From ddd48b6851675cd192e67a143e9dfde051afecad Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 3 Dec 2019 14:00:09 +0000
Subject: [PATCH 1/7] Move account validity bg updates to registration store

---
 synapse/storage/_base.py                      | 66 -------------------
 .../storage/data_stores/main/registration.py  | 64 ++++++++++++++++++
 2 files changed, 64 insertions(+), 66 deletions(-)

diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 459901ac60..7ebab31af0 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -252,8 +252,6 @@ class SQLBaseStore(object):
         # A set of tables that are not safe to use native upserts in.
         self._unsafe_to_upsert_tables = set(UNIQUE_INDEX_BACKGROUND_UPDATES.keys())
 
-        self._account_validity = self.hs.config.account_validity
-
         # We add the user_directory_search table to the blacklist on SQLite
         # because the existing search table does not have an index, making it
         # unsafe to use native upserts.
@@ -272,14 +270,6 @@ class SQLBaseStore(object):
 
         self.rand = random.SystemRandom()
 
-        if self._account_validity.enabled:
-            self._clock.call_later(
-                0.0,
-                run_as_background_process,
-                "account_validity_set_expiration_dates",
-                self._set_expiration_date_when_missing,
-            )
-
     @defer.inlineCallbacks
     def _check_safe_to_upsert(self):
         """
@@ -312,62 +302,6 @@ class SQLBaseStore(object):
                 self._check_safe_to_upsert,
             )
 
-    @defer.inlineCallbacks
-    def _set_expiration_date_when_missing(self):
-        """
-        Retrieves the list of registered users that don't have an expiration date, and
-        adds an expiration date for each of them.
-        """
-
-        def select_users_with_no_expiration_date_txn(txn):
-            """Retrieves the list of registered users with no expiration date from the
-            database, filtering out deactivated users.
-            """
-            sql = (
-                "SELECT users.name FROM users"
-                " LEFT JOIN account_validity ON (users.name = account_validity.user_id)"
-                " WHERE account_validity.user_id is NULL AND users.deactivated = 0;"
-            )
-            txn.execute(sql, [])
-
-            res = self.cursor_to_dict(txn)
-            if res:
-                for user in res:
-                    self.set_expiration_date_for_user_txn(
-                        txn, user["name"], use_delta=True
-                    )
-
-        yield self.runInteraction(
-            "get_users_with_no_expiration_date",
-            select_users_with_no_expiration_date_txn,
-        )
-
-    def set_expiration_date_for_user_txn(self, txn, user_id, use_delta=False):
-        """Sets an expiration date to the account with the given user ID.
-
-        Args:
-             user_id (str): User ID to set an expiration date for.
-             use_delta (bool): If set to False, the expiration date for the user will be
-                now + validity period. If set to True, this expiration date will be a
-                random value in the [now + period - d ; now + period] range, d being a
-                delta equal to 10% of the validity period.
-        """
-        now_ms = self._clock.time_msec()
-        expiration_ts = now_ms + self._account_validity.period
-
-        if use_delta:
-            expiration_ts = self.rand.randrange(
-                expiration_ts - self._account_validity.startup_job_max_delta,
-                expiration_ts,
-            )
-
-        self._simple_upsert_txn(
-            txn,
-            "account_validity",
-            keyvalues={"user_id": user_id},
-            values={"expiration_ts_ms": expiration_ts, "email_sent": False},
-        )
-
     def start_profiling(self):
         self._previous_loop_ts = monotonic_time()
 
diff --git a/synapse/storage/data_stores/main/registration.py b/synapse/storage/data_stores/main/registration.py
index 98cf6427c3..653c9318cb 100644
--- a/synapse/storage/data_stores/main/registration.py
+++ b/synapse/storage/data_stores/main/registration.py
@@ -926,6 +926,14 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
 
