Merge branch 'develop' of github.com:matrix-org/synapse into erikj/censor_redactions

102 files changed, 1680 insertions, 1339 deletions

diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 7b3a5a8221..ddc195bc32 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -276,25 +276,25 @@ class Auth(object):
             self.get_access_token_from_request(request)
         )
         if app_service is None:
-            return (None, None)
+            return None, None
 
         if app_service.ip_range_whitelist:
             ip_address = IPAddress(self.hs.get_ip_from_request(request))
             if ip_address not in app_service.ip_range_whitelist:
-                return (None, None)
+                return None, None
 
         if b"user_id" not in request.args:
-            return (app_service.sender, app_service)
+            return app_service.sender, app_service
 
         user_id = request.args[b"user_id"][0].decode("utf8")
         if app_service.sender == user_id:
-            return (app_service.sender, app_service)
+            return app_service.sender, app_service
 
         if not app_service.is_interested_in_user(user_id):
             raise AuthError(403, "Application service cannot masquerade as this user.")
         if not (yield self.store.get_user_by_id(user_id)):
             raise AuthError(403, "Application service has not registered this user")
-        return (user_id, app_service)
+        return user_id, app_service
 
     @defer.inlineCallbacks
     def get_user_by_access_token(self, token, rights="access"):
@@ -694,7 +694,7 @@ class Auth(object):
             #  * The user is a guest user, and has joined the room
             # else it will throw.
             member_event = yield self.check_user_was_in_room(room_id, user_id)
-            return (member_event.membership, member_event.event_id)
+            return member_event.membership, member_event.event_id
         except AuthError:
             visibility = yield self.state.get_current_state(
                 room_id, EventTypes.RoomHistoryVisibility, ""
@@ -703,8 +703,7 @@ class Auth(object):
                 visibility
                 and visibility.content["history_visibility"] == "world_readable"
             ):
-                return (Membership.JOIN, None)
-                return
+                return Membership.JOIN, None
             raise AuthError(
                 403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
             )
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index 611d285421..9504bfbc70 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -70,12 +70,12 @@ class PresenceStatusStubServlet(RestServlet):
         except HttpResponseException as e:
             raise e.to_synapse_error()
 
-        return (200, result)
+        return 200, result
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
         yield self.auth.get_user_by_req(request)
-        return (200, {})
+        return 200, {}
 
 
 class KeyUploadServlet(RestServlet):
@@ -126,11 +126,11 @@ class KeyUploadServlet(RestServlet):
                 self.main_uri + request.uri.decode("ascii"), body, headers=headers
             )
 
-            return (200, result)
+            return 200, result
         else:
             # Just interested in counts.
             result = yield self.store.count_e2e_one_time_keys(user_id, device_id)
-            return (200, {"one_time_key_counts": result})
+            return 200, {"one_time_key_counts": result}
 
 
 class FrontendProxySlavedStore(
diff --git a/synapse/appservice/api.py b/synapse/appservice/api.py
index 007ca75a94..3e25bf5747 100644
--- a/synapse/appservice/api.py
+++ b/synapse/appservice/api.py
@@ -107,7 +107,6 @@ class ApplicationServiceApi(SimpleHttpClient):
         except CodeMessageException as e:
             if e.code == 404:
                 return False
-                return
             logger.warning("query_user to %s received %s", uri, e.code)
         except Exception as ex:
             logger.warning("query_user to %s threw exception %s", uri, ex)
@@ -127,7 +126,6 @@ class ApplicationServiceApi(SimpleHttpClient):
             logger.warning("query_alias to %s received %s", uri, e.code)
             if e.code == 404:
                 return False
-                return
         except Exception as ex:
             logger.warning("query_alias to %s threw exception %s", uri, ex)
         return False
@@ -230,7 +228,6 @@ class ApplicationServiceApi(SimpleHttpClient):
             sent_transactions_counter.labels(service.id).inc()
             sent_events_counter.labels(service.id).inc(len(events))
             return True
-            return
         except CodeMessageException as e:
             logger.warning("push_bulk to %s received %s", uri, e.code)
         except Exception as ex:
diff --git a/synapse/config/stats.py b/synapse/config/stats.py
index b518a3ed9c..b18ddbd1fa 100644
--- a/synapse/config/stats.py
+++ b/synapse/config/stats.py
@@ -27,19 +27,16 @@ class StatsConfig(Config):
 
     def read_config(self, config, **kwargs):
         self.stats_enabled = True
-        self.stats_bucket_size = 86400
+        self.stats_bucket_size = 86400 * 1000
         self.stats_retention = sys.maxsize
         stats_config = config.get("stats", None)
         if stats_config:
             self.stats_enabled = stats_config.get("enabled", self.stats_enabled)
-            self.stats_bucket_size = (
-                self.parse_duration(stats_config.get("bucket_size", "1d")) / 1000
+            self.stats_bucket_size = self.parse_duration(
+                stats_config.get("bucket_size", "1d")
             )
-            self.stats_retention = (
-                self.parse_duration(
-                    stats_config.get("retention", "%ds" % (sys.maxsize,))
-                )
-                / 1000
+            self.stats_retention = self.parse_duration(
+                stats_config.get("retention", "%ds" % (sys.maxsize,))
             )
 
     def generate_config_section(self, config_dir_path, server_name, **kwargs):
diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py
index 41eabbe717..694fb2c816 100644
--- a/synapse/crypto/event_signing.py
+++ b/synapse/crypto/event_signing.py
@@ -83,7 +83,7 @@ def compute_content_hash(event_dict, hash_algorithm):
     event_json_bytes = encode_canonical_json(event_dict)
 
     hashed = hash_algorithm(event_json_bytes)
-    return (hashed.name, hashed.digest())
+    return hashed.name, hashed.digest()
 
 
 def compute_event_reference_hash(event, hash_algorithm=hashlib.sha256):
@@ -106,7 +106,7 @@ def compute_event_reference_hash(event, hash_algorithm=hashlib.sha256):
     event_dict.pop("unsigned", None)
     event_json_bytes = encode_canonical_json(event_dict)
     hashed = hash_algorithm(event_json_bytes)
-    return (hashed.name, hashed.digest())
+    return hashed.name, hashed.digest()
 
 
 def compute_event_signature(event_dict, signature_name, signing_key):
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index cd52e3f867..4e91df60e6 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -637,11 +637,11 @@ def auth_types_for_event(event):
     if event.type == EventTypes.Create:
         return []
 
-    auth_types = []
-
-    auth_types.append((EventTypes.PowerLevels, ""))
-    auth_types.append((EventTypes.Member, event.sender))
-    auth_types.append((EventTypes.Create, ""))
+    auth_types = [
+        (EventTypes.PowerLevels, ""),
+        (EventTypes.Member, event.sender),
+        (EventTypes.Create, ""),
+    ]
 
     if event.type == EventTypes.Member:
         membership = event.content["membership"]
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index bec3080895..6ee6216660 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -355,7 +355,7 @@ class FederationClient(FederationBase):
 
             auth_chain.sort(key=lambda e: e.depth)
 
-            return (pdus, auth_chain)
+            return pdus, auth_chain
         except HttpResponseException as e:
             if e.code == 400 or e.code == 404:
                 logger.info("Failed to use get_room_state_ids API, falling back")
@@ -404,7 +404,7 @@ class FederationClient(FederationBase):
 
         signed_auth.sort(key=lambda e: e.depth)
 
-        return (signed_pdus, signed_auth)
+        return signed_pdus, signed_auth
 
     @defer.inlineCallbacks
     def get_events_from_store_or_dest(self, destination, room_id, event_ids):
@@ -429,7 +429,7 @@ class FederationClient(FederationBase):
             missing_events.discard(k)
 
         if not missing_events:
-            return (signed_events, failed_to_fetch)
+            return signed_events, failed_to_fetch
 
         logger.debug(
             "Fetching unknown state/auth events %s for room %s",
@@ -465,7 +465,7 @@ class FederationClient(FederationBase):
             # We removed all events we successfully fetched from `batch`
             failed_to_fetch.update(batch)
 
-        return (signed_events, failed_to_fetch)
+        return signed_events, failed_to_fetch
 
     @defer.inlineCallbacks
     @log_function
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 05fd49f3c1..e5f0b90aec 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -100,7 +100,7 @@ class FederationServer(FederationBase):
 
             res = self._transaction_from_pdus(pdus).get_dict()
 
-        return (200, res)
+        return 200, res
 
     @defer.inlineCallbacks
     @log_function
@@ -163,7 +163,7 @@ class FederationServer(FederationBase):
             yield self.transaction_actions.set_response(
                 origin, transaction, 400, response
             )
-            return (400, response)
+            return 400, response
 
         received_pdus_counter.inc(len(transaction.pdus))
 
@@ -265,7 +265,7 @@ class FederationServer(FederationBase):
         logger.debug("Returning: %s", str(response))
 
         yield self.transaction_actions.set_response(origin, transaction, 200, response)
-        return (200, response)
+        return 200, response
 
     @defer.inlineCallbacks
     def received_edu(self, origin, edu_type, content):
@@ -298,7 +298,7 @@ class FederationServer(FederationBase):
                 event_id,
             )
 
-        return (200, resp)
+        return 200, resp
 
     @defer.inlineCallbacks
     def on_state_ids_request(self, origin, room_id, event_id):
@@ -315,7 +315,7 @@ class FederationServer(FederationBase):
         state_ids = yield self.handler.get_state_ids_for_pdu(room_id, event_id)
         auth_chain_ids = yield self.store.get_auth_chain_ids(state_ids)
 
-        return (200, {"pdu_ids": state_ids, "auth_chain_ids": auth_chain_ids})
+        return 200, {"pdu_ids": state_ids, "auth_chain_ids": auth_chain_ids}
 
     @defer.inlineCallbacks
     def _on_context_state_request_compute(self, room_id, event_id):
@@ -345,15 +345,15 @@ class FederationServer(FederationBase):
         pdu = yield self.handler.get_persisted_pdu(origin, event_id)
 
         if pdu:
-            return (200, self._transaction_from_pdus([pdu]).get_dict())
+            return 200, self._transaction_from_pdus([pdu]).get_dict()
         else:
-            return (404, "")
+            return 404, ""
 
     @defer.inlineCallbacks
     def on_query_request(self, query_type, args):
         received_queries_counter.labels(query_type).inc()
         resp = yield self.registry.on_query(query_type, args)
-        return (200, resp)
+        return 200, resp
 
     @defer.inlineCallbacks
     def on_make_join_request(self, origin, room_id, user_id, supported_versions):
@@ -435,7 +435,7 @@ class FederationServer(FederationBase):
 
         logger.debug("on_send_leave_request: pdu sigs: %s", pdu.signatures)
         yield self.handler.on_send_leave_request(origin, pdu)
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_event_auth(self, origin, room_id, event_id):
@@ -446,7 +446,7 @@ class FederationServer(FederationBase):
             time_now = self._clock.time_msec()
             auth_pdus = yield self.handler.on_event_auth(event_id)
             res = {"auth_chain": [a.get_pdu_json(time_now) for a in auth_pdus]}
-        return (200, res)
+        return 200, res
 
     @defer.inlineCallbacks
     def on_query_auth_request(self, origin, content, room_id, event_id):
@@ -499,7 +499,7 @@ class FederationServer(FederationBase):
                 "missing": ret.get("missing", []),
             }
 
-        return (200, send_content)
+        return 200, send_content
 
     @log_function
     def on_query_client_keys(self, origin, content):
diff --git a/synapse/federation/sender/transaction_manager.py b/synapse/federation/sender/transaction_manager.py
index 62ca6a3e87..5b6c79c51a 100644
--- a/synapse/federation/sender/transaction_manager.py
+++ b/synapse/federation/sender/transaction_manager.py
@@ -26,6 +26,7 @@ from synapse.logging.opentracing import (
     set_tag,
     start_active_span_follows_from,
     tags,
+    whitelisted_homeserver,
 )
 from synapse.util.metrics import measure_func
 
@@ -59,9 +60,15 @@ class TransactionManager(object):
         # The span_contexts is a generator so that it won't be evaluated if
         # opentracing is disabled. (Yay speed!)
 
-        span_contexts = (
-            extract_text_map(json.loads(edu.get_context())) for edu in pending_edus
-        )
+        span_contexts = []
+        keep_destination = whitelisted_homeserver(destination)
+
+        for edu in pending_edus:
+            context = edu.get_context()
+            if context:
+                span_contexts.append(extract_text_map(json.loads(context)))
+            if keep_destination:
+                edu.strip_context()
 
         with start_active_span_follows_from("send_transaction", span_contexts):
 
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index f9930b6460..132a8fb5e6 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -342,7 +342,11 @@ class BaseFederationServlet(object):
                 continue
 
             server.register_paths(
-                method, (pattern,), self._wrap(code), self.__class__.__name__
+                method,
+                (pattern,),
+                self._wrap(code),
+                self.__class__.__name__,
+                trace=False,
             )
 
 
diff --git a/synapse/federation/units.py b/synapse/federation/units.py
index aa84621206..b4d743cde7 100644
--- a/synapse/federation/units.py
+++ b/synapse/federation/units.py
@@ -41,6 +41,9 @@ class Edu(JsonEncodedObject):
     def get_context(self):
         return getattr(self, "content", {}).get("org.matrix.opentracing_context", "{}")
 
+    def strip_context(self):
+        getattr(self, "content", {})["org.matrix.opentracing_context"] = "{}"
+
 
 class Transaction(JsonEncodedObject):
     """ A transaction is a list of Pdus and Edus to be sent to a remote home
diff --git a/synapse/handlers/account_data.py b/synapse/handlers/account_data.py
index 8acd9f9a83..38bc67191c 100644
--- a/synapse/handlers/account_data.py
+++ b/synapse/handlers/account_data.py
@@ -51,8 +51,8 @@ class AccountDataEventSource(object):
                     {"type": account_data_type, "content": content, "room_id": room_id}
                 )
 
-        return (results, current_stream_id)
+        return results, current_stream_id
 
     @defer.inlineCallbacks
     def get_pagination_rows(self, user, config, key):
-        return ([], config.to_id)
+        return [], config.to_id
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index d1a51df6f9..3e9b298154 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -294,12 +294,10 @@ class ApplicationServicesHandler(object):
             # we don't know if they are unknown or not since it isn't one of our
             # users. We can't poke ASes.
             return False
-            return
 
         user_info = yield self.store.get_user_by_id(user_id)
         if user_info:
             return False
-            return
 
         # user not found; could be the AS though, so check.
         services = self.store.get_app_services()
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 0f3ebf7ef8..f844409d21 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -280,7 +280,7 @@ class AuthHandler(BaseHandler):
                     creds,
                     list(clientdict),
                 )
-                return (creds, clientdict, session["id"])
+                return creds, clientdict, session["id"]
 
         ret = self._auth_dict_for_flows(flows, session)
         ret["completed"] = list(creds)
@@ -722,7 +722,7 @@ class AuthHandler(BaseHandler):
                 known_login_type = True
                 is_valid = yield provider.check_password(qualified_user_id, password)
                 if is_valid:
-                    return (qualified_user_id, None)
+                    return qualified_user_id, None
 
             if not hasattr(provider, "get_supported_login_types") or not hasattr(
                 provider, "check_auth"
@@ -766,7 +766,7 @@ class AuthHandler(BaseHandler):
             )
 
             if canonical_user_id:
-                return (canonical_user_id, None)
+                return canonical_user_id, None
 
         if not known_login_type:
             raise SynapseError(400, "Unknown login type %s" % login_type)
@@ -816,7 +816,7 @@ class AuthHandler(BaseHandler):
                         result = (result, None)
                     return result
 
-        return (None, None)
+        return None, None
 
     @defer.inlineCallbacks
     def _check_local_password(self, user_id, password):
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 5c1cf83c9d..71a8f33da3 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -25,6 +25,7 @@ from synapse.api.errors import (
     HttpResponseException,
     RequestSendFailed,
 )
+from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.types import RoomStreamToken, get_domain_from_id
 from synapse.util import stringutils
 from synapse.util.async_helpers import Linearizer
@@ -45,6 +46,7 @@ class DeviceWorkerHandler(BaseHandler):
         self.state = hs.get_state_handler()
         self._auth_handler = hs.get_auth_handler()
 
+    @trace
     @defer.inlineCallbacks
     def get_devices_by_user(self, user_id):
         """
@@ -56,6 +58,7 @@ class DeviceWorkerHandler(BaseHandler):
             defer.Deferred: list[dict[str, X]]: info on each device
         """
 
+        set_tag("user_id", user_id)
         device_map = yield self.store.get_devices_by_user(user_id)
 
         ips = yield self.store.get_last_client_ip_by_device(user_id, device_id=None)
@@ -64,8 +67,10 @@ class DeviceWorkerHandler(BaseHandler):
         for device in devices:
             _update_device_from_client_ips(device, ips)
 
+        log_kv(device_map)
         return devices
 
+    @trace
     @defer.inlineCallbacks
     def get_device(self, user_id, device_id):
         """ Retrieve the given device
@@ -85,9 +90,14 @@ class DeviceWorkerHandler(BaseHandler):
             raise errors.NotFoundError
         ips = yield self.store.get_last_client_ip_by_device(user_id, device_id)
         _update_device_from_client_ips(device, ips)
+
+        set_tag("device", device)
+        set_tag("ips", ips)
+
         return device
 
     @measure_func("device.get_user_ids_changed")
+    @trace
     @defer.inlineCallbacks
     def get_user_ids_changed(self, user_id, from_token):
         """Get list of users that have had the devices updated, or have newly
@@ -97,6 +107,9 @@ class DeviceWorkerHandler(BaseHandler):
             user_id (str)
             from_token (StreamToken)
         """
+
+        set_tag("user_id", user_id)
+        set_tag("from_token", from_token)
         now_room_key = yield self.store.get_room_events_max_id()
 
         room_ids = yield self.store.get_rooms_for_user(user_id)
@@ -148,6 +161,9 @@ class DeviceWorkerHandler(BaseHandler):
             # special-case for an empty prev state: include all members
             # in the changed list
             if not event_ids:
+                log_kv(
+                    {"event": "encountered empty previous state", "room_id": room_id}
+                )
                 for key, event_id in iteritems(current_state_ids):
                     etype, state_key = key
                     if etype != EventTypes.Member:
@@ -200,7 +216,11 @@ class DeviceWorkerHandler(BaseHandler):
             possibly_joined = []
             possibly_left = []
 
-        return {"changed": list(possibly_joined), "left": list(possibly_left)}
+        result = {"changed": list(possibly_joined), "left": list(possibly_left)}
+
+        log_kv(result)
+
+        return result
 
 
 class DeviceHandler(DeviceWorkerHandler):
@@ -267,6 +287,7 @@ class DeviceHandler(DeviceWorkerHandler):
 
         raise errors.StoreError(500, "Couldn't generate a device ID.")
 
+    @trace
     @defer.inlineCallbacks
     def delete_device(self, user_id, device_id):
         """ Delete the given device
@@ -284,6 +305,10 @@ class DeviceHandler(DeviceWorkerHandler):
         except errors.StoreError as e:
             if e.code == 404:
                 # no match
+                set_tag("error", True)
+                log_kv(
+                    {"reason": "User doesn't have device id.", "device_id": device_id}
+                )
                 pass
             else:
                 raise
@@ -296,6 +321,7 @@ class DeviceHandler(DeviceWorkerHandler):
 
         yield self.notify_device_update(user_id, [device_id])
 
+    @trace
     @defer.inlineCallbacks
     def delete_all_devices_for_user(self, user_id, except_device_id=None):
         """Delete all of the user's devices
@@ -331,6 +357,8 @@ class DeviceHandler(DeviceWorkerHandler):
         except errors.StoreError as e:
             if e.code == 404:
                 # no match
+                set_tag("error", True)
+                set_tag("reason", "User doesn't have that device id.")
                 pass
             else:
                 raise
@@ -371,6 +399,7 @@ class DeviceHandler(DeviceWorkerHandler):
             else:
                 raise
 
+    @trace
     @measure_func("notify_device_update")
     @defer.inlineCallbacks
     def notify_device_update(self, user_id, device_ids):
@@ -386,6 +415,8 @@ class DeviceHandler(DeviceWorkerHandler):
             hosts.update(get_domain_from_id(u) for u in users_who_share_room)
             hosts.discard(self.server_name)
 
+        set_tag("target_hosts", hosts)
+
         position = yield self.store.add_device_change_to_streams(
             user_id, device_ids, list(hosts)
         )
@@ -405,6 +436,7 @@ class DeviceHandler(DeviceWorkerHandler):
             )
             for host in hosts:
                 self.federation_sender.send_device_messages(host)
+                log_kv({"message": "sent device update to host", "host": host})
 
     @defer.inlineCallbacks
     def on_federation_query_user_devices(self, user_id):
@@ -451,12 +483,15 @@ class DeviceListUpdater(object):
             iterable=True,
         )
 
+    @trace
     @defer.inlineCallbacks
     def incoming_device_list_update(self, origin, edu_content):
         """Called on incoming device list update from federation. Responsible
         for parsing the EDU and adding to pending updates list.
         """
 
+        set_tag("origin", origin)
+        set_tag("edu_content", edu_content)
         user_id = edu_content.pop("user_id")
         device_id = edu_content.pop("device_id")
         stream_id = str(edu_content.pop("stream_id"))  # They may come as ints
@@ -471,12 +506,30 @@ class DeviceListUpdater(object):
                 device_id,
                 origin,
             )
+
+            set_tag("error", True)
+            log_kv(
+                {
+                    "message": "Got a device list update edu from a user and "
+                    "device which does not match the origin of the request.",
+                    "user_id": user_id,
+                    "device_id": device_id,
+                }
+            )
             return
 
         room_ids = yield self.store.get_rooms_for_user(user_id)
         if not room_ids:
             # We don't share any rooms with this user. Ignore update, as we
             # probably won't get any further updates.
+            set_tag("error", True)
+            log_kv(
+                {
+                    "message": "Got an update from a user for which "
+                    "we don't share any rooms",
+                    "other user_id": user_id,
+                }
+            )
             logger.warning(
                 "Got device list update edu for %r/%r, but don't share a room",
                 user_id,
@@ -578,6 +631,7 @@ class DeviceListUpdater(object):
             request:
             https://matrix.org/docs/spec/server_server/r0.1.2#get-matrix-federation-v1-user-devices-userid
         """
+        log_kv({"message": "Doing resync to update device list."})
         # Fetch all devices for the user.
         origin = get_domain_from_id(user_id)
         try:
@@ -594,13 +648,20 @@ class DeviceListUpdater(object):
             # eventually become consistent.
             return
         except FederationDeniedError as e:
+            set_tag("error", True)
+            log_kv({"reason": "FederationDeniedError"})
             logger.info(e)
             return
-        except Exception:
+        except Exception as e:
             # TODO: Remember that we are now out of sync and try again
             # later
+            set_tag("error", True)
+            log_kv(
+                {"message": "Exception raised by federation request", "exception": e}
+            )
             logger.exception("Failed to handle device list update for %s", user_id)
             return
+        log_kv({"result": result})
         stream_id = result["stream_id"]
         devices = result["devices"]
 
diff --git a/synapse/handlers/devicemessage.py b/synapse/handlers/devicemessage.py
index c7d56779b8..0043cbea17 100644
--- a/synapse/handlers/devicemessage.py
+++ b/synapse/handlers/devicemessage.py
@@ -22,9 +22,9 @@ from twisted.internet import defer
 from synapse.api.errors import SynapseError
 from synapse.logging.opentracing import (
     get_active_span_text_map,
+    log_kv,
     set_tag,
     start_active_span,
-    whitelisted_homeserver,
 )
 from synapse.types import UserID, get_domain_from_id
 from synapse.util.stringutils import random_string
@@ -86,7 +86,8 @@ class DeviceMessageHandler(object):
 
     @defer.inlineCallbacks
     def send_device_message(self, sender_user_id, message_type, messages):
-
+        set_tag("number_of_messages", len(messages))
+        set_tag("sender", sender_user_id)
         local_messages = {}
         remote_messages = {}
         for user_id, by_device in messages.items():
@@ -119,11 +120,10 @@ class DeviceMessageHandler(object):
                     "sender": sender_user_id,
                     "type": message_type,
                     "message_id": message_id,
-                    "org.matrix.opentracing_context": json.dumps(context)
-                    if whitelisted_homeserver(destination)
-                    else None,
+                    "org.matrix.opentracing_context": json.dumps(context),
                 }
 
+        log_kv({"local_messages": local_messages})
         stream_id = yield self.store.add_messages_to_device_inbox(
             local_messages, remote_edu_contents
         )
@@ -132,6 +132,7 @@ class DeviceMessageHandler(object):
             "to_device_key", stream_id, users=local_messages.keys()
         )
 
+        log_kv({"remote_messages": remote_messages})
         for destination in remote_messages.keys():
             # Enqueue a new federation transaction to send the new
             # device messages to each remote destination.
diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index 2f1f10a9af..5e748687e3 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -167,7 +167,6 @@ class EventHandler(BaseHandler):
 
         if not event:
             return None
-            return
 
         users = yield self.store.get_users_in_room(event.room_id)
         is_peeking = user.to_string() not in users
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 94306c94a9..538b16efd6 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -1428,7 +1428,7 @@ class FederationHandler(BaseHandler):
         assert event.user_id == user_id
         assert event.state_key == user_id
         assert event.room_id == room_id
-        return (origin, event, format_ver)
+        return origin, event, format_ver
 
     @defer.inlineCallbacks
     @log_function
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index 97daca5fee..583b612dd9 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -61,21 +61,76 @@ class IdentityHandler(BaseHandler):
                 return False
         return True
 
