From 8cbbfaefc1fc597cbbef52a10dbfb8ecd4d8a8cd Mon Sep 17 00:00:00 2001
From: Matthew Hodgson <matthew@matrix.org>
Date: Fri, 23 Mar 2018 10:32:50 +0000
Subject: 404 correctly on missing paths via NoResource

fixes https://github.com/matrix-org/synapse/issues/2043 and https://github.com/matrix-org/synapse/issues/2029
---
 synapse/util/httpresourcetree.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

(limited to 'synapse/util')

diff --git a/synapse/util/httpresourcetree.py b/synapse/util/httpresourcetree.py
index 45be47159a..d747849553 100644
--- a/synapse/util/httpresourcetree.py
+++ b/synapse/util/httpresourcetree.py
@@ -12,7 +12,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from twisted.web.resource import Resource
+from twisted.web.resource import NoResource
 
 import logging
 
@@ -45,7 +45,7 @@ def create_resource_tree(desired_tree, root_resource):
         for path_seg in full_path.split('/')[1:-1]:
             if path_seg not in last_resource.listNames():
                 # resource doesn't exist, so make a "dummy resource"
-                child_resource = Resource()
+                child_resource = NoResource()
                 last_resource.putChild(path_seg, child_resource)
                 res_id = _resource_id(last_resource, path_seg)
                 resource_mappings[res_id] = child_resource
-- 
cgit 1.4.1


From 05630758f25d958bf60fde4df5f80a89e4a9a0ac Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Thu, 29 Mar 2018 22:57:28 +0100
Subject: Use static JSONEncoders

using json.dumps with custom options requires us to create a new JSONEncoder on
each call. It's more efficient to create one upfront and reuse it.
---
 synapse/handlers/message.py         |  4 ++--
 synapse/replication/tcp/commands.py |  8 +++++---
 synapse/storage/events.py           | 23 ++++++++---------------
 synapse/util/frozenutils.py         | 19 +++++++++++++++++++
 4 files changed, 34 insertions(+), 20 deletions(-)

(limited to 'synapse/util')

diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 5a8ddc253e..6de6e13b7b 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -27,7 +27,7 @@ from synapse.types import (
 from synapse.util.async import run_on_reactor, ReadWriteLock, Limiter
 from synapse.util.logcontext import preserve_fn, run_in_background
 from synapse.util.metrics import measure_func
-from synapse.util.frozenutils import unfreeze
+from synapse.util.frozenutils import frozendict_json_encoder
 from synapse.util.stringutils import random_string
 from synapse.visibility import filter_events_for_client
 from synapse.replication.http.send_event import send_event_to_master
@@ -678,7 +678,7 @@ class EventCreationHandler(object):
 
         # Ensure that we can round trip before trying to persist in db
         try:
-            dump = simplejson.dumps(unfreeze(event.content))
+            dump = frozendict_json_encoder.encode(event.content)
             simplejson.loads(dump)
         except Exception:
             logger.exception("Failed to encode content: %r", event.content)
diff --git a/synapse/replication/tcp/commands.py b/synapse/replication/tcp/commands.py
index 0005ad5879..34bcf903a3 100644
--- a/synapse/replication/tcp/commands.py
+++ b/synapse/replication/tcp/commands.py
@@ -24,6 +24,8 @@ import simplejson
 
 logger = logging.getLogger(__name__)
 
+_json_encoder = simplejson.JSONEncoder(namedtuple_as_object=False)
+
 
 class Command(object):
     """The base command class.
@@ -107,7 +109,7 @@ class RdataCommand(Command):
         return " ".join((
             self.stream_name,
             str(self.token) if self.token is not None else "batch",
-            simplejson.dumps(self.row, namedtuple_as_object=False),
+            _json_encoder.dumps(self.row),
         ))
 
 
@@ -302,7 +304,7 @@ class InvalidateCacheCommand(Command):
 
     def to_line(self):
         return " ".join((
-            self.cache_func, simplejson.dumps(self.keys, namedtuple_as_object=False)
+            self.cache_func, _json_encoder.encode(self.keys),
         ))
 
