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authorErik Johnston <erik@matrix.org>2019-08-22 13:41:57 +0100
committerErik Johnston <erik@matrix.org>2019-08-22 13:41:57 +0100
commit1e4b4d85e7f4604d0617bba01b279f3dc2ced1d2 (patch)
tree99baa32e4bc755be4c21f5d711b07a86bfff8020
parentMake changelog entry be a feature (diff)
parentMerge pull request #5850 from matrix-org/erikj/retry_well_known_on_fail (diff)
downloadsynapse-1e4b4d85e7f4604d0617bba01b279f3dc2ced1d2.tar.xz
Merge branch 'develop' of github.com:matrix-org/synapse into erikj/reliable_lookups
-rw-r--r--CHANGES.md15
-rw-r--r--changelog.d/5776.misc1
-rw-r--r--changelog.d/5845.feature1
-rw-r--r--changelog.d/5850.feature1
-rw-r--r--changelog.d/5855.misc1
-rw-r--r--changelog.d/5856.feature1
-rw-r--r--changelog.d/5857.bugfix1
-rw-r--r--changelog.d/5860.misc1
-rw-r--r--changelog.d/5863.bugfix1
-rw-r--r--changelog.d/5885.bugfix1
-rw-r--r--changelog.d/5886.misc1
-rw-r--r--changelog.d/5893.misc1
-rw-r--r--changelog.d/5894.misc1
-rw-r--r--changelog.d/5896.misc1
-rw-r--r--debian/changelog14
-rw-r--r--docs/admin_api/purge_room.md18
-rw-r--r--synapse/__init__.py2
-rw-r--r--synapse/api/auth.py4
-rw-r--r--synapse/app/_base.py47
-rw-r--r--synapse/app/homeserver.py2
-rw-r--r--synapse/appservice/scheduler.py153
-rw-r--r--synapse/config/emailconfig.py16
-rw-r--r--synapse/crypto/keyring.py12
-rw-r--r--synapse/federation/federation_server.py3
-rw-r--r--synapse/federation/transport/server.py13
-rw-r--r--synapse/handlers/e2e_keys.py52
-rw-r--r--synapse/handlers/e2e_room_keys.py28
-rw-r--r--synapse/handlers/pagination.py17
-rw-r--r--synapse/handlers/sync.py22
-rw-r--r--synapse/http/federation/matrix_federation_agent.py26
-rw-r--r--synapse/http/federation/well_known_resolver.py126
-rw-r--r--synapse/http/matrixfederationclient.py23
-rw-r--r--synapse/logging/opentracing.py67
-rw-r--r--synapse/python_dependencies.py1
-rw-r--r--synapse/rest/admin/__init__.py2
-rw-r--r--synapse/rest/admin/purge_room_servlet.py57
-rw-r--r--synapse/rest/client/v2_alpha/account.py4
-rw-r--r--synapse/rest/client/v2_alpha/keys.py13
-rw-r--r--synapse/storage/e2e_room_keys.py16
-rw-r--r--synapse/storage/end_to_end_keys.py38
-rw-r--r--synapse/storage/events.py151
-rw-r--r--synapse/storage/room.py35
-rw-r--r--synapse/storage/schema/delta/56/drop_unused_event_tables.sql20
-rw-r--r--synapse/storage/schema/delta/56/fix_room_keys_index.sql18
-rw-r--r--synapse/storage/schema/delta/56/users_in_public_rooms_idx.sql17
-rw-r--r--tests/appservice/test_scheduler.py6
-rw-r--r--tests/http/federation/test_matrix_federation_agent.py83
47 files changed, 850 insertions, 284 deletions
diff --git a/CHANGES.md b/CHANGES.md
index d13dcb717e..f25c7d0c1a 100644
--- a/CHANGES.md
+++ b/CHANGES.md
@@ -1,3 +1,18 @@
+Synapse 1.3.1 (2019-08-17)
+==========================
+
+Features
+--------
+
+- Drop hard dependency on `sdnotify` python package. ([\#5871](https://github.com/matrix-org/synapse/issues/5871))
+
+
+Bugfixes
+--------
+
+- Fix startup issue (hang on ACME provisioning) due to ordering of Twisted reactor startup. Thanks to @chrismoos for supplying the fix. ([\#5867](https://github.com/matrix-org/synapse/issues/5867))
+
+
 Synapse 1.3.0 (2019-08-15)
 ==========================
 
diff --git a/changelog.d/5776.misc b/changelog.d/5776.misc
new file mode 100644
index 0000000000..1fb1b9c152
--- /dev/null
+++ b/changelog.d/5776.misc
@@ -0,0 +1 @@
+Update opentracing docs to use the unified `trace` method.
diff --git a/changelog.d/5845.feature b/changelog.d/5845.feature
new file mode 100644
index 0000000000..7b0dc9a95e
--- /dev/null
+++ b/changelog.d/5845.feature
@@ -0,0 +1 @@
+Add an admin API to purge old rooms from the database.
diff --git a/changelog.d/5850.feature b/changelog.d/5850.feature
new file mode 100644
index 0000000000..b565929a54
--- /dev/null
+++ b/changelog.d/5850.feature
@@ -0,0 +1 @@
+Add retry to well-known lookups if we have recently seen a valid well-known record for the server.
diff --git a/changelog.d/5855.misc b/changelog.d/5855.misc
new file mode 100644
index 0000000000..32db7fbe37
--- /dev/null
+++ b/changelog.d/5855.misc
@@ -0,0 +1 @@
+Opentracing for room and e2e keys.
diff --git a/changelog.d/5856.feature b/changelog.d/5856.feature
new file mode 100644
index 0000000000..f4310b9244
--- /dev/null
+++ b/changelog.d/5856.feature
@@ -0,0 +1 @@
+Add a tag recording a request's authenticated entity and corresponding servlet in opentracing.
diff --git a/changelog.d/5857.bugfix b/changelog.d/5857.bugfix
new file mode 100644
index 0000000000..008799ccbb
--- /dev/null
+++ b/changelog.d/5857.bugfix
@@ -0,0 +1 @@
+Fix database index so that different backup versions can have the same sessions.
diff --git a/changelog.d/5860.misc b/changelog.d/5860.misc
new file mode 100644
index 0000000000..f9960b17b4
--- /dev/null
+++ b/changelog.d/5860.misc
@@ -0,0 +1 @@
+Remove log line for debugging issue #5407.
diff --git a/changelog.d/5863.bugfix b/changelog.d/5863.bugfix
new file mode 100644
index 0000000000..bceae5be67
--- /dev/null
+++ b/changelog.d/5863.bugfix
@@ -0,0 +1 @@
+Fix Synapse looking for config options `password_reset_failure_template` and `password_reset_success_template`, when they are actually `password_reset_template_failure_html`, `password_reset_template_success_html`.
diff --git a/changelog.d/5885.bugfix b/changelog.d/5885.bugfix
new file mode 100644
index 0000000000..411d925fd4
--- /dev/null
+++ b/changelog.d/5885.bugfix
@@ -0,0 +1 @@
+Fix stack overflow when recovering an appservice which had an outage.
diff --git a/changelog.d/5886.misc b/changelog.d/5886.misc
new file mode 100644
index 0000000000..22adba3d85
--- /dev/null
+++ b/changelog.d/5886.misc
@@ -0,0 +1 @@
+Refactor the Appservice scheduler code.
diff --git a/changelog.d/5893.misc b/changelog.d/5893.misc
new file mode 100644
index 0000000000..07ee4888dc
--- /dev/null
+++ b/changelog.d/5893.misc
@@ -0,0 +1 @@
+Drop some unused tables.
diff --git a/changelog.d/5894.misc b/changelog.d/5894.misc
new file mode 100644
index 0000000000..fca4485ff7
--- /dev/null
+++ b/changelog.d/5894.misc
@@ -0,0 +1 @@
+Add missing index on users_in_public_rooms to improve the performance of directory queries.
diff --git a/changelog.d/5896.misc b/changelog.d/5896.misc
new file mode 100644
index 0000000000..ed47c747bd
--- /dev/null
+++ b/changelog.d/5896.misc
@@ -0,0 +1 @@
+Improve the logging when we have an error when fetching signing keys.
diff --git a/debian/changelog b/debian/changelog
index 83232a0bad..76efc442d7 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,8 +1,19 @@
+matrix-synapse-py3 (1.3.1) stable; urgency=medium
+
+  * New synapse release 1.3.1.
+
+ -- Synapse Packaging team <packages@matrix.org>  Sat, 17 Aug 2019 09:15:49 +0100
+
 matrix-synapse-py3 (1.3.0) stable; urgency=medium
 
   [ Andrew Morgan ]
   * Remove libsqlite3-dev from required build dependencies.
 
+  [ Synapse Packaging team ]
+  * New synapse release 1.3.0.
+
+ -- Synapse Packaging team <packages@matrix.org>  Thu, 15 Aug 2019 12:04:23 +0100
+
 matrix-synapse-py3 (1.2.0) stable; urgency=medium
 
   [ Amber Brown ]
@@ -13,9 +24,8 @@ matrix-synapse-py3 (1.2.0) stable; urgency=medium
 
   [ Synapse Packaging team ]
   * New synapse release 1.2.0.
-  * New synapse release 1.3.0.
 
- -- Synapse Packaging team <packages@matrix.org>  Thu, 15 Aug 2019 12:04:23 +0100
+ -- Synapse Packaging team <packages@matrix.org>  Thu, 25 Jul 2019 14:10:07 +0100
 
 matrix-synapse-py3 (1.1.0) stable; urgency=medium
 
diff --git a/docs/admin_api/purge_room.md b/docs/admin_api/purge_room.md
new file mode 100644
index 0000000000..64ea7b6a64
--- /dev/null
+++ b/docs/admin_api/purge_room.md
@@ -0,0 +1,18 @@
+Purge room API
+==============
+
+This API will remove all trace of a room from your database.
+
+All local users must have left the room before it can be removed.
+
+The API is:
+
+```
+POST /_synapse/admin/v1/purge_room
+
+{
+    "room_id": "!room:id"
+}
+```
+
+You must authenticate using the access token of an admin user.
diff --git a/synapse/__init__.py b/synapse/__init__.py
index 02ae90b072..6766ef445c 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -35,4 +35,4 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.3.0"
+__version__ = "1.3.1"
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 179644852a..7b3a5a8221 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -22,6 +22,7 @@ from netaddr import IPAddress
 
 from twisted.internet import defer
 
+import synapse.logging.opentracing as opentracing
 import synapse.types
 from synapse import event_auth
 from synapse.api.constants import EventTypes, JoinRules, Membership
@@ -178,6 +179,7 @@ class Auth(object):
     def get_public_keys(self, invite_event):
         return event_auth.get_public_keys(invite_event)
 