+    def _extract_items_from_creds_dict(self, creds):
+        """
+        Retrieve entries from a "credentials" dictionary
+
+        Args:
+            creds (dict[str, str]): Dictionary of credentials that contain the following keys:
+                * client_secret|clientSecret: A unique secret str provided by the client
+                * id_server|idServer: the domain of the identity server to query
+                * id_access_token: The access token to authenticate to the identity
+                    server with.
+
+        Returns:
+            tuple(str, str, str|None): A tuple containing the client_secret, the id_server,
+                and the id_access_token value if available.
+        """
+        client_secret = creds.get("client_secret") or creds.get("clientSecret")
+        if not client_secret:
+            raise SynapseError(
+                400, "No client_secret in creds", errcode=Codes.MISSING_PARAM
+            )
+
+        id_server = creds.get("id_server") or creds.get("idServer")
+        if not id_server:
+            raise SynapseError(
+                400, "No id_server in creds", errcode=Codes.MISSING_PARAM
+            )
+
+        id_access_token = creds.get("id_access_token")
+        return client_secret, id_server, id_access_token
+
     @defer.inlineCallbacks
-    def threepid_from_creds(self, creds):
-        if "id_server" in creds:
-            id_server = creds["id_server"]
-        elif "idServer" in creds:
-            id_server = creds["idServer"]
-        else:
-            raise SynapseError(400, "No id_server in creds")
+    def threepid_from_creds(self, creds, use_v2=True):
+        """
+        Retrieve and validate a threepid identitier from a "credentials" dictionary
+
+        Args:
+            creds (dict[str, str]): Dictionary of credentials that contain the following keys:
+                * client_secret|clientSecret: A unique secret str provided by the client
+                * id_server|idServer: the domain of the identity server to query
+                * id_access_token: The access token to authenticate to the identity
+                    server with. Required if use_v2 is true
+            use_v2 (bool): Whether to use v2 Identity Service API endpoints
 
-        if "client_secret" in creds:
-            client_secret = creds["client_secret"]
-        elif "clientSecret" in creds:
-            client_secret = creds["clientSecret"]
+        Returns:
+            Deferred[dict[str,str|int]|None]: A dictionary consisting of response params to
+                the /getValidated3pid endpoint of the Identity Service API, or None if the
+                threepid was not found
+        """
+        client_secret, id_server, id_access_token = self._extract_items_from_creds_dict(
+            creds
+        )
+
+        # If an id_access_token is not supplied, force usage of v1
+        if id_access_token is None:
+            use_v2 = False
+
+        query_params = {"sid": creds["sid"], "client_secret": client_secret}
+
+        # Decide which API endpoint URLs and query parameters to use
+        if use_v2:
+            url = "https://%s%s" % (
+                id_server,
+                "/_matrix/identity/v2/3pid/getValidated3pid",
+            )
+            query_params["id_access_token"] = id_access_token
         else:
-            raise SynapseError(400, "No client_secret in creds")
+            url = "https://%s%s" % (
+                id_server,
+                "/_matrix/identity/api/v1/3pid/getValidated3pid",
+            )
 
         if not self._should_trust_id_server(id_server):
             logger.warn(
@@ -85,43 +140,55 @@ class IdentityHandler(BaseHandler):
             return None
 
         try:
-            data = yield self.http_client.get_json(
-                "https://%s%s"
-                % (id_server, "/_matrix/identity/api/v1/3pid/getValidated3pid"),
-                {"sid": creds["sid"], "client_secret": client_secret},
-            )
+            data = yield self.http_client.get_json(url, query_params)
+            return data if "medium" in data else None
         except HttpResponseException as e:
-            logger.info("getValidated3pid failed with Matrix error: %r", e)
-            raise e.to_synapse_error()
+            if e.code != 404 or not use_v2:
+                # Generic failure
+                logger.info("getValidated3pid failed with Matrix error: %r", e)
+                raise e.to_synapse_error()
 
-        if "medium" in data:
-            return data
-        return None
+        # This identity server is too old to understand Identity Service API v2
+        # Attempt v1 endpoint
+        logger.info("Got 404 when POSTing JSON %s, falling back to v1 URL", url)
+        return (yield self.threepid_from_creds(creds, use_v2=False))
 
     @defer.inlineCallbacks
-    def bind_threepid(self, creds, mxid):
+    def bind_threepid(self, creds, mxid, use_v2=True):
+        """Bind a 3PID to an identity server
+
+        Args:
+            creds (dict[str, str]): Dictionary of credentials that contain the following keys:
+                * client_secret|clientSecret: A unique secret str provided by the client
+                * id_server|idServer: the domain of the identity server to query
+                * id_access_token: The access token to authenticate to the identity
+                    server with. Required if use_v2 is true
+            mxid (str): The MXID to bind the 3PID to
+            use_v2 (bool): Whether to use v2 Identity Service API endpoints
+
+        Returns:
+            Deferred[dict]: The response from the identity server
+        """
         logger.debug("binding threepid %r to %s", creds, mxid)
-        data = None
 
-        if "id_server" in creds:
-            id_server = creds["id_server"]
-        elif "idServer" in creds:
-            id_server = creds["idServer"]
-        else:
-            raise SynapseError(400, "No id_server in creds")
+        client_secret, id_server, id_access_token = self._extract_items_from_creds_dict(
+            creds
+        )
+
+        # If an id_access_token is not supplied, force usage of v1
+        if id_access_token is None:
+            use_v2 = False
 
-        if "client_secret" in creds:
-            client_secret = creds["client_secret"]
-        elif "clientSecret" in creds:
-            client_secret = creds["clientSecret"]
+        # Decide which API endpoint URLs to use
+        bind_data = {"sid": creds["sid"], "client_secret": client_secret, "mxid": mxid}
+        if use_v2:
+            bind_url = "https://%s/_matrix/identity/v2/3pid/bind" % (id_server,)
+            bind_data["id_access_token"] = id_access_token
         else:
-            raise SynapseError(400, "No client_secret in creds")
+            bind_url = "https://%s/_matrix/identity/api/v1/3pid/bind" % (id_server,)
 
         try:
-            data = yield self.http_client.post_json_get_json(
-                "https://%s%s" % (id_server, "/_matrix/identity/api/v1/3pid/bind"),
-                {"sid": creds["sid"], "client_secret": client_secret, "mxid": mxid},
-            )
+            data = yield self.http_client.post_json_get_json(bind_url, bind_data)
             logger.debug("bound threepid %r to %s", creds, mxid)
 
             # Remember where we bound the threepid
@@ -131,13 +198,23 @@ class IdentityHandler(BaseHandler):
                 address=data["address"],
                 id_server=id_server,
             )
+
+            return data
+        except HttpResponseException as e:
+            if e.code != 404 or not use_v2:
+                logger.error("3PID bind failed with Matrix error: %r", e)
+                raise e.to_synapse_error()
         except CodeMessageException as e:
             data = json.loads(e.msg)  # XXX WAT?
-        return data
+            return data
+
+        logger.info("Got 404 when POSTing JSON %s, falling back to v1 URL", bind_url)
+        return (yield self.bind_threepid(creds, mxid, use_v2=False))
 
     @defer.inlineCallbacks
     def try_unbind_threepid(self, mxid, threepid):
-        """Removes a binding from an identity server
+        """Attempt to remove a 3PID from an identity server, or if one is not provided, all
+        identity servers we're aware the binding is present on
 
         Args:
             mxid (str): Matrix user ID of binding to be removed
@@ -188,6 +265,8 @@ class IdentityHandler(BaseHandler):
             server doesn't support unbinding
         """
         url = "https://%s/_matrix/identity/api/v1/3pid/unbind" % (id_server,)
+        url_bytes = "/_matrix/identity/api/v1/3pid/unbind".encode("ascii")
+
         content = {
             "mxid": mxid,
             "threepid": {"medium": threepid["medium"], "address": threepid["address"]},
@@ -199,7 +278,7 @@ class IdentityHandler(BaseHandler):
         auth_headers = self.federation_http_client.build_auth_headers(
             destination=None,
             method="POST",
-            url_bytes="/_matrix/identity/api/v1/3pid/unbind".encode("ascii"),
+            url_bytes=url_bytes,
             content=content,
             destination_is=id_server,
         )
@@ -282,16 +361,3 @@ class IdentityHandler(BaseHandler):
         except HttpResponseException as e:
             logger.info("Proxied requestToken failed: %r", e)
             raise e.to_synapse_error()
-
-
-class LookupAlgorithm:
-    """
-    Supported hashing algorithms when performing a 3PID lookup.
-
-    SHA256 - Hashing an (address, medium, pepper) combo with sha256, then url-safe base64
-        encoding
-    NONE - Not performing any hashing. Simply sending an (address, medium) combo in plaintext
-    """
-
-    SHA256 = "sha256"
-    NONE = "none"
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 42d6650ed9..f991efeee3 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -449,8 +449,7 @@ class InitialSyncHandler(BaseHandler):
             #  * The user is a guest user, and has joined the room
             # else it will throw.
             member_event = yield self.auth.check_user_was_in_room(room_id, user_id)
-            return (member_event.membership, member_event.event_id)
-            return
+            return member_event.membership, member_event.event_id
         except AuthError:
             visibility = yield self.state_handler.get_current_state(
                 room_id, EventTypes.RoomHistoryVisibility, ""
@@ -459,8 +458,7 @@ class InitialSyncHandler(BaseHandler):
                 visibility
                 and visibility.content["history_visibility"] == "world_readable"
             ):
-                return (Membership.JOIN, None)
-                return
+                return Membership.JOIN, None
             raise AuthError(
                 403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
             )
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 94a9ca0357..053cf66b28 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -255,7 +255,7 @@ class PresenceHandler(object):
         self.unpersisted_users_changes = set()
 
         if unpersisted:
-            logger.info("Persisting %d upersisted presence updates", len(unpersisted))
+            logger.info("Persisting %d unpersisted presence updates", len(unpersisted))
             yield self.store.update_presence(
                 [self.user_to_current_state[user_id] for user_id in unpersisted]
             )
@@ -1032,7 +1032,7 @@ class PresenceEventSource(object):
                 #
                 # Hence this guard where we just return nothing so that the sync
                 # doesn't return. C.f. #5503.
-                return ([], max_token)
+                return [], max_token
 
             presence = self.get_presence_handler()
             stream_change_cache = self.store.presence_stream_cache
@@ -1279,7 +1279,7 @@ def get_interested_parties(store, states):
         # Always notify self
         users_to_states.setdefault(state.user_id, []).append(state)
 
-    return (room_ids_to_states, users_to_states)
+    return room_ids_to_states, users_to_states
 
 
 @defer.inlineCallbacks
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index 73973502a4..6854c751a6 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -148,7 +148,7 @@ class ReceiptEventSource(object):
         to_key = yield self.get_current_key()
 
         if from_key == to_key:
-            return ([], to_key)
+            return [], to_key
 
         events = yield self.store.get_linearized_receipts_for_rooms(
             room_ids, from_key=from_key, to_key=to_key
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 4631fab94e..975da57ffd 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -24,13 +24,11 @@ from synapse.api.errors import (
     AuthError,
     Codes,
     ConsentNotGivenError,
-    InvalidCaptchaError,
     LimitExceededError,
     RegistrationError,
     SynapseError,
 )
 from synapse.config.server import is_threepid_reserved
-from synapse.http.client import CaptchaServerHttpClient
 from synapse.http.servlet import assert_params_in_dict
 from synapse.replication.http.login import RegisterDeviceReplicationServlet
 from synapse.replication.http.register import (
@@ -39,7 +37,6 @@ from synapse.replication.http.register import (
 )
 from synapse.types import RoomAlias, RoomID, UserID, create_requester
 from synapse.util.async_helpers import Linearizer
-from synapse.util.threepids import check_3pid_allowed
 
 from ._base import BaseHandler
 
@@ -59,7 +56,6 @@ class RegistrationHandler(BaseHandler):
         self._auth_handler = hs.get_auth_handler()
         self.profile_handler = hs.get_profile_handler()
         self.user_directory_handler = hs.get_user_directory_handler()
-        self.captcha_client = CaptchaServerHttpClient(hs)
         self.identity_handler = self.hs.get_handlers().identity_handler
         self.ratelimiter = hs.get_registration_ratelimiter()
 
@@ -362,70 +358,6 @@ class RegistrationHandler(BaseHandler):
         )
         return user_id
 
-    @defer.inlineCallbacks
-    def check_recaptcha(self, ip, private_key, challenge, response):
-        """
-        Checks a recaptcha is correct.
-
-        Used only by c/s api v1
-        """
-
-        captcha_response = yield self._validate_captcha(
-            ip, private_key, challenge, response
-        )
-        if not captcha_response["valid"]:
-            logger.info(
-                "Invalid captcha entered from %s. Error: %s",
-                ip,
-                captcha_response["error_url"],
-            )
-            raise InvalidCaptchaError(error_url=captcha_response["error_url"])
-        else:
-            logger.info("Valid captcha entered from %s", ip)
-
-    @defer.inlineCallbacks
-    def register_email(self, threepidCreds):
-        """
-        Registers emails with an identity server.
-
-        Used only by c/s api v1
-        """
-
-        for c in threepidCreds:
-            logger.info(
-                "validating threepidcred sid %s on id server %s",
-                c["sid"],
-                c["idServer"],
-            )
-            try:
-                threepid = yield self.identity_handler.threepid_from_creds(c)
-            except Exception:
-                logger.exception("Couldn't validate 3pid")
-                raise RegistrationError(400, "Couldn't validate 3pid")
-
-            if not threepid:
-                raise RegistrationError(400, "Couldn't validate 3pid")
-            logger.info(
-                "got threepid with medium '%s' and address '%s'",
-                threepid["medium"],
-                threepid["address"],
-            )
-
-            if not check_3pid_allowed(self.hs, threepid["medium"], threepid["address"]):
-                raise RegistrationError(403, "Third party identifier is not allowed")
-
-    @defer.inlineCallbacks
-    def bind_emails(self, user_id, threepidCreds):
-        """Links emails with a user ID and informs an identity server.
-
-        Used only by c/s api v1
-        """
-
-        # Now we have a matrix ID, bind it to the threepids we were given
-        for c in threepidCreds:
-            # XXX: This should be a deferred list, shouldn't it?
-            yield self.identity_handler.bind_threepid(c, user_id)
-
     def check_user_id_not_appservice_exclusive(self, user_id, allowed_appservice=None):
         # don't allow people to register the server notices mxid
         if self._server_notices_mxid is not None:
@@ -464,44 +396,7 @@ class RegistrationHandler(BaseHandler):
         return str(id)
 
     @defer.inlineCallbacks
-    def _validate_captcha(self, ip_addr, private_key, challenge, response):
-        """Validates the captcha provided.
-
-        Used only by c/s api v1
-
-        Returns:
-            dict: Containing 'valid'(bool) and 'error_url'(str) if invalid.
-
-        """
-        response = yield self._submit_captcha(ip_addr, private_key, challenge, response)
-        # parse Google's response. Lovely format..
-        lines = response.split("\n")
-        json = {
-            "valid": lines[0] == "true",
-            "error_url": "http://www.recaptcha.net/recaptcha/api/challenge?"
-            + "error=%s" % lines[1],
-        }
-        return json
-
-    @defer.inlineCallbacks
-    def _submit_captcha(self, ip_addr, private_key, challenge, response):
-        """
-        Used only by c/s api v1
-        """
-        data = yield self.captcha_client.post_urlencoded_get_raw(
-            "http://www.recaptcha.net:80/recaptcha/api/verify",
-            args={
-                "privatekey": private_key,
-                "remoteip": ip_addr,
-                "challenge": challenge,
-                "response": response,
-            },
-        )
-        return data
-
-    @defer.inlineCallbacks
     def _join_user_to_room(self, requester, room_identifier):
-        room_id = None
         room_member_handler = self.hs.get_room_member_handler()
         if RoomID.is_valid(room_identifier):
             room_id = room_identifier
@@ -622,7 +517,7 @@ class RegistrationHandler(BaseHandler):
                 initial_display_name=initial_display_name,
                 is_guest=is_guest,
             )
-            return (r["device_id"], r["access_token"])
+            return r["device_id"], r["access_token"]
 
         valid_until_ms = None
         if self.session_lifetime is not None:
@@ -648,9 +543,7 @@ class RegistrationHandler(BaseHandler):
         return (device_id, access_token)
 
     @defer.inlineCallbacks
-    def post_registration_actions(
-        self, user_id, auth_result, access_token, bind_email, bind_msisdn
-    ):
+    def post_registration_actions(self, user_id, auth_result, access_token):
         """A user has completed registration
 
         Args:
@@ -659,18 +552,10 @@ class RegistrationHandler(BaseHandler):
                 registered user.
             access_token (str|None): The access token of the newly logged in
                 device, or None if `inhibit_login` enabled.
-            bind_email (bool): Whether to bind the email with the identity
-                server.
-            bind_msisdn (bool): Whether to bind the msisdn with the identity
-                server.
         """
         if self.hs.config.worker_app:
             yield self._post_registration_client(
-                user_id=user_id,
-                auth_result=auth_result,
-                access_token=access_token,
-                bind_email=bind_email,
-                bind_msisdn=bind_msisdn,
+                user_id=user_id, auth_result=auth_result, access_token=access_token
             )
             return
 
@@ -683,13 +568,11 @@ class RegistrationHandler(BaseHandler):
             ):
                 yield self.store.upsert_monthly_active_user(user_id)
 
-            yield self._register_email_threepid(
-                user_id, threepid, access_token, bind_email
-            )
+            yield self._register_email_threepid(user_id, threepid, access_token)
 
         if auth_result and LoginType.MSISDN in auth_result:
             threepid = auth_result[LoginType.MSISDN]
-            yield self._register_msisdn_threepid(user_id, threepid, bind_msisdn)
+            yield self._register_msisdn_threepid(user_id, threepid)
 
         if auth_result and LoginType.TERMS in auth_result:
             yield self._on_user_consented(user_id, self.hs.config.user_consent_version)
@@ -708,14 +591,12 @@ class RegistrationHandler(BaseHandler):
         yield self.post_consent_actions(user_id)
 
     @defer.inlineCallbacks
-    def _register_email_threepid(self, user_id, threepid, token, bind_email):
+    def _register_email_threepid(self, user_id, threepid, token):
         """Add an email address as a 3pid identifier
 
         Also adds an email pusher for the email address, if configured in the
         HS config
 
-        Also optionally binds emails to the given user_id on the identity server
-
         Must be called on master.
 
         Args:
@@ -723,8 +604,6 @@ class RegistrationHandler(BaseHandler):
             threepid (object): m.login.email.identity auth response
             token (str|None): access_token for the user, or None if not logged
                 in.
-            bind_email (bool): true if the client requested the email to be
-                bound at the identity server
         Returns:
             defer.Deferred:
         """
@@ -766,29 +645,15 @@ class RegistrationHandler(BaseHandler):
                 data={},
             )
 
-        if bind_email:
-            logger.info("bind_email specified: binding")
-            logger.debug("Binding emails %s to %s" % (threepid, user_id))
-            yield self.identity_handler.bind_threepid(
-                threepid["threepid_creds"], user_id
-            )
-        else:
-            logger.info("bind_email not specified: not binding email")
-
     @defer.inlineCallbacks
-    def _register_msisdn_threepid(self, user_id, threepid, bind_msisdn):
+    def _register_msisdn_threepid(self, user_id, threepid):
         """Add a phone number as a 3pid identifier
 
-        Also optionally binds msisdn to the given user_id on the identity server
-
         Must be called on master.
 
         Args:
             user_id (str): id of user
             threepid (object): m.login.msisdn auth response
-            token (str): access_token for the user
-            bind_email (bool): true if the client requested the email to be
-                bound at the identity server
         Returns:
             defer.Deferred:
         """
@@ -804,12 +669,3 @@ class RegistrationHandler(BaseHandler):
         yield self._auth_handler.add_threepid(
             user_id, threepid["medium"], threepid["address"], threepid["validated_at"]
         )
-
-        if bind_msisdn:
-            logger.info("bind_msisdn specified: binding")
-            logger.debug("Binding msisdn %s to %s", threepid, user_id)
-            yield self.identity_handler.bind_threepid(
-                threepid["threepid_creds"], user_id
-            )
-        else:
-            logger.info("bind_msisdn not specified: not binding msisdn")
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 6e47fe7867..a509e11d69 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -852,7 +852,6 @@ class RoomContextHandler(object):
         )
         if not event:
             return None
-            return
 
         filtered = yield (filter_evts([event]))
         if not filtered:
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 4605cb9c0b..093f2ea36e 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -29,11 +29,9 @@ from twisted.internet import defer
 from synapse import types
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import AuthError, Codes, HttpResponseException, SynapseError
-from synapse.handlers.identity import LookupAlgorithm
 from synapse.types import RoomID, UserID
 from synapse.util.async_helpers import Linearizer
 from synapse.util.distributor import user_joined_room, user_left_room
-from synapse.util.hash import sha256_and_url_safe_base64
 
 from ._base import BaseHandler
 
@@ -525,7 +523,7 @@ class RoomMemberHandler(object):
             event (SynapseEvent): The membership event.
             context: The context of the event.
             is_guest (bool): Whether the sender is a guest.
-            remote_room_hosts (list[str]|None): Homeservers which are likely to already be in
+            room_hosts ([str]): Homeservers which are likely to already be in
                 the room, and could be danced with in order to join this
                 homeserver for the first time.
             ratelimit (bool): Whether to rate limit this request.
@@ -636,7 +634,7 @@ class RoomMemberHandler(object):
             servers.remove(room_alias.domain)
         servers.insert(0, room_alias.domain)
 
-        return RoomID.from_string(room_id), servers
+        return (RoomID.from_string(room_id), servers)
 
     @defer.inlineCallbacks
     def _get_inviter(self, user_id, room_id):
@@ -699,44 +697,6 @@ class RoomMemberHandler(object):
             raise SynapseError(
                 403, "Looking up third-party identifiers is denied from this server"
             )
-
-        # Check what hashing details are supported by this identity server
-        use_v1 = False
-        hash_details = None
-        try:
-            hash_details = yield self.simple_http_client.get_json(
-                "%s%s/_matrix/identity/v2/hash_details" % (id_server_scheme, id_server)
-            )
-        except (HttpResponseException, ValueError) as e:
-            # Catch HttpResponseExcept for a non-200 response code
-            # Catch ValueError for non-JSON response body
-
-            # Check if this identity server does not know about v2 lookups
-            if e.code == 404:
-                # This is an old identity server that does not yet support v2 lookups
-                use_v1 = True
-            else:
-                logger.warn("Error when looking up hashing details: %s" % (e,))
-                return None
-
-        if use_v1:
-            return (yield self._lookup_3pid_v1(id_server, medium, address))
-
-        return (yield self._lookup_3pid_v2(id_server, medium, address, hash_details))
-
-    @defer.inlineCallbacks
-    def _lookup_3pid_v1(self, id_server, medium, address):
-        """Looks up a 3pid in the passed identity server using v1 lookup.
-
-        Args:
-            id_server (str): The server name (including port, if required)
-                of the identity server to use.
-            medium (str): The type of the third party identifier (e.g. "email").
-            address (str): The third party identifier (e.g. "foo@example.com").
-
-        Returns:
-            str: the matrix ID of the 3pid, or None if it is not recognized.
-        """
         try:
             data = yield self.simple_http_client.get_json(
                 "%s%s/_matrix/identity/api/v1/lookup" % (id_server_scheme, id_server),
@@ -751,83 +711,8 @@ class RoomMemberHandler(object):
 
         except IOError as e:
             logger.warn("Error from identity server lookup: %s" % (e,))
-
-        return None
-
-    @defer.inlineCallbacks
-    def _lookup_3pid_v2(self, id_server, medium, address, hash_details):
-        """Looks up a 3pid in the passed identity server using v2 lookup.
-
-        Args:
-            id_server (str): The server name (including port, if required)
-                of the identity server to use.
-            medium (str): The type of the third party identifier (e.g. "email").
-            address (str): The third party identifier (e.g. "foo@example.com").
-            hash_details (dict[str, str|list]): A dictionary containing hashing information
-                provided by an identity server.
-
-        Returns:
-            Deferred[str|None]: the matrix ID of the 3pid, or None if it is not recognised.
-        """
-        # Extract information from hash_details
-        supported_lookup_algorithms = hash_details["algorithms"]
-        lookup_pepper = hash_details["lookup_pepper"]
-
-        # Check if any of the supported lookup algorithms are present
-        if LookupAlgorithm.SHA256 in supported_lookup_algorithms:
-            # Perform a hashed lookup
-            lookup_algorithm = LookupAlgorithm.SHA256
-
-            # Hash address, medium and the pepper with sha256
-            to_hash = "%s %s %s" % (address, medium, lookup_pepper)
-            lookup_value = sha256_and_url_safe_base64(to_hash)
-
-        elif LookupAlgorithm.NONE in supported_lookup_algorithms:
-            # Perform a non-hashed lookup
-            lookup_algorithm = LookupAlgorithm.NONE
-
-            # Combine together plaintext address and medium
-            lookup_value = "%s %s" % (address, medium)
-
-        else:
-            logger.warn(
-                "None of the provided lookup algorithms of %s%s are supported: %s",
-                id_server_scheme,
-                id_server,
-                hash_details["algorithms"],
-            )
-            raise SynapseError(
-                400,
-                "Provided identity server does not support any v2 lookup "
-                "algorithms that this homeserver supports.",
-            )
-
-        try:
-            lookup_results = yield self.simple_http_client.post_json_get_json(
-                "%s%s/_matrix/identity/v2/lookup" % (id_server_scheme, id_server),
-                {
-                    "addresses": [lookup_value],
-                    "algorithm": lookup_algorithm,
-                    "pepper": lookup_pepper,
-                },
-            )
-        except (HttpResponseException, ValueError) as e:
-            # Catch HttpResponseExcept for a non-200 response code
-            # Catch ValueError for non-JSON response body
-            logger.warn("Error when performing a 3pid lookup: %s" % (e,))
             return None
 
-        # Check for a mapping from what we looked up to an MXID
-        if "mappings" not in lookup_results or not isinstance(
-            lookup_results["mappings"], dict
-        ):
-            logger.debug("No results from 3pid lookup")
-            return None
-
-        # Return the MXID if it's available, or None otherwise
-        mxid = lookup_results["mappings"].get(lookup_value)
-        return mxid
-
     @defer.inlineCallbacks
     def _verify_any_signature(self, data, server_hostname):
         if server_hostname not in data["signatures"]:
@@ -1018,7 +903,7 @@ class RoomMemberHandler(object):
         if not public_keys:
             public_keys.append(fallback_public_key)
         display_name = data["display_name"]
-        return (token, public_keys, fallback_public_key, display_name)
+        return token, public_keys, fallback_public_key, display_name
 
     @defer.inlineCallbacks
     def _is_host_in_room(self, current_state_ids):
diff --git a/synapse/handlers/stats.py b/synapse/handlers/stats.py
index 4449da6669..921735edb3 100644
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@@ -14,15 +14,14 @@
 # limitations under the License.
 
