2, try to convert to ascii
+                # to save a bit of space in large caches. Py3 does this
+                # internally automatically.
+                if six.PY2 and isinstance(cache_key, string_types):
                     cache_key = to_ascii(cache_key)
 
                 result_d = ObservableDeferred(ret, consumeErrors=True)
@@ -565,7 +569,7 @@ class CacheListDescriptor(_CacheDescriptorBase):
                     return results
 
                 return logcontext.make_deferred_yieldable(defer.gatherResults(
-                    cached_defers.values(),
+                    list(cached_defers.values()),
                     consumeErrors=True,
                 ).addCallback(update_results_dict).addErrback(
                     unwrapFirstError
diff --git a/synapse/util/caches/dictionary_cache.py b/synapse/util/caches/dictionary_cache.py
index 1709e8b429..bdc21e348f 100644
--- a/synapse/util/caches/dictionary_cache.py
+++ b/synapse/util/caches/dictionary_cache.py
@@ -55,7 +55,7 @@ class DictionaryCache(object):
             __slots__ = []
 
         self.sentinel = Sentinel()
-        self.metrics = register_cache(name, self.cache)
+        self.metrics = register_cache("dictionary", name, self.cache)
 
     def check_thread(self):
         expected_thread = self.thread
diff --git a/synapse/util/caches/expiringcache.py b/synapse/util/caches/expiringcache.py
index 0aa103eecb..ff04c91955 100644
--- a/synapse/util/caches/expiringcache.py
+++ b/synapse/util/caches/expiringcache.py
@@ -52,12 +52,12 @@ class ExpiringCache(object):
 
         self._cache = OrderedDict()
 
-        self.metrics = register_cache(cache_name, self)
-
         self.iterable = iterable
 
         self._size_estimate = 0
 
+        self.metrics = register_cache("expiring", cache_name, self)
+
     def start(self):
         if not self._expiry_ms:
             # Don't bother starting the loop if things never expire
diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py
index 7f79333e96..a8491b42d5 100644
--- a/synapse/util/caches/response_cache.py
+++ b/synapse/util/caches/response_cache.py
@@ -17,7 +17,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.util.async import ObservableDeferred
-from synapse.util.caches import metrics as cache_metrics
+from synapse.util.caches import register_cache
 from synapse.util.logcontext import make_deferred_yieldable, run_in_background
 
 logger = logging.getLogger(__name__)
@@ -38,15 +38,16 @@ class ResponseCache(object):
         self.timeout_sec = timeout_ms / 1000.
 
         self._name = name
-        self._metrics = cache_metrics.register_cache(
-            "response_cache",
-            size_callback=lambda: self.size(),
-            cache_name=name,
+        self._metrics = register_cache(
+            "response_cache", name, self
         )
 
     def size(self):
         return len(self.pending_result_cache)
 
+    def __len__(self):
+        return self.size()
+
     def get(self, key):
         """Look up the given key.
 
diff --git a/synapse/util/caches/stream_change_cache.py b/synapse/util/caches/stream_change_cache.py
index 941d873ab8..a7fe0397fa 100644
--- a/synapse/util/caches/stream_change_cache.py
+++ b/synapse/util/caches/stream_change_cache.py
@@ -38,7 +38,7 @@ class StreamChangeCache(object):
         self._cache = sorteddict()
         self._earliest_known_stream_pos = current_stream_pos
         self.name = name
-        self.metrics = register_cache(self.name, self._cache)
+        self.metrics = register_cache("cache", self.name, self._cache)
 
         for entity, stream_pos in prefilled_cache.items():
             self.entity_has_changed(entity, stream_pos)
diff --git a/synapse/util/caches/treecache.py b/synapse/util/caches/treecache.py
index fcc341a6b7..dd4c9e6067 100644
--- a/synapse/util/caches/treecache.py
+++ b/synapse/util/caches/treecache.py
@@ -1,3 +1,5 @@
+from six import itervalues
+
 SENTINEL = object()
 
 
@@ -49,7 +51,7 @@ class TreeCache(object):
         if popped is SENTINEL:
             return default
 
-        node_and_keys = zip(nodes, key)
+        node_and_keys = list(zip(nodes, key))
         node_and_keys.reverse()
         node_and_keys.append((self.root, None))
 
@@ -76,7 +78,7 @@ def iterate_tree_cache_entry(d):
     can contain dicts.
     """
     if isinstance(d, dict):
-        for value_d in d.itervalues():
+        for value_d in itervalues(d):
             for value in iterate_tree_cache_entry(value_d):
                 yield value
     else:
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index f497b51f4a..15f0a7ba9e 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -16,16 +16,17 @@
 from frozendict import frozendict
 import simplejson as json
 
+from six import string_types
+
 
 def freeze(o):
-    t = type(o)
-    if t is dict:
+    if isinstance(o, dict):
         return frozendict({k: freeze(v) for k, v in o.items()})
 