 
@@ -334,7 +336,7 @@ class UserIpCommand(Command):
         )
 
     def to_line(self):
-        return self.user_id + " " + simplejson.dumps((
+        return self.user_id + " " + _json_encoder.encode((
             self.access_token, self.ip, self.user_agent, self.device_id,
             self.last_seen,
         ))
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index f3d65f4338..ece5e6c41f 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -14,15 +14,19 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.events_worker import EventsWorkerStore
+from collections import OrderedDict, deque, namedtuple
+from functools import wraps
+import logging
 
+import simplejson as json
 from twisted.internet import defer
 
-from synapse.events import USE_FROZEN_DICTS
 
+from synapse.storage.events_worker import EventsWorkerStore
 from synapse.util.async import ObservableDeferred
+from synapse.util.frozenutils import frozendict_json_encoder
 from synapse.util.logcontext import (
-    PreserveLoggingContext, make_deferred_yieldable
+    PreserveLoggingContext, make_deferred_yieldable,
 )
 from synapse.util.logutils import log_function
 from synapse.util.metrics import Measure
@@ -30,16 +34,8 @@ from synapse.api.constants import EventTypes
 from synapse.api.errors import SynapseError
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 from synapse.types import get_domain_from_id
-
-from canonicaljson import encode_canonical_json
-from collections import deque, namedtuple, OrderedDict
-from functools import wraps
-
 import synapse.metrics
 
-import logging
-import simplejson as json
-
 # these are only included to make the type annotations work
 from synapse.events import EventBase    # noqa: F401
 from synapse.events.snapshot import EventContext   # noqa: F401
@@ -71,10 +67,7 @@ state_delta_reuse_delta_counter = metrics.register_counter(
 
 
 def encode_json(json_object):
-    if USE_FROZEN_DICTS:
-        return encode_canonical_json(json_object)
-    else:
-        return json.dumps(json_object, ensure_ascii=False)
+    return frozendict_json_encoder.encode(json_object)
 
 
 class _EventPeristenceQueue(object):
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index 6322f0f55c..f497b51f4a 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 from frozendict import frozendict
+import simplejson as json
 
 
 def freeze(o):
@@ -49,3 +50,21 @@ def unfreeze(o):
         pass
 
     return o
+
+
+def _handle_frozendict(obj):
+    """Helper for EventEncoder. Makes frozendicts serializable by returning
+    the underlying dict
+    """
+    if type(obj) is frozendict:
+        # fishing the protected dict out of the object is a bit nasty,
+        # but we don't really want the overhead of copying the dict.
+        return obj._dict
+    raise TypeError('Object of type %s is not JSON serializable' %
+                    obj.__class__.__name__)
+
+
+# A JSONEncoder which is capable of encoding frozendics without barfing
+frozendict_json_encoder = json.JSONEncoder(
+    default=_handle_frozendict,
+)
-- 
cgit 1.4.1


From 518f6de0881378b1fa356e21256436491d43c93c Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Wed, 4 Apr 2018 19:46:28 +0100
Subject: Remove redundant metrics which were deprecated in 0.27.0.

---
 CHANGES.rst             |  9 +++++++++
 UPGRADE.rst             |  9 ++++++++-
 docs/metrics-howto.rst  | 11 +++++++++++
 synapse/http/server.py  | 26 --------------------------
 synapse/util/metrics.py | 25 -------------------------
 5 files changed, 28 insertions(+), 52 deletions(-)