         self._account_validity = hs.config.account_validity
 
+        if self._account_validity.enabled:
+            self._clock.call_later(
+                0.0,
+                run_as_background_process,
+                "account_validity_set_expiration_dates",
+                self._set_expiration_date_when_missing,
+            )
+
         # Create a background job for culling expired 3PID validity tokens
         def start_cull():
             # run as a background process to make sure that the database transactions
@@ -1502,3 +1510,59 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         self._invalidate_cache_and_stream(
             txn, self.get_user_deactivated_status, (user_id,)
         )
+
+    @defer.inlineCallbacks
+    def _set_expiration_date_when_missing(self):
+        """
+        Retrieves the list of registered users that don't have an expiration date, and
+        adds an expiration date for each of them.
+        """
+
+        def select_users_with_no_expiration_date_txn(txn):
+            """Retrieves the list of registered users with no expiration date from the
+            database, filtering out deactivated users.
+            """
+            sql = (
+                "SELECT users.name FROM users"
+                " LEFT JOIN account_validity ON (users.name = account_validity.user_id)"
+                " WHERE account_validity.user_id is NULL AND users.deactivated = 0;"
+            )
+            txn.execute(sql, [])
+
+            res = self.cursor_to_dict(txn)
+            if res:
+                for user in res:
+                    self.set_expiration_date_for_user_txn(
+                        txn, user["name"], use_delta=True
+                    )
+
+        yield self.runInteraction(
+            "get_users_with_no_expiration_date",
+            select_users_with_no_expiration_date_txn,
+        )
+
+    def set_expiration_date_for_user_txn(self, txn, user_id, use_delta=False):
+        """Sets an expiration date to the account with the given user ID.
+
+        Args:
+             user_id (str): User ID to set an expiration date for.
+             use_delta (bool): If set to False, the expiration date for the user will be
+                now + validity period. If set to True, this expiration date will be a
+                random value in the [now + period - d ; now + period] range, d being a
+                delta equal to 10% of the validity period.
+        """
+        now_ms = self._clock.time_msec()
+        expiration_ts = now_ms + self._account_validity.period
+
+        if use_delta:
+            expiration_ts = self.rand.randrange(
+                expiration_ts - self._account_validity.startup_job_max_delta,
+                expiration_ts,
+            )
+
+        self._simple_upsert_txn(
+            txn,
+            "account_validity",
+            keyvalues={"user_id": user_id},
+            values={"expiration_ts_ms": expiration_ts, "email_sent": False},
+        )

From 6b2867096b8a2cf8afdb5de2bab93bbf31f76065 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 3 Dec 2019 14:08:48 +0000
Subject: [PATCH 2/7] Move event fetch vars to EventWorkStore

---
 synapse/storage/_base.py                          | 12 ------------
 synapse/storage/data_stores/main/client_ips.py    |  2 +-
 synapse/storage/data_stores/main/devices.py       |  2 +-
 synapse/storage/data_stores/main/events_worker.py | 13 +++++++++++++
 4 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 7ebab31af0..6b8120a608 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -18,7 +18,6 @@ import itertools
 import logging
 import random
 import sys
-import threading
 import time
 from typing import Iterable, Tuple
 
@@ -36,7 +35,6 @@ from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.types import get_domain_from_id
 from synapse.util import batch_iter
-from synapse.util.caches.descriptors import Cache
 from synapse.util.stringutils import exception_to_unicode
 
 # import a function which will return a monotonic time, in seconds
@@ -237,16 +235,6 @@ class SQLBaseStore(object):
         #   to watch it
         self._txn_perf_counters = PerformanceCounters()
 
-        self._get_event_cache = Cache(
-            "*getEvent*", keylen=3, max_entries=hs.config.event_cache_size
-        )
-
-        self._event_fetch_lock = threading.Condition()
-        self._event_fetch_list = []
-        self._event_fetch_ongoing = 0
-
-        self._pending_ds = []
-
         self.database_engine = hs.database_engine
 