+    @opentracing.trace
     @defer.inlineCallbacks
     def get_user_by_req(
         self, request, allow_guest=False, rights="access", allow_expired=False
@@ -209,6 +211,7 @@ class Auth(object):
             user_id, app_service = yield self._get_appservice_user_id(request)
             if user_id:
                 request.authenticated_entity = user_id
+                opentracing.set_tag("authenticated_entity", user_id)
 
                 if ip_addr and self.hs.config.track_appservice_user_ips:
                     yield self.store.insert_client_ip(
@@ -259,6 +262,7 @@ class Auth(object):
                 )
 
             request.authenticated_entity = user.to_string()
+            opentracing.set_tag("authenticated_entity", user.to_string())
 
             return synapse.types.create_requester(
                 user, token_id, is_guest, device_id, app_service=app_service
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index c010e70955..69dcf3523f 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -17,10 +17,10 @@ import gc
 import logging
 import os
 import signal
+import socket
 import sys
 import traceback
 
-import sdnotify
 from daemonize import Daemonize
 
 from twisted.internet import defer, error, reactor
@@ -246,13 +246,12 @@ def start(hs, listeners=None):
             def handle_sighup(*args, **kwargs):
                 # Tell systemd our state, if we're using it. This will silently fail if
                 # we're not using systemd.
-                sd_channel = sdnotify.SystemdNotifier()
-                sd_channel.notify("RELOADING=1")
+                sdnotify(b"RELOADING=1")
 
                 for i in _sighup_callbacks:
                     i(hs)
 
-                sd_channel.notify("READY=1")
+                sdnotify(b"READY=1")
 
             signal.signal(signal.SIGHUP, handle_sighup)
 
@@ -308,16 +307,12 @@ def setup_sdnotify(hs):
 
     # Tell systemd our state, if we're using it. This will silently fail if
     # we're not using systemd.
-    sd_channel = sdnotify.SystemdNotifier()
-
     hs.get_reactor().addSystemEventTrigger(
-        "after",
-        "startup",
-        lambda: sd_channel.notify("READY=1\nMAINPID=%s" % (os.getpid())),
+        "after", "startup", sdnotify, b"READY=1\nMAINPID=%i" % (os.getpid(),)
     )
 
     hs.get_reactor().addSystemEventTrigger(
-        "before", "shutdown", lambda: sd_channel.notify("STOPPING=1")
+        "before", "shutdown", sdnotify, b"STOPPING=1"
     )
 
 
@@ -414,3 +409,35 @@ class _DeferredResolutionReceiver(object):
     def resolutionComplete(self):
         self._deferred.callback(())
         self._receiver.resolutionComplete()
+
+
+sdnotify_sockaddr = os.getenv("NOTIFY_SOCKET")
+
+
+def sdnotify(state):
+    """
+    Send a notification to systemd, if the NOTIFY_SOCKET env var is set.
+
+    This function is based on the sdnotify python package, but since it's only a few
+    lines of code, it's easier to duplicate it here than to add a dependency on a
+    package which many OSes don't include as a matter of principle.
+
+    Args:
+        state (bytes): notification to send
+    """
+    if not isinstance(state, bytes):
+        raise TypeError("sdnotify should be called with a bytes")
+    if not sdnotify_sockaddr:
+        return
+    addr = sdnotify_sockaddr
+    if addr[0] == "@":
+        addr = "\0" + addr[1:]
+
+    try:
+        with socket.socket(socket.AF_UNIX, socket.SOCK_DGRAM) as sock:
+            sock.connect(addr)
+            sock.sendall(state)
+    except Exception as e:
+        # this is a bit surprising, since we don't expect to have a NOTIFY_SOCKET
+        # unless systemd is expecting us to notify it.
+        logger.warning("Unable to send notification to systemd: %s", e)
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index 7d6b51b5bc..8233905844 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -447,7 +447,7 @@ def setup(config_options):
                 reactor.stop()
             sys.exit(1)
 
-    reactor.addSystemEventTrigger("before", "startup", start)
+    reactor.callWhenRunning(start)
 
     return hs
 
diff --git a/synapse/appservice/scheduler.py b/synapse/appservice/scheduler.py
index 42a350bff8..9998f822f1 100644
--- a/synapse/appservice/scheduler.py
+++ b/synapse/appservice/scheduler.py
@@ -70,35 +70,37 @@ class ApplicationServiceScheduler(object):
         self.store = hs.get_datastore()
         self.as_api = hs.get_application_service_api()
 
-        def create_recoverer(service, callback):
-            return _Recoverer(self.clock, self.store, self.as_api, service, callback)
-
-        self.txn_ctrl = _TransactionController(
-            self.clock, self.store, self.as_api, create_recoverer
-        )
+        self.txn_ctrl = _TransactionController(self.clock, self.store, self.as_api)
         self.queuer = _ServiceQueuer(self.txn_ctrl, self.clock)
 
     @defer.inlineCallbacks
     def start(self):
         logger.info("Starting appservice scheduler")
+
         # check for any DOWN ASes and start recoverers for them.
-        recoverers = yield _Recoverer.start(
-            self.clock, self.store, self.as_api, self.txn_ctrl.on_recovered
+        services = yield self.store.get_appservices_by_state(
+            ApplicationServiceState.DOWN
         )
-        self.txn_ctrl.add_recoverers(recoverers)
+
+        for service in services:
+            self.txn_ctrl.start_recoverer(service)
 
     def submit_event_for_as(self, service, event):
         self.queuer.enqueue(service, event)
 
 
 class _ServiceQueuer(object):
-    """Queues events for the same application service together, sending
-    transactions as soon as possible. Once a transaction is sent successfully,
-    this schedules any other events in the queue to run.
+    """Queue of events waiting to be sent to appservices.
+
+    Groups events into transactions per-appservice, and sends them on to the
+    TransactionController. Makes sure that we only have one transaction in flight per
+    appservice at a given time.
     """
 
     def __init__(self, txn_ctrl, clock):
         self.queued_events = {}  # dict of {service_id: [events]}
+
+        # the appservices which currently have a transaction in flight
         self.requests_in_flight = set()
         self.txn_ctrl = txn_ctrl
         self.clock = clock
@@ -136,13 +138,29 @@ class _ServiceQueuer(object):
 
 
 class _TransactionController(object):
-    def __init__(self, clock, store, as_api, recoverer_fn):
+    """Transaction manager.
+
+    Builds AppServiceTransactions and runs their lifecycle. Also starts a Recoverer
+    if a transaction fails.
+
+    (Note we have only have one of these in the homeserver.)
+
+    Args:
+        clock (synapse.util.Clock):
+        store (synapse.storage.DataStore):
+        as_api (synapse.appservice.api.ApplicationServiceApi):
+    """
+
+    def __init__(self, clock, store, as_api):
         self.clock = clock
         self.store = store
         self.as_api = as_api
-        self.recoverer_fn = recoverer_fn
-        # keep track of how many recoverers there are
-        self.recoverers = []
+
+        # map from service id to recoverer instance
+        self.recoverers = {}
+
+        # for UTs
+        self.RECOVERER_CLASS = _Recoverer
 
     @defer.inlineCallbacks
     def send(self, service, events):
@@ -154,42 +172,45 @@ class _TransactionController(object):
                 if sent:
                     yield txn.complete(self.store)
                 else:
-                    run_in_background(self._start_recoverer, service)
+                    run_in_background(self._on_txn_fail, service)
         except Exception:
             logger.exception("Error creating appservice transaction")
-            run_in_background(self._start_recoverer, service)
+            run_in_background(self._on_txn_fail, service)
 
     @defer.inlineCallbacks
     def on_recovered(self, recoverer):
-        self.recoverers.remove(recoverer)
         logger.info(
             "Successfully recovered application service AS ID %s", recoverer.service.id
         )
+        self.recoverers.pop(recoverer.service.id)
         logger.info("Remaining active recoverers: %s", len(self.recoverers))
         yield self.store.set_appservice_state(
             recoverer.service, ApplicationServiceState.UP
         )
 
-    def add_recoverers(self, recoverers):
-        for r in recoverers:
-            self.recoverers.append(r)
-        if len(recoverers) > 0:
-            logger.info("New active recoverers: %s", len(self.recoverers))
-
     @defer.inlineCallbacks
-    def _start_recoverer(self, service):
+    def _on_txn_fail(self, service):
         try:
             yield self.store.set_appservice_state(service, ApplicationServiceState.DOWN)
-            logger.info(
-                "Application service falling behind. Starting recoverer. AS ID %s",
-                service.id,
-            )
-            recoverer = self.recoverer_fn(service, self.on_recovered)
-            self.add_recoverers([recoverer])
-            recoverer.recover()
+            self.start_recoverer(service)
         except Exception:
             logger.exception("Error starting AS recoverer")
 
+    def start_recoverer(self, service):
+        """Start a Recoverer for the given service
+
+        Args:
+            service (synapse.appservice.ApplicationService):
+        """
+        logger.info("Starting recoverer for AS ID %s", service.id)
+        assert service.id not in self.recoverers
+        recoverer = self.RECOVERER_CLASS(
+            self.clock, self.store, self.as_api, service, self.on_recovered
+        )
+        self.recoverers[service.id] = recoverer
+        recoverer.recover()
+        logger.info("Now %i active recoverers", len(self.recoverers))
+
     @defer.inlineCallbacks
     def _is_service_up(self, service):
         state = yield self.store.get_appservice_state(service)
@@ -197,18 +218,17 @@ class _TransactionController(object):
 
 
 class _Recoverer(object):
-    @staticmethod
-    @defer.inlineCallbacks
-    def start(clock, store, as_api, callback):
-        services = yield store.get_appservices_by_state(ApplicationServiceState.DOWN)
-        recoverers = [_Recoverer(clock, store, as_api, s, callback) for s in services]
-        for r in recoverers:
-            logger.info(
-                "Starting recoverer for AS ID %s which was marked as " "DOWN",
-                r.service.id,
-            )
-            r.recover()
-        return recoverers
+    """Manages retries and backoff for a DOWN appservice.
+
+    We have one of these for each appservice which is currently considered DOWN.
+
+    Args:
+        clock (synapse.util.Clock):
+        store (synapse.storage.DataStore):
+        as_api (synapse.appservice.api.ApplicationServiceApi):
+        service (synapse.appservice.ApplicationService): the service we are managing
+        callback (callable[_Recoverer]): called once the service recovers.
+    """
 
     def __init__(self, clock, store, as_api, service, callback):
         self.clock = clock
@@ -224,7 +244,9 @@ class _Recoverer(object):
                 "as-recoverer-%s" % (self.service.id,), self.retry
             )
 
-        self.clock.call_later((2 ** self.backoff_counter), _retry)
+        delay = 2 ** self.backoff_counter
+        logger.info("Scheduling retries on %s in %fs", self.service.id, delay)
+        self.clock.call_later(delay, _retry)
 
     def _backoff(self):
         # cap the backoff to be around 8.5min => (2^9) = 512 secs
@@ -234,25 +256,30 @@ class _Recoverer(object):
 