(limited to 'synapse/util')

diff --git a/CHANGES.rst b/CHANGES.rst
index 38372381ac..5fbad54427 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,3 +1,12 @@
+Changes in synapse v0.28.0 (2018-xx-xx)
+=======================================
+
+As previously advised, this release removes a number of redundant Prometheus
+metrics. Administrators may need to update their dashboards and alerting rules
+to use the updated metric names, if they have not already done so. See
+`docs/metrics-howto.rst <docs/metrics-howto.rst#deprecated-metrics-removed-in-0-28-0>`_
+for more details.
+
 Changes in synapse v0.27.2 (2018-03-26)
 =======================================
 
diff --git a/UPGRADE.rst b/UPGRADE.rst
index f6bb1070b1..39a16b1c0c 100644
--- a/UPGRADE.rst
+++ b/UPGRADE.rst
@@ -52,7 +52,7 @@ Upgrading to $NEXT_VERSION
 ====================
 
 This release expands the anonymous usage stats sent if the opt-in
-``report_stats`` configuration is set to ``true``. We now capture RSS memory 
+``report_stats`` configuration is set to ``true``. We now capture RSS memory
 and cpu use at a very coarse level. This requires administrators to install
 the optional ``psutil`` python module.
 
@@ -60,6 +60,13 @@ We would appreciate it if you could assist by ensuring this module is available
 and ``report_stats`` is enabled. This will let us see if performance changes to
 synapse are having an impact to the general community.
 
+This release also removes a number of redundant Prometheus metrics.
+Administrators may need to update their dashboards and alerting rules to use
+the updated metric names, if they have not already done so. See
+`docs/metrics-howto.rst <docs/metrics-howto.rst#deprecated-metrics-removed-in-0-28-0>`_
+for more details.
+
+
 Upgrading to v0.15.0
 ====================
 
diff --git a/docs/metrics-howto.rst b/docs/metrics-howto.rst
index 8acc479bc3..5e2d7c52ec 100644
--- a/docs/metrics-howto.rst
+++ b/docs/metrics-howto.rst
@@ -34,6 +34,17 @@ How to monitor Synapse metrics using Prometheus
    Restart prometheus.
 
 
+Deprecated metrics removed in 0.28.0
+------------------------------------
+
+Synapse 0.28.0 removes all of the metrics deprecated by 0.27.0, which are those
+listed under "Old name" below. This has been done to reduce the bandwidth used
+by gathering metrics and the storage requirements for the Prometheus server, as
+well as reducing CPU overhead for both Synapse and Prometheus.
+
+Administrators should update any alerts or monitoring dashboards to use the
+"New name" listed below.
+
 Block and response metrics renamed for 0.27.0
 ---------------------------------------------
 
diff --git a/synapse/http/server.py b/synapse/http/server.py
index f19c068ef6..02c7e46f08 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -47,17 +47,6 @@ metrics = synapse.metrics.get_metrics_for(__name__)
 response_count = metrics.register_counter(
     "response_count",
     labels=["method", "servlet", "tag"],
-    alternative_names=(
-        # the following are all deprecated aliases for the same metric
-        metrics.name_prefix + x for x in (
-            "_requests",
-            "_response_time:count",
-            "_response_ru_utime:count",
-            "_response_ru_stime:count",
-            "_response_db_txn_count:count",
-            "_response_db_txn_duration:count",
-        )
-    )
 )
 
 requests_counter = metrics.register_counter(
@@ -73,39 +62,24 @@ outgoing_responses_counter = metrics.register_counter(
 response_timer = metrics.register_counter(
     "response_time_seconds",
     labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_time:total",
-    ),
 )
 
 response_ru_utime = metrics.register_counter(
     "response_ru_utime_seconds", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_ru_utime:total",
-    ),
 )
 
 response_ru_stime = metrics.register_counter(
     "response_ru_stime_seconds", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_ru_stime:total",
-    ),
 )
 
 response_db_txn_count = metrics.register_counter(
     "response_db_txn_count", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_db_txn_count:total",
-    ),
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, when processing
 # this request
 response_db_txn_duration = metrics.register_counter(
     "response_db_txn_duration_seconds", labels=["method", "servlet", "tag"],
-    alternative_names=(
-        metrics.name_prefix + "_response_db_txn_duration:total",
-    ),
 )
 