         # A set of tables that are not safe to use native upserts in.
diff --git a/synapse/storage/data_stores/main/client_ips.py b/synapse/storage/data_stores/main/client_ips.py
index 706c6a1f3f..7931b876ce 100644
--- a/synapse/storage/data_stores/main/client_ips.py
+++ b/synapse/storage/data_stores/main/client_ips.py
@@ -21,7 +21,7 @@ from twisted.internet import defer
 
 from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage import background_updates
-from synapse.storage._base import Cache
+from synapse.util.caches.descriptors import Cache
 from synapse.util.caches import CACHE_SIZE_FACTOR
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/storage/data_stores/main/devices.py b/synapse/storage/data_stores/main/devices.py
index 71f62036c0..b50ee026a2 100644
--- a/synapse/storage/data_stores/main/devices.py
+++ b/synapse/storage/data_stores/main/devices.py
@@ -31,11 +31,11 @@ from synapse.logging.opentracing import (
 )
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import (
-    Cache,
     SQLBaseStore,
     db_to_json,
     make_in_list_sql_clause,
 )
+from synapse.util.caches.descriptors import Cache
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.types import get_verify_key_from_cross_signing_key
 from synapse.util import batch_iter
diff --git a/synapse/storage/data_stores/main/events_worker.py b/synapse/storage/data_stores/main/events_worker.py
index 4c4b76bd93..e782e8f481 100644
--- a/synapse/storage/data_stores/main/events_worker.py
+++ b/synapse/storage/data_stores/main/events_worker.py
@@ -17,6 +17,7 @@ from __future__ import division
 
 import itertools
 import logging
+import threading
 from collections import namedtuple
 
 from canonicaljson import json
@@ -34,6 +35,7 @@ from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import SQLBaseStore, make_in_list_sql_clause
 from synapse.types import get_domain_from_id
 from synapse.util import batch_iter
+from synapse.util.caches.descriptors import Cache
 from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
@@ -53,6 +55,17 @@ _EventCacheEntry = namedtuple("_EventCacheEntry", ("event", "redacted_event"))
 
 
 class EventsWorkerStore(SQLBaseStore):
+    def __init__(self, db_conn, hs):
+        super(EventsWorkerStore, self).__init__(db_conn, hs)
+
+        self._get_event_cache = Cache(
+            "*getEvent*", keylen=3, max_entries=hs.config.event_cache_size
+        )
+
+        self._event_fetch_lock = threading.Condition()
+        self._event_fetch_list = []
+        self._event_fetch_ongoing = 0
+
     def get_received_ts(self, event_id):
         """Get received_ts (when it was persisted) for the event.
 

From 1056d6885a7b96be85c5ff19e26eba2ed3f90dd4 Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 3 Dec 2019 14:28:46 +0000
Subject: [PATCH 3/7] Move cache invalidation to main data store

---
 synapse/replication/slave/storage/_base.py    |   3 +-
 synapse/storage/_base.py                      | 104 --------------
 synapse/storage/data_stores/main/__init__.py  |   2 +
 synapse/storage/data_stores/main/cache.py     | 131 ++++++++++++++++++
 .../storage/data_stores/main/client_ips.py    |   2 +-
 synapse/storage/data_stores/main/devices.py   |  14 +-
 6 files changed, 143 insertions(+), 113 deletions(-)
 create mode 100644 synapse/storage/data_stores/main/cache.py

diff --git a/synapse/replication/slave/storage/_base.py b/synapse/replication/slave/storage/_base.py
index 456bc005a0..71e5877aca 100644
--- a/synapse/replication/slave/storage/_base.py
+++ b/synapse/replication/slave/storage/_base.py
@@ -18,7 +18,8 @@ from typing import Dict
 
 import six
 
-from synapse.storage._base import _CURRENT_STATE_CACHE_NAME, SQLBaseStore
+from synapse.storage._base import SQLBaseStore
+from synapse.storage.data_stores.main.cache import _CURRENT_STATE_CACHE_NAME
 from synapse.storage.engines import PostgresEngine
 
 from ._slaved_id_tracker import SlavedIdTracker
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 6b8120a608..c02248cfe9 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -14,7 +14,6 @@
 # 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 itertools
 import logging
 import random
 import sys
@@ -34,7 +33,6 @@ from synapse.logging.context import LoggingContext, make_deferred_yieldable
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.types import get_domain_from_id
-from synapse.util import batch_iter
 from synapse.util.stringutils import exception_to_unicode
 