     @defer.inlineCallbacks
     def retry(self):
+        logger.info("Starting retries on %s", self.service.id)
         try:
-            txn = yield self.store.get_oldest_unsent_txn(self.service)
-            if txn:
+            while True:
+                txn = yield self.store.get_oldest_unsent_txn(self.service)
+                if not txn:
+                    # nothing left: we're done!
+                    self.callback(self)
+                    return
+
                 logger.info(
                     "Retrying transaction %s for AS ID %s", txn.id, txn.service.id
                 )
                 sent = yield txn.send(self.as_api)
-                if sent:
-                    yield txn.complete(self.store)
-                    # reset the backoff counter and retry immediately
-                    self.backoff_counter = 1
-                    yield self.retry()
-                else:
-                    self._backoff()
-            else:
-                self._set_service_recovered()
-        except Exception as e:
-            logger.exception(e)
-            self._backoff()
-
-    def _set_service_recovered(self):
-        self.callback(self)
+                if not sent:
+                    break
+
+                yield txn.complete(self.store)
+
+                # reset the backoff counter and then process the next transaction
+                self.backoff_counter = 1
+
+        except Exception:
+            logger.exception("Unexpected error running retries")
+
+        # we didn't manage to send all of the transactions before we got an error of
+        # some flavour: reschedule the next retry.
+        self._backoff()
diff --git a/synapse/config/emailconfig.py b/synapse/config/emailconfig.py
index 8381b8eb29..36d01a10af 100644
--- a/synapse/config/emailconfig.py
+++ b/synapse/config/emailconfig.py
@@ -132,21 +132,21 @@ class EmailConfig(Config):
             self.email_password_reset_template_text = email_config.get(
                 "password_reset_template_text", "password_reset.txt"
             )
-            self.email_password_reset_failure_template = email_config.get(
-                "password_reset_failure_template", "password_reset_failure.html"
+            self.email_password_reset_template_failure_html = email_config.get(
+                "password_reset_template_failure_html", "password_reset_failure.html"
             )
             # This template does not support any replaceable variables, so we will
             # read it from the disk once during setup
-            email_password_reset_success_template = email_config.get(
-                "password_reset_success_template", "password_reset_success.html"
+            email_password_reset_template_success_html = email_config.get(
+                "password_reset_template_success_html", "password_reset_success.html"
             )
 
             # Check templates exist
             for f in [
                 self.email_password_reset_template_html,
                 self.email_password_reset_template_text,
-                self.email_password_reset_failure_template,
-                email_password_reset_success_template,
+                self.email_password_reset_template_failure_html,
+                email_password_reset_template_success_html,
             ]:
                 p = os.path.join(self.email_template_dir, f)
                 if not os.path.isfile(p):
@@ -154,9 +154,9 @@ class EmailConfig(Config):
 
             # Retrieve content of web templates
             filepath = os.path.join(
-                self.email_template_dir, email_password_reset_success_template
+                self.email_template_dir, email_password_reset_template_success_html
             )
-            self.email_password_reset_success_html_content = self.read_file(
+            self.email_password_reset_template_success_html_content = self.read_file(
                 filepath, "email.password_reset_template_success_html"
             )
 
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 6c3e885e72..654accc843 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -18,7 +18,6 @@ import logging
 from collections import defaultdict
 
 import six
-from six import raise_from
 from six.moves import urllib
 
 import attr
@@ -657,9 +656,10 @@ class PerspectivesKeyFetcher(BaseV2KeyFetcher):
                 },
             )
         except (NotRetryingDestination, RequestSendFailed) as e:
-            raise_from(KeyLookupError("Failed to connect to remote server"), e)
+            # these both have str() representations which we can't really improve upon
+            raise KeyLookupError(str(e))
         except HttpResponseException as e:
-            raise_from(KeyLookupError("Remote server returned an error"), e)
+            raise KeyLookupError("Remote server returned an error: %s" % (e,))
 
         keys = {}
         added_keys = []
@@ -821,9 +821,11 @@ class ServerKeyFetcher(BaseV2KeyFetcher):
                     timeout=10000,
                 )
             except (NotRetryingDestination, RequestSendFailed) as e:
-                raise_from(KeyLookupError("Failed to connect to remote server"), e)
+                # these both have str() representations which we can't really improve
+                # upon
+                raise KeyLookupError(str(e))
             except HttpResponseException as e:
-                raise_from(KeyLookupError("Remote server returned an error"), e)
+                raise KeyLookupError("Remote server returned an error: %s" % (e,))
 
             if response["server_name"] != server_name:
                 raise KeyLookupError(
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index d216c46dfe..9286ca3202 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -43,6 +43,7 @@ from synapse.federation.persistence import TransactionActions
 from synapse.federation.units import Edu, Transaction
 from synapse.http.endpoint import parse_server_name
 from synapse.logging.context import nested_logging_context
+from synapse.logging.opentracing import log_kv, trace
 from synapse.logging.utils import log_function
 from synapse.replication.http.federation import (
     ReplicationFederationSendEduRestServlet,
@@ -507,6 +508,7 @@ class FederationServer(FederationBase):
     def on_query_user_devices(self, origin, user_id):
         return self.on_query_request("user_devices", user_id)
 
+    @trace
     @defer.inlineCallbacks
     @log_function
     def on_claim_client_keys(self, origin, content):
@@ -515,6 +517,7 @@ class FederationServer(FederationBase):
             for device_id, algorithm in device_keys.items():
                 query.append((user_id, device_id, algorithm))
 
+        log_kv({"message": "Claiming one time keys.", "user, device pairs": query})
         results = yield self.store.claim_e2e_one_time_keys(query)
 
         json_result = {}
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 9a86bd0263..a17148fc3c 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -22,7 +22,6 @@ import re
 from twisted.internet.defer import maybeDeferred
 
 import synapse
-import synapse.logging.opentracing as opentracing
 from synapse.api.errors import Codes, FederationDeniedError, SynapseError
 from synapse.api.room_versions import RoomVersions
 from synapse.api.urls import (
@@ -39,6 +38,7 @@ from synapse.http.servlet import (
     parse_string_from_args,
 )
 from synapse.logging.context import run_in_background
+from synapse.logging.opentracing import start_active_span_from_context, tags
 from synapse.types import ThirdPartyInstanceID, get_domain_from_id
 from synapse.util.ratelimitutils import FederationRateLimiter
 from synapse.util.versionstring import get_version_string
@@ -289,16 +289,17 @@ class BaseFederationServlet(object):
                 raise
 
             # Start an opentracing span
-            with opentracing.start_active_span_from_context(
+            with start_active_span_from_context(
                 request.requestHeaders,
                 "incoming-federation-request",
                 tags={
                     "request_id": request.get_request_id(),
-                    opentracing.tags.SPAN_KIND: opentracing.tags.SPAN_KIND_RPC_SERVER,
-                    opentracing.tags.HTTP_METHOD: request.get_method(),
-                    opentracing.tags.HTTP_URL: request.get_redacted_uri(),
-                    opentracing.tags.PEER_HOST_IPV6: request.getClientIP(),
+                    tags.SPAN_KIND: tags.SPAN_KIND_RPC_SERVER,
+                    tags.HTTP_METHOD: request.get_method(),
+                    tags.HTTP_URL: request.get_redacted_uri(),
+                    tags.PEER_HOST_IPV6: request.getClientIP(),
                     "authenticated_entity": origin,
+                    "servlet_name": request.request_metrics.name,
                 },
             ):
                 if origin:
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 1f90b0d278..056fb97acb 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -24,6 +24,7 @@ from twisted.internet import defer
 
 from synapse.api.errors import CodeMessageException, SynapseError
 from synapse.logging.context import make_deferred_yieldable, run_in_background
+from synapse.logging.opentracing import log_kv, set_tag, tag_args, trace
 from synapse.types import UserID, get_domain_from_id
 from synapse.util import unwrapFirstError
 from synapse.util.retryutils import NotRetryingDestination
@@ -46,6 +47,7 @@ class E2eKeysHandler(object):
             "client_keys", self.on_federation_query_client_keys
         )
 
+    @trace
     @defer.inlineCallbacks
     def query_devices(self, query_body, timeout):
         """ Handle a device key query from a client
@@ -81,6 +83,9 @@ class E2eKeysHandler(object):
             else:
                 remote_queries[user_id] = device_ids
 
+        set_tag("local_key_query", local_query)
+        set_tag("remote_key_query", remote_queries)
+
         # First get local devices.
         failures = {}
         results = {}
@@ -121,6 +126,7 @@ class E2eKeysHandler(object):
                 r[user_id] = remote_queries[user_id]
 
         # Now fetch any devices that we don't have in our cache
+        @trace
         @defer.inlineCallbacks
         def do_remote_query(destination):
             """This is called when we are querying the device list of a user on
@@ -185,6 +191,8 @@ class E2eKeysHandler(object):
             except Exception as e:
                 failure = _exception_to_failure(e)
                 failures[destination] = failure
+                set_tag("error", True)
+                set_tag("reason", failure)
 
         yield make_deferred_yieldable(
             defer.gatherResults(
@@ -198,6 +206,7 @@ class E2eKeysHandler(object):
 
         return {"device_keys": results, "failures": failures}
 
+    @trace
     @defer.inlineCallbacks
     def query_local_devices(self, query):
         """Get E2E device keys for local users
@@ -210,6 +219,7 @@ class E2eKeysHandler(object):
             defer.Deferred: (resolves to dict[string, dict[string, dict]]):
                  map from user_id -> device_id -> device details
         """
+        set_tag("local_query", query)
         local_query = []
 
         result_dict = {}
@@ -217,6 +227,14 @@ class E2eKeysHandler(object):
             # we use UserID.from_string to catch invalid user ids
             if not self.is_mine(UserID.from_string(user_id)):
                 logger.warning("Request for keys for non-local user %s", user_id)
+                log_kv(
+                    {
+                        "message": "Requested a local key for a user which"
+                        " was not local to the homeserver",
+                        "user_id": user_id,
+                    }
+                )
+                set_tag("error", True)
                 raise SynapseError(400, "Not a user here")
 
             if not device_ids:
@@ -241,6 +259,7 @@ class E2eKeysHandler(object):
                     r["unsigned"]["device_display_name"] = display_name
                 result_dict[user_id][device_id] = r
 
+        log_kv(results)
         return result_dict
 
     @defer.inlineCallbacks
@@ -251,6 +270,7 @@ class E2eKeysHandler(object):
         res = yield self.query_local_devices(device_keys_query)
         return {"device_keys": res}
 
+    @trace
     @defer.inlineCallbacks
     def claim_one_time_keys(self, query, timeout):
         local_query = []
@@ -265,6 +285,9 @@ class E2eKeysHandler(object):
                 domain = get_domain_from_id(user_id)
                 remote_queries.setdefault(domain, {})[user_id] = device_keys
 