 # seconds spent waiting for a db connection, when processing this request
diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index e4b5687a4b..c3d8237e8f 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -31,53 +31,28 @@ metrics = synapse.metrics.get_metrics_for(__name__)
 block_counter = metrics.register_counter(
     "block_count",
     labels=["block_name"],
-    alternative_names=(
-        # the following are all deprecated aliases for the same metric
-        metrics.name_prefix + x for x in (
-            "_block_timer:count",
-            "_block_ru_utime:count",
-            "_block_ru_stime:count",
-            "_block_db_txn_count:count",
-            "_block_db_txn_duration:count",
-        )
-    )
 )
 
 block_timer = metrics.register_counter(
     "block_time_seconds",
     labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_timer:total",
-    ),
 )
 
 block_ru_utime = metrics.register_counter(
     "block_ru_utime_seconds", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_ru_utime:total",
-    ),
 )
 
 block_ru_stime = metrics.register_counter(
     "block_ru_stime_seconds", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_ru_stime:total",
-    ),
 )
 
 block_db_txn_count = metrics.register_counter(
     "block_db_txn_count", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_db_txn_count:total",
-    ),
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, in this block
 block_db_txn_duration = metrics.register_counter(
     "block_db_txn_duration_seconds", labels=["block_name"],
-    alternative_names=(
-        metrics.name_prefix + "_block_db_txn_duration:total",
-    ),
 )
 
 # seconds spent waiting for a db connection, in this block
-- 
cgit 1.4.1


From 01afc563c39006c21bb7752831cd62c146edc135 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Thu, 5 Apr 2018 16:24:04 +0100
Subject: Fix overzealous cache invalidation

Fixes an issue where a cache invalidation would invalidate *all* pending
entries, rather than just the entry that we intended to invalidate.
---
 synapse/util/caches/descriptors.py    | 64 +++++++++++++++++++++--------------
 tests/util/caches/test_descriptors.py | 46 +++++++++++++++++++++++++
 2 files changed, 84 insertions(+), 26 deletions(-)

(limited to 'synapse/util')

diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index bf3a66eae4..68285a7594 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2015, 2016 OpenMarket Ltd
+# Copyright 2018 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -39,12 +40,11 @@ _CacheSentinel = object()
 
 class CacheEntry(object):
     __slots__ = [
-        "deferred", "sequence", "callbacks", "invalidated"
+        "deferred", "callbacks", "invalidated"
     ]
 
-    def __init__(self, deferred, sequence, callbacks):
+    def __init__(self, deferred, callbacks):
         self.deferred = deferred
-        self.sequence = sequence
         self.callbacks = set(callbacks)
         self.invalidated = False
 
@@ -62,7 +62,6 @@ class Cache(object):
         "max_entries",
         "name",
         "keylen",
-        "sequence",
         "thread",
         "metrics",
         "_pending_deferred_cache",
@@ -80,7 +79,6 @@ class Cache(object):
 
         self.name = name
         self.keylen = keylen
-        self.sequence = 0
         self.thread = None
         self.metrics = register_cache(name, self.cache)
 
@@ -113,11 +111,10 @@ class Cache(object):
         callbacks = [callback] if callback else []
         val = self._pending_deferred_cache.get(key, _CacheSentinel)
         if val is not _CacheSentinel:
-            if val.sequence == self.sequence:
-                val.callbacks.update(callbacks)
-                if update_metrics:
-                    self.metrics.inc_hits()
-                return val.deferred
+            val.callbacks.update(callbacks)
+            if update_metrics:
+                self.metrics.inc_hits()
+            return val.deferred
 
         val = self.cache.get(key, _CacheSentinel, callbacks=callbacks)
         if val is not _CacheSentinel:
@@ -137,12 +134,9 @@ class Cache(object):
         self.check_thread()
         entry = CacheEntry(
             deferred=value,
-            sequence=self.sequence,
             callbacks=callbacks,
         )
 