 # import a function which will return a monotonic time, in seconds
@@ -77,10 +75,6 @@ UNIQUE_INDEX_BACKGROUND_UPDATES = {
     "event_search": "event_search_event_id_idx",
 }
 
-# This is a special cache name we use to batch multiple invalidations of caches
-# based on the current state when notifying workers over replication.
-_CURRENT_STATE_CACHE_NAME = "cs_cache_fake"
-
 
 class LoggingTransaction(object):
     """An object that almost-transparently proxies for the 'txn' object
@@ -1322,47 +1316,6 @@ class SQLBaseStore(object):
 
         return cache, min_val
 
-    def _invalidate_cache_and_stream(self, txn, cache_func, keys):
-        """Invalidates the cache and adds it to the cache stream so slaves
-        will know to invalidate their caches.
-
-        This should only be used to invalidate caches where slaves won't
-        otherwise know from other replication streams that the cache should
-        be invalidated.
-        """
-        txn.call_after(cache_func.invalidate, keys)
-        self._send_invalidation_to_replication(txn, cache_func.__name__, keys)
-
-    def _invalidate_state_caches_and_stream(self, txn, room_id, members_changed):
-        """Special case invalidation of caches based on current state.
-
-        We special case this so that we can batch the cache invalidations into a
-        single replication poke.
-
-        Args:
-            txn
-            room_id (str): Room where state changed
-            members_changed (iterable[str]): The user_ids of members that have changed
-        """
-        txn.call_after(self._invalidate_state_caches, room_id, members_changed)
-
-        if members_changed:
-            # We need to be careful that the size of the `members_changed` list
-            # isn't so large that it causes problems sending over replication, so we
-            # send them in chunks.
-            # Max line length is 16K, and max user ID length is 255, so 50 should
-            # be safe.
-            for chunk in batch_iter(members_changed, 50):
-                keys = itertools.chain([room_id], chunk)
-                self._send_invalidation_to_replication(
-                    txn, _CURRENT_STATE_CACHE_NAME, keys
-                )
-        else:
-            # if no members changed, we still need to invalidate the other caches.
-            self._send_invalidation_to_replication(
-                txn, _CURRENT_STATE_CACHE_NAME, [room_id]
-            )
-
     def _invalidate_state_caches(self, room_id, members_changed):
         """Invalidates caches that are based on the current state, but does
         not stream invalidations down replication.
@@ -1396,63 +1349,6 @@ class SQLBaseStore(object):
             # which is fine.
             pass
 