+        set_tag("local_key_query", local_query)
+        set_tag("remote_key_query", remote_queries)
+
         results = yield self.store.claim_e2e_one_time_keys(local_query)
 
         json_result = {}
@@ -276,8 +299,10 @@ class E2eKeysHandler(object):
                         key_id: json.loads(json_bytes)
                     }
 
+        @trace
         @defer.inlineCallbacks
         def claim_client_keys(destination):
+            set_tag("destination", destination)
             device_keys = remote_queries[destination]
             try:
                 remote_result = yield self.federation.claim_client_keys(
@@ -290,6 +315,8 @@ class E2eKeysHandler(object):
             except Exception as e:
                 failure = _exception_to_failure(e)
                 failures[destination] = failure
+                set_tag("error", True)
+                set_tag("reason", failure)
 
         yield make_deferred_yieldable(
             defer.gatherResults(
@@ -313,9 +340,11 @@ class E2eKeysHandler(object):
             ),
         )
 
+        log_kv({"one_time_keys": json_result, "failures": failures})
         return {"one_time_keys": json_result, "failures": failures}
 
     @defer.inlineCallbacks
+    @tag_args
     def upload_keys_for_user(self, user_id, device_id, keys):
 
         time_now = self.clock.time_msec()
@@ -329,6 +358,13 @@ class E2eKeysHandler(object):
                 user_id,
                 time_now,
             )
+            log_kv(
+                {
+                    "message": "Updating device_keys for user.",
+                    "user_id": user_id,
+                    "device_id": device_id,
+                }
+            )
             # TODO: Sign the JSON with the server key
             changed = yield self.store.set_e2e_device_keys(
                 user_id, device_id, time_now, device_keys
@@ -336,12 +372,24 @@ class E2eKeysHandler(object):
             if changed:
                 # Only notify about device updates *if* the keys actually changed
                 yield self.device_handler.notify_device_update(user_id, [device_id])
-
+        else:
+            log_kv({"message": "Not updating device_keys for user", "user_id": user_id})
         one_time_keys = keys.get("one_time_keys", None)
         if one_time_keys:
+            log_kv(
+                {
+                    "message": "Updating one_time_keys for device.",
+                    "user_id": user_id,
+                    "device_id": device_id,
+                }
+            )
             yield self._upload_one_time_keys_for_user(
                 user_id, device_id, time_now, one_time_keys
             )
+        else:
+            log_kv(
+                {"message": "Did not update one_time_keys", "reason": "no keys given"}
+            )
 
         # the device should have been registered already, but it may have been
         # deleted due to a race with a DELETE request. Or we may be using an
@@ -352,6 +400,7 @@ class E2eKeysHandler(object):
 
         result = yield self.store.count_e2e_one_time_keys(user_id, device_id)
 
+        set_tag("one_time_key_counts", result)
         return {"one_time_key_counts": result}
 
     @defer.inlineCallbacks
@@ -395,6 +444,7 @@ class E2eKeysHandler(object):
                     (algorithm, key_id, encode_canonical_json(key).decode("ascii"))
                 )
 
+        log_kv({"message": "Inserting new one_time_keys.", "keys": new_keys})
         yield self.store.add_e2e_one_time_keys(user_id, device_id, time_now, new_keys)
 
 
diff --git a/synapse/handlers/e2e_room_keys.py b/synapse/handlers/e2e_room_keys.py
index 41b871fc59..a9d80f708c 100644
--- a/synapse/handlers/e2e_room_keys.py
+++ b/synapse/handlers/e2e_room_keys.py
@@ -26,6 +26,7 @@ from synapse.api.errors import (
     StoreError,
     SynapseError,
 )
+from synapse.logging.opentracing import log_kv, trace
 from synapse.util.async_helpers import Linearizer
 
 logger = logging.getLogger(__name__)
@@ -49,6 +50,7 @@ class E2eRoomKeysHandler(object):
         # changed.
         self._upload_linearizer = Linearizer("upload_room_keys_lock")
 
+    @trace
     @defer.inlineCallbacks
     def get_room_keys(self, user_id, version, room_id=None, session_id=None):
         """Bulk get the E2E room keys for a given backup, optionally filtered to a given
@@ -84,8 +86,10 @@ class E2eRoomKeysHandler(object):
                 user_id, version, room_id, session_id
             )
 
+            log_kv(results)
             return results
 
+    @trace
     @defer.inlineCallbacks
     def delete_room_keys(self, user_id, version, room_id=None, session_id=None):
         """Bulk delete the E2E room keys for a given backup, optionally filtered to a given
@@ -107,6 +111,7 @@ class E2eRoomKeysHandler(object):
         with (yield self._upload_linearizer.queue(user_id)):
             yield self.store.delete_e2e_room_keys(user_id, version, room_id, session_id)
 
+    @trace
     @defer.inlineCallbacks
     def upload_room_keys(self, user_id, version, room_keys):
         """Bulk upload a list of room keys into a given backup version, asserting
@@ -186,7 +191,14 @@ class E2eRoomKeysHandler(object):
             session_id(str): the session whose room_key we're setting
             room_key(dict): the room_key being set
         """
-
+        log_kv(
+            {
+                "message": "Trying to upload room key",
+                "room_id": room_id,
+                "session_id": session_id,
+                "user_id": user_id,
+            }
+        )
         # get the room_key for this particular row
         current_room_key = None
         try:
@@ -195,14 +207,23 @@ class E2eRoomKeysHandler(object):
             )
         except StoreError as e:
             if e.code == 404:
-                pass
+                log_kv(
+                    {
+                        "message": "Room key not found.",
+                        "room_id": room_id,
+                        "user_id": user_id,
+                    }
+                )
             else:
                 raise
 
         if self._should_replace_room_key(current_room_key, room_key):
+            log_kv({"message": "Replacing room key."})
             yield self.store.set_e2e_room_key(
                 user_id, version, room_id, session_id, room_key
             )
+        else:
+            log_kv({"message": "Not replacing room_key."})
 
     @staticmethod
     def _should_replace_room_key(current_room_key, room_key):
@@ -236,6 +257,7 @@ class E2eRoomKeysHandler(object):
                 return False
         return True
 
+    @trace
     @defer.inlineCallbacks
     def create_version(self, user_id, version_info):
         """Create a new backup version.  This automatically becomes the new
@@ -294,6 +316,7 @@ class E2eRoomKeysHandler(object):
                     raise
             return res
 
+    @trace
     @defer.inlineCallbacks
     def delete_version(self, user_id, version=None):
         """Deletes a given version of the user's e2e_room_keys backup
@@ -314,6 +337,7 @@ class E2eRoomKeysHandler(object):
                 else:
                     raise
 
+    @trace
     @defer.inlineCallbacks
     def update_version(self, user_id, version, version_info):
         """Update the info about a given version of the user's backup
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index d83aab3f74..5744f4579d 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -70,6 +70,7 @@ class PaginationHandler(object):
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
         self.clock = hs.get_clock()
+        self._server_name = hs.hostname
 
         self.pagination_lock = ReadWriteLock()
         self._purges_in_progress_by_room = set()
@@ -153,6 +154,22 @@ class PaginationHandler(object):
         """
         return self._purges_by_id.get(purge_id)
 
+    async def purge_room(self, room_id):
+        """Purge the given room from the database"""
+        with (await self.pagination_lock.write(room_id)):
+            # check we know about the room
+            await self.store.get_room_version(room_id)
+
+            # first check that we have no users in this room
+            joined = await defer.maybeDeferred(
+                self.store.is_host_joined, room_id, self._server_name
+            )
+
+            if joined:
+                raise SynapseError(400, "Users are still joined to this room")
+
+            await self.store.purge_room(room_id)
+
     @defer.inlineCallbacks
     def get_messages(
         self,
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 98da2318a0..ef7f2ca980 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -786,9 +786,8 @@ class SyncHandler(object):
                         batch.events[0].event_id, state_filter=state_filter
                     )
                 else:
-                    # Its not clear how we get here, but empirically we do
-                    # (#5407). Logging has been added elsewhere to try and
-                    # figure out where this state comes from.
+                    # We can get here if the user has ignored the senders of all
+                    # the recent events.
                     state_at_timeline_start = yield self.get_state_at(
                         room_id, stream_position=now_token, state_filter=state_filter
                     )
@@ -1771,20 +1770,9 @@ class SyncHandler(object):
             newly_joined_room=newly_joined,
         )
 
-        if not batch and batch.limited:
-            # This resulted in #5407, which is weird, so lets log! We do it
-            # here as we have the maximum amount of information.
-            user_id = sync_result_builder.sync_config.user.to_string()
-            logger.info(
-                "Issue #5407: Found limited batch with no events. user %s, room %s,"
-                " sync_config %s, newly_joined %s, events %s, batch %s.",
-                user_id,
-                room_id,
-                sync_config,
-                newly_joined,
-                events,
-                batch,
-            )
+        # Note: `batch` can be both empty and limited here in the case where
+        # `_load_filtered_recents` can't find any events the user should see
+        # (e.g. due to having ignored the sender of the last 50 events).
 
         if newly_joined:
             # debug for https://github.com/matrix-org/synapse/issues/4422
diff --git a/synapse/http/federation/matrix_federation_agent.py b/synapse/http/federation/matrix_federation_agent.py
index c208185791..a8815f078a 100644
--- a/synapse/http/federation/matrix_federation_agent.py
+++ b/synapse/http/federation/matrix_federation_agent.py
@@ -52,9 +52,9 @@ class MatrixFederationAgent(object):
             SRVResolver impl to use for looking up SRV records. None to use a default
             implementation.
 