-        entry.callbacks.update(callbacks)
-
         existing_entry = self._pending_deferred_cache.pop(key, None)
         if existing_entry:
             existing_entry.invalidate()
@@ -150,13 +144,25 @@ class Cache(object):
         self._pending_deferred_cache[key] = entry
 
         def shuffle(result):
-            if self.sequence == entry.sequence:
-                existing_entry = self._pending_deferred_cache.pop(key, None)
-                if existing_entry is entry:
-                    self.cache.set(key, result, entry.callbacks)
-                else:
-                    entry.invalidate()
+            existing_entry = self._pending_deferred_cache.pop(key, None)
+            if existing_entry is entry:
+                self.cache.set(key, result, entry.callbacks)
             else:
+                # oops, the _pending_deferred_cache has been updated since
+                # we started our query, so we are out of date.
+                #
+                # Better put back whatever we took out. (We do it this way
+                # round, rather than peeking into the _pending_deferred_cache
+                # and then removing on a match, to make the common case faster)
+                if existing_entry is not None:
+                    self._pending_deferred_cache[key] = existing_entry
+
+                # we're not going to put this entry into the cache, so need
+                # to make sure that the invalidation callbacks are called.
+                # That was probably done when _pending_deferred_cache was
+                # updated, but it's possible that `set` was called without
+                # `invalidate` being previously called, in which case it may
+                # not have been. Either way, let's double-check now.
                 entry.invalidate()
             return result
 
@@ -168,25 +174,29 @@ class Cache(object):
 
     def invalidate(self, key):
         self.check_thread()
+        self.cache.pop(key, None)
 
-        # Increment the sequence number so that any SELECT statements that
-        # raced with the INSERT don't update the cache (SYN-369)
-        self.sequence += 1
+        # if we have a pending lookup for this key, remove it from the
+        # _pending_deferred_cache, which will (a) stop it being returned
+        # for future queries and (b) stop it being persisted as a proper entry
+        # in self.cache.
         entry = self._pending_deferred_cache.pop(key, None)
+
+        # run the invalidation callbacks now, rather than waiting for the
+        # deferred to resolve.
         if entry:
             entry.invalidate()
 
-        self.cache.pop(key, None)
-
     def invalidate_many(self, key):
         self.check_thread()
         if not isinstance(key, tuple):
             raise TypeError(
                 "The cache key must be a tuple not %r" % (type(key),)
             )
-        self.sequence += 1
         self.cache.del_multi(key)
 
+        # if we have a pending lookup for this key, remove it from the
+        # _pending_deferred_cache, as above
         entry_dict = self._pending_deferred_cache.pop(key, None)
         if entry_dict is not None:
             for entry in iterate_tree_cache_entry(entry_dict):
@@ -194,8 +204,10 @@ class Cache(object):
 
     def invalidate_all(self):
         self.check_thread()
-        self.sequence += 1
         self.cache.clear()
+        for entry in self._pending_deferred_cache.itervalues():
+            entry.invalidate()
+        self._pending_deferred_cache.clear()
 
 
 class _CacheDescriptorBase(object):
diff --git a/tests/util/caches/test_descriptors.py b/tests/util/caches/test_descriptors.py
index 3f14ab503f..2516fe40f4 100644
--- a/tests/util/caches/test_descriptors.py
+++ b/tests/util/caches/test_descriptors.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2016 OpenMarket Ltd
+# Copyright 2018 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -12,6 +13,7 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
+from functools import partial
 import logging
 
 import mock
@@ -25,6 +27,50 @@ from tests import unittest
 logger = logging.getLogger(__name__)
 