 import logging
+from collections import Counter
 
 from twisted.internet import defer
 
-from synapse.api.constants import EventTypes, JoinRules, Membership
+from synapse.api.constants import EventTypes, Membership
 from synapse.handlers.state_deltas import StateDeltasHandler
 from synapse.metrics import event_processing_positions
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.types import UserID
-from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
@@ -62,11 +61,10 @@ class StatsHandler(StateDeltasHandler):
     def notify_new_event(self):
         """Called when there may be more deltas to process
         """
-        if not self.hs.config.stats_enabled:
+        if not self.hs.config.stats_enabled or self._is_processing:
             return
 
-        if self._is_processing:
-            return
+        self._is_processing = True
 
         @defer.inlineCallbacks
         def process():
@@ -75,39 +73,72 @@ class StatsHandler(StateDeltasHandler):
             finally:
                 self._is_processing = False
 
-        self._is_processing = True
         run_as_background_process("stats.notify_new_event", process)
 
     @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:
-            self.pos = yield self.store.get_stats_stream_pos()
-
-        # If still None then the initial background update hasn't happened yet
-        if self.pos is None:
-            return None
+            self.pos = yield self.store.get_stats_positions()
 
         # Loop round handling deltas until we're up to date
+
         while True:
-            with Measure(self.clock, "stats_delta"):
-                deltas = yield self.store.get_current_state_deltas(self.pos)
-                if not deltas:
-                    return
+            deltas = yield self.store.get_current_state_deltas(self.pos)
+
+            if deltas:
+                logger.debug("Handling %d state deltas", len(deltas))
+                room_deltas, user_deltas = yield self._handle_deltas(deltas)
+
+                max_pos = deltas[-1]["stream_id"]
+            else:
+                room_deltas = {}
+                user_deltas = {}
+                max_pos = yield self.store.get_room_max_stream_ordering()
 
-                logger.info("Handling %d state deltas", len(deltas))
-                yield self._handle_deltas(deltas)
+            # Then count deltas for total_events and total_event_bytes.
+            room_count, user_count = yield self.store.get_changes_room_total_events_and_bytes(
+                self.pos, max_pos
+            )
+
+            for room_id, fields in room_count.items():
+                room_deltas.setdefault(room_id, {}).update(fields)
+
+            for user_id, fields in user_count.items():
+                user_deltas.setdefault(user_id, {}).update(fields)
+
+            logger.debug("room_deltas: %s", room_deltas)
+            logger.debug("user_deltas: %s", user_deltas)
 
-                self.pos = deltas[-1]["stream_id"]
-                yield self.store.update_stats_stream_pos(self.pos)
+            # Always call this so that we update the stats position.
+            yield self.store.bulk_update_stats_delta(
+                self.clock.time_msec(),
+                updates={"room": room_deltas, "user": user_deltas},
+                stream_id=max_pos,
+            )
+
+            event_processing_positions.labels("stats").set(max_pos)
 
-                event_processing_positions.labels("stats").set(self.pos)
+            if self.pos == max_pos:
+                break
+
+            self.pos = max_pos
 
     @defer.inlineCallbacks
     def _handle_deltas(self, deltas):
+        """Called with the state deltas to process
+
+        Returns:
+            Deferred[tuple[dict[str, Counter], dict[str, counter]]]
+            Resovles to two dicts, the room deltas and the user deltas,
+            mapping from room/user ID to changes in the various fields.
         """
-        Called with the state deltas to process
-        """
+
+        room_to_stats_deltas = {}
+        user_to_stats_deltas = {}
+
+        room_to_state_updates = {}
+
         for delta in deltas:
             typ = delta["type"]
             state_key = delta["state_key"]
@@ -115,11 +146,10 @@ class StatsHandler(StateDeltasHandler):
             event_id = delta["event_id"]
             stream_id = delta["stream_id"]
             prev_event_id = delta["prev_event_id"]
-            stream_pos = delta["stream_id"]
 
-            logger.debug("Handling: %r %r, %s", typ, state_key, event_id)
+            logger.debug("Handling: %r, %r %r, %s", room_id, typ, state_key, event_id)
 
-            token = yield self.store.get_earliest_token_for_room_stats(room_id)
+            token = yield self.store.get_earliest_token_for_stats("room", room_id)
 
             # If the earliest token to begin from is larger than our current
             # stream ID, skip processing this delta.
@@ -131,203 +161,130 @@ class StatsHandler(StateDeltasHandler):
                 continue
 
             if event_id is None and prev_event_id is None:
-                # Errr...
+                logger.error(
+                    "event ID is None and so is the previous event ID. stream_id: %s",
+                    stream_id,
+                )
                 continue
 
             event_content = {}
 
+            sender = None
             if event_id is not None:
                 event = yield self.store.get_event(event_id, allow_none=True)
                 if event:
                     event_content = event.content or {}
+                    sender = event.sender
+
+            # All the values in this dict are deltas (RELATIVE changes)
+            room_stats_delta = room_to_stats_deltas.setdefault(room_id, Counter())
 
-            # We use stream_pos here rather than fetch by event_id as event_id
-            # may be None
-            now = yield self.store.get_received_ts_by_stream_pos(stream_pos)
+            room_state = room_to_state_updates.setdefault(room_id, {})
 
-            # quantise time to the nearest bucket
-            now = (now // 1000 // self.stats_bucket_size) * self.stats_bucket_size
+            if prev_event_id is None:
+                # this state event doesn't overwrite another,
+                # so it is a new effective/current state event
+                room_stats_delta["current_state_events"] += 1
 
             if typ == EventTypes.Member:
                 # we could use _get_key_change here but it's a bit inefficient
                 # given we're not testing for a specific result; might as well
                 # just grab the prev_membership and membership strings and
                 # compare them.
-                prev_event_content = {}
+                # We take None rather than leave as a previous membership
+                # in the absence of a previous event because we do not want to
+                # reduce the leave count when a new-to-the-room user joins.
+                prev_membership = None
                 if prev_event_id is not None:
                     prev_event = yield self.store.get_event(
                         prev_event_id, allow_none=True
                     )
                     if prev_event:
                         prev_event_content = prev_event.content
+                        prev_membership = prev_event_content.get(
+                            "membership", Membership.LEAVE
+                        )
 
                 membership = event_content.get("membership", Membership.LEAVE)
-                prev_membership = prev_event_content.get("membership", Membership.LEAVE)
-
-                if prev_membership == membership:
-                    continue
 
-                if prev_membership == Membership.JOIN:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "joined_members", -1
-                    )
+                if prev_membership is None:
+                    logger.debug("No previous membership for this user.")
+                elif membership == prev_membership:
+                    pass  # noop
+                elif prev_membership == Membership.JOIN:
+                    room_stats_delta["joined_members"] -= 1
                 elif prev_membership == Membership.INVITE:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "invited_members", -1
-                    )
+                    room_stats_delta["invited_members"] -= 1
                 elif prev_membership == Membership.LEAVE:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "left_members", -1
-                    )
+                    room_stats_delta["left_members"] -= 1
                 elif prev_membership == Membership.BAN:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "banned_members", -1
-                    )
+                    room_stats_delta["banned_members"] -= 1
                 else:
-                    err = "%s is not a valid prev_membership" % (repr(prev_membership),)
-                    logger.error(err)
-                    raise ValueError(err)
+                    raise ValueError(
+                        "%r is not a valid prev_membership" % (prev_membership,)
+                    )
 
+                if membership == prev_membership:
+                    pass  # noop
                 if membership == Membership.JOIN:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "joined_members", +1
-                    )
+                    room_stats_delta["joined_members"] += 1
                 elif membership == Membership.INVITE:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "invited_members", +1
-                    )
+                    room_stats_delta["invited_members"] += 1
+
+                    if sender and self.is_mine_id(sender):
+                        user_to_stats_deltas.setdefault(sender, Counter())[
+                            "invites_sent"
+                        ] += 1
+
                 elif membership == Membership.LEAVE:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "left_members", +1
-                    )
+                    room_stats_delta["left_members"] += 1
                 elif membership == Membership.BAN:
-                    yield self.store.update_stats_delta(
-                        now, "room", room_id, "banned_members", +1
-                    )
+                    room_stats_delta["banned_members"] += 1
                 else:
-                    err = "%s is not a valid membership" % (repr(membership),)
-                    logger.error(err)
-                    raise ValueError(err)
+                    raise ValueError("%r is not a valid membership" % (membership,))
 
                 user_id = state_key
                 if self.is_mine_id(user_id):
-                    # update user_stats as it's one of our users
-                    public = yield self._is_public_room(room_id)
-
-                    if membership == Membership.LEAVE:
-                        yield self.store.update_stats_delta(
-                            now,
-                            "user",
-                            user_id,
-                            "public_rooms" if public else "private_rooms",
-                            -1,
-                        )
-                    elif membership == Membership.JOIN:
-                        yield self.store.update_stats_delta(
-                            now,
-                            "user",
-                            user_id,
-                            "public_rooms" if public else "private_rooms",
-                            +1,
-                        )
+                    # this accounts for transitions like leave → ban and so on.
+                    has_changed_joinedness = (prev_membership == Membership.JOIN) != (
+                        membership == Membership.JOIN
+                    )
 
-            elif typ == EventTypes.Create:
-                # Newly created room. Add it with all blank portions.
-                yield self.store.update_room_state(
-                    room_id,
-                    {
-                        "join_rules": None,
-                        "history_visibility": None,
-                        "encryption": None,
-                        "name": None,
-                        "topic": None,
-                        "avatar": None,
-                        "canonical_alias": None,
-                    },
-                )
+                    if has_changed_joinedness:
+                        delta = +1 if membership == Membership.JOIN else -1
 
-            elif typ == EventTypes.JoinRules:
-                yield self.store.update_room_state(
-                    room_id, {"join_rules": event_content.get("join_rule")}
-                )
+                        user_to_stats_deltas.setdefault(user_id, Counter())[
+                            "joined_rooms"
+                        ] += delta
 
-                is_public = yield self._get_key_change(
-                    prev_event_id, event_id, "join_rule", JoinRules.PUBLIC
-                )
-                if is_public is not None:
-                    yield self.update_public_room_stats(now, room_id, is_public)
+                        room_stats_delta["local_users_in_room"] += delta
 
+            elif typ == EventTypes.Create:
+                room_state["is_federatable"] = event_content.get("m.federate", True)
+                if sender and self.is_mine_id(sender):
+                    user_to_stats_deltas.setdefault(sender, Counter())[
+                        "rooms_created"
+                    ] += 1
+            elif typ == EventTypes.JoinRules:
+                room_state["join_rules"] = event_content.get("join_rule")
             elif typ == EventTypes.RoomHistoryVisibility:
-                yield self.store.update_room_state(
-                    room_id,
-                    {"history_visibility": event_content.get("history_visibility")},
-                )
-
-                is_public = yield self._get_key_change(
-                    prev_event_id, event_id, "history_visibility", "world_readable"
+                room_state["history_visibility"] = event_content.get(
+                    "history_visibility"
                 )
-                if is_public is not None:
-                    yield self.update_public_room_stats(now, room_id, is_public)
-
             elif typ == EventTypes.Encryption:
-                yield self.store.update_room_state(
-                    room_id, {"encryption": event_content.get("algorithm")}
-                )
+                room_state["encryption"] = event_content.get("algorithm")
             elif typ == EventTypes.Name:
-                yield self.store.update_room_state(
-                    room_id, {"name": event_content.get("name")}
-                )
+                room_state["name"] = event_content.get("name")
             elif typ == EventTypes.Topic:
-                yield self.store.update_room_state(
-                    room_id, {"topic": event_content.get("topic")}
-                )
+                room_state["topic"] = event_content.get("topic")
             elif typ == EventTypes.RoomAvatar:
-                yield self.store.update_room_state(
-                    room_id, {"avatar": event_content.get("url")}
-                )
+                room_state["avatar"] = event_content.get("url")
             elif typ == EventTypes.CanonicalAlias:
-                yield self.store.update_room_state(
-                    room_id, {"canonical_alias": event_content.get("alias")}
-                )
+                room_state["canonical_alias"] = event_content.get("alias")
+            elif typ == EventTypes.GuestAccess:
+                room_state["guest_access"] = event_content.get("guest_access")
 
-    @defer.inlineCallbacks
-    def update_public_room_stats(self, ts, room_id, is_public):
-        """
-        Increment/decrement a user's number of public rooms when a room they are
-        in changes to/from public visibility.
+        for room_id, state in room_to_state_updates.items():
+            yield self.store.update_room_state(room_id, state)
 
-        Args:
-            ts (int): Timestamp in seconds
-            room_id (str)
-            is_public (bool)
-        """
-        # For now, blindly iterate over all local users in the room so that
-        # we can handle the whole problem of copying buckets over as needed
-        user_ids = yield self.store.get_users_in_room(room_id)
-
-        for user_id in user_ids:
-            if self.hs.is_mine(UserID.from_string(user_id)):
-                yield self.store.update_stats_delta(
-                    ts, "user", user_id, "public_rooms", +1 if is_public else -1
-                )
-                yield self.store.update_stats_delta(
-                    ts, "user", user_id, "private_rooms", -1 if is_public else +1
-                )
-
-    @defer.inlineCallbacks
-    def _is_public_room(self, room_id):
-        join_rules = yield self.state.get_current_state(room_id, EventTypes.JoinRules)
-        history_visibility = yield self.state.get_current_state(
-            room_id, EventTypes.RoomHistoryVisibility
-        )
-
-        if (join_rules and join_rules.content.get("join_rule") == JoinRules.PUBLIC) or (
-            (
-                history_visibility
-                and history_visibility.content.get("history_visibility")
-                == "world_readable"
-            )
-        ):
-            return True
-        else:
-            return False
+        return room_to_stats_deltas, user_to_stats_deltas
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index ef7f2ca980..19bca6717f 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -378,7 +378,7 @@ class SyncHandler(object):
                 event_copy = {k: v for (k, v) in iteritems(event) if k != "room_id"}
                 ephemeral_by_room.setdefault(room_id, []).append(event_copy)
 
-        return (now_token, ephemeral_by_room)
+        return now_token, ephemeral_by_room
 
     @defer.inlineCallbacks
     def _load_filtered_recents(
@@ -578,7 +578,6 @@ class SyncHandler(object):
 
         if not last_events:
             return None
-            return
 
         last_event = last_events[-1]
         state_ids = yield self.store.get_state_ids_for_event(
@@ -1332,7 +1331,7 @@ class SyncHandler(object):
                     )
                     if not tags_by_room:
                         logger.debug("no-oping sync")
-                        return ([], [], [], [])
+                        return [], [], [], []
 
         ignored_account_data = yield self.store.get_global_account_data_by_type_for_user(
             "m.ignored_user_list", user_id=user_id
@@ -1642,7 +1641,7 @@ class SyncHandler(object):
                 )
             room_entries.append(entry)
 
-        return (room_entries, invited, newly_joined_rooms, newly_left_rooms)
+        return room_entries, invited, newly_joined_rooms, newly_left_rooms
 
     @defer.inlineCallbacks
     def _get_all_rooms(self, sync_result_builder, ignored_users):
@@ -1716,7 +1715,7 @@ class SyncHandler(object):
                     )
                 )
 
-        return (room_entries, invited, [])
+        return room_entries, invited, []
 
     @defer.inlineCallbacks
     def _generate_room_entry(
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index f882330293..ca8ae9fb5b 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -319,4 +319,4 @@ class TypingNotificationEventSource(object):
         return self.get_typing_handler()._latest_room_serial
 
     def get_pagination_rows(self, user, pagination_config, key):
-        return ([], pagination_config.from_key)
+        return [], pagination_config.from_key
diff --git a/synapse/http/client.py b/synapse/http/client.py
index 0ac20ebefc..0ae6db8ea7 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -35,7 +35,7 @@ from twisted.internet.interfaces import (
 )
 from twisted.python.failure import Failure
 from twisted.web._newclient import ResponseDone
-from twisted.web.client import Agent, HTTPConnectionPool, PartialDownloadError, readBody
+from twisted.web.client import Agent, HTTPConnectionPool, readBody
 from twisted.web.http import PotentialDataLoss
 from twisted.web.http_headers import Headers
 
@@ -599,38 +599,6 @@ def _readBodyToFile(response, stream, max_size):
     return d
 
 
-class CaptchaServerHttpClient(SimpleHttpClient):
-    """
-    Separate HTTP client for talking to google's captcha servers
-    Only slightly special because accepts partial download responses
-
-    used only by c/s api v1
-    """
-
-    @defer.inlineCallbacks
-    def post_urlencoded_get_raw(self, url, args={}):
-        query_bytes = urllib.parse.urlencode(encode_urlencode_args(args), True)
-
-        response = yield self.request(
-            "POST",
-            url,
-            data=query_bytes,
-            headers=Headers(
-                {
-                    b"Content-Type": [b"application/x-www-form-urlencoded"],
-                    b"User-Agent": [self.user_agent],
-                }
-            ),
-        )
-
-        try:
-            body = yield make_deferred_yieldable(readBody(response))
-            return body
-        except PartialDownloadError as e:
-            # twisted dislikes google's response, no content length.
-            return e.response
-
-
 def encode_urlencode_args(args):
     return {k: encode_urlencode_arg(v) for k, v in args.items()}
 
diff --git a/synapse/http/federation/well_known_resolver.py b/synapse/http/federation/well_known_resolver.py
index 5e9b0befb0..7ddfad286d 100644
--- a/synapse/http/federation/well_known_resolver.py
+++ b/synapse/http/federation/well_known_resolver.py
@@ -207,7 +207,7 @@ class WellKnownResolver(object):
             cache_period + WELL_KNOWN_REMEMBER_DOMAIN_HAD_VALID,
         )
 
-        return (result, cache_period)
+        return result, cache_period
 
     @defer.inlineCallbacks
     def _make_well_known_request(self, server_name, retry):
diff --git a/synapse/http/server.py b/synapse/http/server.py
index e6f351ba3b..cb9158fe1b 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -40,6 +40,7 @@ from synapse.api.errors import (
     UnrecognizedRequestError,
 )
 from synapse.logging.context import preserve_fn
+from synapse.logging.opentracing import trace_servlet
 from synapse.util.caches import intern_dict
 
 logger = logging.getLogger(__name__)
@@ -257,7 +258,9 @@ class JsonResource(HttpServer, resource.Resource):
         self.path_regexs = {}
         self.hs = hs
 
-    def register_paths(self, method, path_patterns, callback, servlet_classname):
+    def register_paths(
+        self, method, path_patterns, callback, servlet_classname, trace=True
+    ):
         """
         Registers a request handler against a regular expression. Later request URLs are
         checked against these regular expressions in order to identify an appropriate
@@ -273,8 +276,16 @@ class JsonResource(HttpServer, resource.Resource):
 
             servlet_classname (str): The name of the handler to be used in prometheus
                 and opentracing logs.
+
+            trace (bool): Whether we should start a span to trace the servlet.
         """
         method = method.encode("utf-8")  # method is bytes on py3
+
+        if trace:
+            # We don't extract the context from the servlet because we can't
+            # trust the sender
+            callback = trace_servlet(servlet_classname)(callback)
+
         for path_pattern in path_patterns:
             logger.debug("Registering for %s %s", method, path_pattern.pattern)
             self.path_regexs.setdefault(method, []).append(
diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index c186b31f59..274c1a6a87 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -20,7 +20,6 @@ import logging
 from canonicaljson import json
 
 from synapse.api.errors import Codes, SynapseError
-from synapse.logging.opentracing import trace_servlet
 
 logger = logging.getLogger(__name__)
 
@@ -298,10 +297,7 @@ class RestServlet(object):
                     servlet_classname = self.__class__.__name__
                     method_handler = getattr(self, "on_%s" % (method,))
                     http_server.register_paths(
-                        method,
-                        patterns,
-                        trace_servlet(servlet_classname)(method_handler),
-                        servlet_classname,
+                        method, patterns, method_handler, servlet_classname
                     )
 
         else:
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index dd296027a1..2c34b54702 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -85,14 +85,14 @@ the function becomes the operation name for the span.
        return something_usual_and_useful
 
 
-Operation names can be explicitly set for functions by using
-``trace_using_operation_name``
+Operation names can be explicitly set for a function by passing the
+operation name to ``trace``
 
 .. code-block:: python
 
-   from synapse.logging.opentracing import trace_using_operation_name
+   from synapse.logging.opentracing import trace
 
-   @trace_using_operation_name("A *much* better operation name")
+   @trace(opname="a_better_operation_name")
    def interesting_badly_named_function(*args, **kwargs):
        # Does all kinds of cool and expected things
        return something_usual_and_useful
@@ -319,7 +319,7 @@ def whitelisted_homeserver(destination):
     Args:
         destination (str)
         """
-    _homeserver_whitelist
+
     if _homeserver_whitelist:
         return _homeserver_whitelist.match(destination)
     return False
@@ -493,6 +493,11 @@ def inject_active_span_twisted_headers(headers, destination, check_destination=T
 
     Args:
         headers (twisted.web.http_headers.Headers)
+        destination (str): address of entity receiving the span context. If check_destination
+            is true the context will only be injected if the destination matches the
+            opentracing whitelist
+        check_destination (bool): If false, destination will be ignored and the context
+            will always be injected.
         span (opentracing.Span)
 
     Returns:
@@ -525,6 +530,11 @@ def inject_active_span_byte_dict(headers, destination, check_destination=True):
 
     Args:
         headers (dict)
+        destination (str): address of entity receiving the span context. If check_destination
+            is true the context will only be injected if the destination matches the
+            opentracing whitelist
+        check_destination (bool): If false, destination will be ignored and the context
+            will always be injected.
         span (opentracing.Span)
 
     Returns:
@@ -537,7 +547,7 @@ def inject_active_span_byte_dict(headers, destination, check_destination=True):
         here:
         https://github.com/jaegertracing/jaeger-client-python/blob/master/jaeger_client/constants.py
     """
-    if not whitelisted_homeserver(destination):
+    if check_destination and not whitelisted_homeserver(destination):
         return
 
     span = opentracing.tracer.active_span
@@ -556,9 +566,11 @@ def inject_active_span_text_map(carrier, destination, check_destination=True):
 
     Args:
         carrier (dict)
-        destination (str): the name of the remote server. The span context
-        will only be injected if the destination matches the homeserver_whitelist
-        or destination is None.
+        destination (str): address of entity receiving the span context. If check_destination
+            is true the context will only be injected if the destination matches the
+            opentracing whitelist
+        check_destination (bool): If false, destination will be ignored and the context
+            will always be injected.
 
     Returns:
         In-place modification of carrier
@@ -641,66 +653,26 @@ def extract_text_map(carrier):
 # Tracing decorators
 
 
-def trace(func):
+def trace(func=None, opname=None):
     """
     Decorator to trace a function.
-    Sets the operation name to that of the function's.
+    Sets the operation name to that of the function's or that given
+    as operation_name. See the module's doc string for usage
+    examples.
     """
-    if opentracing is None:
-        return func
 
-    @wraps(func)
-    def _trace_inner(self, *args, **kwargs):
-        if opentracing is None:
-            return func(self, *args, **kwargs)
-
-        scope = start_active_span(func.__name__)
-        scope.__enter__()
-
-        try:
-            result = func(self, *args, **kwargs)
-            if isinstance(result, defer.Deferred):
-
-                def call_back(result):
-                    scope.__exit__(None, None, None)
-                    return result
-
-                def err_back(result):
-                    scope.span.set_tag(tags.ERROR, True)
-                    scope.__exit__(None, None, None)
-                    return result
-
-                result.addCallbacks(call_back, err_back)
-
-            else:
-                scope.__exit__(None, None, None)
-
-            return result
-
-        except Exception as e:
-            scope.__exit__(type(e), None, e.__traceback__)
-            raise
-
-    return _trace_inner
-
-
-def trace_using_operation_name(operation_name):
-    """Decorator to trace a function. Explicitely sets the operation_name."""
-
-    def trace(func):
-        """
-        Decorator to trace a function.
-        Sets the operation name to that of the function's.
-        """
+    def decorator(func):
         if opentracing is None:
             return func
 
+        _opname = opname if opname else func.__name__
+
         @wraps(func)
         def _trace_inner(self, *args, **kwargs):
             if opentracing is None:
                 return func(self, *args, **kwargs)
 
-            scope = start_active_span(operation_name)
+            scope = start_active_span(_opname)
             scope.__enter__()
 
             try:
@@ -717,6 +689,7 @@ def trace_using_operation_name(operation_name):
                         return result
 
                     result.addCallbacks(call_back, err_back)
+
                 else:
                     scope.__exit__(None, None, None)
 
@@ -728,7 +701,10 @@ def trace_using_operation_name(operation_name):
 
         return _trace_inner
 
-    return trace
+    if func:
+        return decorator(func)
+    else:
+        return decorator
 
 
 def tag_args(func):
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index 41147d4292..735b882363 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -101,7 +101,7 @@ class ModuleApi(object):
         )
         user_id = yield self.register_user(localpart, displayname, emails)
         _, access_token = yield self.register_device(user_id)
-        return (user_id, access_token)
+        return user_id, access_token
 
     def register_user(self, localpart, displayname=None, emails=[]):
         """Registers a new user with given localpart and optional displayname, emails.
diff --git a/synapse/notifier.py b/synapse/notifier.py
index bd80c801b6..4e091314e6 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -472,11 +472,11 @@ class Notifier(object):
         joined_room_ids = yield self.store.get_rooms_for_user(user.to_string())
         if explicit_room_id:
             if explicit_room_id in joined_room_ids:
-                return ([explicit_room_id], True)
+                return [explicit_room_id], True
             if (yield self._is_world_readable(explicit_room_id)):
-                return ([explicit_room_id], False)
+                return [explicit_room_id], False
             raise AuthError(403, "Non-joined access not allowed")
-        return (joined_room_ids, True)
+        return joined_room_ids, True
 
     @defer.inlineCallbacks
     def _is_world_readable(self, room_id):
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index c831975635..22491f3700 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -134,7 +134,7 @@ class BulkPushRuleEvaluator(object):
 
         pl_event = auth_events.get(POWER_KEY)
 
-        return (pl_event.content if pl_event else {}, sender_level)
+        return pl_event.content if pl_event else {}, sender_level
 
     @defer.inlineCallbacks
     def action_for_event_by_user(self, event, context):
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index c4be9273f6..afc9a8ff29 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -22,13 +22,13 @@ from six.moves import urllib
 
 from twisted.internet import defer
 
-import synapse.logging.opentracing as opentracing
 from synapse.api.errors import (
     CodeMessageException,
     HttpResponseException,
     RequestSendFailed,
     SynapseError,
 )
+from synapse.logging.opentracing import inject_active_span_byte_dict, trace_servlet
 from synapse.util.caches.response_cache import ResponseCache
 from synapse.util.stringutils import random_string
 