-        _well_known_cache (TTLCache|None):
-            TTLCache impl for storing cached well-known lookups. None to use a default
-            implementation.
+        _well_known_resolver (WellKnownResolver|None):
+            WellKnownResolver to use to perform well-known lookups. None to use a
+            default implementation.
     """
 
     def __init__(
@@ -62,7 +62,7 @@ class MatrixFederationAgent(object):
         reactor,
         tls_client_options_factory,
         _srv_resolver=None,
-        _well_known_cache=None,
+        _well_known_resolver=None,
     ):
         self._reactor = reactor
         self._clock = Clock(reactor)
@@ -79,15 +79,17 @@ class MatrixFederationAgent(object):
             pool=self._pool,
         )
 
-        self._well_known_resolver = WellKnownResolver(
-            self._reactor,
-            agent=Agent(
+        if _well_known_resolver is None:
+            _well_known_resolver = WellKnownResolver(
                 self._reactor,
-                contextFactory=tls_client_options_factory,
-                pool=self._pool,
-            ),
-            well_known_cache=_well_known_cache,
-        )
+                agent=Agent(
+                    self._reactor,
+                    pool=self._pool,
+                    contextFactory=tls_client_options_factory,
+                ),
+            )
+
+        self._well_known_resolver = _well_known_resolver
 
     @defer.inlineCallbacks
     def request(self, method, uri, headers=None, bodyProducer=None):
diff --git a/synapse/http/federation/well_known_resolver.py b/synapse/http/federation/well_known_resolver.py
index bb250c6922..5e9b0befb0 100644
--- a/synapse/http/federation/well_known_resolver.py
+++ b/synapse/http/federation/well_known_resolver.py
@@ -32,12 +32,19 @@ from synapse.util.metrics import Measure
 # period to cache .well-known results for by default
 WELL_KNOWN_DEFAULT_CACHE_PERIOD = 24 * 3600
 
-# jitter to add to the .well-known default cache ttl
-WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 10 * 60
+# jitter factor to add to the .well-known default cache ttls
+WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER = 0.1
 
 # period to cache failure to fetch .well-known for
 WELL_KNOWN_INVALID_CACHE_PERIOD = 1 * 3600
 
+# period to cache failure to fetch .well-known if there has recently been a
+# valid well-known for that domain.
+WELL_KNOWN_DOWN_CACHE_PERIOD = 2 * 60
+
+# period to remember there was a valid well-known after valid record expires
+WELL_KNOWN_REMEMBER_DOMAIN_HAD_VALID = 2 * 3600
+
 # cap for .well-known cache period
 WELL_KNOWN_MAX_CACHE_PERIOD = 48 * 3600
 
@@ -49,11 +56,16 @@ WELL_KNOWN_MIN_CACHE_PERIOD = 5 * 60
 # we'll start trying to refetch 1 minute before it expires.
 WELL_KNOWN_GRACE_PERIOD_FACTOR = 0.2
 
+# Number of times we retry fetching a well-known for a domain we know recently
+# had a valid entry.
+WELL_KNOWN_RETRY_ATTEMPTS = 3
+
 
 logger = logging.getLogger(__name__)
 
 
 _well_known_cache = TTLCache("well-known")
+_had_valid_well_known_cache = TTLCache("had-valid-well-known")
 
 
 @attr.s(slots=True, frozen=True)
@@ -65,14 +77,20 @@ class WellKnownResolver(object):
     """Handles well-known lookups for matrix servers.
     """
 
-    def __init__(self, reactor, agent, well_known_cache=None):
+    def __init__(
+        self, reactor, agent, well_known_cache=None, had_well_known_cache=None
+    ):
         self._reactor = reactor
         self._clock = Clock(reactor)
 
         if well_known_cache is None:
             well_known_cache = _well_known_cache
 
+        if had_well_known_cache is None:
+            had_well_known_cache = _had_valid_well_known_cache
+
         self._well_known_cache = well_known_cache
+        self._had_valid_well_known_cache = had_well_known_cache
         self._well_known_agent = RedirectAgent(agent)
 
     @defer.inlineCallbacks
@@ -100,7 +118,7 @@ class WellKnownResolver(object):
         # requests for the same server in parallel?
         try:
             with Measure(self._clock, "get_well_known"):
-                result, cache_period = yield self._do_get_well_known(server_name)
+                result, cache_period = yield self._fetch_well_known(server_name)
 
         except _FetchWellKnownFailure as e:
             if prev_result and e.temporary:
@@ -111,10 +129,18 @@ class WellKnownResolver(object):
 
             result = None
 
-            # add some randomness to the TTL to avoid a stampeding herd every hour
-            # after startup
-            cache_period = WELL_KNOWN_INVALID_CACHE_PERIOD
-            cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
+            if self._had_valid_well_known_cache.get(server_name, False):
+                # We have recently seen a valid well-known record for this
+                # server, so we cache the lack of well-known for a shorter time.
+                cache_period = WELL_KNOWN_DOWN_CACHE_PERIOD
+            else:
+                cache_period = WELL_KNOWN_INVALID_CACHE_PERIOD
+
+            # add some randomness to the TTL to avoid a stampeding herd
+            cache_period *= random.uniform(
+                1 - WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER,
+                1 + WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER,
+            )
 
         if cache_period > 0:
             self._well_known_cache.set(server_name, result, cache_period)
@@ -122,7 +148,7 @@ class WellKnownResolver(object):
         return WellKnownLookupResult(delegated_server=result)
 
     @defer.inlineCallbacks
-    def _do_get_well_known(self, server_name):
+    def _fetch_well_known(self, server_name):
         """Actually fetch and parse a .well-known, without checking the cache
 
         Args:
@@ -134,24 +160,15 @@ class WellKnownResolver(object):
         Returns:
             Deferred[Tuple[bytes,int]]: The lookup result and cache period.
         """
-        uri = b"https://%s/.well-known/matrix/server" % (server_name,)
-        uri_str = uri.decode("ascii")
-        logger.info("Fetching %s", uri_str)
+
+        had_valid_well_known = self._had_valid_well_known_cache.get(server_name, False)
 
         # We do this in two steps to differentiate between possibly transient
         # errors (e.g. can't connect to host, 503 response) and more permenant
         # errors (such as getting a 404 response).
-        try:
-            response = yield make_deferred_yieldable(
-                self._well_known_agent.request(b"GET", uri)
-            )
-            body = yield make_deferred_yieldable(readBody(response))
-
-            if 500 <= response.code < 600:
-                raise Exception("Non-200 response %s" % (response.code,))
-        except Exception as e:
-            logger.info("Error fetching %s: %s", uri_str, e)
-            raise _FetchWellKnownFailure(temporary=True)
+        response, body = yield self._make_well_known_request(
+            server_name, retry=had_valid_well_known
+        )
 
         try:
             if response.code != 200:
@@ -161,8 +178,11 @@ class WellKnownResolver(object):
             logger.info("Response from .well-known: %s", parsed_body)
 
             result = parsed_body["m.server"].encode("ascii")
+        except defer.CancelledError:
+            # Bail if we've been cancelled
+            raise
         except Exception as e:
-            logger.info("Error fetching %s: %s", uri_str, e)
+            logger.info("Error parsing well-known for %s: %s", server_name, e)
             raise _FetchWellKnownFailure(temporary=False)
 
         cache_period = _cache_period_from_headers(
@@ -172,13 +192,69 @@ class WellKnownResolver(object):
             cache_period = WELL_KNOWN_DEFAULT_CACHE_PERIOD
             # add some randomness to the TTL to avoid a stampeding herd every 24 hours
             # after startup
-            cache_period += random.uniform(0, WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER)
+            cache_period *= random.uniform(
+                1 - WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER,
+                1 + WELL_KNOWN_DEFAULT_CACHE_PERIOD_JITTER,
+            )
         else:
             cache_period = min(cache_period, WELL_KNOWN_MAX_CACHE_PERIOD)
             cache_period = max(cache_period, WELL_KNOWN_MIN_CACHE_PERIOD)
 
+        # We got a success, mark as such in the cache
+        self._had_valid_well_known_cache.set(
+            server_name,
+            bool(result),
+            cache_period + WELL_KNOWN_REMEMBER_DOMAIN_HAD_VALID,
+        )
+
         return (result, cache_period)
 
+    @defer.inlineCallbacks
+    def _make_well_known_request(self, server_name, retry):
+        """Make the well known request.
+
+        This will retry the request if requested and it fails (with unable
+        to connect or receives a 5xx error).
+
+        Args:
+            server_name (bytes)
+            retry (bool): Whether to retry the request if it fails.
+
+        Returns:
+            Deferred[tuple[IResponse, bytes]] Returns the response object and
+            body. Response may be a non-200 response.
+        """
+        uri = b"https://%s/.well-known/matrix/server" % (server_name,)
+        uri_str = uri.decode("ascii")
+
+        i = 0
+        while True:
+            i += 1
+
+            logger.info("Fetching %s", uri_str)
+            try:
+                response = yield make_deferred_yieldable(
+                    self._well_known_agent.request(b"GET", uri)
+                )
+                body = yield make_deferred_yieldable(readBody(response))
+
+                if 500 <= response.code < 600:
+                    raise Exception("Non-200 response %s" % (response.code,))
+
+                return response, body
+            except defer.CancelledError:
+                # Bail if we've been cancelled
+                raise
+            except Exception as e:
+                if not retry or i >= WELL_KNOWN_RETRY_ATTEMPTS:
+                    logger.info("Error fetching %s: %s", uri_str, e)
+                    raise _FetchWellKnownFailure(temporary=True)
+
+                logger.info("Error fetching %s: %s. Retrying", uri_str, e)
+
+            # Sleep briefly in the hopes that they come back up
+            yield self._clock.sleep(0.5)
+
 
 def _cache_period_from_headers(headers, time_now=time.time):
     cache_controls = _parse_cache_control(headers)
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index d07d356464..4326e98a28 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -36,7 +36,6 @@ from twisted.internet.task import _EPSILON, Cooperator
 from twisted.web._newclient import ResponseDone
 from twisted.web.http_headers import Headers
 
-import synapse.logging.opentracing as opentracing
 import synapse.metrics
 import synapse.util.retryutils
 from synapse.api.errors import (
@@ -50,6 +49,12 @@ from synapse.http import QuieterFileBodyProducer
 from synapse.http.client import BlacklistingAgentWrapper, IPBlacklistingResolver
 from synapse.http.federation.matrix_federation_agent import MatrixFederationAgent
 from synapse.logging.context import make_deferred_yieldable
+from synapse.logging.opentracing import (
+    inject_active_span_byte_dict,
+    set_tag,
+    start_active_span,
+    tags,
+)
 from synapse.util.async_helpers import timeout_deferred
 from synapse.util.metrics import Measure
 
@@ -341,20 +346,20 @@ class MatrixFederationHttpClient(object):
             query_bytes = b""
 
         # Retreive current span
-        scope = opentracing.start_active_span(
+        scope = start_active_span(
             "outgoing-federation-request",
             tags={
-                opentracing.tags.SPAN_KIND: opentracing.tags.SPAN_KIND_RPC_CLIENT,
-                opentracing.tags.PEER_ADDRESS: request.destination,
-                opentracing.tags.HTTP_METHOD: request.method,
-                opentracing.tags.HTTP_URL: request.path,
+                tags.SPAN_KIND: tags.SPAN_KIND_RPC_CLIENT,
+                tags.PEER_ADDRESS: request.destination,
+                tags.HTTP_METHOD: request.method,
+                tags.HTTP_URL: request.path,
             },
             finish_on_close=True,
         )
 
         # Inject the span into the headers
         headers_dict = {}
-        opentracing.inject_active_span_byte_dict(headers_dict, request.destination)
+        inject_active_span_byte_dict(headers_dict, request.destination)
 
         headers_dict[b"User-Agent"] = [self.version_string_bytes]
 
@@ -436,9 +441,7 @@ class MatrixFederationHttpClient(object):
                         response.phrase.decode("ascii", errors="replace"),
                     )
 
-                    opentracing.set_tag(
-                        opentracing.tags.HTTP_STATUS_CODE, response.code
-                    )
+                    set_tag(tags.HTTP_STATUS_CODE, response.code)
 
                     if 200 <= response.code < 300:
                         pass
diff --git a/synapse/logging/opentracing.py b/synapse/logging/opentracing.py
index d2c209c471..6b706e1892 100644
--- a/synapse/logging/opentracing.py
+++ b/synapse/logging/opentracing.py
@@ -43,6 +43,9 @@ OpenTracing to be easily disabled in Synapse and thereby have OpenTracing as
 an optional dependency. This does however limit the number of modifiable spans
 at any point in the code to one. From here out references to `opentracing`
 in the code snippets refer to the Synapses module.
+Most methods provided in the module have a direct correlation to those provided
+by opentracing. Refer to docs there for a more in-depth documentation on some of
+the args and methods.
 