 
+class CacheTestCase(unittest.TestCase):
+    def test_invalidate_all(self):
+        cache = descriptors.Cache("testcache")
+
+        callback_record = [False, False]
+
+        def record_callback(idx):
+            callback_record[idx] = True
+
+        # add a couple of pending entries
+        d1 = defer.Deferred()
+        cache.set("key1", d1, partial(record_callback, 0))
+
+        d2 = defer.Deferred()
+        cache.set("key2", d2, partial(record_callback, 1))
+
+        # lookup should return the deferreds
+        self.assertIs(cache.get("key1"), d1)
+        self.assertIs(cache.get("key2"), d2)
+
+        # let one of the lookups complete
+        d2.callback("result2")
+        self.assertEqual(cache.get("key2"), "result2")
+
+        # now do the invalidation
+        cache.invalidate_all()
+
+        # lookup should return none
+        self.assertIsNone(cache.get("key1", None))
+        self.assertIsNone(cache.get("key2", None))
+
+        # both callbacks should have been callbacked
+        self.assertTrue(
+            callback_record[0], "Invalidation callback for key1 not called",
+        )
+        self.assertTrue(
+            callback_record[1], "Invalidation callback for key2 not called",
+        )
+
+        # letting the other lookup complete should do nothing
+        d1.callback("result1")
+        self.assertIsNone(cache.get("key1", None))
+
+
 class DescriptorTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def test_cache(self):
-- 
cgit 1.4.1


From 13decdbf96981782616a3ee1826fce1213a1bc89 Mon Sep 17 00:00:00 2001
From: Richard van der Hoff <richard@matrix.org>
Date: Mon, 9 Apr 2018 12:58:37 +0100
Subject: Revert "Merge pull request #3066 from
 matrix-org/rav/remove_redundant_metrics"

We aren't ready to release this yet, so I'm reverting it for now.

This reverts commit d1679a4ed7947b0814e0f2af9b888a16c588f1a1, reversing
changes made to e089100c6231541c446e37e157dec8feed02d283.
---
 CHANGES.rst             |  9 ---------
 UPGRADE.rst             |  9 +--------
 docs/metrics-howto.rst  | 11 -----------
 synapse/http/server.py  | 26 ++++++++++++++++++++++++++
 synapse/util/metrics.py | 25 +++++++++++++++++++++++++
 5 files changed, 52 insertions(+), 28 deletions(-)

(limited to 'synapse/util')

diff --git a/CHANGES.rst b/CHANGES.rst
index 5fbad54427..38372381ac 100644
--- a/CHANGES.rst
+++ b/CHANGES.rst
@@ -1,12 +1,3 @@
-Changes in synapse v0.28.0 (2018-xx-xx)
-=======================================
-
-As previously advised, this release removes a number of redundant Prometheus
-metrics. Administrators may need to update their dashboards and alerting rules
-to use the updated metric names, if they have not already done so. See
-`docs/metrics-howto.rst <docs/metrics-howto.rst#deprecated-metrics-removed-in-0-28-0>`_
-for more details.
-
 Changes in synapse v0.27.2 (2018-03-26)
 =======================================
 
diff --git a/UPGRADE.rst b/UPGRADE.rst
index 39a16b1c0c..f6bb1070b1 100644
--- a/UPGRADE.rst
+++ b/UPGRADE.rst
@@ -52,7 +52,7 @@ Upgrading to $NEXT_VERSION
 ====================
 
 This release expands the anonymous usage stats sent if the opt-in
-``report_stats`` configuration is set to ``true``. We now capture RSS memory
+``report_stats`` configuration is set to ``true``. We now capture RSS memory 
 and cpu use at a very coarse level. This requires administrators to install
 the optional ``psutil`` python module.
 
@@ -60,13 +60,6 @@ We would appreciate it if you could assist by ensuring this module is available
 and ``report_stats`` is enabled. This will let us see if performance changes to
 synapse are having an impact to the general community.
 
-This release also removes a number of redundant Prometheus metrics.
-Administrators may need to update their dashboards and alerting rules to use
-the updated metric names, if they have not already done so. See
-`docs/metrics-howto.rst <docs/metrics-howto.rst#deprecated-metrics-removed-in-0-28-0>`_
-for more details.
-
-
 Upgrading to v0.15.0
 ====================
 
diff --git a/docs/metrics-howto.rst b/docs/metrics-howto.rst
index 5e2d7c52ec..8acc479bc3 100644
--- a/docs/metrics-howto.rst
+++ b/docs/metrics-howto.rst
@@ -34,17 +34,6 @@ How to monitor Synapse metrics using Prometheus
    Restart prometheus.
 