-    def _send_invalidation_to_replication(self, txn, cache_name, keys):
-        """Notifies replication that given cache has been invalidated.
-
-        Note that this does *not* invalidate the cache locally.
-
-        Args:
-            txn
-            cache_name (str)
-            keys (iterable[str])
-        """
-
-        if isinstance(self.database_engine, PostgresEngine):
-            # get_next() returns a context manager which is designed to wrap
-            # the transaction. However, we want to only get an ID when we want
-            # to use it, here, so we need to call __enter__ manually, and have
-            # __exit__ called after the transaction finishes.
-            ctx = self._cache_id_gen.get_next()
-            stream_id = ctx.__enter__()
-            txn.call_on_exception(ctx.__exit__, None, None, None)
-            txn.call_after(ctx.__exit__, None, None, None)
-            txn.call_after(self.hs.get_notifier().on_new_replication_data)
-
-            self._simple_insert_txn(
-                txn,
-                table="cache_invalidation_stream",
-                values={
-                    "stream_id": stream_id,
-                    "cache_func": cache_name,
-                    "keys": list(keys),
-                    "invalidation_ts": self.clock.time_msec(),
-                },
-            )
-
-    def get_all_updated_caches(self, last_id, current_id, limit):
-        if last_id == current_id:
-            return defer.succeed([])
-
-        def get_all_updated_caches_txn(txn):
-            # We purposefully don't bound by the current token, as we want to
-            # send across cache invalidations as quickly as possible. Cache
-            # invalidations are idempotent, so duplicates are fine.
-            sql = (
-                "SELECT stream_id, cache_func, keys, invalidation_ts"
-                " FROM cache_invalidation_stream"
-                " WHERE stream_id > ? ORDER BY stream_id ASC LIMIT ?"
-            )
-            txn.execute(sql, (last_id, limit))
-            return txn.fetchall()
-
-        return self.runInteraction("get_all_updated_caches", get_all_updated_caches_txn)
-
-    def get_cache_stream_token(self):
-        if self._cache_id_gen:
-            return self._cache_id_gen.get_current_token()
-        else:
-            return 0
-
     def _simple_select_list_paginate(
         self,
         table,
diff --git a/synapse/storage/data_stores/main/__init__.py b/synapse/storage/data_stores/main/__init__.py
index 10c940df1e..474924c68f 100644
--- a/synapse/storage/data_stores/main/__init__.py
+++ b/synapse/storage/data_stores/main/__init__.py
@@ -32,6 +32,7 @@ from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 from .account_data import AccountDataStore
 from .appservice import ApplicationServiceStore, ApplicationServiceTransactionStore
+from .cache import CacheInvalidationStore
 from .client_ips import ClientIpStore
 from .deviceinbox import DeviceInboxStore
 from .devices import DeviceStore
@@ -110,6 +111,7 @@ class DataStore(
     MonthlyActiveUsersStore,
     StatsStore,
     RelationsStore,
+    CacheInvalidationStore,
 ):
     def __init__(self, db_conn, hs):
         self.hs = hs
diff --git a/synapse/storage/data_stores/main/cache.py b/synapse/storage/data_stores/main/cache.py
new file mode 100644
index 0000000000..6efcc5f3b0
--- /dev/null
+++ b/synapse/storage/data_stores/main/cache.py
@@ -0,0 +1,131 @@
+# -*- 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 itertools
+import logging
+
+from twisted.internet import defer
+
+from synapse.storage._base import SQLBaseStore
+from synapse.storage.engines import PostgresEngine
+from synapse.util import batch_iter
+
+logger = logging.getLogger(__name__)
+
+
+# This is a special cache name we use to batch multiple invalidations of caches
+# based on the current state when notifying workers over replication.
+_CURRENT_STATE_CACHE_NAME = "cs_cache_fake"
+
+
+class CacheInvalidationStore(SQLBaseStore):
+    def _invalidate_cache_and_stream(self, txn, cache_func, keys):
+        """Invalidates the cache and adds it to the cache stream so slaves
+        will know to invalidate their caches.
+
+        This should only be used to invalidate caches where slaves won't