 Tracing
 -------
@@ -68,52 +71,62 @@ set a tag on the current active span.
 Tracing functions
 -----------------
 
-Functions can be easily traced using decorators. There is a decorator for
-'normal' function and for functions which are actually deferreds. The name of
+Functions can be easily traced using decorators. The name of
 the function becomes the operation name for the span.
 
 .. code-block:: python
 
-   from synapse.logging.opentracing import trace, trace_deferred
+   from synapse.logging.opentracing import trace
 
-   # Start a span using 'normal_function' as the operation name
+   # Start a span using 'interesting_function' as the operation name
    @trace
-   def normal_function(*args, **kwargs):
+   def interesting_function(*args, **kwargs):
        # Does all kinds of cool and expected things
        return something_usual_and_useful
 
-   # Start a span using 'deferred_function' as the operation name
-   @trace_deferred
-   @defer.inlineCallbacks
-   def deferred_function(*args, **kwargs):
-       # We start
-       yield we_wait
-       # we finish
-       return something_usual_and_useful
 
 Operation names can be explicitly set for functions by using
-``trace_using_operation_name`` and
-``trace_deferred_using_operation_name``
+``trace_using_operation_name``
 
 .. code-block:: python
 
-   from synapse.logging.opentracing import (
-       trace_using_operation_name,
-       trace_deferred_using_operation_name
-   )
+   from synapse.logging.opentracing import trace_using_operation_name
 
    @trace_using_operation_name("A *much* better operation name")
-   def normal_function(*args, **kwargs):
+   def interesting_badly_named_function(*args, **kwargs):
        # Does all kinds of cool and expected things
        return something_usual_and_useful
 
-   @trace_deferred_using_operation_name("Another exciting operation name!")
-   @defer.inlineCallbacks
-   def deferred_function(*args, **kwargs):
-       # We start
-       yield we_wait
-       # we finish
-       return something_usual_and_useful
+Setting Tags
+------------
+
+To set a tag on the active span do
+
+.. code-block:: python
+
+   from synapse.logging.opentracing import set_tag
+
+   set_tag(tag_name, tag_value)
+
+There's a convenient decorator to tag all the args of the method. It uses
+inspection in order to use the formal parameter names prefixed with 'ARG_' as
+tag names. It uses kwarg names as tag names without the prefix.
+
+.. code-block:: python
+
+   from synapse.logging.opentracing import tag_args
+
+   @tag_args
+   def set_fates(clotho, lachesis, atropos, father="Zues", mother="Themis"):
+       pass
+
+   set_fates("the story", "the end", "the act")
+   # This will have the following tags
+   #  - ARG_clotho: "the story"
+   #  - ARG_lachesis: "the end"
+   #  - ARG_atropos: "the act"
+   #  - father: "Zues"
+   #  - mother: "Themis"
 
 Contexts and carriers
 ---------------------
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index 195a7a70c8..c6465c0386 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -72,7 +72,6 @@ REQUIREMENTS = [
     "netaddr>=0.7.18",
     "Jinja2>=2.9",
     "bleach>=1.4.3",
-    "sdnotify>=0.3",
 ]
 
 CONDITIONAL_REQUIREMENTS = {
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 5720cab425..0dce256840 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -42,6 +42,7 @@ from synapse.rest.admin._base import (
     historical_admin_path_patterns,
 )
 from synapse.rest.admin.media import 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.types import UserID, create_requester
 from synapse.util.versionstring import get_version_string
@@ -738,6 +739,7 @@ def register_servlets(hs, http_server):
     Register all the admin servlets.
     """
     register_servlets_for_client_rest_resource(hs, http_server)
+    PurgeRoomServlet(hs).register(http_server)
     SendServerNoticeServlet(hs).register(http_server)
     VersionServlet(hs).register(http_server)
 
diff --git a/synapse/rest/admin/purge_room_servlet.py b/synapse/rest/admin/purge_room_servlet.py
new file mode 100644
index 0000000000..2922eb543e
--- /dev/null
+++ b/synapse/rest/admin/purge_room_servlet.py
@@ -0,0 +1,57 @@
+# -*- 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 re
+
+from synapse.http.servlet import (
+    RestServlet,
+    assert_params_in_dict,
+    parse_json_object_from_request,
+)
+from synapse.rest.admin import assert_requester_is_admin
+
+
+class PurgeRoomServlet(RestServlet):
+    """Servlet which will remove all trace of a room from the database
+
+    POST /_synapse/admin/v1/purge_room
+    {
+        "room_id": "!room:id"
+    }
+
+    returns:
+
+    {}
+    """
+
+    PATTERNS = (re.compile("^/_synapse/admin/v1/purge_room$"),)
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        self.hs = hs
+        self.auth = hs.get_auth()
+        self.pagination_handler = hs.get_pagination_handler()
+
+    async def on_POST(self, request):
+        await assert_requester_is_admin(self.auth, request)
+
+        body = parse_json_object_from_request(request)
+        assert_params_in_dict(body, ("room_id",))
+
+        await self.pagination_handler.purge_room(body["room_id"])
+
+        return (200, {})
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 7ac456812a..934ed5d16d 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -282,13 +282,13 @@ class PasswordResetSubmitTokenServlet(RestServlet):
                     return None
 
             # Otherwise show the success template
-            html = self.config.email_password_reset_success_html_content
+            html = self.config.email_password_reset_template_success_html_content
             request.setResponseCode(200)
         except ThreepidValidationError as e:
             # Show a failure page with a reason
             html = self.load_jinja2_template(
                 self.config.email_template_dir,
-                self.config.email_password_reset_failure_template,
+                self.config.email_password_reset_template_failure_html,
                 template_vars={"failure_reason": e.msg},
             )
             request.setResponseCode(e.code)
diff --git a/synapse/rest/client/v2_alpha/keys.py b/synapse/rest/client/v2_alpha/keys.py
index 6008adec7c..b218a3f334 100644
--- a/synapse/rest/client/v2_alpha/keys.py
+++ b/synapse/rest/client/v2_alpha/keys.py
@@ -24,6 +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.types import StreamToken
 
 from ._base import client_patterns
@@ -68,6 +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")
     @defer.inlineCallbacks
     def on_POST(self, request, device_id):
         requester = yield self.auth.get_user_by_req(request, allow_guest=True)
@@ -78,6 +80,14 @@ class KeyUploadServlet(RestServlet):
             # passing the device_id here is deprecated; however, we allow it
             # for now for compatibility with older clients.
             if requester.device_id is not None and device_id != requester.device_id:
+                set_tag("error", True)
+                log_kv(
+                    {
+                        "message": "Client uploading keys for a different device",
+                        "logged_in_id": requester.device_id,
+                        "key_being_uploaded": device_id,
+                    }
+                )
                 logger.warning(
                     "Client uploading keys for a different device "
                     "(logged in as %s, uploading for %s)",
@@ -178,10 +188,11 @@ class KeyChangesServlet(RestServlet):
         requester = yield self.auth.get_user_by_req(request, allow_guest=True)
 
         from_token_string = parse_string(request, "from")
+        set_tag("from", from_token_string)
 
         # We want to enforce they do pass us one, but we ignore it and return
         # changes after the "to" as well as before.
-        parse_string(request, "to")
+        set_tag("to", parse_string(request, "to"))
 
         from_token = StreamToken.from_string(from_token_string)
 
diff --git a/synapse/storage/e2e_room_keys.py b/synapse/storage/e2e_room_keys.py
index 99128f2df7..be2fe2bab6 100644
--- a/synapse/storage/e2e_room_keys.py
+++ b/synapse/storage/e2e_room_keys.py
@@ -18,6 +18,7 @@ import json
 from twisted.internet import defer
 
 from synapse.api.errors import StoreError
+from synapse.logging.opentracing import log_kv, trace
 
 from ._base import SQLBaseStore
 
@@ -82,11 +83,11 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             table="e2e_room_keys",
             keyvalues={
                 "user_id": user_id,
+                "version": version,
                 "room_id": room_id,
                 "session_id": session_id,
             },
             values={
-                "version": version,
                 "first_message_index": room_key["first_message_index"],
                 "forwarded_count": room_key["forwarded_count"],
                 "is_verified": room_key["is_verified"],
@@ -94,7 +95,16 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             },
             lock=False,
         )
+        log_kv(
+            {
+                "message": "Set room key",
+                "room_id": room_id,
+                "session_id": session_id,
+                "room_key": room_key,
+            }
+        )
 
+    @trace
     @defer.inlineCallbacks
     def get_e2e_room_keys(self, user_id, version, room_id=None, session_id=None):
         """Bulk get the E2E room keys for a given backup, optionally filtered to a given
@@ -153,6 +163,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
 
         return sessions
 
+    @trace
     @defer.inlineCallbacks
     def delete_e2e_room_keys(self, user_id, version, room_id=None, session_id=None):
         """Bulk delete the E2E room keys for a given backup, optionally filtered to a given
@@ -236,6 +247,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             "get_e2e_room_keys_version_info", _get_e2e_room_keys_version_info_txn
         )
 
+    @trace
     def create_e2e_room_keys_version(self, user_id, info):
         """Atomically creates a new version of this user's e2e_room_keys store
         with the given version info.
@@ -276,6 +288,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             "create_e2e_room_keys_version_txn", _create_e2e_room_keys_version_txn
         )
 
+    @trace
     def update_e2e_room_keys_version(self, user_id, version, info):
         """Update a given backup version
 
@@ -292,6 +305,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             desc="update_e2e_room_keys_version",
         )
 
+    @trace
     def delete_e2e_room_keys_version(self, user_id, version=None):
         """Delete a given backup version of the user's room keys.
         Doesn't delete their actual key data.
diff --git a/synapse/storage/end_to_end_keys.py b/synapse/storage/end_to_end_keys.py
index 1e07474e70..33e3a84933 100644
--- a/synapse/storage/end_to_end_keys.py
+++ b/synapse/storage/end_to_end_keys.py
@@ -18,12 +18,14 @@ from canonicaljson import encode_canonical_json
 
 from twisted.internet import defer
 
+from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.util.caches.descriptors import cached
 
 from ._base import SQLBaseStore, db_to_json
 
 
 class EndToEndKeyWorkerStore(SQLBaseStore):
+    @trace
     @defer.inlineCallbacks
     def get_e2e_device_keys(
         self, query_list, include_all_devices=False, include_deleted_devices=False
@@ -40,6 +42,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             Dict mapping from user-id to dict mapping from device_id to
             dict containing "key_json", "device_display_name".
         """
+        set_tag("query_list", query_list)
         if not query_list:
             return {}
 