@@ -167,9 +167,7 @@ class ReplicationEndpoint(object):
                 # the master, and so whether we should clean up or not.
                 while True:
                     headers = {}
-                    opentracing.inject_active_span_byte_dict(
-                        headers, None, check_destination=False
-                    )
+                    inject_active_span_byte_dict(headers, None, check_destination=False)
                     try:
                         result = yield request_func(uri, data, headers=headers)
                         break
@@ -210,13 +208,11 @@ class ReplicationEndpoint(object):
         args = "/".join("(?P<%s>[^/]+)" % (arg,) for arg in url_args)
         pattern = re.compile("^/_synapse/replication/%s/%s$" % (self.NAME, args))
 
+        handler = trace_servlet(self.__class__.__name__, extract_context=True)(handler)
+        # We don't let register paths trace this servlet using the default tracing
+        # options because we wish to extract the context explicitly.
         http_server.register_paths(
-            method,
-            [pattern],
-            opentracing.trace_servlet(self.__class__.__name__, extract_context=True)(
-                handler
-            ),
-            self.__class__.__name__,
+            method, [pattern], handler, self.__class__.__name__, trace=False
         )
 
     def _cached_handler(self, request, txn_id, **kwargs):
diff --git a/synapse/replication/http/federation.py b/synapse/replication/http/federation.py
index fed4f08820..2f16955954 100644
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@@ -113,7 +113,7 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
             event_and_contexts, backfilled
         )
 
-        return (200, {})
+        return 200, {}
 
 
 class ReplicationFederationSendEduRestServlet(ReplicationEndpoint):
@@ -156,7 +156,7 @@ class ReplicationFederationSendEduRestServlet(ReplicationEndpoint):
 
         result = yield self.registry.on_edu(edu_type, origin, edu_content)
 
-        return (200, result)
+        return 200, result
 
 
 class ReplicationGetQueryRestServlet(ReplicationEndpoint):
@@ -204,7 +204,7 @@ class ReplicationGetQueryRestServlet(ReplicationEndpoint):
 
         result = yield self.registry.on_query(query_type, args)
 
-        return (200, result)
+        return 200, result
 
 
 class ReplicationCleanRoomRestServlet(ReplicationEndpoint):
@@ -238,7 +238,7 @@ class ReplicationCleanRoomRestServlet(ReplicationEndpoint):
     def _handle_request(self, request, room_id):
         yield self.store.clean_room_for_join(room_id)
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/replication/http/login.py b/synapse/replication/http/login.py
index f17d3a2da4..786f5232b2 100644
--- a/synapse/replication/http/login.py
+++ b/synapse/replication/http/login.py
@@ -64,7 +64,7 @@ class RegisterDeviceReplicationServlet(ReplicationEndpoint):
             user_id, device_id, initial_display_name, is_guest
         )
 
-        return (200, {"device_id": device_id, "access_token": access_token})
+        return 200, {"device_id": device_id, "access_token": access_token}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index 4217335d88..b9ce3477ad 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -83,7 +83,7 @@ class ReplicationRemoteJoinRestServlet(ReplicationEndpoint):
             remote_room_hosts, room_id, user_id, event_content
         )
 
-        return (200, {})
+        return 200, {}
 
 
 class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
@@ -153,7 +153,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
             yield self.store.locally_reject_invite(user_id, room_id)
             ret = {}
 
-        return (200, ret)
+        return 200, ret
 
 
 class ReplicationUserJoinedLeftRoomRestServlet(ReplicationEndpoint):
@@ -202,7 +202,7 @@ class ReplicationUserJoinedLeftRoomRestServlet(ReplicationEndpoint):
         else:
             raise Exception("Unrecognized change: %r", change)
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/replication/http/register.py b/synapse/replication/http/register.py
index 3341320a87..38260256cf 100644
--- a/synapse/replication/http/register.py
+++ b/synapse/replication/http/register.py
@@ -90,7 +90,7 @@ class ReplicationRegisterServlet(ReplicationEndpoint):
             address=content["address"],
         )
 
-        return (200, {})
+        return 200, {}
 
 
 class ReplicationPostRegisterActionsServlet(ReplicationEndpoint):
@@ -106,7 +106,7 @@ class ReplicationPostRegisterActionsServlet(ReplicationEndpoint):
         self.registration_handler = hs.get_registration_handler()
 
     @staticmethod
-    def _serialize_payload(user_id, auth_result, access_token, bind_email, bind_msisdn):
+    def _serialize_payload(user_id, auth_result, access_token):
         """
         Args:
             user_id (str): The user ID that consented
@@ -114,17 +114,8 @@ class ReplicationPostRegisterActionsServlet(ReplicationEndpoint):
                 registered user.
             access_token (str|None): The access token of the newly logged in
                 device, or None if `inhibit_login` enabled.
-            bind_email (bool): Whether to bind the email with the identity
-                server
-            bind_msisdn (bool): Whether to bind the msisdn with the identity
-                server
         """
-        return {
-            "auth_result": auth_result,
-            "access_token": access_token,
-            "bind_email": bind_email,
-            "bind_msisdn": bind_msisdn,
-        }
+        return {"auth_result": auth_result, "access_token": access_token}
 
     @defer.inlineCallbacks
     def _handle_request(self, request, user_id):
@@ -132,18 +123,12 @@ class ReplicationPostRegisterActionsServlet(ReplicationEndpoint):
 
         auth_result = content["auth_result"]
         access_token = content["access_token"]
-        bind_email = content["bind_email"]
-        bind_msisdn = content["bind_msisdn"]
 
         yield self.registration_handler.post_registration_actions(
-            user_id=user_id,
-            auth_result=auth_result,
-            access_token=access_token,
-            bind_email=bind_email,
-            bind_msisdn=bind_msisdn,
+            user_id=user_id, auth_result=auth_result, access_token=access_token
         )
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/replication/http/send_event.py b/synapse/replication/http/send_event.py
index eff7bd7305..adb9b2f7f4 100644
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@@ -117,7 +117,7 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
             requester, event, context, ratelimit=ratelimit, extra_users=extra_users
         )
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index c10b85d2ff..f03111c259 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -158,7 +158,7 @@ class Stream(object):
         updates, current_token = yield self.get_updates_since(self.last_token)
         self.last_token = current_token
 
-        return (updates, current_token)
+        return updates, current_token
 
     @defer.inlineCallbacks
     def get_updates_since(self, from_token):
@@ -172,14 +172,14 @@ class Stream(object):
                 sent over the replication steam.
         """
         if from_token in ("NOW", "now"):
-            return ([], self.upto_token)
+            return [], self.upto_token
 
         current_token = self.upto_token
 
         from_token = int(from_token)
 
         if from_token == current_token:
-            return ([], current_token)
+            return [], current_token
 
         if self._LIMITED:
             rows = yield self.update_function(
@@ -198,7 +198,7 @@ class Stream(object):
         if self._LIMITED and len(updates) >= MAX_EVENTS_BEHIND:
             raise Exception("stream %s has fallen behind" % (self.NAME))
 
-        return (updates, current_token)
+        return updates, current_token
 
     def current_token(self):
         """Gets the current token of the underlying streams. Should be provided
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index fa91cc8dee..81b6bd8816 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -41,7 +41,7 @@ from synapse.rest.admin._base import (
     assert_user_is_admin,
     historical_admin_path_patterns,
 )
-from synapse.rest.admin.media import register_servlets_for_media_repo
+from synapse.rest.admin.media import ListMediaInRoom, register_servlets_for_media_repo
 from synapse.rest.admin.purge_room_servlet import PurgeRoomServlet
 from synapse.rest.admin.server_notice_servlet import SendServerNoticeServlet
 from synapse.rest.admin.users import UserAdminServlet
@@ -69,7 +69,7 @@ class UsersRestServlet(RestServlet):
 
         ret = yield self.handlers.admin_handler.get_users()
 
-        return (200, ret)
+        return 200, ret
 
 
 class VersionServlet(RestServlet):
@@ -120,7 +120,7 @@ class UserRegisterServlet(RestServlet):
 
         nonce = self.hs.get_secrets().token_hex(64)
         self.nonces[nonce] = int(self.reactor.seconds())
-        return (200, {"nonce": nonce})
+        return 200, {"nonce": nonce}
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -212,7 +212,7 @@ class UserRegisterServlet(RestServlet):
         )
 
         result = yield register._create_registration_details(user_id, body)
-        return (200, result)
+        return 200, result
 
 
 class WhoisRestServlet(RestServlet):
@@ -237,7 +237,7 @@ class WhoisRestServlet(RestServlet):
 
         ret = yield self.handlers.admin_handler.get_whois(target_user)
 
-        return (200, ret)
+        return 200, ret
 
 
 class PurgeHistoryRestServlet(RestServlet):
@@ -322,7 +322,7 @@ class PurgeHistoryRestServlet(RestServlet):
             room_id, token, delete_local_events=delete_local_events
         )
 
-        return (200, {"purge_id": purge_id})
+        return 200, {"purge_id": purge_id}
 
 
 class PurgeHistoryStatusRestServlet(RestServlet):
@@ -347,7 +347,7 @@ class PurgeHistoryStatusRestServlet(RestServlet):
         if purge_status is None:
             raise NotFoundError("purge id '%s' not found" % purge_id)
 
-        return (200, purge_status.asdict())
+        return 200, purge_status.asdict()
 
 
 class DeactivateAccountRestServlet(RestServlet):
@@ -379,7 +379,7 @@ class DeactivateAccountRestServlet(RestServlet):
         else:
             id_server_unbind_result = "no-support"
 
-        return (200, {"id_server_unbind_result": id_server_unbind_result})
+        return 200, {"id_server_unbind_result": id_server_unbind_result}
 
 
 class ShutdownRoomRestServlet(RestServlet):
@@ -549,7 +549,7 @@ class ResetPasswordRestServlet(RestServlet):
         yield self._set_password_handler.set_password(
             target_user_id, new_password, requester
         )
-        return (200, {})
+        return 200, {}
 
 
 class GetUsersPaginatedRestServlet(RestServlet):
@@ -591,7 +591,7 @@ class GetUsersPaginatedRestServlet(RestServlet):
         logger.info("limit: %s, start: %s", limit, start)
 
         ret = yield self.handlers.admin_handler.get_users_paginate(order, start, limit)
-        return (200, ret)
+        return 200, ret
 
     @defer.inlineCallbacks
     def on_POST(self, request, target_user_id):
@@ -619,7 +619,7 @@ class GetUsersPaginatedRestServlet(RestServlet):
         logger.info("limit: %s, start: %s", limit, start)
 
         ret = yield self.handlers.admin_handler.get_users_paginate(order, start, limit)
-        return (200, ret)
+        return 200, ret
 
 
 class SearchUsersRestServlet(RestServlet):
@@ -662,7 +662,7 @@ class SearchUsersRestServlet(RestServlet):
         logger.info("term: %s ", term)
 
         ret = yield self.handlers.admin_handler.search_users(term)
-        return (200, ret)
+        return 200, ret
 
 
 class DeleteGroupAdminRestServlet(RestServlet):
@@ -685,7 +685,7 @@ class DeleteGroupAdminRestServlet(RestServlet):
             raise SynapseError(400, "Can only delete local groups")
 
         yield self.group_server.delete_group(group_id, requester.user.to_string())
-        return (200, {})
+        return 200, {}
 
 
 class AccountValidityRenewServlet(RestServlet):
@@ -716,7 +716,7 @@ class AccountValidityRenewServlet(RestServlet):
         )
 
         res = {"expiration_ts": expiration_ts}
-        return (200, res)
+        return 200, res
 
 
 ########################################################################################
@@ -761,9 +761,12 @@ def register_servlets_for_client_rest_resource(hs, http_server):
     DeleteGroupAdminRestServlet(hs).register(http_server)
     AccountValidityRenewServlet(hs).register(http_server)
 
-    # Load the media repo ones if we're using them.
+    # Load the media repo ones if we're using them. Otherwise load the servlets which
+    # don't need a media repo (typically readonly admin APIs).
     if hs.config.can_load_media_repo:
         register_servlets_for_media_repo(hs, http_server)
+    else:
+        ListMediaInRoom(hs).register(http_server)
 
     # don't add more things here: new servlets should only be exposed on
     # /_synapse/admin so should not go here. Instead register them in AdminRestResource.
diff --git a/synapse/rest/admin/media.py b/synapse/rest/admin/media.py
index 824df919f2..ed7086d09c 100644
--- a/synapse/rest/admin/media.py
+++ b/synapse/rest/admin/media.py
@@ -49,7 +49,7 @@ class QuarantineMediaInRoom(RestServlet):
             room_id, requester.user.to_string()
         )
 
-        return (200, {"num_quarantined": num_quarantined})
+        return 200, {"num_quarantined": num_quarantined}
 
 
 class ListMediaInRoom(RestServlet):
@@ -60,6 +60,7 @@ class ListMediaInRoom(RestServlet):
 
     def __init__(self, hs):
         self.store = hs.get_datastore()
+        self.auth = hs.get_auth()
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
@@ -70,7 +71,7 @@ class ListMediaInRoom(RestServlet):
 
         local_mxcs, remote_mxcs = yield self.store.get_media_mxcs_in_room(room_id)
 
-        return (200, {"local": local_mxcs, "remote": remote_mxcs})
+        return 200, {"local": local_mxcs, "remote": remote_mxcs}
 
 
 class PurgeMediaCacheRestServlet(RestServlet):
@@ -89,7 +90,7 @@ class PurgeMediaCacheRestServlet(RestServlet):
 
         ret = yield self.media_repository.delete_old_remote_media(before_ts)
 
-        return (200, ret)
+        return 200, ret
 
 
 def register_servlets_for_media_repo(hs, http_server):
diff --git a/synapse/rest/admin/purge_room_servlet.py b/synapse/rest/admin/purge_room_servlet.py
index 2922eb543e..f474066542 100644
--- a/synapse/rest/admin/purge_room_servlet.py
+++ b/synapse/rest/admin/purge_room_servlet.py
@@ -54,4 +54,4 @@ class PurgeRoomServlet(RestServlet):
 
         await self.pagination_handler.purge_room(body["room_id"])
 
-        return (200, {})
+        return 200, {}
diff --git a/synapse/rest/admin/server_notice_servlet.py b/synapse/rest/admin/server_notice_servlet.py
index 656526fea5..ae2cbe2e0a 100644
--- a/synapse/rest/admin/server_notice_servlet.py
+++ b/synapse/rest/admin/server_notice_servlet.py
@@ -92,7 +92,7 @@ class SendServerNoticeServlet(RestServlet):
             event_content=body["content"],
         )
 
-        return (200, {"event_id": event.event_id})
+        return 200, {"event_id": event.event_id}
 
     def on_PUT(self, request, txn_id):
         return self.txns.fetch_or_execute_request(
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 5364117420..9720a3bab0 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -71,7 +71,7 @@ class UserAdminServlet(RestServlet):
         is_admin = yield self.handlers.admin_handler.get_user_server_admin(target_user)
         is_admin = bool(is_admin)
 
-        return (200, {"admin": is_admin})
+        return 200, {"admin": is_admin}
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
@@ -97,4 +97,4 @@ class UserAdminServlet(RestServlet):
             target_user, set_admin_to
         )
 
-        return (200, {})
+        return 200, {}
diff --git a/synapse/rest/client/v1/directory.py b/synapse/rest/client/v1/directory.py
index 4284738021..4ea3666874 100644
--- a/synapse/rest/client/v1/directory.py
+++ b/synapse/rest/client/v1/directory.py
@@ -54,7 +54,7 @@ class ClientDirectoryServer(RestServlet):
         dir_handler = self.handlers.directory_handler
         res = yield dir_handler.get_association(room_alias)
 
-        return (200, res)
+        return 200, res
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_alias):
@@ -87,7 +87,7 @@ class ClientDirectoryServer(RestServlet):
             requester, room_alias, room_id, servers
         )
 
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, room_alias):
@@ -102,7 +102,7 @@ class ClientDirectoryServer(RestServlet):
                 service.url,
                 room_alias.to_string(),
             )
-            return (200, {})
+            return 200, {}
         except InvalidClientCredentialsError:
             # fallback to default user behaviour if they aren't an AS
             pass
@@ -118,7 +118,7 @@ class ClientDirectoryServer(RestServlet):
             "User %s deleted alias %s", user.to_string(), room_alias.to_string()
         )
 
-        return (200, {})
+        return 200, {}
 
 
 class ClientDirectoryListServer(RestServlet):
@@ -136,7 +136,7 @@ class ClientDirectoryListServer(RestServlet):
         if room is None:
             raise NotFoundError("Unknown room")
 
-        return (200, {"visibility": "public" if room["is_public"] else "private"})
+        return 200, {"visibility": "public" if room["is_public"] else "private"}
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id):
@@ -149,7 +149,7 @@ class ClientDirectoryListServer(RestServlet):
             requester, room_id, visibility
         )
 
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, room_id):
@@ -159,7 +159,7 @@ class ClientDirectoryListServer(RestServlet):
             requester, room_id, "private"
         )
 
-        return (200, {})
+        return 200, {}
 
 
 class ClientAppserviceDirectoryListServer(RestServlet):
@@ -193,4 +193,4 @@ class ClientAppserviceDirectoryListServer(RestServlet):
             requester.app_service.id, network_id, room_id, visibility
         )
 
-        return (200, {})
+        return 200, {}
diff --git a/synapse/rest/client/v1/events.py b/synapse/rest/client/v1/events.py
index 53ebed2203..6651b4cf07 100644
--- a/synapse/rest/client/v1/events.py
+++ b/synapse/rest/client/v1/events.py
@@ -67,10 +67,10 @@ class EventStreamRestServlet(RestServlet):
             is_guest=is_guest,
         )
 
-        return (200, chunk)
+        return 200, chunk
 
     def on_OPTIONS(self, request):
-        return (200, {})
+        return 200, {}
 
 
 # TODO: Unit test gets, with and without auth, with different kinds of events.
@@ -91,9 +91,9 @@ class EventRestServlet(RestServlet):
         time_now = self.clock.time_msec()
         if event:
             event = yield self._event_serializer.serialize_event(event, time_now)
-            return (200, event)
+            return 200, event
         else:
-            return (404, "Event not found.")
+            return 404, "Event not found."
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/initial_sync.py b/synapse/rest/client/v1/initial_sync.py
index 70b8478e90..2da3cd7511 100644
--- a/synapse/rest/client/v1/initial_sync.py
+++ b/synapse/rest/client/v1/initial_sync.py
@@ -42,7 +42,7 @@ class InitialSyncRestServlet(RestServlet):
             include_archived=include_archived,
         )
 
-        return (200, content)
+        return 200, content
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 5762b9fd06..25a1b67092 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -121,10 +121,10 @@ class LoginRestServlet(RestServlet):
             ({"type": t} for t in self.auth_handler.get_supported_login_types())
         )
 
-        return (200, {"flows": flows})
+        return 200, {"flows": flows}
 
     def on_OPTIONS(self, request):
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -152,7 +152,7 @@ class LoginRestServlet(RestServlet):
         well_known_data = self._well_known_builder.get_well_known()
         if well_known_data:
             result["well_known"] = well_known_data
-        return (200, result)
+        return 200, result
 
     @defer.inlineCallbacks
     def _do_other_login(self, login_submission):
diff --git a/synapse/rest/client/v1/logout.py b/synapse/rest/client/v1/logout.py
index 2769f3a189..4785a34d75 100644
--- a/synapse/rest/client/v1/logout.py
+++ b/synapse/rest/client/v1/logout.py
@@ -33,7 +33,7 @@ class LogoutRestServlet(RestServlet):
         self._device_handler = hs.get_device_handler()
 
     def on_OPTIONS(self, request):
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -49,7 +49,7 @@ class LogoutRestServlet(RestServlet):
                 requester.user.to_string(), requester.device_id
             )
 
-        return (200, {})
+        return 200, {}
 
 
 class LogoutAllRestServlet(RestServlet):
@@ -62,7 +62,7 @@ class LogoutAllRestServlet(RestServlet):
         self._device_handler = hs.get_device_handler()
 
     def on_OPTIONS(self, request):
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -75,7 +75,7 @@ class LogoutAllRestServlet(RestServlet):
         # .. and then delete any access tokens which weren't associated with
         # devices.
         yield self._auth_handler.delete_access_tokens_for_user(user_id)
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/presence.py b/synapse/rest/client/v1/presence.py
index 1eb1068c98..0153525cef 100644
--- a/synapse/rest/client/v1/presence.py
+++ b/synapse/rest/client/v1/presence.py
@@ -56,7 +56,7 @@ class PresenceStatusRestServlet(RestServlet):
         state = yield self.presence_handler.get_state(target_user=user)
         state = format_user_presence_state(state, self.clock.time_msec())
 
-        return (200, state)
+        return 200, state
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
@@ -88,10 +88,10 @@ class PresenceStatusRestServlet(RestServlet):
         if self.hs.config.use_presence:
             yield self.presence_handler.set_state(user, state)
 
-        return (200, {})
+        return 200, {}
 
     def on_OPTIONS(self, request):
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/profile.py b/synapse/rest/client/v1/profile.py
index 2657ae45bb..bbce2e2b71 100644
--- a/synapse/rest/client/v1/profile.py
+++ b/synapse/rest/client/v1/profile.py
@@ -48,7 +48,7 @@ class ProfileDisplaynameRestServlet(RestServlet):
         if displayname is not None:
             ret["displayname"] = displayname
 
-        return (200, ret)
+        return 200, ret
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
@@ -61,14 +61,14 @@ class ProfileDisplaynameRestServlet(RestServlet):
         try:
             new_name = content["displayname"]
         except Exception:
-            return (400, "Unable to parse name")
+            return 400, "Unable to parse name"
 
         yield self.profile_handler.set_displayname(user, requester, new_name, is_admin)
 
-        return (200, {})
+        return 200, {}
 
     def on_OPTIONS(self, request, user_id):
-        return (200, {})
+        return 200, {}
 
 
 class ProfileAvatarURLRestServlet(RestServlet):
@@ -98,7 +98,7 @@ class ProfileAvatarURLRestServlet(RestServlet):
         if avatar_url is not None:
             ret["avatar_url"] = avatar_url
 
-        return (200, ret)
+        return 200, ret
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
@@ -110,14 +110,14 @@ class ProfileAvatarURLRestServlet(RestServlet):
         try:
             new_name = content["avatar_url"]
         except Exception:
-            return (400, "Unable to parse name")
+            return 400, "Unable to parse name"
 
         yield self.profile_handler.set_avatar_url(user, requester, new_name, is_admin)
 
-        return (200, {})
+        return 200, {}
 
     def on_OPTIONS(self, request, user_id):
-        return (200, {})
+        return 200, {}
 
 
 class ProfileRestServlet(RestServlet):
@@ -150,7 +150,7 @@ class ProfileRestServlet(RestServlet):
         if avatar_url is not None:
             ret["avatar_url"] = avatar_url
 
-        return (200, ret)
+        return 200, ret
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v1/push_rule.py b/synapse/rest/client/v1/push_rule.py
index c3ae8b98a8..9f8c3d09e3 100644
--- a/synapse/rest/client/v1/push_rule.py
+++ b/synapse/rest/client/v1/push_rule.py
@@ -69,7 +69,7 @@ class PushRuleRestServlet(RestServlet):
         if "attr" in spec:
             yield self.set_rule_attr(user_id, spec, content)
             self.notify_user(user_id)
-            return (200, {})
+            return 200, {}
 
         if spec["rule_id"].startswith("."):
             # Rule ids starting with '.' are reserved for server default rules.
@@ -106,7 +106,7 @@ class PushRuleRestServlet(RestServlet):
         except RuleNotFoundException as e:
             raise SynapseError(400, str(e))
 
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, path):
@@ -123,7 +123,7 @@ class PushRuleRestServlet(RestServlet):
         try:
             yield self.store.delete_push_rule(user_id, namespaced_rule_id)
             self.notify_user(user_id)
-            return (200, {})
+            return 200, {}
         except StoreError as e:
             if e.code == 404:
                 raise NotFoundError()
@@ -151,10 +151,10 @@ class PushRuleRestServlet(RestServlet):
             )
 
         if path[0] == "":
-            return (200, rules)
+            return 200, rules
         elif path[0] == "global":
             result = _filter_ruleset_with_path(rules["global"], path[1:])
-            return (200, result)
+            return 200, result
         else:
             raise UnrecognizedRequestError()
 
diff --git a/synapse/rest/client/v1/pusher.py b/synapse/rest/client/v1/pusher.py
index ebc3dec516..41660682d9 100644
--- a/synapse/rest/client/v1/pusher.py
+++ b/synapse/rest/client/v1/pusher.py
@@ -62,7 +62,7 @@ class PushersRestServlet(RestServlet):
                 if k not in allowed_keys:
                     del p[k]
 
-        return (200, {"pushers": pushers})
+        return 200, {"pushers": pushers}
 
     def on_OPTIONS(self, _):
         return 200, {}
@@ -94,7 +94,7 @@ class PushersSetRestServlet(RestServlet):
             yield self.pusher_pool.remove_pusher(
                 content["app_id"], content["pushkey"], user_id=user.to_string()
             )
-            return (200, {})
+            return 200, {}
 
         assert_params_in_dict(
             content,
@@ -143,7 +143,7 @@ class PushersSetRestServlet(RestServlet):
 
         self.notifier.on_new_replication_data()
 
-        return (200, {})
+        return 200, {}
 
     def on_OPTIONS(self, _):
         return 200, {}
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 4b2344e696..3582259026 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -91,14 +91,14 @@ class RoomCreateRestServlet(TransactionRestServlet):
             requester, self.get_room_config(request)
         )
 
-        return (200, info)
+        return 200, info
 
     def get_room_config(self, request):
         user_supplied_config = parse_json_object_from_request(request)
         return user_supplied_config
 
     def on_OPTIONS(self, request):
-        return (200, {})
+        return 200, {}
 
 
 # TODO: Needs unit testing for generic events
@@ -173,9 +173,9 @@ class RoomStateEventRestServlet(TransactionRestServlet):
 
         if format == "event":
             event = format_event_for_client_v2(data.get_dict())
-            return (200, event)
+            return 200, event
         elif format == "content":
-            return (200, data.get_dict()["content"])
+            return 200, data.get_dict()["content"]
 