+        otherwise know from other replication streams that the cache should
+        be invalidated.
+        """
+        txn.call_after(cache_func.invalidate, keys)
+        self._send_invalidation_to_replication(txn, cache_func.__name__, keys)
+
+    def _invalidate_state_caches_and_stream(self, txn, room_id, members_changed):
+        """Special case invalidation of caches based on current state.
+
+        We special case this so that we can batch the cache invalidations into a
+        single replication poke.
+
+        Args:
+            txn
+            room_id (str): Room where state changed
+            members_changed (iterable[str]): The user_ids of members that have changed
+        """
+        txn.call_after(self._invalidate_state_caches, room_id, members_changed)
+
+        if members_changed:
+            # We need to be careful that the size of the `members_changed` list
+            # isn't so large that it causes problems sending over replication, so we
+            # send them in chunks.
+            # Max line length is 16K, and max user ID length is 255, so 50 should
+            # be safe.
+            for chunk in batch_iter(members_changed, 50):
+                keys = itertools.chain([room_id], chunk)
+                self._send_invalidation_to_replication(
+                    txn, _CURRENT_STATE_CACHE_NAME, keys
+                )
+        else:
+            # if no members changed, we still need to invalidate the other caches.
+            self._send_invalidation_to_replication(
+                txn, _CURRENT_STATE_CACHE_NAME, [room_id]
+            )
+
+    def _send_invalidation_to_replication(self, txn, cache_name, keys):
+        """Notifies replication that given cache has been invalidated.
+
+        Note that this does *not* invalidate the cache locally.
+
+        Args:
+            txn
+            cache_name (str)
+            keys (iterable[str])
+        """
+
+        if isinstance(self.database_engine, PostgresEngine):
+            # get_next() returns a context manager which is designed to wrap
+            # the transaction. However, we want to only get an ID when we want
+            # to use it, here, so we need to call __enter__ manually, and have
+            # __exit__ called after the transaction finishes.
+            ctx = self._cache_id_gen.get_next()
+            stream_id = ctx.__enter__()
+            txn.call_on_exception(ctx.__exit__, None, None, None)
+            txn.call_after(ctx.__exit__, None, None, None)
+            txn.call_after(self.hs.get_notifier().on_new_replication_data)
+
+            self._simple_insert_txn(
+                txn,
+                table="cache_invalidation_stream",
+                values={
+                    "stream_id": stream_id,
+                    "cache_func": cache_name,
+                    "keys": list(keys),
+                    "invalidation_ts": self.clock.time_msec(),
+                },
+            )
+
+    def get_all_updated_caches(self, last_id, current_id, limit):
+        if last_id == current_id:
+            return defer.succeed([])
+
+        def get_all_updated_caches_txn(txn):
+            # We purposefully don't bound by the current token, as we want to
+            # send across cache invalidations as quickly as possible. Cache
+            # invalidations are idempotent, so duplicates are fine.
+            sql = (
+                "SELECT stream_id, cache_func, keys, invalidation_ts"
+                " FROM cache_invalidation_stream"
+                " WHERE stream_id > ? ORDER BY stream_id ASC LIMIT ?"
+            )
+            txn.execute(sql, (last_id, limit))
+            return txn.fetchall()
+
+        return self.runInteraction("get_all_updated_caches", get_all_updated_caches_txn)
+
+    def get_cache_stream_token(self):
+        if self._cache_id_gen:
+            return self._cache_id_gen.get_current_token()
+        else:
+            return 0
diff --git a/synapse/storage/data_stores/main/client_ips.py b/synapse/storage/data_stores/main/client_ips.py
index 7931b876ce..cae93b0e22 100644
--- a/synapse/storage/data_stores/main/client_ips.py
+++ b/synapse/storage/data_stores/main/client_ips.py
@@ -21,8 +21,8 @@ from twisted.internet import defer
 