-    if t is frozendict:
+    if isinstance(o, frozendict):
         return o
 
-    if t is str or t is unicode:
+    if isinstance(o, string_types):
         return o
 
     try:
@@ -37,11 +38,10 @@ def freeze(o):
 
 
 def unfreeze(o):
-    t = type(o)
-    if t is dict or t is frozendict:
+    if isinstance(o, (dict, frozendict)):
         return dict({k: unfreeze(v) for k, v in o.items()})
 
-    if t is str or t is unicode:
+    if isinstance(o, string_types):
         return o
 
     try:
diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py
index 914f616312..a58c723403 100644
--- a/synapse/util/logcontext.py
+++ b/synapse/util/logcontext.py
@@ -59,7 +59,7 @@ class LoggingContext(object):
 
     __slots__ = [
         "previous_context", "name", "ru_stime", "ru_utime",
-        "db_txn_count", "db_txn_duration_ms", "db_sched_duration_ms",
+        "db_txn_count", "db_txn_duration_sec", "db_sched_duration_sec",
         "usage_start",
         "main_thread", "alive",
         "request", "tag",
@@ -84,10 +84,10 @@ class LoggingContext(object):
         def stop(self):
             pass
 
-        def add_database_transaction(self, duration_ms):
+        def add_database_transaction(self, duration_sec):
             pass
 
-        def add_database_scheduled(self, sched_ms):
+        def add_database_scheduled(self, sched_sec):
             pass
 
         def __nonzero__(self):
@@ -103,11 +103,11 @@ class LoggingContext(object):
         self.ru_utime = 0.
         self.db_txn_count = 0
 
-        # ms spent waiting for db txns, excluding scheduling time
-        self.db_txn_duration_ms = 0
+        # sec spent waiting for db txns, excluding scheduling time
+        self.db_txn_duration_sec = 0
 
-        # ms spent waiting for db txns to be scheduled
-        self.db_sched_duration_ms = 0
+        # sec spent waiting for db txns to be scheduled
+        self.db_sched_duration_sec = 0
 
         # If alive has the thread resource usage when the logcontext last
         # became active.
@@ -230,18 +230,18 @@ class LoggingContext(object):
 
         return ru_utime, ru_stime
 
-    def add_database_transaction(self, duration_ms):
+    def add_database_transaction(self, duration_sec):
         self.db_txn_count += 1
-        self.db_txn_duration_ms += duration_ms
+        self.db_txn_duration_sec += duration_sec
 
-    def add_database_scheduled(self, sched_ms):
+    def add_database_scheduled(self, sched_sec):
         """Record a use of the database pool
 
         Args:
-            sched_ms (int): number of milliseconds it took us to get a
+            sched_sec (float): number of seconds it took us to get a
                 connection
         """
-        self.db_sched_duration_ms += sched_ms
+        self.db_sched_duration_sec += sched_sec
 
 
 class LoggingContextFilter(logging.Filter):
diff --git a/synapse/util/logutils.py b/synapse/util/logutils.py
index 3a83828d25..03249c5dc8 100644
--- a/synapse/util/logutils.py
+++ b/synapse/util/logutils.py
@@ -96,7 +96,7 @@ def time_function(f):
         id = _TIME_FUNC_ID
         _TIME_FUNC_ID += 1
 
-        start = time.clock() * 1000
+        start = time.clock()
 
         try:
             _log_debug_as_f(
@@ -107,10 +107,10 @@ def time_function(f):
 
             r = f(*args, **kwargs)
         finally:
-            end = time.clock() * 1000
+            end = time.clock()
             _log_debug_as_f(
                 f,
-                "[FUNC END] {%s-%d} %f",
+                "[FUNC END] {%s-%d} %.3f sec",
                 (func_name, id, end - start,),
             )
 
diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index e4b5687a4b..1ba7d65c7c 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -15,8 +15,8 @@
 
 from twisted.internet import defer
 
+from prometheus_client import Counter
 from synapse.util.logcontext import LoggingContext
-import synapse.metrics
 
 from functools import wraps
 import logging
@@ -24,66 +24,26 @@ import logging
 
 logger = logging.getLogger(__name__)
 
+block_counter = Counter("synapse_util_metrics_block_count", "", ["block_name"])
 