     @defer.inlineCallbacks
     def on_PUT(self, request, room_id, event_type, state_key, txn_id=None):
@@ -210,7 +210,7 @@ class RoomStateEventRestServlet(TransactionRestServlet):
         ret = {}
         if event:
             ret = {"event_id": event.event_id}
-        return (200, ret)
+        return 200, ret
 
 
 # TODO: Needs unit testing for generic events + feedback
@@ -244,10 +244,10 @@ class RoomSendEventRestServlet(TransactionRestServlet):
             requester, event_dict, txn_id=txn_id
         )
 
-        return (200, {"event_id": event.event_id})
+        return 200, {"event_id": event.event_id}
 
     def on_GET(self, request, room_id, event_type, txn_id):
-        return (200, "Not implemented")
+        return 200, "Not implemented"
 
     def on_PUT(self, request, room_id, event_type, txn_id):
         return self.txns.fetch_or_execute_request(
@@ -307,7 +307,7 @@ class JoinRoomAliasServlet(TransactionRestServlet):
             third_party_signed=content.get("third_party_signed", None),
         )
 
-        return (200, {"room_id": room_id})
+        return 200, {"room_id": room_id}
 
     def on_PUT(self, request, room_identifier, txn_id):
         return self.txns.fetch_or_execute_request(
@@ -360,7 +360,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
                 limit=limit, since_token=since_token
             )
 
-        return (200, data)
+        return 200, data
 
     @defer.inlineCallbacks
     def on_POST(self, request):
@@ -405,7 +405,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
                 network_tuple=network_tuple,
             )
 
-        return (200, data)
+        return 200, data
 
 
 # TODO: Needs unit testing
@@ -456,7 +456,7 @@ class RoomMemberListRestServlet(RestServlet):
                 continue
             chunk.append(event)
 
-        return (200, {"chunk": chunk})
+        return 200, {"chunk": chunk}
 
 
 # deprecated in favour of /members?membership=join?
@@ -477,7 +477,7 @@ class JoinedRoomMemberListRestServlet(RestServlet):
             requester, room_id
         )
 
-        return (200, {"joined": users_with_profile})
+        return 200, {"joined": users_with_profile}
 
 
 # TODO: Needs better unit testing
@@ -510,7 +510,7 @@ class RoomMessageListRestServlet(RestServlet):
             event_filter=event_filter,
         )
 
-        return (200, msgs)
+        return 200, msgs
 
 
 # TODO: Needs unit testing
@@ -531,7 +531,7 @@ class RoomStateRestServlet(RestServlet):
             user_id=requester.user.to_string(),
             is_guest=requester.is_guest,
         )
-        return (200, events)
+        return 200, events
 
 
 # TODO: Needs unit testing
@@ -550,7 +550,7 @@ class RoomInitialSyncRestServlet(RestServlet):
         content = yield self.initial_sync_handler.room_initial_sync(
             room_id=room_id, requester=requester, pagin_config=pagination_config
         )
-        return (200, content)
+        return 200, content
 
 
 class RoomEventServlet(RestServlet):
@@ -581,7 +581,7 @@ class RoomEventServlet(RestServlet):
         time_now = self.clock.time_msec()
         if event:
             event = yield self._event_serializer.serialize_event(event, time_now)
-            return (200, event)
+            return 200, event
 
         return SynapseError(404, "Event not found.", errcode=Codes.NOT_FOUND)
 
@@ -633,7 +633,7 @@ class RoomEventContextServlet(RestServlet):
             results["state"], time_now
         )
 
-        return (200, results)
+        return 200, results
 
 
 class RoomForgetRestServlet(TransactionRestServlet):
@@ -652,7 +652,7 @@ class RoomForgetRestServlet(TransactionRestServlet):
 
         yield self.room_member_handler.forget(user=requester.user, room_id=room_id)
 
-        return (200, {})
+        return 200, {}
 
     def on_PUT(self, request, room_id, txn_id):
         return self.txns.fetch_or_execute_request(
@@ -702,8 +702,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
                 requester,
                 txn_id,
             )
-            return (200, {})
-            return
+            return 200, {}
 
         target = requester.user
         if membership_action in ["invite", "ban", "unban", "kick"]:
@@ -729,7 +728,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
         if membership_action == "join":
             return_value["room_id"] = room_id
 
-        return (200, return_value)
+        return 200, return_value
 
     def _has_3pid_invite_keys(self, content):
         for key in {"id_server", "medium", "address"}:
@@ -771,7 +770,7 @@ class RoomRedactEventRestServlet(TransactionRestServlet):
             txn_id=txn_id,
         )
 
-        return (200, {"event_id": event.event_id})
+        return 200, {"event_id": event.event_id}
 
     def on_PUT(self, request, room_id, event_id, txn_id):
         return self.txns.fetch_or_execute_request(
@@ -816,7 +815,7 @@ class RoomTypingRestServlet(RestServlet):
                 target_user=target_user, auth_user=requester.user, room_id=room_id
             )
 
-        return (200, {})
+        return 200, {}
 
 
 class SearchRestServlet(RestServlet):
@@ -838,7 +837,7 @@ class SearchRestServlet(RestServlet):
             requester.user, content, batch
         )
 
-        return (200, results)
+        return 200, results
 
 
 class JoinedRoomsRestServlet(RestServlet):
@@ -854,7 +853,7 @@ class JoinedRoomsRestServlet(RestServlet):
         requester = yield self.auth.get_user_by_req(request, allow_guest=True)
 
         room_ids = yield self.store.get_rooms_for_user(requester.user.to_string())
-        return (200, {"joined_rooms": list(room_ids)})
+        return 200, {"joined_rooms": list(room_ids)}
 
 
 def register_txn_path(servlet, regex_string, http_server, with_get=False):
diff --git a/synapse/rest/client/v1/voip.py b/synapse/rest/client/v1/voip.py
index 497cddf8b8..2afdbb89e5 100644
--- a/synapse/rest/client/v1/voip.py
+++ b/synapse/rest/client/v1/voip.py
@@ -60,7 +60,7 @@ class VoipRestServlet(RestServlet):
             password = turnPassword
 
         else:
-            return (200, {})
+            return 200, {}
 
         return (
             200,
@@ -73,7 +73,7 @@ class VoipRestServlet(RestServlet):
         )
 
     def on_OPTIONS(self, request):
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 934ed5d16d..e9cc953bdd 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -117,7 +117,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
             # Wrap the session id in a JSON object
             ret = {"sid": sid}
 
-        return (200, ret)
+        return 200, ret
 
     @defer.inlineCallbacks
     def send_password_reset(self, email, client_secret, send_attempt, next_link=None):
@@ -221,7 +221,7 @@ class MsisdnPasswordRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "MSISDN not found", Codes.THREEPID_NOT_FOUND)
 
         ret = yield self.identity_handler.requestMsisdnToken(**body)
-        return (200, ret)
+        return 200, ret
 
 
 class PasswordResetSubmitTokenServlet(RestServlet):
@@ -330,7 +330,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
         )
         response_code = 200 if valid else 400
 
-        return (response_code, {"success": valid})
+        return response_code, {"success": valid}
 
 
 class PasswordRestServlet(RestServlet):
@@ -399,7 +399,7 @@ class PasswordRestServlet(RestServlet):
 
         yield self._set_password_handler.set_password(user_id, new_password, requester)
 
-        return (200, {})
+        return 200, {}
 
     def on_OPTIONS(self, _):
         return 200, {}
@@ -434,7 +434,7 @@ class DeactivateAccountRestServlet(RestServlet):
             yield self._deactivate_account_handler.deactivate_account(
                 requester.user.to_string(), erase
             )
-            return (200, {})
+            return 200, {}
 
         yield self.auth_handler.validate_user_via_ui_auth(
             requester, body, self.hs.get_ip_from_request(request)
@@ -447,7 +447,7 @@ class DeactivateAccountRestServlet(RestServlet):
         else:
             id_server_unbind_result = "no-support"
 
-        return (200, {"id_server_unbind_result": id_server_unbind_result})
+        return 200, {"id_server_unbind_result": id_server_unbind_result}
 
 
 class EmailThreepidRequestTokenRestServlet(RestServlet):
@@ -481,7 +481,7 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         ret = yield self.identity_handler.requestEmailToken(**body)
-        return (200, ret)
+        return 200, ret
 
 
 class MsisdnThreepidRequestTokenRestServlet(RestServlet):
@@ -516,7 +516,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "MSISDN is already in use", Codes.THREEPID_IN_USE)
 
         ret = yield self.identity_handler.requestMsisdnToken(**body)
-        return (200, ret)
+        return 200, ret
 
 
 class ThreepidRestServlet(RestServlet):
@@ -536,21 +536,22 @@ class ThreepidRestServlet(RestServlet):
 
         threepids = yield self.datastore.user_get_threepids(requester.user.to_string())
 
-        return (200, {"threepids": threepids})
+        return 200, {"threepids": threepids}
 
     @defer.inlineCallbacks
     def on_POST(self, request):
         body = parse_json_object_from_request(request)
 
-        threePidCreds = body.get("threePidCreds")
-        threePidCreds = body.get("three_pid_creds", threePidCreds)
-        if threePidCreds is None:
-            raise SynapseError(400, "Missing param", Codes.MISSING_PARAM)
+        threepid_creds = body.get("threePidCreds") or body.get("three_pid_creds")
+        if threepid_creds is None:
+            raise SynapseError(
+                400, "Missing param three_pid_creds", Codes.MISSING_PARAM
+            )
 
         requester = yield self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
 
-        threepid = yield self.identity_handler.threepid_from_creds(threePidCreds)
+        threepid = yield self.identity_handler.threepid_from_creds(threepid_creds)
 
         if not threepid:
             raise SynapseError(400, "Failed to auth 3pid", Codes.THREEPID_AUTH_FAILED)
@@ -566,9 +567,41 @@ class ThreepidRestServlet(RestServlet):
 
         if "bind" in body and body["bind"]:
             logger.debug("Binding threepid %s to %s", threepid, user_id)
-            yield self.identity_handler.bind_threepid(threePidCreds, user_id)
+            yield self.identity_handler.bind_threepid(threepid_creds, user_id)
+
+        return 200, {}
+
+
+class ThreepidUnbindRestServlet(RestServlet):
+    PATTERNS = client_patterns("/account/3pid/unbind$")
+
+    def __init__(self, hs):
+        super(ThreepidUnbindRestServlet, self).__init__()
+        self.hs = hs
+        self.identity_handler = hs.get_handlers().identity_handler
+        self.auth = hs.get_auth()
+        self.datastore = self.hs.get_datastore()
 
-        return (200, {})
+    @defer.inlineCallbacks
+    def on_POST(self, request):
+        """Unbind the given 3pid from a specific identity server, or identity servers that are
+        known to have this 3pid bound
+        """
+        requester = yield self.auth.get_user_by_req(request)
+        body = parse_json_object_from_request(request)
+        assert_params_in_dict(body, ["medium", "address"])
+
+        medium = body.get("medium")
+        address = body.get("address")
+        id_server = body.get("id_server")
+
+        # Attempt to unbind the threepid from an identity server. If id_server is None, try to
+        # unbind from all identity servers this threepid has been added to in the past
+        result = yield self.identity_handler.try_unbind_threepid(
+            requester.user.to_string(),
+            {"address": address, "medium": medium, "id_server": id_server},
+        )
+        return 200, {"id_server_unbind_result": "success" if result else "no-support"}
 
 
 class ThreepidDeleteRestServlet(RestServlet):
@@ -603,7 +636,7 @@ class ThreepidDeleteRestServlet(RestServlet):
         else:
             id_server_unbind_result = "no-support"
 
-        return (200, {"id_server_unbind_result": id_server_unbind_result})
+        return 200, {"id_server_unbind_result": id_server_unbind_result}
 
 
 class WhoamiRestServlet(RestServlet):
@@ -617,7 +650,7 @@ class WhoamiRestServlet(RestServlet):
     def on_GET(self, request):
         requester = yield self.auth.get_user_by_req(request)
 
-        return (200, {"user_id": requester.user.to_string()})
+        return 200, {"user_id": requester.user.to_string()}
 
 
 def register_servlets(hs, http_server):
@@ -629,5 +662,6 @@ def register_servlets(hs, http_server):
     EmailThreepidRequestTokenRestServlet(hs).register(http_server)
     MsisdnThreepidRequestTokenRestServlet(hs).register(http_server)
     ThreepidRestServlet(hs).register(http_server)
+    ThreepidUnbindRestServlet(hs).register(http_server)
     ThreepidDeleteRestServlet(hs).register(http_server)
     WhoamiRestServlet(hs).register(http_server)
diff --git a/synapse/rest/client/v2_alpha/account_data.py b/synapse/rest/client/v2_alpha/account_data.py
index 98f2f6f4b5..f0db204ffa 100644
--- a/synapse/rest/client/v2_alpha/account_data.py
+++ b/synapse/rest/client/v2_alpha/account_data.py
@@ -55,7 +55,7 @@ class AccountDataServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id, account_data_type):
@@ -70,7 +70,7 @@ class AccountDataServlet(RestServlet):
         if event is None:
             raise NotFoundError("Account data not found")
 
-        return (200, event)
+        return 200, event
 
 
 class RoomAccountDataServlet(RestServlet):
@@ -112,7 +112,7 @@ class RoomAccountDataServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_GET(self, request, user_id, room_id, account_data_type):
@@ -127,7 +127,7 @@ class RoomAccountDataServlet(RestServlet):
         if event is None:
             raise NotFoundError("Room account data not found")
 
-        return (200, event)
+        return 200, event
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/capabilities.py b/synapse/rest/client/v2_alpha/capabilities.py
index a4fa45fe11..acd58af193 100644
--- a/synapse/rest/client/v2_alpha/capabilities.py
+++ b/synapse/rest/client/v2_alpha/capabilities.py
@@ -58,7 +58,7 @@ class CapabilitiesRestServlet(RestServlet):
                 "m.change_password": {"enabled": change_password},
             }
         }
-        return (200, response)
+        return 200, response
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/devices.py b/synapse/rest/client/v2_alpha/devices.py
index 9adf76cc0c..26d0235208 100644
--- a/synapse/rest/client/v2_alpha/devices.py
+++ b/synapse/rest/client/v2_alpha/devices.py
@@ -48,7 +48,7 @@ class DevicesRestServlet(RestServlet):
         devices = yield self.device_handler.get_devices_by_user(
             requester.user.to_string()
         )
-        return (200, {"devices": devices})
+        return 200, {"devices": devices}
 
 
 class DeleteDevicesRestServlet(RestServlet):
@@ -91,7 +91,7 @@ class DeleteDevicesRestServlet(RestServlet):
         yield self.device_handler.delete_devices(
             requester.user.to_string(), body["devices"]
         )
-        return (200, {})
+        return 200, {}
 
 
 class DeviceRestServlet(RestServlet):
@@ -114,7 +114,7 @@ class DeviceRestServlet(RestServlet):
         device = yield self.device_handler.get_device(
             requester.user.to_string(), device_id
         )
-        return (200, device)
+        return 200, device
 
     @interactive_auth_handler
     @defer.inlineCallbacks
@@ -137,7 +137,7 @@ class DeviceRestServlet(RestServlet):
         )
 
         yield self.device_handler.delete_device(requester.user.to_string(), device_id)
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_PUT(self, request, device_id):
@@ -147,7 +147,7 @@ class DeviceRestServlet(RestServlet):
         yield self.device_handler.update_device(
             requester.user.to_string(), device_id, body
         )
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/filter.py b/synapse/rest/client/v2_alpha/filter.py
index 22be0ee3c5..c6ddf24c8d 100644
--- a/synapse/rest/client/v2_alpha/filter.py
+++ b/synapse/rest/client/v2_alpha/filter.py
@@ -56,7 +56,7 @@ class GetFilterRestServlet(RestServlet):
                 user_localpart=target_user.localpart, filter_id=filter_id
             )
 
-            return (200, filter.get_filter_json())
+            return 200, filter.get_filter_json()
         except (KeyError, StoreError):
             raise SynapseError(400, "No such filter", errcode=Codes.NOT_FOUND)
 
@@ -89,7 +89,7 @@ class CreateFilterRestServlet(RestServlet):
             user_localpart=target_user.localpart, user_filter=content
         )
 
-        return (200, {"filter_id": str(filter_id)})
+        return 200, {"filter_id": str(filter_id)}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/groups.py b/synapse/rest/client/v2_alpha/groups.py
index e629c4256d..999a0fa80c 100644
--- a/synapse/rest/client/v2_alpha/groups.py
+++ b/synapse/rest/client/v2_alpha/groups.py
@@ -47,7 +47,7 @@ class GroupServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        return (200, group_description)
+        return 200, group_description
 
     @defer.inlineCallbacks
     def on_POST(self, request, group_id):
@@ -59,7 +59,7 @@ class GroupServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        return (200, {})
+        return 200, {}
 
 
 class GroupSummaryServlet(RestServlet):
@@ -83,7 +83,7 @@ class GroupSummaryServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        return (200, get_group_summary)
+        return 200, get_group_summary
 
 
 class GroupSummaryRoomsCatServlet(RestServlet):
@@ -120,7 +120,7 @@ class GroupSummaryRoomsCatServlet(RestServlet):
             content=content,
         )
 
-        return (200, resp)
+        return 200, resp
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, category_id, room_id):
@@ -131,7 +131,7 @@ class GroupSummaryRoomsCatServlet(RestServlet):
             group_id, requester_user_id, room_id=room_id, category_id=category_id
         )
 
-        return (200, resp)
+        return 200, resp
 
 
 class GroupCategoryServlet(RestServlet):
@@ -157,7 +157,7 @@ class GroupCategoryServlet(RestServlet):
             group_id, requester_user_id, category_id=category_id
         )
 
-        return (200, category)
+        return 200, category
 
     @defer.inlineCallbacks
     def on_PUT(self, request, group_id, category_id):
@@ -169,7 +169,7 @@ class GroupCategoryServlet(RestServlet):
             group_id, requester_user_id, category_id=category_id, content=content
         )
 
-        return (200, resp)
+        return 200, resp
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, category_id):
@@ -180,7 +180,7 @@ class GroupCategoryServlet(RestServlet):
             group_id, requester_user_id, category_id=category_id
         )
 
-        return (200, resp)
+        return 200, resp
 
 
 class GroupCategoriesServlet(RestServlet):
@@ -204,7 +204,7 @@ class GroupCategoriesServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        return (200, category)
+        return 200, category
 
 
 class GroupRoleServlet(RestServlet):
@@ -228,7 +228,7 @@ class GroupRoleServlet(RestServlet):
             group_id, requester_user_id, role_id=role_id
         )
 
-        return (200, category)
+        return 200, category
 
     @defer.inlineCallbacks
     def on_PUT(self, request, group_id, role_id):
@@ -240,7 +240,7 @@ class GroupRoleServlet(RestServlet):
             group_id, requester_user_id, role_id=role_id, content=content
         )
 
-        return (200, resp)
+        return 200, resp
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, role_id):
@@ -251,7 +251,7 @@ class GroupRoleServlet(RestServlet):
             group_id, requester_user_id, role_id=role_id
         )
 
-        return (200, resp)
+        return 200, resp
 
 
 class GroupRolesServlet(RestServlet):
@@ -275,7 +275,7 @@ class GroupRolesServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        return (200, category)
+        return 200, category
 
 
 class GroupSummaryUsersRoleServlet(RestServlet):
@@ -312,7 +312,7 @@ class GroupSummaryUsersRoleServlet(RestServlet):
             content=content,
         )
 
-        return (200, resp)
+        return 200, resp
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, role_id, user_id):
@@ -323,7 +323,7 @@ class GroupSummaryUsersRoleServlet(RestServlet):
             group_id, requester_user_id, user_id=user_id, role_id=role_id
         )
 
-        return (200, resp)
+        return 200, resp
 
 
 class GroupRoomServlet(RestServlet):
@@ -347,7 +347,7 @@ class GroupRoomServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupUsersServlet(RestServlet):
@@ -371,7 +371,7 @@ class GroupUsersServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupInvitedUsersServlet(RestServlet):
@@ -395,7 +395,7 @@ class GroupInvitedUsersServlet(RestServlet):
             group_id, requester_user_id
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupSettingJoinPolicyServlet(RestServlet):
@@ -420,7 +420,7 @@ class GroupSettingJoinPolicyServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupCreateServlet(RestServlet):
@@ -450,7 +450,7 @@ class GroupCreateServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupAdminRoomsServlet(RestServlet):
@@ -477,7 +477,7 @@ class GroupAdminRoomsServlet(RestServlet):
             group_id, requester_user_id, room_id, content
         )
 
-        return (200, result)
+        return 200, result
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, group_id, room_id):
@@ -488,7 +488,7 @@ class GroupAdminRoomsServlet(RestServlet):
             group_id, requester_user_id, room_id
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupAdminRoomsConfigServlet(RestServlet):
@@ -516,7 +516,7 @@ class GroupAdminRoomsConfigServlet(RestServlet):
             group_id, requester_user_id, room_id, config_key, content
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupAdminUsersInviteServlet(RestServlet):
@@ -546,7 +546,7 @@ class GroupAdminUsersInviteServlet(RestServlet):
             group_id, user_id, requester_user_id, config
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupAdminUsersKickServlet(RestServlet):
@@ -573,7 +573,7 @@ class GroupAdminUsersKickServlet(RestServlet):
             group_id, user_id, requester_user_id, content
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupSelfLeaveServlet(RestServlet):
@@ -598,7 +598,7 @@ class GroupSelfLeaveServlet(RestServlet):
             group_id, requester_user_id, requester_user_id, content
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupSelfJoinServlet(RestServlet):
@@ -623,7 +623,7 @@ class GroupSelfJoinServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupSelfAcceptInviteServlet(RestServlet):
@@ -648,7 +648,7 @@ class GroupSelfAcceptInviteServlet(RestServlet):
             group_id, requester_user_id, content
         )
 
-        return (200, result)
+        return 200, result
 
 
 class GroupSelfUpdatePublicityServlet(RestServlet):
@@ -672,7 +672,7 @@ class GroupSelfUpdatePublicityServlet(RestServlet):
         publicise = content["publicise"]
         yield self.store.update_group_publicity(group_id, requester_user_id, publicise)
 
-        return (200, {})
+        return 200, {}
 
 
 class PublicisedGroupsForUserServlet(RestServlet):
@@ -694,7 +694,7 @@ class PublicisedGroupsForUserServlet(RestServlet):
 
         result = yield self.groups_handler.get_publicised_groups_for_user(user_id)
 
-        return (200, result)
+        return 200, result
 
 
 class PublicisedGroupsForUsersServlet(RestServlet):
@@ -719,7 +719,7 @@ class PublicisedGroupsForUsersServlet(RestServlet):
 
         result = yield self.groups_handler.bulk_get_publicised_groups(user_ids)
 
-        return (200, result)
+        return 200, result
 
 
 class GroupsForUserServlet(RestServlet):
@@ -741,7 +741,7 @@ class GroupsForUserServlet(RestServlet):
 
         result = yield self.groups_handler.get_joined_groups(requester_user_id)
 
-        return (200, result)
+        return 200, result
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index b218a3f334..2e680134a0 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -24,7 +24,7 @@ from synapse.http.servlet import (
     parse_json_object_from_request,
     parse_string,
 )
-from synapse.logging.opentracing import log_kv, set_tag, trace_using_operation_name
+from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.types import StreamToken
 
 from ._base import client_patterns
@@ -69,7 +69,7 @@ class KeyUploadServlet(RestServlet):
         self.auth = hs.get_auth()
         self.e2e_keys_handler = hs.get_e2e_keys_handler()
 
-    @trace_using_operation_name("upload_keys")
+    @trace(opname="upload_keys")
     @defer.inlineCallbacks
     def on_POST(self, request, device_id):
         requester = yield self.auth.get_user_by_req(request, allow_guest=True)
@@ -105,7 +105,7 @@ class KeyUploadServlet(RestServlet):
         result = yield self.e2e_keys_handler.upload_keys_for_user(
             user_id, device_id, body
         )
-        return (200, result)
+        return 200, result
 
 
 class KeyQueryServlet(RestServlet):
@@ -159,7 +159,7 @@ class KeyQueryServlet(RestServlet):
         timeout = parse_integer(request, "timeout", 10 * 1000)
         body = parse_json_object_from_request(request)
         result = yield self.e2e_keys_handler.query_devices(body, timeout)
-        return (200, result)
+        return 200, result
 
 
 class KeyChangesServlet(RestServlet):
@@ -200,7 +200,7 @@ class KeyChangesServlet(RestServlet):
 
         results = yield self.device_handler.get_user_ids_changed(user_id, from_token)
 
-        return (200, results)
+        return 200, results
 
 
 class OneTimeKeyServlet(RestServlet):
@@ -235,7 +235,7 @@ class OneTimeKeyServlet(RestServlet):
         timeout = parse_integer(request, "timeout", 10 * 1000)
         body = parse_json_object_from_request(request)
         result = yield self.e2e_keys_handler.claim_one_time_keys(body, timeout)
-        return (200, result)
+        return 200, result
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/notifications.py b/synapse/rest/client/v2_alpha/notifications.py
index d034863a3c..10c1ad5b07 100644
--- a/synapse/rest/client/v2_alpha/notifications.py
+++ b/synapse/rest/client/v2_alpha/notifications.py
@@ -88,7 +88,7 @@ class NotificationsServlet(RestServlet):
             returned_push_actions.append(returned_pa)
             next_token = str(pa["stream_ordering"])
 
-        return (200, {"notifications": returned_push_actions, "next_token": next_token})
+        return 200, {"notifications": returned_push_actions, "next_token": next_token}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/read_marker.py b/synapse/rest/client/v2_alpha/read_marker.py
index d93d6a9f24..b3bf8567e1 100644
--- a/synapse/rest/client/v2_alpha/read_marker.py
+++ b/synapse/rest/client/v2_alpha/read_marker.py
@@ -59,7 +59,7 @@ class ReadMarkerRestServlet(RestServlet):
                 event_id=read_marker_event_id,
             )
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/receipts.py b/synapse/rest/client/v2_alpha/receipts.py
index 98a97b7059..0dab03d227 100644
--- a/synapse/rest/client/v2_alpha/receipts.py
+++ b/synapse/rest/client/v2_alpha/receipts.py
@@ -52,7 +52,7 @@ class ReceiptRestServlet(RestServlet):
             room_id, receipt_type, user_id=requester.user.to_string(), event_id=event_id
         )
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 9510a1e2b0..1ccd2bed2f 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -94,7 +94,7 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "Email is already in use", Codes.THREEPID_IN_USE)
 
         ret = yield self.identity_handler.requestEmailToken(**body)
-        return (200, ret)
+        return 200, ret
 
 
 class MsisdnRegisterRequestTokenRestServlet(RestServlet):
@@ -137,7 +137,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
             )
 
         ret = yield self.identity_handler.requestMsisdnToken(**body)
-        return (200, ret)
+        return 200, ret
 
 
 class UsernameAvailabilityRestServlet(RestServlet):
@@ -177,7 +177,7 @@ class UsernameAvailabilityRestServlet(RestServlet):
 
             yield self.registration_handler.check_username(username)
 