 from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage import background_updates
-from synapse.util.caches.descriptors import Cache
 from synapse.util.caches import CACHE_SIZE_FACTOR
+from synapse.util.caches.descriptors import Cache
 
 logger = logging.getLogger(__name__)
 
diff --git a/synapse/storage/data_stores/main/devices.py b/synapse/storage/data_stores/main/devices.py
index b50ee026a2..a3ad23e783 100644
--- a/synapse/storage/data_stores/main/devices.py
+++ b/synapse/storage/data_stores/main/devices.py
@@ -30,16 +30,16 @@ from synapse.logging.opentracing import (
     whitelisted_homeserver,
 )
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage._base import (
-    SQLBaseStore,
-    db_to_json,
-    make_in_list_sql_clause,
-)
-from synapse.util.caches.descriptors import Cache
+from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.types import get_verify_key_from_cross_signing_key
 from synapse.util import batch_iter
-from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
+from synapse.util.caches.descriptors import (
+    Cache,
+    cached,
+    cachedInlineCallbacks,
+    cachedList,
+)
 
 logger = logging.getLogger(__name__)
 

From a785a2febe6783bfa800504c6750028bc61c84ea Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Tue, 3 Dec 2019 14:32:00 +0000
Subject: [PATCH 4/7] Newsfile

---
 changelog.d/6454.misc | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/6454.misc

diff --git a/changelog.d/6454.misc b/changelog.d/6454.misc
new file mode 100644
index 0000000000..9e5259157c
--- /dev/null
+++ b/changelog.d/6454.misc
@@ -0,0 +1 @@
+Move data store specific code out of `SQLBaseStore`.

From 00f0d67566cdfe8eae44aeae1c982c42a255cfcd Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 4 Dec 2019 10:45:59 +0000
Subject: [PATCH 5/7] Move get_user_count_txn out of base store

---
 synapse/storage/_base.py                     | 12 ------------
 synapse/storage/data_stores/main/__init__.py | 12 ++++++++++++
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index c02248cfe9..90019c8b0a 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -1440,18 +1440,6 @@ class SQLBaseStore(object):
 
         return cls.cursor_to_dict(txn)
 
-    def get_user_count_txn(self, txn):
-        """Get a total number of registered users in the users list.
-
-        Args:
-            txn : Transaction object
-        Returns:
-            int : number of users
-        """
-        sql_count = "SELECT COUNT(*) FROM users WHERE is_guest = 0;"
-        txn.execute(sql_count)
-        return txn.fetchone()[0]
-
     def _simple_search_list(
         self, table, term, col, retcols, desc="_simple_search_list"
     ):
diff --git a/synapse/storage/data_stores/main/__init__.py b/synapse/storage/data_stores/main/__init__.py
index 474924c68f..76315935dd 100644
--- a/synapse/storage/data_stores/main/__init__.py
+++ b/synapse/storage/data_stores/main/__init__.py
@@ -516,6 +516,18 @@ class DataStore(
         retval = {"users": users, "total": count}
         return retval
 
+    def get_user_count_txn(self, txn):
+        """Get a total number of registered users in the users list.
+
+        Args:
+            txn : Transaction object
+        Returns:
+            int : number of users
+        """
+        sql_count = "SELECT COUNT(*) FROM users WHERE is_guest = 0;"
+        txn.execute(sql_count)
+        return txn.fetchone()[0]
+
     def search_users(self, term):
         """Function to search users list for one or more users with
         the matched term.

From a7f20500ff39399634d4623e284fb2f9892776ae Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 4 Dec 2019 15:45:42 +0000
Subject: [PATCH 6/7] _CURRENT_STATE_CACHE_NAME is public

---
 synapse/replication/slave/storage/_base.py | 4 ++--
 synapse/storage/data_stores/main/cache.py  | 6 +++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/synapse/replication/slave/storage/_base.py b/synapse/replication/slave/storage/_base.py
index 71e5877aca..6ece1d6745 100644
--- a/synapse/replication/slave/storage/_base.py
+++ b/synapse/replication/slave/storage/_base.py
@@ -19,7 +19,7 @@ from typing import Dict
 import six
 