 
-Deprecated metrics removed in 0.28.0
-------------------------------------
-
-Synapse 0.28.0 removes all of the metrics deprecated by 0.27.0, which are those
-listed under "Old name" below. This has been done to reduce the bandwidth used
-by gathering metrics and the storage requirements for the Prometheus server, as
-well as reducing CPU overhead for both Synapse and Prometheus.
-
-Administrators should update any alerts or monitoring dashboards to use the
-"New name" listed below.
-
 Block and response metrics renamed for 0.27.0
 ---------------------------------------------
 
diff --git a/synapse/http/server.py b/synapse/http/server.py
index ac75206ef5..64e083ebfc 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -47,6 +47,17 @@ metrics = synapse.metrics.get_metrics_for(__name__)
 response_count = metrics.register_counter(
     "response_count",
     labels=["method", "servlet", "tag"],
+    alternative_names=(
+        # the following are all deprecated aliases for the same metric
+        metrics.name_prefix + x for x in (
+            "_requests",
+            "_response_time:count",
+            "_response_ru_utime:count",
+            "_response_ru_stime:count",
+            "_response_db_txn_count:count",
+            "_response_db_txn_duration:count",
+        )
+    )
 )
 
 requests_counter = metrics.register_counter(
@@ -62,24 +73,39 @@ outgoing_responses_counter = metrics.register_counter(
 response_timer = metrics.register_counter(
     "response_time_seconds",
     labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_time:total",
+    ),
 )
 
 response_ru_utime = metrics.register_counter(
     "response_ru_utime_seconds", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_ru_utime:total",
+    ),
 )
 
 response_ru_stime = metrics.register_counter(
     "response_ru_stime_seconds", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_ru_stime:total",
+    ),
 )
 
 response_db_txn_count = metrics.register_counter(
     "response_db_txn_count", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_db_txn_count:total",
+    ),
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, when processing
 # this request
 response_db_txn_duration = metrics.register_counter(
     "response_db_txn_duration_seconds", labels=["method", "servlet", "tag"],
+    alternative_names=(
+        metrics.name_prefix + "_response_db_txn_duration:total",
+    ),
 )
 
 # seconds spent waiting for a db connection, when processing this request
diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index c3d8237e8f..e4b5687a4b 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -31,28 +31,53 @@ metrics = synapse.metrics.get_metrics_for(__name__)
 block_counter = metrics.register_counter(
     "block_count",
     labels=["block_name"],
+    alternative_names=(
+        # the following are all deprecated aliases for the same metric
+        metrics.name_prefix + x for x in (
+            "_block_timer:count",
+            "_block_ru_utime:count",
+            "_block_ru_stime:count",
+            "_block_db_txn_count:count",
+            "_block_db_txn_duration:count",
+        )
+    )
 )
 
 block_timer = metrics.register_counter(
     "block_time_seconds",
     labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_timer:total",
+    ),
 )
 
 block_ru_utime = metrics.register_counter(
     "block_ru_utime_seconds", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_ru_utime:total",
+    ),
 )
 
 block_ru_stime = metrics.register_counter(
     "block_ru_stime_seconds", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_ru_stime:total",
+    ),
 )
 
 block_db_txn_count = metrics.register_counter(
     "block_db_txn_count", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_db_txn_count:total",
+    ),
 )
 
 # seconds spent waiting for db txns, excluding scheduling time, in this block
 block_db_txn_duration = metrics.register_counter(
     "block_db_txn_duration_seconds", labels=["block_name"],
+    alternative_names=(
+        metrics.name_prefix + "_block_db_txn_duration:total",
+    ),
 )
 
 # seconds spent waiting for a db connection, in this block
-- 
cgit 1.4.1