-            return (200, {"available": True})
+            return 200, {"available": True}
 
 
 class RegisterRestServlet(RestServlet):
@@ -230,7 +230,6 @@ class RegisterRestServlet(RestServlet):
         if kind == b"guest":
             ret = yield self._do_guest_registration(body, address=client_addr)
             return ret
-            return
         elif kind != b"user":
             raise UnrecognizedRequestError(
                 "Do not understand membership kind: %s" % (kind,)
@@ -279,8 +278,7 @@ class RegisterRestServlet(RestServlet):
                 result = yield self._do_appservice_registration(
                     desired_username, access_token, body
                 )
-            return (200, result)  # we throw for non 200 responses
-            return
+            return 200, result  # we throw for non 200 responses
 
         # for regular registration, downcase the provided username before
         # attempting to register it. This should mean
@@ -483,11 +481,9 @@ class RegisterRestServlet(RestServlet):
                 user_id=registered_user_id,
                 auth_result=auth_result,
                 access_token=return_dict.get("access_token"),
-                bind_email=params.get("bind_email"),
-                bind_msisdn=params.get("bind_msisdn"),
             )
 
-        return (200, return_dict)
+        return 200, return_dict
 
     def on_OPTIONS(self, _):
         return 200, {}
diff --git a/synapse/rest/client/v2_alpha/relations.py b/synapse/rest/client/v2_alpha/relations.py
index 1538b247e5..040b37c504 100644
--- a/synapse/rest/client/v2_alpha/relations.py
+++ b/synapse/rest/client/v2_alpha/relations.py
@@ -118,7 +118,7 @@ class RelationSendServlet(RestServlet):
             requester, event_dict=event_dict, txn_id=txn_id
         )
 
-        return (200, {"event_id": event.event_id})
+        return 200, {"event_id": event.event_id}
 
 
 class RelationPaginationServlet(RestServlet):
@@ -198,7 +198,7 @@ class RelationPaginationServlet(RestServlet):
         return_value["chunk"] = events
         return_value["original_event"] = original_event
 
-        return (200, return_value)
+        return 200, return_value
 
 
 class RelationAggregationPaginationServlet(RestServlet):
@@ -270,7 +270,7 @@ class RelationAggregationPaginationServlet(RestServlet):
                 to_token=to_token,
             )
 
-        return (200, pagination_chunk.to_dict())
+        return 200, pagination_chunk.to_dict()
 
 
 class RelationAggregationGroupPaginationServlet(RestServlet):
@@ -356,7 +356,7 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
         return_value = result.to_dict()
         return_value["chunk"] = events
 
-        return (200, return_value)
+        return 200, return_value
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/report_event.py b/synapse/rest/client/v2_alpha/report_event.py
index 3fdd4584a3..e7449864cd 100644
--- a/synapse/rest/client/v2_alpha/report_event.py
+++ b/synapse/rest/client/v2_alpha/report_event.py
@@ -72,7 +72,7 @@ class ReportEventRestServlet(RestServlet):
             received_ts=self.clock.time_msec(),
         )
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/room_keys.py b/synapse/rest/client/v2_alpha/room_keys.py
index 10dec96208..df4f44cd36 100644
--- a/synapse/rest/client/v2_alpha/room_keys.py
+++ b/synapse/rest/client/v2_alpha/room_keys.py
@@ -135,7 +135,7 @@ class RoomKeysServlet(RestServlet):
             body = {"rooms": {room_id: body}}
 
         yield self.e2e_room_keys_handler.upload_room_keys(user_id, version, body)
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id, session_id):
@@ -218,7 +218,7 @@ class RoomKeysServlet(RestServlet):
             else:
                 room_keys = room_keys["rooms"][room_id]
 
-        return (200, room_keys)
+        return 200, room_keys
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, room_id, session_id):
@@ -242,7 +242,7 @@ class RoomKeysServlet(RestServlet):
         yield self.e2e_room_keys_handler.delete_room_keys(
             user_id, version, room_id, session_id
         )
-        return (200, {})
+        return 200, {}
 
 
 class RoomKeysNewVersionServlet(RestServlet):
@@ -293,7 +293,7 @@ class RoomKeysNewVersionServlet(RestServlet):
         info = parse_json_object_from_request(request)
 
         new_version = yield self.e2e_room_keys_handler.create_version(user_id, info)
-        return (200, {"version": new_version})
+        return 200, {"version": new_version}
 
     # we deliberately don't have a PUT /version, as these things really should
     # be immutable to avoid people footgunning
@@ -338,7 +338,7 @@ class RoomKeysVersionServlet(RestServlet):
         except SynapseError as e:
             if e.code == 404:
                 raise SynapseError(404, "No backup found", Codes.NOT_FOUND)
-        return (200, info)
+        return 200, info
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, version):
@@ -358,7 +358,7 @@ class RoomKeysVersionServlet(RestServlet):
         user_id = requester.user.to_string()
 
         yield self.e2e_room_keys_handler.delete_version(user_id, version)
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_PUT(self, request, version):
@@ -392,7 +392,7 @@ class RoomKeysVersionServlet(RestServlet):
             )
 
         yield self.e2e_room_keys_handler.update_version(user_id, version, info)
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py b/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
index 14ba61a63e..d2c3316eb7 100644
--- a/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
+++ b/synapse/rest/client/v2_alpha/room_upgrade_rest_servlet.py
@@ -80,7 +80,7 @@ class RoomUpgradeRestServlet(RestServlet):
 
         ret = {"replacement_room": new_room_id}
 
-        return (200, ret)
+        return 200, ret
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/sendtodevice.py b/synapse/rest/client/v2_alpha/sendtodevice.py
index 2613648d82..d90e52ed1a 100644
--- a/synapse/rest/client/v2_alpha/sendtodevice.py
+++ b/synapse/rest/client/v2_alpha/sendtodevice.py
@@ -19,6 +19,7 @@ from twisted.internet import defer
 
 from synapse.http import servlet
 from synapse.http.servlet import parse_json_object_from_request
+from synapse.logging.opentracing import set_tag, trace
 from synapse.rest.client.transactions import HttpTransactionCache
 
 from ._base import client_patterns
@@ -42,7 +43,10 @@ class SendToDeviceRestServlet(servlet.RestServlet):
         self.txns = HttpTransactionCache(hs)
         self.device_message_handler = hs.get_device_message_handler()
 
+    @trace(opname="sendToDevice")
     def on_PUT(self, request, message_type, txn_id):
+        set_tag("message_type", message_type)
+        set_tag("txn_id", txn_id)
         return self.txns.fetch_or_execute_request(
             request, self._put, request, message_type, txn_id
         )
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index 7b32dd2212..c98c5a3802 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -174,7 +174,7 @@ class SyncRestServlet(RestServlet):
             time_now, sync_result, requester.access_token_id, filter
         )
 
-        return (200, response_content)
+        return 200, response_content
 
     @defer.inlineCallbacks
     def encode_response(self, time_now, sync_result, access_token_id, filter):
diff --git a/synapse/rest/client/v2_alpha/tags.py b/synapse/rest/client/v2_alpha/tags.py
index d173544355..3b555669a0 100644
--- a/synapse/rest/client/v2_alpha/tags.py
+++ b/synapse/rest/client/v2_alpha/tags.py
@@ -45,7 +45,7 @@ class TagListServlet(RestServlet):
 
         tags = yield self.store.get_tags_for_room(user_id, room_id)
 
-        return (200, {"tags": tags})
+        return 200, {"tags": tags}
 
 
 class TagServlet(RestServlet):
@@ -76,7 +76,7 @@ class TagServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        return (200, {})
+        return 200, {}
 
     @defer.inlineCallbacks
     def on_DELETE(self, request, user_id, room_id, tag):
@@ -88,7 +88,7 @@ class TagServlet(RestServlet):
 
         self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
 
-        return (200, {})
+        return 200, {}
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/thirdparty.py b/synapse/rest/client/v2_alpha/thirdparty.py
index 158e686b01..2e8d672471 100644
--- a/synapse/rest/client/v2_alpha/thirdparty.py
+++ b/synapse/rest/client/v2_alpha/thirdparty.py
@@ -40,7 +40,7 @@ class ThirdPartyProtocolsServlet(RestServlet):
         yield self.auth.get_user_by_req(request, allow_guest=True)
 
         protocols = yield self.appservice_handler.get_3pe_protocols()
-        return (200, protocols)
+        return 200, protocols
 
 
 class ThirdPartyProtocolServlet(RestServlet):
@@ -60,9 +60,9 @@ class ThirdPartyProtocolServlet(RestServlet):
             only_protocol=protocol
         )
         if protocol in protocols:
-            return (200, protocols[protocol])
+            return 200, protocols[protocol]
         else:
-            return (404, {"error": "Unknown protocol"})
+            return 404, {"error": "Unknown protocol"}
 
 
 class ThirdPartyUserServlet(RestServlet):
@@ -85,7 +85,7 @@ class ThirdPartyUserServlet(RestServlet):
             ThirdPartyEntityKind.USER, protocol, fields
         )
 
-        return (200, results)
+        return 200, results
 
 
 class ThirdPartyLocationServlet(RestServlet):
@@ -108,7 +108,7 @@ class ThirdPartyLocationServlet(RestServlet):
             ThirdPartyEntityKind.LOCATION, protocol, fields
         )
 
-        return (200, results)
+        return 200, results
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/user_directory.py b/synapse/rest/client/v2_alpha/user_directory.py
index 7ab2b80e46..2863affbab 100644
--- a/synapse/rest/client/v2_alpha/user_directory.py
+++ b/synapse/rest/client/v2_alpha/user_directory.py
@@ -60,7 +60,7 @@ class UserDirectorySearchRestServlet(RestServlet):
         user_id = requester.user.to_string()
 
         if not self.hs.config.user_directory_search_enabled:
-            return (200, {"limited": False, "results": []})
+            return 200, {"limited": False, "results": []}
 
         body = parse_json_object_from_request(request)
 
@@ -76,7 +76,7 @@ class UserDirectorySearchRestServlet(RestServlet):
             user_id, search_term, limit
         )
 
-        return (200, results)
+        return 200, results
 
 
 def register_servlets(hs, http_server):
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index cf5759e9a6..b972e152a9 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -318,14 +318,14 @@ class MediaRepository(object):
 
             responder = yield self.media_storage.fetch_media(file_info)
             if responder:
-                return (responder, media_info)
+                return responder, media_info
 
         # Failed to find the file anywhere, lets download it.
 
         media_info = yield self._download_remote_file(server_name, media_id, file_id)
 
         responder = yield self.media_storage.fetch_media(file_info)
-        return (responder, media_info)
+        return responder, media_info
 
     @defer.inlineCallbacks
     def _download_remote_file(self, server_name, media_id, file_id):
@@ -526,7 +526,7 @@ class MediaRepository(object):
             try:
                 file_info = FileInfo(
                     server_name=server_name,
-                    file_id=media_id,
+                    file_id=file_id,
                     thumbnail=True,
                     thumbnail_width=t_width,
                     thumbnail_height=t_height,
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index bd40891a7f..7a56cd4b6c 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -183,7 +183,6 @@ class PreviewUrlResource(DirectServeResource):
             if isinstance(og, six.text_type):
                 og = og.encode("utf8")
             return og
-            return
 
         media_info = yield self._download_url(url, user)
 
diff --git a/synapse/rest/media/v1/thumbnailer.py b/synapse/rest/media/v1/thumbnailer.py
index 90d8e6bffe..c995d7e043 100644
--- a/synapse/rest/media/v1/thumbnailer.py
+++ b/synapse/rest/media/v1/thumbnailer.py
@@ -78,9 +78,9 @@ class Thumbnailer(object):
         """
 
         if max_width * self.height < max_height * self.width:
-            return (max_width, (max_width * self.height) // self.width)
+            return max_width, (max_width * self.height) // self.width
         else:
-            return ((max_height * self.width) // self.height, max_height)
+            return (max_height * self.width) // self.height, max_height
 
     def scale(self, width, height, output_type):
         """Rescales the image to the given dimensions.
diff --git a/synapse/server_notices/resource_limits_server_notices.py b/synapse/server_notices/resource_limits_server_notices.py
index 729c097e6d..81c4aff496 100644
--- a/synapse/server_notices/resource_limits_server_notices.py
+++ b/synapse/server_notices/resource_limits_server_notices.py
@@ -193,4 +193,4 @@ class ResourceLimitsServerNotices(object):
                 if event_id in referenced_events:
                     referenced_events.remove(event.event_id)
 
-        return (currently_blocked, referenced_events)
+        return currently_blocked, referenced_events
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index a0d34f16ea..2b0f4c79ee 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -136,7 +136,6 @@ class StateHandler(object):
             if event_id:
                 event = yield self.store.get_event(event_id, allow_none=True)
             return event
-            return
 
         state_map = yield self.store.get_events(
             list(state.values()), get_prev_content=False
diff --git a/synapse/storage/account_data.py b/synapse/storage/account_data.py
index 9fa5b4f3d6..6afbfc0d74 100644
--- a/synapse/storage/account_data.py
+++ b/synapse/storage/account_data.py
@@ -90,7 +90,7 @@ class AccountDataWorkerStore(SQLBaseStore):
                 room_data = by_room.setdefault(row["room_id"], {})
                 room_data[row["account_data_type"]] = json.loads(row["content"])
 
-            return (global_account_data, by_room)
+            return global_account_data, by_room
 
         return self.runInteraction(
             "get_account_data_for_user", get_account_data_for_user_txn
@@ -205,7 +205,7 @@ class AccountDataWorkerStore(SQLBaseStore):
             )
             txn.execute(sql, (last_room_id, current_id, limit))
             room_results = txn.fetchall()
-            return (global_results, room_results)
+            return global_results, room_results
 
         return self.runInteraction(
             "get_all_updated_account_data_txn", get_updated_account_data_txn
@@ -244,13 +244,13 @@ class AccountDataWorkerStore(SQLBaseStore):
                 room_account_data = account_data_by_room.setdefault(row[0], {})
                 room_account_data[row[1]] = json.loads(row[2])
 
-            return (global_account_data, account_data_by_room)
+            return global_account_data, account_data_by_room
 
         changed = self._account_data_stream_cache.has_entity_changed(
             user_id, int(stream_id)
         )
         if not changed:
-            return ({}, {})
+            return {}, {}
 
         return self.runInteraction(
             "get_updated_account_data_for_user", get_updated_account_data_for_user_txn
diff --git a/synapse/storage/appservice.py b/synapse/storage/appservice.py
index 05d9c05c3f..435b2acd4d 100644
--- a/synapse/storage/appservice.py
+++ b/synapse/storage/appservice.py
@@ -165,7 +165,6 @@ class ApplicationServiceTransactionWorkerStore(
         )
         if result:
             return result.get("state")
-            return
         return None
 
     def set_appservice_state(self, service, state):
@@ -358,7 +357,7 @@ class ApplicationServiceTransactionWorkerStore(
 
         events = yield self.get_events_as_list(event_ids)
 
-        return (upper_bound, events)
+        return upper_bound, events
 
 
 class ApplicationServiceTransactionStore(ApplicationServiceTransactionWorkerStore):
diff --git a/synapse/storage/deviceinbox.py b/synapse/storage/deviceinbox.py
index 79bb0ea46d..6b7458304e 100644
--- a/synapse/storage/deviceinbox.py
+++ b/synapse/storage/deviceinbox.py
@@ -19,6 +19,7 @@ from canonicaljson import json
 
 from twisted.internet import defer
 
+from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.util.caches.expiringcache import ExpiringCache
@@ -66,12 +67,13 @@ class DeviceInboxWorkerStore(SQLBaseStore):
                 messages.append(json.loads(row[1]))
             if len(messages) < limit:
                 stream_pos = current_stream_id
-            return (messages, stream_pos)
+            return messages, stream_pos
 
         return self.runInteraction(
             "get_new_messages_for_device", get_new_messages_for_device_txn
         )
 
+    @trace
     @defer.inlineCallbacks
     def delete_messages_for_device(self, user_id, device_id, up_to_stream_id):
         """
@@ -87,11 +89,15 @@ class DeviceInboxWorkerStore(SQLBaseStore):
         last_deleted_stream_id = self._last_device_delete_cache.get(
             (user_id, device_id), None
         )
+
+        set_tag("last_deleted_stream_id", last_deleted_stream_id)
+
         if last_deleted_stream_id:
             has_changed = self._device_inbox_stream_cache.has_entity_changed(
                 user_id, last_deleted_stream_id
             )
             if not has_changed:
+                log_kv({"message": "No changes in cache since last check"})
                 return 0
 
         def delete_messages_for_device_txn(txn):
@@ -107,6 +113,10 @@ class DeviceInboxWorkerStore(SQLBaseStore):
             "delete_messages_for_device", delete_messages_for_device_txn
         )
 
+        log_kv(
+            {"message": "deleted {} messages for device".format(count), "count": count}
+        )
+
         # Update the cache, ensuring that we only ever increase the value
         last_deleted_stream_id = self._last_device_delete_cache.get(
             (user_id, device_id), 0
@@ -117,6 +127,7 @@ class DeviceInboxWorkerStore(SQLBaseStore):
 
         return count
 
+    @trace
     def get_new_device_msgs_for_remote(
         self, destination, last_stream_id, current_stream_id, limit
     ):
@@ -132,16 +143,23 @@ class DeviceInboxWorkerStore(SQLBaseStore):
                 in the stream the messages got to.
         """
 
+        set_tag("destination", destination)
+        set_tag("last_stream_id", last_stream_id)
+        set_tag("current_stream_id", current_stream_id)
+        set_tag("limit", limit)
+
         has_changed = self._device_federation_outbox_stream_cache.has_entity_changed(
             destination, last_stream_id
         )
         if not has_changed or last_stream_id == current_stream_id:
+            log_kv({"message": "No new messages in stream"})
             return defer.succeed(([], current_stream_id))
 
         if limit <= 0:
             # This can happen if we run out of room for EDUs in the transaction.
             return defer.succeed(([], last_stream_id))
 
+        @trace
         def get_new_messages_for_remote_destination_txn(txn):
             sql = (
                 "SELECT stream_id, messages_json FROM device_federation_outbox"
@@ -156,14 +174,16 @@ class DeviceInboxWorkerStore(SQLBaseStore):
                 stream_pos = row[0]
                 messages.append(json.loads(row[1]))
             if len(messages) < limit:
+                log_kv({"message": "Set stream position to current position"})
                 stream_pos = current_stream_id
-            return (messages, stream_pos)
+            return messages, stream_pos
 
         return self.runInteraction(
             "get_new_device_msgs_for_remote",
             get_new_messages_for_remote_destination_txn,
         )
 
+    @trace
     def delete_device_msgs_for_remote(self, destination, up_to_stream_id):
         """Used to delete messages when the remote destination acknowledges
         their receipt.
@@ -214,6 +234,7 @@ class DeviceInboxStore(DeviceInboxWorkerStore, BackgroundUpdateStore):
             expiry_ms=30 * 60 * 1000,
         )
 
+    @trace
     @defer.inlineCallbacks
     def add_messages_to_device_inbox(
         self, local_messages_by_user_then_device, remote_messages_by_destination
diff --git a/synapse/storage/devices.py b/synapse/storage/devices.py
index e11881161d..79a58df591 100644
--- a/synapse/storage/devices.py
+++ b/synapse/storage/devices.py
@@ -23,6 +23,7 @@ from twisted.internet import defer
 from synapse.api.errors import StoreError
 from synapse.logging.opentracing import (
     get_active_span_text_map,
+    set_tag,
     trace,
     whitelisted_homeserver,
 )
@@ -94,7 +95,7 @@ class DeviceWorkerStore(SQLBaseStore):
             destination, int(from_stream_id)
         )
         if not has_changed:
-            return (now_stream_id, [])
+            return now_stream_id, []
 
         # We retrieve n+1 devices from the list of outbound pokes where n is
         # our outbound device update limit. We then check if the very last
@@ -117,7 +118,7 @@ class DeviceWorkerStore(SQLBaseStore):
 
         # Return an empty list if there are no updates
         if not updates:
-            return (now_stream_id, [])
+            return now_stream_id, []
 
         # if we have exceeded the limit, we need to exclude any results with the
         # same stream_id as the last row.
@@ -167,13 +168,13 @@ class DeviceWorkerStore(SQLBaseStore):
         # skip that stream_id and return an empty list, and continue with the next
         # stream_id next time.
         if not query_map:
-            return (stream_id_cutoff, [])
+            return stream_id_cutoff, []
 
         results = yield self._get_device_update_edus_by_remote(
             destination, from_stream_id, query_map
         )
 
-        return (now_stream_id, results)
+        return now_stream_id, results
 
     def _get_devices_by_remote_txn(
         self, txn, destination, from_stream_id, now_stream_id, limit
@@ -321,6 +322,7 @@ class DeviceWorkerStore(SQLBaseStore):
     def get_device_stream_token(self):
         return self._device_list_id_gen.get_current_token()
 
+    @trace
     @defer.inlineCallbacks
     def get_user_devices_from_cache(self, query_list):
         """Get the devices (and keys if any) for remote users from the cache.
@@ -352,7 +354,10 @@ class DeviceWorkerStore(SQLBaseStore):
             else:
                 results[user_id] = yield self._get_cached_devices_for_user(user_id)
 
-        return (user_ids_not_in_cache, results)
+        set_tag("in_cache", results)
+        set_tag("not_in_cache", user_ids_not_in_cache)
+
+        return user_ids_not_in_cache, results
 
     @cachedInlineCallbacks(num_args=2, tree=True)
     def _get_cached_user_device(self, user_id, device_id):
@@ -851,7 +856,7 @@ class DeviceStore(DeviceWorkerStore, BackgroundUpdateStore):
                     "ts": now,
                     "opentracing_context": json.dumps(context)
                     if whitelisted_homeserver(destination)
-                    else None,
+                    else "{}",
                 }
                 for destination in hosts
                 for device_id in device_ids
diff --git a/synapse/storage/directory.py b/synapse/storage/directory.py
index e966a73f3d..eed7757ed5 100644
--- a/synapse/storage/directory.py
+++ b/synapse/storage/directory.py
@@ -47,7 +47,6 @@ class DirectoryWorkerStore(SQLBaseStore):
 
         if not room_id:
             return None
-            return
 
         servers = yield self._simple_select_onecol(
             "room_alias_servers",
@@ -58,7 +57,6 @@ class DirectoryWorkerStore(SQLBaseStore):
 
         if not servers:
             return None
-            return
 
         return RoomAliasMapping(room_id, room_alias.to_string(), servers)
 
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index d0d1781c90..a5d13ddc49 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -818,7 +818,7 @@ class EventsStore(
         # If they old and new groups are the same then we don't need to do
         # anything.
         if old_state_groups == new_state_groups:
-            return (None, None)
+            return None, None
 
         if len(new_state_groups) == 1 and len(old_state_groups) == 1:
             # If we're going from one state group to another, lets check if
@@ -835,7 +835,7 @@ class EventsStore(
                 # the current state in memory then lets also return that,
                 # but it doesn't matter if we don't.
                 new_state = state_groups_map.get(new_state_group)
-                return (new_state, delta_ids)
+                return new_state, delta_ids
 
         # Now that we have calculated new_state_groups we need to get
         # their state IDs so we can resolve to a single state set.
@@ -847,7 +847,7 @@ class EventsStore(
         if len(new_state_groups) == 1:
             # If there is only one state group, then we know what the current
             # state is.
-            return (state_groups_map[new_state_groups.pop()], None)
+            return state_groups_map[new_state_groups.pop()], None
 
         # Ok, we need to defer to the state handler to resolve our state sets.
 
@@ -876,7 +876,7 @@ class EventsStore(
             state_res_store=StateResolutionStore(self),
         )
 
-        return (res.state, None)
+        return res.state, None
 
     @defer.inlineCallbacks
     def _calculate_state_delta(self, room_id, current_state):
@@ -899,7 +899,7 @@ class EventsStore(
             if ev_id != existing_state.get(key)
         }
 
-        return (to_delete, to_insert)
+        return to_delete, to_insert
 
     @log_function
     def _persist_events_txn(
@@ -2358,8 +2358,9 @@ class EventsStore(
             "room_aliases",
             "room_depth",
             "room_memberships",
-            "room_state",
-            "room_stats",
+            "room_stats_state",
+            "room_stats_current",
+            "room_stats_historical",
             "room_stats_earliest_token",
             "rooms",
             "stream_ordering_to_exterm",
diff --git a/synapse/storage/presence.py b/synapse/storage/presence.py
index 1a0f2d5768..5db6f2d84a 100644
--- a/synapse/storage/presence.py
+++ b/synapse/storage/presence.py
@@ -90,7 +90,7 @@ class PresenceStore(SQLBaseStore):
                 presence_states,
             )
 
-        return (stream_orderings[-1], self._presence_id_gen.get_current_token())
+        return stream_orderings[-1], self._presence_id_gen.get_current_token()
 
     def _update_presence_txn(self, txn, stream_orderings, presence_states):
         for stream_id, state in zip(stream_orderings, presence_states):
diff --git a/synapse/storage/profile.py b/synapse/storage/profile.py
index 8a5d8e9b18..912c1df6be 100644
--- a/synapse/storage/profile.py
+++ b/synapse/storage/profile.py
@@ -35,7 +35,6 @@ class ProfileWorkerStore(SQLBaseStore):
             if e.code == 404:
                 # no match
                 return ProfileInfo(None, None)
-                return
             else:
                 raise
 
diff --git a/synapse/storage/pusher.py b/synapse/storage/pusher.py
index b431d24b8a..3e0e834a62 100644
--- a/synapse/storage/pusher.py
+++ b/synapse/storage/pusher.py
@@ -133,7 +133,7 @@ class PusherWorkerStore(SQLBaseStore):
             txn.execute(sql, (last_id, current_id, limit))
             deleted = txn.fetchall()
 