-metrics = synapse.metrics.get_metrics_for(__name__)
-
-# total number of times we have hit this block
-block_counter = metrics.register_counter(
-    "block_count",
-    labels=["block_name"],
-    alternative_names=(
-        # the following are all deprecated aliases for the same metric
-        metrics.name_prefix + x for x in (
-            "_block_timer:count",
-            "_block_ru_utime:count",
-            "_block_ru_stime:count",
-            "_block_db_txn_count:count",
-            "_block_db_txn_duration:count",
-        )
-    )
-)
-
-block_timer = metrics.register_counter(
-    "block_time_seconds",
-    labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_timer:total",
-    ),
-)
-
-block_ru_utime = metrics.register_counter(
-    "block_ru_utime_seconds", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_ru_utime:total",
-    ),
-)
-
-block_ru_stime = metrics.register_counter(
-    "block_ru_stime_seconds", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_ru_stime:total",
-    ),
-)
-
-block_db_txn_count = metrics.register_counter(
-    "block_db_txn_count", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_db_txn_count:total",
-    ),
-)
+block_timer = Counter("synapse_util_metrics_block_time_seconds", "", ["block_name"])
+
+block_ru_utime = Counter(
+    "synapse_util_metrics_block_ru_utime_seconds", "", ["block_name"])
+
+block_ru_stime = Counter(
+    "synapse_util_metrics_block_ru_stime_seconds", "", ["block_name"])
+
+block_db_txn_count = Counter(
+    "synapse_util_metrics_block_db_txn_count", "", ["block_name"])
 
 # seconds spent waiting for db txns, excluding scheduling time, in this block
-block_db_txn_duration = metrics.register_counter(
-    "block_db_txn_duration_seconds", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_db_txn_duration:total",
-    ),
-)
+block_db_txn_duration = Counter(
+    "synapse_util_metrics_block_db_txn_duration_seconds", "", ["block_name"])
 
 # seconds spent waiting for a db connection, in this block
-block_db_sched_duration = metrics.register_counter(
-    "block_db_sched_duration_seconds", labels=["block_name"],
-)
+block_db_sched_duration = Counter(
+    "synapse_util_metrics_block_db_sched_duration_seconds", "", ["block_name"])
 
 
 def measure_func(name):
@@ -102,7 +62,7 @@ class Measure(object):
     __slots__ = [
         "clock", "name", "start_context", "start", "new_context", "ru_utime",
         "ru_stime",
-        "db_txn_count", "db_txn_duration_ms", "db_sched_duration_ms",
+        "db_txn_count", "db_txn_duration_sec", "db_sched_duration_sec",
         "created_context",
     ]
 
@@ -114,7 +74,7 @@ class Measure(object):
         self.created_context = False
 
     def __enter__(self):
-        self.start = self.clock.time_msec()
+        self.start = self.clock.time()
         self.start_context = LoggingContext.current_context()
         if not self.start_context:
             self.start_context = LoggingContext("Measure")
@@ -123,17 +83,17 @@ class Measure(object):
 
         self.ru_utime, self.ru_stime = self.start_context.get_resource_usage()
         self.db_txn_count = self.start_context.db_txn_count
-        self.db_txn_duration_ms = self.start_context.db_txn_duration_ms
-        self.db_sched_duration_ms = self.start_context.db_sched_duration_ms
+        self.db_txn_duration_sec = self.start_context.db_txn_duration_sec
+        self.db_sched_duration_sec = self.start_context.db_sched_duration_sec
 
     def __exit__(self, exc_type, exc_val, exc_tb):
         if isinstance(exc_type, Exception) or not self.start_context:
             return
 
-        duration = self.clock.time_msec() - self.start
+        duration = self.clock.time() - self.start
 
-        block_counter.inc(self.name)
-        block_timer.inc_by(duration, self.name)
+        block_counter.labels(self.name).inc()
+        block_timer.labels(self.name).inc(duration)
 
         context = LoggingContext.current_context()
 
@@ -150,19 +110,13 @@ class Measure(object):
 
         ru_utime, ru_stime = context.get_resource_usage()
 
-        block_ru_utime.inc_by(ru_utime - self.ru_utime, self.name)
-        block_ru_stime.inc_by(ru_stime - self.ru_stime, self.name)
-        block_db_txn_count.inc_by(
-            context.db_txn_count - self.db_txn_count, self.name
-        )
-        block_db_txn_duration.inc_by(
-            (context.db_txn_duration_ms - self.db_txn_duration_ms) / 1000.,
-            self.name
-        )
-        block_db_sched_duration.inc_by(
-            (context.db_sched_duration_ms - self.db_sched_duration_ms) / 1000.,
-            self.name
-        )
+        block_ru_utime.labels(self.name).inc(ru_utime - self.ru_utime)
+        block_ru_stime.labels(self.name).inc(ru_stime - self.ru_stime)
+        block_db_txn_count.labels(self.name).inc(context.db_txn_count - self.db_txn_count)
+        block_db_txn_duration.labels(self.name).inc(
+            context.db_txn_duration_sec - self.db_txn_duration_sec)
+        block_db_sched_duration.labels(self.name).inc(
+            context.db_sched_duration_sec - self.db_sched_duration_sec)
 
         if self.created_context:
             self.start_context.__exit__(exc_type, exc_val, exc_tb)