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.cache import _CURRENT_STATE_CACHE_NAME
+from synapse.storage.data_stores.main.cache import CURRENT_STATE_CACHE_NAME
 from synapse.storage.engines import PostgresEngine
 
 from ._slaved_id_tracker import SlavedIdTracker
@@ -63,7 +63,7 @@ class BaseSlavedStore(SQLBaseStore):
         if stream_name == "caches":
             self._cache_id_gen.advance(token)
             for row in rows:
-                if row.cache_func == _CURRENT_STATE_CACHE_NAME:
+                if row.cache_func == CURRENT_STATE_CACHE_NAME:
                     room_id = row.keys[0]
                     members_changed = set(row.keys[1:])
                     self._invalidate_state_caches(room_id, members_changed)
diff --git a/synapse/storage/data_stores/main/cache.py b/synapse/storage/data_stores/main/cache.py
index 6efcc5f3b0..258c08722a 100644
--- a/synapse/storage/data_stores/main/cache.py
+++ b/synapse/storage/data_stores/main/cache.py
@@ -28,7 +28,7 @@ logger = logging.getLogger(__name__)
 
 # This is a special cache name we use to batch multiple invalidations of caches
 # based on the current state when notifying workers over replication.
-_CURRENT_STATE_CACHE_NAME = "cs_cache_fake"
+CURRENT_STATE_CACHE_NAME = "cs_cache_fake"
 
 
 class CacheInvalidationStore(SQLBaseStore):
@@ -65,12 +65,12 @@ class CacheInvalidationStore(SQLBaseStore):
             for chunk in batch_iter(members_changed, 50):
                 keys = itertools.chain([room_id], chunk)
                 self._send_invalidation_to_replication(
-                    txn, _CURRENT_STATE_CACHE_NAME, keys
+                    txn, CURRENT_STATE_CACHE_NAME, keys
                 )
         else:
             # if no members changed, we still need to invalidate the other caches.
             self._send_invalidation_to_replication(
-                txn, _CURRENT_STATE_CACHE_NAME, [room_id]
+                txn, CURRENT_STATE_CACHE_NAME, [room_id]
             )
 
     def _send_invalidation_to_replication(self, txn, cache_name, keys):

From 9186c105a0d49c60582ff93cf108e511334c57fd Mon Sep 17 00:00:00 2001
From: Erik Johnston <erik@matrix.org>
Date: Wed, 4 Dec 2019 15:46:19 +0000
Subject: [PATCH 7/7] Revert "Move get_user_count_txn out of base store"

This reverts commit 00f0d67566cdfe8eae44aeae1c982c42a255cfcd.

Its going to get removed soon, so lets not make merge conflicts.
---
 synapse/storage/_base.py                     | 12 ++++++++++++
 synapse/storage/data_stores/main/__init__.py | 12 ------------
 2 files changed, 12 insertions(+), 12 deletions(-)

diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 90019c8b0a..c02248cfe9 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -1440,6 +1440,18 @@ class SQLBaseStore(object):
 
         return cls.cursor_to_dict(txn)
 
+    def get_user_count_txn(self, txn):
+        """Get a total number of registered users in the users list.
+
+        Args:
+            txn : Transaction object
+        Returns:
+            int : number of users
+        """
+        sql_count = "SELECT COUNT(*) FROM users WHERE is_guest = 0;"
+        txn.execute(sql_count)
+        return txn.fetchone()[0]
+
     def _simple_search_list(
         self, table, term, col, retcols, desc="_simple_search_list"
     ):
diff --git a/synapse/storage/data_stores/main/__init__.py b/synapse/storage/data_stores/main/__init__.py
index 76315935dd..474924c68f 100644
--- a/synapse/storage/data_stores/main/__init__.py
+++ b/synapse/storage/data_stores/main/__init__.py
@@ -516,18 +516,6 @@ class DataStore(
         retval = {"users": users, "total": count}
         return retval
 
-    def get_user_count_txn(self, txn):
-        """Get a total number of registered users in the users list.
-
-        Args:
-            txn : Transaction object
-        Returns:
-            int : number of users
-        """
-        sql_count = "SELECT COUNT(*) FROM users WHERE is_guest = 0;"
-        txn.execute(sql_count)
-        return txn.fetchone()[0]
-
     def search_users(self, term):
         """Function to search users list for one or more users with
         the matched term.