-            return (updated, deleted)
+            return updated, deleted
 
         return self.runInteraction(
             "get_all_updated_pushers", get_all_updated_pushers_txn
diff --git a/synapse/storage/receipts.py b/synapse/storage/receipts.py
index 6aa6d98ebb..290ddb30e8 100644
--- a/synapse/storage/receipts.py
+++ b/synapse/storage/receipts.py
@@ -478,7 +478,7 @@ class ReceiptsStore(ReceiptsWorkerStore):
 
         max_persisted_id = self._receipts_id_gen.get_current_token()
 
-        return (stream_id, max_persisted_id)
+        return stream_id, max_persisted_id
 
     def insert_graph_receipt(self, room_id, receipt_type, user_id, event_ids, data):
         return self.runInteraction(
diff --git a/synapse/storage/registration.py b/synapse/storage/registration.py
index 3f50324253..2d3c7e2dc9 100644
--- a/synapse/storage/registration.py
+++ b/synapse/storage/registration.py
@@ -869,6 +869,17 @@ class RegistrationStore(
                 (user_id_obj.localpart, create_profile_with_displayname),
             )
 
+        if self.hs.config.stats_enabled:
+            # we create a new completed user statistics row
+
+            # we don't strictly need current_token since this user really can't
+            # have any state deltas before now (as it is a new user), but still,
+            # we include it for completeness.
+            current_token = self._get_max_stream_id_in_current_state_deltas_txn(txn)
+            self._update_stats_delta_txn(
+                txn, now, "user", user_id, {}, complete_with_stream_id=current_token
+            )
+
         self._invalidate_cache_and_stream(txn, self.get_user_by_id, (user_id,))
         txn.call_after(self.is_guest.invalidate, (user_id,))
 
@@ -1140,6 +1151,7 @@ class RegistrationStore(
             deferred str|None: A str representing a link to redirect the user
             to if there is one.
         """
+
         # Insert everything into a transaction in order to run atomically
         def validate_threepid_session_txn(txn):
             row = self._simple_select_one_txn(
diff --git a/synapse/storage/roommember.py b/synapse/storage/roommember.py
index eecb276465..f8b682ebd9 100644
--- a/synapse/storage/roommember.py
+++ b/synapse/storage/roommember.py
@@ -112,29 +112,31 @@ class RoomMemberWorkerStore(EventsWorkerStore):
 
     @cached(max_entries=100000, iterable=True)
     def get_users_in_room(self, room_id):
-        def f(txn):
-            # If we can assume current_state_events.membership is up to date
-            # then we can avoid a join, which is a Very Good Thing given how
-            # frequently this function gets called.
-            if self._current_state_events_membership_up_to_date:
-                sql = """
-                    SELECT state_key FROM current_state_events
-                    WHERE type = 'm.room.member' AND room_id = ? AND membership = ?
-                """
-            else:
-                sql = """
-                    SELECT state_key FROM room_memberships as m
-                    INNER JOIN current_state_events as c
-                    ON m.event_id = c.event_id
-                    AND m.room_id = c.room_id
-                    AND m.user_id = c.state_key
-                    WHERE c.type = 'm.room.member' AND c.room_id = ? AND m.membership = ?
-                """
+        return self.runInteraction(
+            "get_users_in_room", self.get_users_in_room_txn, room_id
+        )
 
-            txn.execute(sql, (room_id, Membership.JOIN))
-            return [to_ascii(r[0]) for r in txn]
+    def get_users_in_room_txn(self, txn, room_id):
+        # If we can assume current_state_events.membership is up to date
+        # then we can avoid a join, which is a Very Good Thing given how
+        # frequently this function gets called.
+        if self._current_state_events_membership_up_to_date:
+            sql = """
+                SELECT state_key FROM current_state_events
+                WHERE type = 'm.room.member' AND room_id = ? AND membership = ?
+            """
+        else:
+            sql = """
+                SELECT state_key FROM room_memberships as m
+                INNER JOIN current_state_events as c
+                ON m.event_id = c.event_id
+                AND m.room_id = c.room_id
+                AND m.user_id = c.state_key
+                WHERE c.type = 'm.room.member' AND c.room_id = ? AND m.membership = ?
+            """
 
-        return self.runInteraction("get_users_in_room", f)
+        txn.execute(sql, (room_id, Membership.JOIN))
+        return [to_ascii(r[0]) for r in txn]
 
     @cached(max_entries=100000)
     def get_room_summary(self, room_id):
diff --git a/synapse/storage/schema/delta/56/stats_separated.sql b/synapse/storage/schema/delta/56/stats_separated.sql
new file mode 100644
index 0000000000..163529c071
--- /dev/null
+++ b/synapse/storage/schema/delta/56/stats_separated.sql
@@ -0,0 +1,152 @@
+/* Copyright 2018 New Vector Ltd
+ * Copyright 2019 The Matrix.org Foundation C.I.C.
+ *
+ * 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.
+ */
+
+
+----- First clean up from previous versions of room stats.
+
+-- First remove old stats stuff
+DROP TABLE IF EXISTS room_stats;
+DROP TABLE IF EXISTS room_state;
+DROP TABLE IF EXISTS room_stats_state;
+DROP TABLE IF EXISTS user_stats;
+DROP TABLE IF EXISTS room_stats_earliest_tokens;
+DROP TABLE IF EXISTS _temp_populate_stats_position;
+DROP TABLE IF EXISTS _temp_populate_stats_rooms;
+DROP TABLE IF EXISTS stats_stream_pos;
+
+-- Unschedule old background updates if they're still scheduled
+DELETE FROM background_updates WHERE update_name IN (
+    'populate_stats_createtables',
+    'populate_stats_process_rooms',
+    'populate_stats_process_users',
+    'populate_stats_cleanup'
+);
+
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_stats_process_rooms', '{}', '');
+
+INSERT INTO background_updates (update_name, progress_json, depends_on) VALUES
+    ('populate_stats_process_users', '{}', 'populate_stats_process_rooms');
+
+----- Create tables for our version of room stats.
+
+-- single-row table to track position of incremental updates
+DROP TABLE IF EXISTS stats_incremental_position;
+CREATE TABLE stats_incremental_position (
+    Lock CHAR(1) NOT NULL DEFAULT 'X' UNIQUE,  -- Makes sure this table only has one row.
+    stream_id  BIGINT NOT NULL,
+    CHECK (Lock='X')
+);
+
+-- insert a null row and make sure it is the only one.
+INSERT INTO stats_incremental_position (
+    stream_id
+) SELECT COALESCE(MAX(stream_ordering), 0) from events;
+
+-- represents PRESENT room statistics for a room
+-- only holds absolute fields
+DROP TABLE IF EXISTS room_stats_current;
+CREATE TABLE room_stats_current (
+    room_id TEXT NOT NULL PRIMARY KEY,
+
+    -- These are absolute counts
+    current_state_events INT NOT NULL,
+    joined_members INT NOT NULL,
+    invited_members INT NOT NULL,
+    left_members INT NOT NULL,
+    banned_members INT NOT NULL,
+
+    local_users_in_room INT NOT NULL,
+
+    -- The maximum delta stream position that this row takes into account.
+    completed_delta_stream_id BIGINT NOT NULL
+);
+
+
+-- represents HISTORICAL room statistics for a room
+DROP TABLE IF EXISTS room_stats_historical;
+CREATE TABLE room_stats_historical (
+    room_id TEXT NOT NULL,
+    -- These stats cover the time from (end_ts - bucket_size)...end_ts (in ms).
+    -- Note that end_ts is quantised.
+    end_ts BIGINT NOT NULL,
+    bucket_size BIGINT NOT NULL,
+
+    -- These stats are absolute counts
+    current_state_events BIGINT NOT NULL,
+    joined_members BIGINT NOT NULL,
+    invited_members BIGINT NOT NULL,
+    left_members BIGINT NOT NULL,
+    banned_members BIGINT NOT NULL,
+    local_users_in_room BIGINT NOT NULL,
+
+    -- These stats are per time slice
+    total_events BIGINT NOT NULL,
+    total_event_bytes BIGINT NOT NULL,
+
+    PRIMARY KEY (room_id, end_ts)
+);
+
+-- We use this index to speed up deletion of ancient room stats.
+CREATE INDEX room_stats_historical_end_ts ON room_stats_historical (end_ts);
+
+-- represents PRESENT statistics for a user
+-- only holds absolute fields
+DROP TABLE IF EXISTS user_stats_current;
+CREATE TABLE user_stats_current (
+    user_id TEXT NOT NULL PRIMARY KEY,
+
+    joined_rooms BIGINT NOT NULL,
+
+    -- The maximum delta stream position that this row takes into account.
+    completed_delta_stream_id BIGINT NOT NULL
+);
+
+-- represents HISTORICAL statistics for a user
+DROP TABLE IF EXISTS user_stats_historical;
+CREATE TABLE user_stats_historical (
+    user_id TEXT NOT NULL,
+    end_ts BIGINT NOT NULL,
+    bucket_size BIGINT NOT NULL,
+
+    joined_rooms BIGINT NOT NULL,
+
+    invites_sent BIGINT NOT NULL,
+    rooms_created BIGINT NOT NULL,
+    total_events BIGINT NOT NULL,
+    total_event_bytes BIGINT NOT NULL,
+
+    PRIMARY KEY (user_id, end_ts)
+);
+
+-- We use this index to speed up deletion of ancient user stats.
+CREATE INDEX user_stats_historical_end_ts ON user_stats_historical (end_ts);
+
+
+CREATE TABLE room_stats_state (
+    room_id TEXT NOT NULL,
+    name TEXT,
+    canonical_alias TEXT,
+    join_rules TEXT,
+    history_visibility TEXT,
+    encryption TEXT,
+    avatar TEXT,
+    guest_access TEXT,
+    is_federatable BOOLEAN,
+    topic TEXT
+);
+
+CREATE UNIQUE INDEX room_stats_state_room ON room_stats_state(room_id);
diff --git a/synapse/storage/stats.py b/synapse/storage/stats.py
index e13efed417..6560173c08 100644
--- a/synapse/storage/stats.py
+++ b/synapse/storage/stats.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2018, 2019 New Vector Ltd
+# Copyright 2019 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -14,17 +15,22 @@
 # limitations under the License.
 
 import logging
+from itertools import chain
 
 from twisted.internet import defer
+from twisted.internet.defer import DeferredLock
 
 from synapse.api.constants import EventTypes, Membership
-from synapse.storage.prepare_database import get_statements
+from synapse.storage import PostgresEngine
 from synapse.storage.state_deltas import StateDeltasStore
 from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
 
 # these fields track absolutes (e.g. total number of rooms on the server)
+# You can think of these as Prometheus Gauges.
+# You can draw these stats on a line graph.
+# Example: number of users in a room
 ABSOLUTE_STATS_FIELDS = {
     "room": (
         "current_state_events",
@@ -32,14 +38,23 @@ ABSOLUTE_STATS_FIELDS = {
         "invited_members",
         "left_members",
         "banned_members",
-        "state_events",
+        "local_users_in_room",
     ),
-    "user": ("public_rooms", "private_rooms"),
+    "user": ("joined_rooms",),
 }
 
-TYPE_TO_ROOM = {"room": ("room_stats", "room_id"), "user": ("user_stats", "user_id")}
+# these fields are per-timeslice and so should be reset to 0 upon a new slice
+# You can draw these stats on a histogram.
+# Example: number of events sent locally during a time slice
+PER_SLICE_FIELDS = {
+    "room": ("total_events", "total_event_bytes"),
+    "user": ("invites_sent", "rooms_created", "total_events", "total_event_bytes"),
+}
+
+TYPE_TO_TABLE = {"room": ("room_stats", "room_id"), "user": ("user_stats", "user_id")}
 
-TEMP_TABLE = "_temp_populate_stats"
+# these are the tables (& ID columns) which contain our actual subjects
+TYPE_TO_ORIGIN_TABLE = {"room": ("rooms", "room_id"), "user": ("users", "name")}
 
 
 class StatsStore(StateDeltasStore):
@@ -51,136 +66,102 @@ class StatsStore(StateDeltasStore):
         self.stats_enabled = hs.config.stats_enabled
         self.stats_bucket_size = hs.config.stats_bucket_size
 
-        self.register_background_update_handler(
-            "populate_stats_createtables", self._populate_stats_createtables
-        )
+        self.stats_delta_processing_lock = DeferredLock()
+
         self.register_background_update_handler(
             "populate_stats_process_rooms", self._populate_stats_process_rooms
         )
         self.register_background_update_handler(
-            "populate_stats_cleanup", self._populate_stats_cleanup
+            "populate_stats_process_users", self._populate_stats_process_users
         )
+        # we no longer need to perform clean-up, but we will give ourselves
+        # the potential to reintroduce it in the future – so documentation
+        # will still encourage the use of this no-op handler.
+        self.register_noop_background_update("populate_stats_cleanup")
+        self.register_noop_background_update("populate_stats_prepare")
 
-    @defer.inlineCallbacks
-    def _populate_stats_createtables(self, progress, batch_size):
-
-        if not self.stats_enabled:
-            yield self._end_background_update("populate_stats_createtables")
-            return 1
-
-        # Get all the rooms that we want to process.
-        def _make_staging_area(txn):
-            # Create the temporary tables
-            stmts = get_statements(
-                """
-                -- We just recreate the table, we'll be reinserting the
-                -- correct entries again later anyway.
-                DROP TABLE IF EXISTS {temp}_rooms;
-
-                CREATE TABLE IF NOT EXISTS {temp}_rooms(
-                    room_id TEXT NOT NULL,
-                    events BIGINT NOT NULL
-                );
-
-                CREATE INDEX {temp}_rooms_events
-                    ON {temp}_rooms(events);
-                CREATE INDEX {temp}_rooms_id
-                    ON {temp}_rooms(room_id);
-            """.format(
-                    temp=TEMP_TABLE
-                ).splitlines()
-            )
-
-            for statement in stmts:
-                txn.execute(statement)
-
-            sql = (
-                "CREATE TABLE IF NOT EXISTS "
-                + TEMP_TABLE
-                + "_position(position TEXT NOT NULL)"
-            )
-            txn.execute(sql)
-
-            # Get rooms we want to process from the database, only adding
-            # those that we haven't (i.e. those not in room_stats_earliest_token)
-            sql = """
-                INSERT INTO %s_rooms (room_id, events)
-                SELECT c.room_id, count(*) FROM current_state_events AS c
-                LEFT JOIN room_stats_earliest_token AS t USING (room_id)
-                WHERE t.room_id IS NULL
-                GROUP BY c.room_id
-            """ % (
-                TEMP_TABLE,
-            )
-            txn.execute(sql)
+    def quantise_stats_time(self, ts):
+        """
+        Quantises a timestamp to be a multiple of the bucket size.
 
-        new_pos = yield self.get_max_stream_id_in_current_state_deltas()
-        yield self.runInteraction("populate_stats_temp_build", _make_staging_area)
-        yield self._simple_insert(TEMP_TABLE + "_position", {"position": new_pos})
-        self.get_earliest_token_for_room_stats.invalidate_all()
+        Args:
+            ts (int): the timestamp to quantise, in milliseconds since the Unix
+                Epoch
 
-        yield self._end_background_update("populate_stats_createtables")
-        return 1
+        Returns:
+            int: a timestamp which
+              - is divisible by the bucket size;
+              - is no later than `ts`; and
+              - is the largest such timestamp.
+        """
+        return (ts // self.stats_bucket_size) * self.stats_bucket_size
 
     @defer.inlineCallbacks
-    def _populate_stats_cleanup(self, progress, batch_size):
+    def _populate_stats_process_users(self, progress, batch_size):
         """
-        Update the user directory stream position, then clean up the old tables.
+        This is a background update which regenerates statistics for users.
         """
         if not self.stats_enabled:
-            yield self._end_background_update("populate_stats_cleanup")
+            yield self._end_background_update("populate_stats_process_users")
             return 1
 
-        position = yield self._simple_select_one_onecol(
-            TEMP_TABLE + "_position", None, "position"
+        last_user_id = progress.get("last_user_id", "")
+
+        def _get_next_batch(txn):
+            sql = """
+                    SELECT DISTINCT name FROM users
+                    WHERE name > ?
+                    ORDER BY name ASC
+                    LIMIT ?
+                """
+            txn.execute(sql, (last_user_id, batch_size))
+            return [r for r, in txn]
+
+        users_to_work_on = yield self.runInteraction(
+            "_populate_stats_process_users", _get_next_batch
         )
-        yield self.update_stats_stream_pos(position)
 
-        def _delete_staging_area(txn):
-            txn.execute("DROP TABLE IF EXISTS " + TEMP_TABLE + "_rooms")
-            txn.execute("DROP TABLE IF EXISTS " + TEMP_TABLE + "_position")
+        # No more rooms -- complete the transaction.
+        if not users_to_work_on:
+            yield self._end_background_update("populate_stats_process_users")
+            return 1
 
-        yield self.runInteraction("populate_stats_cleanup", _delete_staging_area)
+        for user_id in users_to_work_on:
+            yield self._calculate_and_set_initial_state_for_user(user_id)
+            progress["last_user_id"] = user_id
 
-        yield self._end_background_update("populate_stats_cleanup")
-        return 1
+        yield self.runInteraction(
+            "populate_stats_process_users",
+            self._background_update_progress_txn,
+            "populate_stats_process_users",
+            progress,
+        )
+
+        return len(users_to_work_on)
 
     @defer.inlineCallbacks
     def _populate_stats_process_rooms(self, progress, batch_size):
-
+        """
+        This is a background update which regenerates statistics for rooms.
+        """
         if not self.stats_enabled:
             yield self._end_background_update("populate_stats_process_rooms")
             return 1
 
-        # If we don't have progress filed, delete everything.
-        if not progress:
-            yield self.delete_all_stats()
+        last_room_id = progress.get("last_room_id", "")
 
         def _get_next_batch(txn):
-            # Only fetch 250 rooms, so we don't fetch too many at once, even
-            # if those 250 rooms have less than batch_size state events.
             sql = """
-                SELECT room_id, events FROM %s_rooms
-                ORDER BY events DESC
-                LIMIT 250
-            """ % (
-                TEMP_TABLE,
-            )
-            txn.execute(sql)
-            rooms_to_work_on = txn.fetchall()
-
-            if not rooms_to_work_on:
-                return None
-
-            # Get how many are left to process, so we can give status on how
-            # far we are in processing
-            txn.execute("SELECT COUNT(*) FROM " + TEMP_TABLE + "_rooms")
-            progress["remaining"] = txn.fetchone()[0]
-
-            return rooms_to_work_on
+                    SELECT DISTINCT room_id FROM current_state_events
+                    WHERE room_id > ?
+                    ORDER BY room_id ASC
+                    LIMIT ?
+                """
+            txn.execute(sql, (last_room_id, batch_size))
+            return [r for r, in txn]
 
         rooms_to_work_on = yield self.runInteraction(
-            "populate_stats_temp_read", _get_next_batch
+            "populate_stats_rooms_get_batch", _get_next_batch
         )
 
         # No more rooms -- complete the transaction.
@@ -188,154 +169,28 @@ class StatsStore(StateDeltasStore):
             yield self._end_background_update("populate_stats_process_rooms")
             return 1
 
-        logger.info(
-            "Processing the next %d rooms of %d remaining",
-            len(rooms_to_work_on),
-            progress["remaining"],
-        )
-
-        # Number of state events we've processed by going through each room
-        processed_event_count = 0
-
-        for room_id, event_count in rooms_to_work_on:
-
-            current_state_ids = yield self.get_current_state_ids(room_id)
-
-            join_rules_id = current_state_ids.get((EventTypes.JoinRules, ""))
-            history_visibility_id = current_state_ids.get(
-                (EventTypes.RoomHistoryVisibility, "")
-            )
-            encryption_id = current_state_ids.get((EventTypes.RoomEncryption, ""))
-            name_id = current_state_ids.get((EventTypes.Name, ""))
-            topic_id = current_state_ids.get((EventTypes.Topic, ""))
-            avatar_id = current_state_ids.get((EventTypes.RoomAvatar, ""))
-            canonical_alias_id = current_state_ids.get((EventTypes.CanonicalAlias, ""))
-
-            event_ids = [
-                join_rules_id,
-                history_visibility_id,
-                encryption_id,
-                name_id,
-                topic_id,
-                avatar_id,
-                canonical_alias_id,
-            ]
-
-            state_events = yield self.get_events(
-                [ev for ev in event_ids if ev is not None]
-            )
-
-            def _get_or_none(event_id, arg):
-                event = state_events.get(event_id)
-                if event:
-                    return event.content.get(arg)
-                return None
-
-            yield self.update_room_state(
-                room_id,
-                {
-                    "join_rules": _get_or_none(join_rules_id, "join_rule"),
-                    "history_visibility": _get_or_none(
-                        history_visibility_id, "history_visibility"
-                    ),
-                    "encryption": _get_or_none(encryption_id, "algorithm"),
-                    "name": _get_or_none(name_id, "name"),
-                    "topic": _get_or_none(topic_id, "topic"),
-                    "avatar": _get_or_none(avatar_id, "url"),
-                    "canonical_alias": _get_or_none(canonical_alias_id, "alias"),
-                },
-            )
+        for room_id in rooms_to_work_on:
+            yield self._calculate_and_set_initial_state_for_room(room_id)
+            progress["last_room_id"] = room_id
 
-            now = self.hs.get_reactor().seconds()
-
-            # quantise time to the nearest bucket
-            now = (now // self.stats_bucket_size) * self.stats_bucket_size
-
-            def _fetch_data(txn):
-
-                # Get the current token of the room
-                current_token = self._get_max_stream_id_in_current_state_deltas_txn(txn)
-
-                current_state_events = len(current_state_ids)
-
-                membership_counts = self._get_user_counts_in_room_txn(txn, room_id)
-
-                total_state_events = self._get_total_state_event_counts_txn(
-                    txn, room_id
-                )
-
-                self._update_stats_txn(
-                    txn,
-                    "room",
-                    room_id,
-                    now,
-                    {
-                        "bucket_size": self.stats_bucket_size,
-                        "current_state_events": current_state_events,
-                        "joined_members": membership_counts.get(Membership.JOIN, 0),
-                        "invited_members": membership_counts.get(Membership.INVITE, 0),
-                        "left_members": membership_counts.get(Membership.LEAVE, 0),
-                        "banned_members": membership_counts.get(Membership.BAN, 0),
-                        "state_events": total_state_events,
-                    },
-                )
-                self._simple_insert_txn(
-                    txn,
-                    "room_stats_earliest_token",
-                    {"room_id": room_id, "token": current_token},
-                )
-
-                # We've finished a room. Delete it from the table.
-                self._simple_delete_one_txn(
-                    txn, TEMP_TABLE + "_rooms", {"room_id": room_id}
-                )
-
-            yield self.runInteraction("update_room_stats", _fetch_data)
-
-            # Update the remaining counter.
-            progress["remaining"] -= 1
-            yield self.runInteraction(
-                "populate_stats",
-                self._background_update_progress_txn,
-                "populate_stats_process_rooms",
-                progress,
-            )
-
-            processed_event_count += event_count
-
-            if processed_event_count > batch_size:
-                # Don't process any more rooms, we've hit our batch size.
-                return processed_event_count
+        yield self.runInteraction(
+            "_populate_stats_process_rooms",
+            self._background_update_progress_txn,
+            "populate_stats_process_rooms",
+            progress,
+        )
 
-        return processed_event_count
+        return len(rooms_to_work_on)
 
-    def delete_all_stats(self):
+    def get_stats_positions(self):
         """
-        Delete all statistics records.
+        Returns the stats processor positions.
         """
-
-        def _delete_all_stats_txn(txn):
-            txn.execute("DELETE FROM room_state")
-            txn.execute("DELETE FROM room_stats")
-            txn.execute("DELETE FROM room_stats_earliest_token")
-            txn.execute("DELETE FROM user_stats")
-
-        return self.runInteraction("delete_all_stats", _delete_all_stats_txn)
-
-    def get_stats_stream_pos(self):
         return self._simple_select_one_onecol(
-            table="stats_stream_pos",
+            table="stats_incremental_position",
             keyvalues={},
             retcol="stream_id",
-            desc="stats_stream_pos",
-        )
-
-    def update_stats_stream_pos(self, stream_id):
-        return self._simple_update_one(
-            table="stats_stream_pos",
-            keyvalues={},
-            updatevalues={"stream_id": stream_id},
-            desc="update_stats_stream_pos",
+            desc="stats_incremental_position",
         )
 
     def update_room_state(self, room_id, fields):
@@ -361,42 +216,87 @@ class StatsStore(StateDeltasStore):
                 fields[col] = None
 
         return self._simple_upsert(
-            table="room_state",
+            table="room_stats_state",
             keyvalues={"room_id": room_id},
             values=fields,
             desc="update_room_state",
         )
 
-    def get_deltas_for_room(self, room_id, start, size=100):
+    def get_statistics_for_subject(self, stats_type, stats_id, start, size=100):
         """
-        Get statistics deltas for a given room.
+        Get statistics for a given subject.
 
         Args:
-            room_id (str)
+            stats_type (str): The type of subject
+            stats_id (str): The ID of the subject (e.g. room_id or user_id)
             start (int): Pagination start. Number of entries, not timestamp.
             size (int): How many entries to return.
 