@@ -57,9 +60,13 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
 
         return results
 
+    @trace
     def _get_e2e_device_keys_txn(
         self, txn, query_list, include_all_devices=False, include_deleted_devices=False
     ):
+        set_tag("include_all_devices", include_all_devices)
+        set_tag("include_deleted_devices", include_deleted_devices)
+
         query_clauses = []
         query_params = []
 
@@ -104,6 +111,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             for user_id, device_id in deleted_devices:
                 result.setdefault(user_id, {})[device_id] = None
 
+        log_kv(result)
         return result
 
     @defer.inlineCallbacks
@@ -129,8 +137,9 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             keyvalues={"user_id": user_id, "device_id": device_id},
             desc="add_e2e_one_time_keys_check",
         )
-
-        return {(row["algorithm"], row["key_id"]): row["key_json"] for row in rows}
+        result = {(row["algorithm"], row["key_id"]): row["key_json"] for row in rows}
+        log_kv({"message": "Fetched one time keys for user", "one_time_keys": result})
+        return result
 
     @defer.inlineCallbacks
     def add_e2e_one_time_keys(self, user_id, device_id, time_now, new_keys):
@@ -146,6 +155,9 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
         """
 
         def _add_e2e_one_time_keys(txn):
+            set_tag("user_id", user_id)
+            set_tag("device_id", device_id)
+            set_tag("new_keys", new_keys)
             # We are protected from race between lookup and insertion due to
             # a unique constraint. If there is a race of two calls to
             # `add_e2e_one_time_keys` then they'll conflict and we will only
@@ -202,6 +214,11 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
         """
 
         def _set_e2e_device_keys_txn(txn):
+            set_tag("user_id", user_id)
+            set_tag("device_id", device_id)
+            set_tag("time_now", time_now)
+            set_tag("device_keys", device_keys)
+
             old_key_json = self._simple_select_one_onecol_txn(
                 txn,
                 table="e2e_device_keys_json",
@@ -215,6 +232,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
             new_key_json = encode_canonical_json(device_keys).decode("utf-8")
 
             if old_key_json == new_key_json:
+                log_kv({"Message": "Device key already stored."})
                 return False
 
             self._simple_upsert_txn(
@@ -223,7 +241,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 keyvalues={"user_id": user_id, "device_id": device_id},
                 values={"ts_added_ms": time_now, "key_json": new_key_json},
             )
-
+            log_kv({"message": "Device keys stored."})
             return True
 
         return self.runInteraction("set_e2e_device_keys", _set_e2e_device_keys_txn)
@@ -231,6 +249,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
     def claim_e2e_one_time_keys(self, query_list):
         """Take a list of one time keys out of the database"""
 
+        @trace
         def _claim_e2e_one_time_keys(txn):
             sql = (
                 "SELECT key_id, key_json FROM e2e_one_time_keys_json"
@@ -252,7 +271,13 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 " AND key_id = ?"
             )
             for user_id, device_id, algorithm, key_id in delete:
+                log_kv(
+                    {
+                        "message": "Executing claim e2e_one_time_keys transaction on database."
+                    }
+                )
                 txn.execute(sql, (user_id, device_id, algorithm, key_id))
+                log_kv({"message": "finished executing and invalidating cache"})
                 self._invalidate_cache_and_stream(
                     txn, self.count_e2e_one_time_keys, (user_id, device_id)
                 )
@@ -262,6 +287,13 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
 
     def delete_e2e_keys_by_device(self, user_id, device_id):
         def delete_e2e_keys_by_device_txn(txn):
+            log_kv(
+                {
+                    "message": "Deleting keys for device",
+                    "device_id": device_id,
+                    "user_id": user_id,
+                }
+            )
             self._simple_delete_txn(
                 txn,
                 table="e2e_device_keys_json",
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index ac876287fc..5a95c36a8b 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -1302,15 +1302,11 @@ class EventsStore(
             "event_reference_hashes",
             "event_search",
             "event_to_state_groups",
-            "guest_access",
-            "history_visibility",
             "local_invites",
-            "room_names",
             "state_events",
             "rejections",
             "redactions",
             "room_memberships",
-            "topics",
         ):
             txn.executemany(
                 "DELETE FROM %s WHERE event_id = ?" % (table,),
@@ -1454,10 +1450,10 @@ class EventsStore(
 
         for event, _ in events_and_contexts:
             if event.type == EventTypes.Name:
-                # Insert into the room_names and event_search tables.
+                # Insert into the event_search table.
                 self._store_room_name_txn(txn, event)
             elif event.type == EventTypes.Topic:
-                # Insert into the topics table and event_search table.
+                # Insert into the event_search table.
                 self._store_room_topic_txn(txn, event)
             elif event.type == EventTypes.Message:
                 # Insert into the event_search table.
@@ -1465,12 +1461,6 @@ class EventsStore(
             elif event.type == EventTypes.Redaction:
                 # Insert into the redactions table.
                 self._store_redaction(txn, event)
-            elif event.type == EventTypes.RoomHistoryVisibility:
-                # Insert into the event_search table.
-                self._store_history_visibility_txn(txn, event)
-            elif event.type == EventTypes.GuestAccess:
-                # Insert into the event_search table.
-                self._store_guest_access_txn(txn, event)
 
             self._handle_event_relations(txn, event)
 
@@ -2191,6 +2181,143 @@ class EventsStore(
 
         return to_delete, to_dedelta
 
+    def purge_room(self, room_id):
+        """Deletes all record of a room
+
+        Args:
+            room_id (str):
+        """
+
+        return self.runInteraction("purge_room", self._purge_room_txn, room_id)
+
+    def _purge_room_txn(self, txn, room_id):
+        # first we have to delete the state groups states
+        logger.info("[purge] removing %s from state_groups_state", room_id)
+
+        txn.execute(
+            """
+            DELETE FROM state_groups_state WHERE state_group IN (
+              SELECT state_group FROM events JOIN event_to_state_groups USING(event_id)
+              WHERE events.room_id=?
+            )
+            """,
+            (room_id,),
+        )
+
+        # ... and the state group edges
+        logger.info("[purge] removing %s from state_group_edges", room_id)
+
+        txn.execute(
+            """
+            DELETE FROM state_group_edges WHERE state_group IN (
+              SELECT state_group FROM events JOIN event_to_state_groups USING(event_id)
+              WHERE events.room_id=?
+            )
+            """,
+            (room_id,),
+        )
+
+        # ... and the state groups
+        logger.info("[purge] removing %s from state_groups", room_id)
+
+        txn.execute(
+            """
+            DELETE FROM state_groups WHERE id IN (
+              SELECT state_group FROM events JOIN event_to_state_groups USING(event_id)
+              WHERE events.room_id=?
+            )
+            """,
+            (room_id,),
+        )
+
+        # and then tables which lack an index on room_id but have one on event_id
+        for table in (
+            "event_auth",
+            "event_edges",
+            "event_push_actions_staging",
+            "event_reference_hashes",
+            "event_relations",
+            "event_to_state_groups",
+            "redactions",
+            "rejections",
+            "state_events",
+        ):
+            logger.info("[purge] removing %s from %s", room_id, table)
+
+            txn.execute(
+                """
+                DELETE FROM %s WHERE event_id IN (
+                  SELECT event_id FROM events WHERE room_id=?
+                )
+                """
+                % (table,),
+                (room_id,),
+            )
+
+        # and finally, the tables with an index on room_id (or no useful index)
+        for table in (
+            "current_state_events",
+            "event_backward_extremities",
+            "event_forward_extremities",
+            "event_json",
+            "event_push_actions",
+            "event_search",
+            "events",
+            "group_rooms",
+            "public_room_list_stream",
+            "receipts_graph",
+            "receipts_linearized",
+            "room_aliases",
+            "room_depth",
+            "room_memberships",
+            "room_state",
+            "room_stats",
+            "room_stats_earliest_token",
+            "rooms",
+            "stream_ordering_to_exterm",
+            "topics",
+            "users_in_public_rooms",
+            "users_who_share_private_rooms",
+            # no useful index, but let's clear them anyway
+            "appservice_room_list",
+            "e2e_room_keys",
+            "event_push_summary",
+            "pusher_throttle",
+            "group_summary_rooms",
+            "local_invites",
+            "room_account_data",
+            "room_tags",
+        ):
+            logger.info("[purge] removing %s from %s", room_id, table)
+            txn.execute("DELETE FROM %s WHERE room_id=?" % (table,), (room_id,))
+
+        # Other tables we do NOT need to clear out:
+        #
+        #  - blocked_rooms
+        #    This is important, to make sure that we don't accidentally rejoin a blocked
+        #    room after it was purged
+        #
+        #  - user_directory
+        #    This has a room_id column, but it is unused
+        #
+
+        # Other tables that we might want to consider clearing out include:
+        #
+        #  - event_reports
+        #       Given that these are intended for abuse management my initial
+        #       inclination is to leave them in place.
+        #
+        #  - current_state_delta_stream
+        #  - ex_outlier_stream
+        #  - room_tags_revisions
+        #       The problem with these is that they are largeish and there is no room_id
+        #       index on them. In any case we should be clearing out 'stream' tables
+        #       periodically anyway (#5888)
+
+        # TODO: we could probably usefully do a bunch of cache invalidation here
+
+        logger.info("[purge] done")
+
     @defer.inlineCallbacks
     def is_event_after(self, event_id1, event_id2):
         """Returns True if event_id1 is after event_id2 in the stream
diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index bc606292b8..08e13f3a3b 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -386,32 +386,12 @@ class RoomStore(RoomWorkerStore, SearchStore):
 
     def _store_room_topic_txn(self, txn, event):
         if hasattr(event, "content") and "topic" in event.content:
-            self._simple_insert_txn(
-                txn,
-                "topics",
-                {
-                    "event_id": event.event_id,
-                    "room_id": event.room_id,
-                    "topic": event.content["topic"],
-                },
-            )
-
             self.store_event_search_txn(
                 txn, event, "content.topic", event.content["topic"]
             )
 
     def _store_room_name_txn(self, txn, event):
         if hasattr(event, "content") and "name" in event.content:
-            self._simple_insert_txn(
-                txn,
-                "room_names",
-                {
-                    "event_id": event.event_id,
-                    "room_id": event.room_id,
-                    "name": event.content["name"],
-                },
-            )
-
             self.store_event_search_txn(
                 txn, event, "content.name", event.content["name"]
             )
@@ -422,21 +402,6 @@ class RoomStore(RoomWorkerStore, SearchStore):
                 txn, event, "content.body", event.content["body"]
             )
 