         Returns:
             Deferred[list[dict]], where the dict has the keys of
-            ABSOLUTE_STATS_FIELDS["room"] and "ts".
+            ABSOLUTE_STATS_FIELDS[stats_type],  and "bucket_size" and "end_ts".
         """
-        return self._simple_select_list_paginate(
-            "room_stats",
-            {"room_id": room_id},
-            "ts",
+        return self.runInteraction(
+            "get_statistics_for_subject",
+            self._get_statistics_for_subject_txn,
+            stats_type,
+            stats_id,
+            start,
+            size,
+        )
+
+    def _get_statistics_for_subject_txn(
+        self, txn, stats_type, stats_id, start, size=100
+    ):
+        """
+        Transaction-bound version of L{get_statistics_for_subject}.
+        """
+
+        table, id_col = TYPE_TO_TABLE[stats_type]
+        selected_columns = list(
+            ABSOLUTE_STATS_FIELDS[stats_type] + PER_SLICE_FIELDS[stats_type]
+        )
+
+        slice_list = self._simple_select_list_paginate_txn(
+            txn,
+            table + "_historical",
+            {id_col: stats_id},
+            "end_ts",
             start,
             size,
-            retcols=(list(ABSOLUTE_STATS_FIELDS["room"]) + ["ts"]),
+            retcols=selected_columns + ["bucket_size", "end_ts"],
             order_direction="DESC",
         )
 
-    def get_all_room_state(self):
-        return self._simple_select_list(
-            "room_state", None, retcols=("name", "topic", "canonical_alias")
+        return slice_list
+
+    def get_room_stats_state(self, room_id):
+        """
+        Returns the current room_stats_state for a room.
+
+        Args:
+            room_id (str): The ID of the room to return state for.
+
+        Returns (dict):
+            Dictionary containing these keys:
+                "name", "topic", "canonical_alias", "avatar", "join_rules",
+                "history_visibility"
+        """
+        return self._simple_select_one(
+            "room_stats_state",
+            {"room_id": room_id},
+            retcols=(
+                "name",
+                "topic",
+                "canonical_alias",
+                "avatar",
+                "join_rules",
+                "history_visibility",
+            ),
         )
 
     @cached()
-    def get_earliest_token_for_room_stats(self, room_id):
+    def get_earliest_token_for_stats(self, stats_type, id):
         """
         Fetch the "earliest token". This is used by the room stats delta
         processor to ignore deltas that have been processed between the
@@ -406,79 +306,571 @@ class StatsStore(StateDeltasStore):
         Returns:
             Deferred[int]
         """
+        table, id_col = TYPE_TO_TABLE[stats_type]
+
         return self._simple_select_one_onecol(
-            "room_stats_earliest_token",
-            {"room_id": room_id},
-            retcol="token",
+            "%s_current" % (table,),
+            keyvalues={id_col: id},
+            retcol="completed_delta_stream_id",
             allow_none=True,
         )
 
-    def update_stats(self, stats_type, stats_id, ts, fields):
-        table, id_col = TYPE_TO_ROOM[stats_type]
-        return self._simple_upsert(
-            table=table,
-            keyvalues={id_col: stats_id, "ts": ts},
-            values=fields,
-            desc="update_stats",
+    def bulk_update_stats_delta(self, ts, updates, stream_id):
+        """Bulk update stats tables for a given stream_id and updates the stats
+        incremental position.
+
+        Args:
+            ts (int): Current timestamp in ms
+            updates(dict[str, dict[str, dict[str, Counter]]]): The updates to
+                commit as a mapping stats_type -> stats_id -> field -> delta.
+            stream_id (int): Current position.
+
+        Returns:
+            Deferred
+        """
+
+        def _bulk_update_stats_delta_txn(txn):
+            for stats_type, stats_updates in updates.items():
+                for stats_id, fields in stats_updates.items():
+                    self._update_stats_delta_txn(
+                        txn,
+                        ts=ts,
+                        stats_type=stats_type,
+                        stats_id=stats_id,
+                        fields=fields,
+                        complete_with_stream_id=stream_id,
+                    )
+
+            self._simple_update_one_txn(
+                txn,
+                table="stats_incremental_position",
+                keyvalues={},
+                updatevalues={"stream_id": stream_id},
+            )
+
+        return self.runInteraction(
+            "bulk_update_stats_delta", _bulk_update_stats_delta_txn
         )
 
-    def _update_stats_txn(self, txn, stats_type, stats_id, ts, fields):
-        table, id_col = TYPE_TO_ROOM[stats_type]
-        return self._simple_upsert_txn(
-            txn, table=table, keyvalues={id_col: stats_id, "ts": ts}, values=fields
+    def update_stats_delta(
+        self,
+        ts,
+        stats_type,
+        stats_id,
+        fields,
+        complete_with_stream_id,
+        absolute_field_overrides=None,
+    ):
+        """
+        Updates the statistics for a subject, with a delta (difference/relative
+        change).
+
+        Args:
+            ts (int): timestamp of the change
+            stats_type (str): "room" or "user" – the kind of subject
+            stats_id (str): the subject's ID (room ID or user ID)
+            fields (dict[str, int]): Deltas of stats values.
+            complete_with_stream_id (int, optional):
+                If supplied, converts an incomplete row into a complete row,
+                with the supplied stream_id marked as the stream_id where the
+                row was completed.
+            absolute_field_overrides (dict[str, int]): Current stats values
+                (i.e. not deltas) of absolute fields.
+                Does not work with per-slice fields.
+        """
+
+        return self.runInteraction(
+            "update_stats_delta",
+            self._update_stats_delta_txn,
+            ts,
+            stats_type,
+            stats_id,
+            fields,
+            complete_with_stream_id=complete_with_stream_id,
+            absolute_field_overrides=absolute_field_overrides,
         )
 
-    def update_stats_delta(self, ts, stats_type, stats_id, field, value):
-        def _update_stats_delta(txn):
-            table, id_col = TYPE_TO_ROOM[stats_type]
-
-            sql = (
-                "SELECT * FROM %s"
-                " WHERE %s=? and ts=("
-                "  SELECT MAX(ts) FROM %s"
-                "  WHERE %s=?"
-                ")"
-            ) % (table, id_col, table, id_col)
-            txn.execute(sql, (stats_id, stats_id))
-            rows = self.cursor_to_dict(txn)
-            if len(rows) == 0:
-                # silently skip as we don't have anything to apply a delta to yet.
-                # this tries to minimise any race between the initial sync and
-                # subsequent deltas arriving.
-                return
-
-            current_ts = ts
-            latest_ts = rows[0]["ts"]
-            if current_ts < latest_ts:
-                # This one is in the past, but we're just encountering it now.
-                # Mark it as part of the current bucket.
-                current_ts = latest_ts
-            elif ts != latest_ts:
-                # we have to copy our absolute counters over to the new entry.
-                values = {
-                    key: rows[0][key] for key in ABSOLUTE_STATS_FIELDS[stats_type]
-                }
-                values[id_col] = stats_id
-                values["ts"] = ts
-                values["bucket_size"] = self.stats_bucket_size
-
-                self._simple_insert_txn(txn, table=table, values=values)
-
-            # actually update the new value
-            if stats_type in ABSOLUTE_STATS_FIELDS[stats_type]:
-                self._simple_update_txn(
-                    txn,
-                    table=table,
-                    keyvalues={id_col: stats_id, "ts": current_ts},
-                    updatevalues={field: value},
+    def _update_stats_delta_txn(
+        self,
+        txn,
+        ts,
+        stats_type,
+        stats_id,
+        fields,
+        complete_with_stream_id,
+        absolute_field_overrides=None,
+    ):
+        if absolute_field_overrides is None:
+            absolute_field_overrides = {}
+
+        table, id_col = TYPE_TO_TABLE[stats_type]
+
+        quantised_ts = self.quantise_stats_time(int(ts))
+        end_ts = quantised_ts + self.stats_bucket_size
+
+        # Lets be paranoid and check that all the given field names are known
+        abs_field_names = ABSOLUTE_STATS_FIELDS[stats_type]
+        slice_field_names = PER_SLICE_FIELDS[stats_type]
+        for field in chain(fields.keys(), absolute_field_overrides.keys()):
+            if field not in abs_field_names and field not in slice_field_names:
+                # guard against potential SQL injection dodginess
+                raise ValueError(
+                    "%s is not a recognised field"
+                    " for stats type %s" % (field, stats_type)
                 )
+
+        # Per slice fields do not get added to the _current table
+
+        # This calculates the deltas (`field = field + ?` values)
+        # for absolute fields,
+        # * defaulting to 0 if not specified
+        #     (required for the INSERT part of upserting to work)
+        # * omitting overrides specified in `absolute_field_overrides`
+        deltas_of_absolute_fields = {
+            key: fields.get(key, 0)
+            for key in abs_field_names
+            if key not in absolute_field_overrides
+        }
+
+        # Keep the delta stream ID field up to date
+        absolute_field_overrides = absolute_field_overrides.copy()
+        absolute_field_overrides["completed_delta_stream_id"] = complete_with_stream_id
+
+        # first upsert the `_current` table
+        self._upsert_with_additive_relatives_txn(
+            txn=txn,
+            table=table + "_current",
+            keyvalues={id_col: stats_id},
+            absolutes=absolute_field_overrides,
+            additive_relatives=deltas_of_absolute_fields,
+        )
+
+        per_slice_additive_relatives = {
+            key: fields.get(key, 0) for key in slice_field_names
+        }
+        self._upsert_copy_from_table_with_additive_relatives_txn(
+            txn=txn,
+            into_table=table + "_historical",
+            keyvalues={id_col: stats_id},
+            extra_dst_insvalues={"bucket_size": self.stats_bucket_size},
+            extra_dst_keyvalues={"end_ts": end_ts},
+            additive_relatives=per_slice_additive_relatives,
+            src_table=table + "_current",
+            copy_columns=abs_field_names,
+        )
+
+    def _upsert_with_additive_relatives_txn(
+        self, txn, table, keyvalues, absolutes, additive_relatives
+    ):
+        """Used to update values in the stats tables.
+
+        This is basically a slightly convoluted upsert that *adds* to any
+        existing rows.
+
+        Args:
+            txn
+            table (str): Table name
+            keyvalues (dict[str, any]): Row-identifying key values
+            absolutes (dict[str, any]): Absolute (set) fields
+            additive_relatives (dict[str, int]): Fields that will be added onto
+                if existing row present.
+        """
+        if self.database_engine.can_native_upsert:
+            absolute_updates = [
+                "%(field)s = EXCLUDED.%(field)s" % {"field": field}
+                for field in absolutes.keys()
+            ]
+
+            relative_updates = [
+                "%(field)s = EXCLUDED.%(field)s + %(table)s.%(field)s"
+                % {"table": table, "field": field}
+                for field in additive_relatives.keys()
+            ]
+
+            insert_cols = []
+            qargs = []
+
+            for (key, val) in chain(
+                keyvalues.items(), absolutes.items(), additive_relatives.items()
+            ):
+                insert_cols.append(key)
+                qargs.append(val)
+
+            sql = """
+                INSERT INTO %(table)s (%(insert_cols_cs)s)
+                VALUES (%(insert_vals_qs)s)
+                ON CONFLICT (%(key_columns)s) DO UPDATE SET %(updates)s
+            """ % {
+                "table": table,
+                "insert_cols_cs": ", ".join(insert_cols),
+                "insert_vals_qs": ", ".join(
+                    ["?"] * (len(keyvalues) + len(absolutes) + len(additive_relatives))
+                ),
+                "key_columns": ", ".join(keyvalues),
+                "updates": ", ".join(chain(absolute_updates, relative_updates)),
+            }
+
+            txn.execute(sql, qargs)
+        else:
+            self.database_engine.lock_table(txn, table)
+            retcols = list(chain(absolutes.keys(), additive_relatives.keys()))
+            current_row = self._simple_select_one_txn(
+                txn, table, keyvalues, retcols, allow_none=True
+            )
+            if current_row is None:
+                merged_dict = {**keyvalues, **absolutes, **additive_relatives}
+                self._simple_insert_txn(txn, table, merged_dict)
+            else:
+                for (key, val) in additive_relatives.items():
+                    current_row[key] += val
+                current_row.update(absolutes)
+                self._simple_update_one_txn(txn, table, keyvalues, current_row)
+
+    def _upsert_copy_from_table_with_additive_relatives_txn(
+        self,
+        txn,
+        into_table,
+        keyvalues,
+        extra_dst_keyvalues,
+        extra_dst_insvalues,
+        additive_relatives,
+        src_table,
+        copy_columns,
+    ):
+        """Updates the historic stats table with latest updates.
+
+        This involves copying "absolute" fields from the `_current` table, and
+        adding relative fields to any existing values.
+
+        Args:
+             txn: Transaction
+             into_table (str): The destination table to UPSERT the row into
+             keyvalues (dict[str, any]): Row-identifying key values
+             extra_dst_keyvalues (dict[str, any]): Additional keyvalues
+                for `into_table`.
+             extra_dst_insvalues (dict[str, any]): Additional values to insert
+                on new row creation for `into_table`.
+             additive_relatives (dict[str, any]): Fields that will be added onto
+                if existing row present. (Must be disjoint from copy_columns.)
+             src_table (str): The source table to copy from
+             copy_columns (iterable[str]): The list of columns to copy
+        """
+        if self.database_engine.can_native_upsert:
+            ins_columns = chain(
+                keyvalues,
+                copy_columns,
+                additive_relatives,
+                extra_dst_keyvalues,
+                extra_dst_insvalues,
+            )
+            sel_exprs = chain(
+                keyvalues,
+                copy_columns,
+                (
+                    "?"
+                    for _ in chain(
+                        additive_relatives, extra_dst_keyvalues, extra_dst_insvalues
+                    )
+                ),
+            )
+            keyvalues_where = ("%s = ?" % f for f in keyvalues)
+
+            sets_cc = ("%s = EXCLUDED.%s" % (f, f) for f in copy_columns)
+            sets_ar = (
+                "%s = EXCLUDED.%s + %s.%s" % (f, f, into_table, f)
+                for f in additive_relatives
+            )
+
+            sql = """
+                INSERT INTO %(into_table)s (%(ins_columns)s)
+                SELECT %(sel_exprs)s
+                FROM %(src_table)s
+                WHERE %(keyvalues_where)s
+                ON CONFLICT (%(keyvalues)s)
+                DO UPDATE SET %(sets)s
+            """ % {
+                "into_table": into_table,
+                "ins_columns": ", ".join(ins_columns),
+                "sel_exprs": ", ".join(sel_exprs),
+                "keyvalues_where": " AND ".join(keyvalues_where),
+                "src_table": src_table,
+                "keyvalues": ", ".join(
+                    chain(keyvalues.keys(), extra_dst_keyvalues.keys())
+                ),
+                "sets": ", ".join(chain(sets_cc, sets_ar)),
+            }
+
+            qargs = list(
+                chain(
+                    additive_relatives.values(),
+                    extra_dst_keyvalues.values(),
+                    extra_dst_insvalues.values(),
+                    keyvalues.values(),
+                )
+            )
+            txn.execute(sql, qargs)
+        else:
+            self.database_engine.lock_table(txn, into_table)
+            src_row = self._simple_select_one_txn(
+                txn, src_table, keyvalues, copy_columns
+            )
+            all_dest_keyvalues = {**keyvalues, **extra_dst_keyvalues}
+            dest_current_row = self._simple_select_one_txn(
+                txn,
+                into_table,
+                keyvalues=all_dest_keyvalues,
+                retcols=list(chain(additive_relatives.keys(), copy_columns)),
+                allow_none=True,
+            )
+
+            if dest_current_row is None:
+                merged_dict = {
+                    **keyvalues,
+                    **extra_dst_keyvalues,
+                    **extra_dst_insvalues,
+                    **src_row,
+                    **additive_relatives,
+                }
+                self._simple_insert_txn(txn, into_table, merged_dict)
             else:
-                sql = ("UPDATE %s SET %s=%s+? WHERE %s=? AND ts=?") % (
-                    table,
-                    field,
-                    field,
-                    id_col,
+                for (key, val) in additive_relatives.items():
+                    src_row[key] = dest_current_row[key] + val
+                self._simple_update_txn(txn, into_table, all_dest_keyvalues, src_row)
+
+    def get_changes_room_total_events_and_bytes(self, min_pos, max_pos):
+        """Fetches the counts of events in the given range of stream IDs.
+
+        Args:
+            min_pos (int)
+            max_pos (int)
+
+        Returns:
+            Deferred[dict[str, dict[str, int]]]: Mapping of room ID to field
+            changes.
+        """
+
+        return self.runInteraction(
+            "stats_incremental_total_events_and_bytes",
+            self.get_changes_room_total_events_and_bytes_txn,
+            min_pos,
+            max_pos,
+        )
+
+    def get_changes_room_total_events_and_bytes_txn(self, txn, low_pos, high_pos):
+        """Gets the total_events and total_event_bytes counts for rooms and
+        senders, in a range of stream_orderings (including backfilled events).
+
+        Args:
+            txn
+            low_pos (int): Low stream ordering
+            high_pos (int): High stream ordering
+
+        Returns:
+            tuple[dict[str, dict[str, int]], dict[str, dict[str, int]]]: The
+            room and user deltas for total_events/total_event_bytes in the
+            format of `stats_id` -> fields
+        """
+
+        if low_pos >= high_pos:
+            # nothing to do here.
+            return {}, {}
+
+        if isinstance(self.database_engine, PostgresEngine):
+            new_bytes_expression = "OCTET_LENGTH(json)"
+        else:
+            new_bytes_expression = "LENGTH(CAST(json AS BLOB))"
+
+        sql = """
+            SELECT events.room_id, COUNT(*) AS new_events, SUM(%s) AS new_bytes
+            FROM events INNER JOIN event_json USING (event_id)
+            WHERE (? < stream_ordering AND stream_ordering <= ?)
+                OR (? <= stream_ordering AND stream_ordering <= ?)
+            GROUP BY events.room_id
+        """ % (
+            new_bytes_expression,
+        )
+
+        txn.execute(sql, (low_pos, high_pos, -high_pos, -low_pos))
+
+        room_deltas = {
+            room_id: {"total_events": new_events, "total_event_bytes": new_bytes}
+            for room_id, new_events, new_bytes in txn
+        }
+
+        sql = """
+            SELECT events.sender, COUNT(*) AS new_events, SUM(%s) AS new_bytes
+            FROM events INNER JOIN event_json USING (event_id)
+            WHERE (? < stream_ordering AND stream_ordering <= ?)
+                OR (? <= stream_ordering AND stream_ordering <= ?)
+            GROUP BY events.sender
+        """ % (
+            new_bytes_expression,
+        )
+
+        txn.execute(sql, (low_pos, high_pos, -high_pos, -low_pos))
+
+        user_deltas = {
+            user_id: {"total_events": new_events, "total_event_bytes": new_bytes}
+            for user_id, new_events, new_bytes in txn
+            if self.hs.is_mine_id(user_id)
+        }
+
+        return room_deltas, user_deltas
+
+    @defer.inlineCallbacks
+    def _calculate_and_set_initial_state_for_room(self, room_id):
+        """Calculate and insert an entry into room_stats_current.
+
+        Args:
+            room_id (str)
+
+        Returns:
+            Deferred[tuple[dict, dict, int]]: A tuple of room state, membership
+            counts and stream position.
+        """
+
+        def _fetch_current_state_stats(txn):
+            pos = self.get_room_max_stream_ordering()
+
+            rows = self._simple_select_many_txn(
+                txn,
+                table="current_state_events",
+                column="type",
+                iterable=[
+                    EventTypes.Create,
+                    EventTypes.JoinRules,
+                    EventTypes.RoomHistoryVisibility,
+                    EventTypes.Encryption,
+                    EventTypes.Name,
+                    EventTypes.Topic,
+                    EventTypes.RoomAvatar,
+                    EventTypes.CanonicalAlias,
+                ],
+                keyvalues={"room_id": room_id, "state_key": ""},
+                retcols=["event_id"],
+            )
+
+            event_ids = [row["event_id"] for row in rows]
+
+            txn.execute(
+                """
+                    SELECT membership, count(*) FROM current_state_events
+                    WHERE room_id = ? AND type = 'm.room.member'
+                    GROUP BY membership
+                """,
+                (room_id,),
+            )
+            membership_counts = {membership: cnt for membership, cnt in txn}
+
+            txn.execute(
+                """
+                    SELECT COALESCE(count(*), 0) FROM current_state_events
+                    WHERE room_id = ?
+                """,
+                (room_id,),
+            )
+
+            current_state_events_count, = txn.fetchone()
+
+            users_in_room = self.get_users_in_room_txn(txn, room_id)
+
+            return (
+                event_ids,
+                membership_counts,
+                current_state_events_count,
+                users_in_room,
+                pos,
+            )
+
+        (
+            event_ids,
+            membership_counts,
+            current_state_events_count,
+            users_in_room,
+            pos,
+        ) = yield self.runInteraction(
+            "get_initial_state_for_room", _fetch_current_state_stats
+        )
+
+        state_event_map = yield self.get_events(event_ids, get_prev_content=False)
+
+        room_state = {
+            "join_rules": None,
+            "history_visibility": None,
+            "encryption": None,
+            "name": None,
+            "topic": None,
+            "avatar": None,
+            "canonical_alias": None,
+            "is_federatable": True,
+        }
+
+        for event in state_event_map.values():
+            if event.type == EventTypes.JoinRules:
+                room_state["join_rules"] = event.content.get("join_rule")
+            elif event.type == EventTypes.RoomHistoryVisibility:
+                room_state["history_visibility"] = event.content.get(
+                    "history_visibility"
                 )
-                txn.execute(sql, (value, stats_id, current_ts))
+            elif event.type == EventTypes.Encryption:
+                room_state["encryption"] = event.content.get("algorithm")
+            elif event.type == EventTypes.Name:
+                room_state["name"] = event.content.get("name")
+            elif event.type == EventTypes.Topic:
+                room_state["topic"] = event.content.get("topic")
+            elif event.type == EventTypes.RoomAvatar:
+                room_state["avatar"] = event.content.get("url")
+            elif event.type == EventTypes.CanonicalAlias:
+                room_state["canonical_alias"] = event.content.get("alias")
+            elif event.type == EventTypes.Create:
+                room_state["is_federatable"] = event.content.get("m.federate", True)
+
+        yield self.update_room_state(room_id, room_state)
+
+        local_users_in_room = [u for u in users_in_room if self.hs.is_mine_id(u)]
+
+        yield self.update_stats_delta(
+            ts=self.clock.time_msec(),
+            stats_type="room",
+            stats_id=room_id,
+            fields={},
+            complete_with_stream_id=pos,
+            absolute_field_overrides={
+                "current_state_events": current_state_events_count,
+                "joined_members": membership_counts.get(Membership.JOIN, 0),
+                "invited_members": membership_counts.get(Membership.INVITE, 0),
+                "left_members": membership_counts.get(Membership.LEAVE, 0),
+                "banned_members": membership_counts.get(Membership.BAN, 0),
+                "local_users_in_room": len(local_users_in_room),
+            },
+        )
+
+    @defer.inlineCallbacks
+    def _calculate_and_set_initial_state_for_user(self, user_id):
+        def _calculate_and_set_initial_state_for_user_txn(txn):
+            pos = self._get_max_stream_id_in_current_state_deltas_txn(txn)
 
-        return self.runInteraction("update_stats_delta", _update_stats_delta)
+            txn.execute(
+                """
+                SELECT COUNT(distinct room_id) FROM current_state_events
+                    WHERE type = 'm.room.member' AND state_key = ?
+                        AND membership = 'join'
+                """,
+                (user_id,),
+            )
+            count, = txn.fetchone()
+            return count, pos
+
+        joined_rooms, pos = yield self.runInteraction(
+            "calculate_and_set_initial_state_for_user",
+            _calculate_and_set_initial_state_for_user_txn,
+        )
+
+        yield self.update_stats_delta(
+            ts=self.clock.time_msec(),
+            stats_type="user",
+            stats_id=user_id,
+            fields={},
+            complete_with_stream_id=pos,
+            absolute_field_overrides={"joined_rooms": joined_rooms},
+        )
diff --git a/synapse/storage/stream.py b/synapse/storage/stream.py
index 856c2ee8d8..490454f19a 100644
--- a/synapse/storage/stream.py
+++ b/synapse/storage/stream.py
@@ -364,7 +364,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             the chunk of events returned.
         """
         if from_key == to_key:
-            return ([], from_key)
+            return [], from_key
 
         from_id = RoomStreamToken.parse_stream_token(from_key).stream
         to_id = RoomStreamToken.parse_stream_token(to_key).stream
@@ -374,7 +374,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         )
 
         if not has_changed:
-            return ([], from_key)
+            return [], from_key
 
         def f(txn):
             sql = (
@@ -407,7 +407,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             # get.
             key = from_key
 
-        return (ret, key)
+        return ret, key
 
     @defer.inlineCallbacks
     def get_membership_changes_for_user(self, user_id, from_key, to_key):
@@ -496,7 +496,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         """
         # Allow a zero limit here, and no-op.
         if limit == 0:
-            return ([], end_token)
+            return [], end_token
 
         end_token = RoomStreamToken.parse(end_token)
 
@@ -511,7 +511,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         # We want to return the results in ascending order.
         rows.reverse()
 
-        return (rows, token)
+        return rows, token
 
     def get_room_event_after_stream_ordering(self, room_id, stream_ordering):
         """Gets details of the first event in a room at or after a stream ordering
@@ -783,7 +783,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         events = yield self.get_events_as_list(event_ids)
 
-        return (upper_bound, events)
+        return upper_bound, events
 
     def get_federation_out_pos(self, typ):
         return self._simple_select_one_onecol(
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index f1c8d99419..cbb0a4810a 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -195,6 +195,6 @@ class ChainedIdGenerator(object):
         with self._lock:
             if self._unfinished_ids:
                 stream_id, chained_id = self._unfinished_ids[0]
-                return (stream_id - 1, chained_id)
+                return stream_id - 1, chained_id
 
-            return (self._current_max, self.chained_generator.get_current_token())
+            return self._current_max, self.chained_generator.get_current_token()
diff --git a/synapse/streams/config.py b/synapse/streams/config.py
index f7f5906a99..02994ab2a5 100644
--- a/synapse/streams/config.py
+++ b/synapse/streams/config.py
@@ -37,7 +37,7 @@ class SourcePaginationConfig(object):
         self.limit = min(int(limit), MAX_LIMIT) if limit is not None else None
 
     def __repr__(self):
-        return ("StreamConfig(from_key=%r, to_key=%r, direction=%r, limit=%r)") % (
+        return "StreamConfig(from_key=%r, to_key=%r, direction=%r, limit=%r)" % (
             self.from_key,
             self.to_key,
             self.direction,
diff --git a/synapse/util/hash.py b/synapse/util/hash.py
deleted file mode 100644
index 359168704e..0000000000
--- a/synapse/util/hash.py
+++ /dev/null
@@ -1,33 +0,0 @@
-# -*- coding: utf-8 -*-
-
-# Copyright 2019 The Matrix.org Foundation C.I.C.
-#
-# 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 hashlib
-
-import unpaddedbase64
-
-
-def sha256_and_url_safe_base64(input_text):
-    """SHA256 hash an input string, encode the digest as url-safe base64, and
-    return
-
-    :param input_text: string to hash
-    :type input_text: str
-
-    :returns a sha256 hashed and url-safe base64 encoded digest
-    :rtype: str
-    """
-    digest = hashlib.sha256(input_text.encode()).digest()
-    return unpaddedbase64.encode_base64(digest, urlsafe=True)