-    def _store_history_visibility_txn(self, txn, event):
-        self._store_content_index_txn(txn, event, "history_visibility")
-
-    def _store_guest_access_txn(self, txn, event):
-        self._store_content_index_txn(txn, event, "guest_access")
-
-    def _store_content_index_txn(self, txn, event, key):
-        if hasattr(event, "content") and key in event.content:
-            sql = (
-                "INSERT INTO %(key)s"
-                " (event_id, room_id, %(key)s)"
-                " VALUES (?, ?, ?)" % {"key": key}
-            )
-            txn.execute(sql, (event.event_id, event.room_id, event.content[key]))
-
     def add_event_report(
         self, room_id, event_id, user_id, reason, content, received_ts
     ):
diff --git a/synapse/storage/schema/delta/56/drop_unused_event_tables.sql b/synapse/storage/schema/delta/56/drop_unused_event_tables.sql
new file mode 100644
index 0000000000..9f09922c67
--- /dev/null
+++ b/synapse/storage/schema/delta/56/drop_unused_event_tables.sql
@@ -0,0 +1,20 @@
+/* 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.
+ */
+
+-- these tables are never used.
+DROP TABLE IF EXISTS room_names;
+DROP TABLE IF EXISTS topics;
+DROP TABLE IF EXISTS history_visibility;
+DROP TABLE IF EXISTS guest_access;
diff --git a/synapse/storage/schema/delta/56/fix_room_keys_index.sql b/synapse/storage/schema/delta/56/fix_room_keys_index.sql
new file mode 100644
index 0000000000..014cb3b538
--- /dev/null
+++ b/synapse/storage/schema/delta/56/fix_room_keys_index.sql
@@ -0,0 +1,18 @@
+/* Copyright 2019 Matrix.org Foundation CIC
+ *
+ * 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.
+ */
+
+-- version is supposed to be part of the room keys index
+CREATE UNIQUE INDEX e2e_room_keys_with_version_idx ON e2e_room_keys(user_id, version, room_id, session_id);
+DROP INDEX IF EXISTS e2e_room_keys_idx;
diff --git a/synapse/storage/schema/delta/56/users_in_public_rooms_idx.sql b/synapse/storage/schema/delta/56/users_in_public_rooms_idx.sql
new file mode 100644
index 0000000000..149f8be8b6
--- /dev/null
+++ b/synapse/storage/schema/delta/56/users_in_public_rooms_idx.sql
@@ -0,0 +1,17 @@
+/* Copyright 2019 Matrix.org Foundation CIC
+ *
+ * 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.
+ */
+
+-- this was apparently forgotten when the table was created back in delta 53.
+CREATE INDEX users_in_public_rooms_r_idx ON users_in_public_rooms(room_id);
diff --git a/tests/appservice/test_scheduler.py b/tests/appservice/test_scheduler.py
index 04b8c2c07c..52f89d3f83 100644
--- a/tests/appservice/test_scheduler.py
+++ b/tests/appservice/test_scheduler.py
@@ -37,11 +37,9 @@ class ApplicationServiceSchedulerTransactionCtrlTestCase(unittest.TestCase):
         self.recoverer = Mock()
         self.recoverer_fn = Mock(return_value=self.recoverer)
         self.txnctrl = _TransactionController(
-            clock=self.clock,
-            store=self.store,
-            as_api=self.as_api,
-            recoverer_fn=self.recoverer_fn,
+            clock=self.clock, store=self.store, as_api=self.as_api
         )
+        self.txnctrl.RECOVERER_CLASS = self.recoverer_fn
 
     def test_single_service_up_txn_sent(self):
         # Test: The AS is up and the txn is successfully sent.
diff --git a/tests/http/federation/test_matrix_federation_agent.py b/tests/http/federation/test_matrix_federation_agent.py
index 445a0e76ab..71d7025264 100644
--- a/tests/http/federation/test_matrix_federation_agent.py
+++ b/tests/http/federation/test_matrix_federation_agent.py
@@ -73,8 +73,6 @@ class MatrixFederationAgentTests(unittest.TestCase):
 
         self.mock_resolver = Mock()
 
-        self.well_known_cache = TTLCache("test_cache", timer=self.reactor.seconds)
-
         config_dict = default_config("test", parse=False)
         config_dict["federation_custom_ca_list"] = [get_test_ca_cert_file()]
 
@@ -82,11 +80,21 @@ class MatrixFederationAgentTests(unittest.TestCase):
         config.parse_config_dict(config_dict, "", "")
 
         self.tls_factory = ClientTLSOptionsFactory(config)
+
+        self.well_known_cache = TTLCache("test_cache", timer=self.reactor.seconds)
+        self.had_well_known_cache = TTLCache("test_cache", timer=self.reactor.seconds)
+        self.well_known_resolver = WellKnownResolver(
+            self.reactor,
+            Agent(self.reactor, contextFactory=self.tls_factory),
+            well_known_cache=self.well_known_cache,
+            had_well_known_cache=self.had_well_known_cache,
+        )
+
         self.agent = MatrixFederationAgent(
             reactor=self.reactor,
             tls_client_options_factory=self.tls_factory,
             _srv_resolver=self.mock_resolver,
-            _well_known_cache=self.well_known_cache,
+            _well_known_resolver=self.well_known_resolver,
         )
 
     def _make_connection(self, client_factory, expected_sni):
@@ -543,7 +551,7 @@ class MatrixFederationAgentTests(unittest.TestCase):
         self.assertEqual(self.well_known_cache[b"testserv"], b"target-server")
 
         # check the cache expires
-        self.reactor.pump((25 * 3600,))
+        self.reactor.pump((48 * 3600,))
         self.well_known_cache.expire()
         self.assertNotIn(b"testserv", self.well_known_cache)
 
@@ -631,7 +639,7 @@ class MatrixFederationAgentTests(unittest.TestCase):
         self.assertEqual(self.well_known_cache[b"testserv"], b"target-server")
 
         # check the cache expires
-        self.reactor.pump((25 * 3600,))
+        self.reactor.pump((48 * 3600,))
         self.well_known_cache.expire()
         self.assertNotIn(b"testserv", self.well_known_cache)
 
@@ -701,11 +709,18 @@ class MatrixFederationAgentTests(unittest.TestCase):
 
         config = default_config("test", parse=True)
 
+        # Build a new agent and WellKnownResolver with a different tls factory
+        tls_factory = ClientTLSOptionsFactory(config)
         agent = MatrixFederationAgent(
             reactor=self.reactor,
-            tls_client_options_factory=ClientTLSOptionsFactory(config),
+            tls_client_options_factory=tls_factory,
             _srv_resolver=self.mock_resolver,
-            _well_known_cache=self.well_known_cache,
+            _well_known_resolver=WellKnownResolver(
+                self.reactor,
+                Agent(self.reactor, contextFactory=tls_factory),
+                well_known_cache=self.well_known_cache,
+                had_well_known_cache=self.had_well_known_cache,
+            ),
         )
 
         test_d = agent.request(b"GET", b"matrix://testserv/foo/bar")
@@ -932,15 +947,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
         self.successResultOf(test_d)
 
     def test_well_known_cache(self):
-        well_known_resolver = WellKnownResolver(
-            self.reactor,
-            Agent(self.reactor, contextFactory=self.tls_factory),
-            well_known_cache=self.well_known_cache,
-        )
-
         self.reactor.lookups["testserv"] = "1.2.3.4"
 
-        fetch_d = well_known_resolver.get_well_known(b"testserv")
+        fetch_d = self.well_known_resolver.get_well_known(b"testserv")
 
         # there should be an attempt to connect on port 443 for the .well-known
         clients = self.reactor.tcpClients
@@ -963,7 +972,7 @@ class MatrixFederationAgentTests(unittest.TestCase):
         well_known_server.loseConnection()
 
         # repeat the request: it should hit the cache
-        fetch_d = well_known_resolver.get_well_known(b"testserv")
+        fetch_d = self.well_known_resolver.get_well_known(b"testserv")
         r = self.successResultOf(fetch_d)
         self.assertEqual(r.delegated_server, b"target-server")
 
@@ -971,7 +980,7 @@ class MatrixFederationAgentTests(unittest.TestCase):
         self.reactor.pump((1000.0,))
 
         # now it should connect again
-        fetch_d = well_known_resolver.get_well_known(b"testserv")
+        fetch_d = self.well_known_resolver.get_well_known(b"testserv")
 
         self.assertEqual(len(clients), 1)
         (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
@@ -992,15 +1001,9 @@ class MatrixFederationAgentTests(unittest.TestCase):
         it ignores transient errors.
         """
 
-        well_known_resolver = WellKnownResolver(
-            self.reactor,
-            Agent(self.reactor, contextFactory=self.tls_factory),
-            well_known_cache=self.well_known_cache,
-        )
-
         self.reactor.lookups["testserv"] = "1.2.3.4"
 
-        fetch_d = well_known_resolver.get_well_known(b"testserv")
+        fetch_d = self.well_known_resolver.get_well_known(b"testserv")
 
         # there should be an attempt to connect on port 443 for the .well-known
         clients = self.reactor.tcpClients
@@ -1026,27 +1029,37 @@ class MatrixFederationAgentTests(unittest.TestCase):
         # another lookup.
         self.reactor.pump((900.0,))
 
-        fetch_d = well_known_resolver.get_well_known(b"testserv")
-        clients = self.reactor.tcpClients
-        (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
+        fetch_d = self.well_known_resolver.get_well_known(b"testserv")
 
-        # fonx the connection attempt, this will be treated as a temporary
-        # failure.
-        client_factory.clientConnectionFailed(None, Exception("nope"))
+        # The resolver may retry a few times, so fonx all requests that come along
+        attempts = 0
+        while self.reactor.tcpClients:
+            clients = self.reactor.tcpClients
+            (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)
 
-        # attemptdelay on the hostnameendpoint is 0.3, so takes that long before the
-        # .well-known request fails.
-        self.reactor.pump((0.4,))
+            attempts += 1
+
+            # fonx the connection attempt, this will be treated as a temporary
+            # failure.
+            client_factory.clientConnectionFailed(None, Exception("nope"))
+
+            # There's a few sleeps involved, so we have to pump the reactor a
+            # bit.
+            self.reactor.pump((1.0, 1.0))
+
+        # We expect to see more than one attempt as there was previously a valid
+        # well known.
+        self.assertGreater(attempts, 1)
 
         # Resolver should return cached value, despite the lookup failing.
         r = self.successResultOf(fetch_d)
         self.assertEqual(r.delegated_server, b"target-server")
 
-        # Expire the cache and repeat the request
-        self.reactor.pump((100.0,))
+        # Expire both caches and repeat the request
+        self.reactor.pump((10000.0,))
 
         # Repated the request, this time it should fail if the lookup fails.
-        fetch_d = well_known_resolver.get_well_known(b"testserv")
+        fetch_d = self.well_known_resolver.get_well_known(b"testserv")
 
         clients = self.reactor.tcpClients
         (host, port, client_factory, _timeout, _bindAddress) = clients.pop(0)