Optimise some references to hs.config (#7546)

These are surprisingly expensive, and we only really need to do them at startup.

3 files changed, 32 insertions, 19 deletions

diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index ea25f0515a..681f92cafd 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -366,7 +366,9 @@ class EventCreationHandler(object):
         self.notifier = hs.get_notifier()
         self.config = hs.config
         self.require_membership_for_aliases = hs.config.require_membership_for_aliases
-        self._instance_name = hs.get_instance_name()
+        self._is_event_writer = (
+            self.config.worker.writers.events == hs.get_instance_name()
+        )
 
         self.room_invite_state_types = self.hs.config.room_invite_state_types
 
@@ -836,7 +838,7 @@ class EventCreationHandler(object):
         success = False
         try:
             # If we're a worker we need to hit out to the master.
-            if self.config.worker.writers.events != self._instance_name:
+            if not self._is_event_writer:
                 result = await self.send_event(
                     instance_name=self.config.worker.writers.events,
                     event_id=event.event_id,
@@ -906,7 +908,7 @@ class EventCreationHandler(object):
 
         This should only be run on the instance in charge of persisting events.
         """
-        assert self.config.worker.writers.events == self._instance_name
+        assert self._is_event_writer
 
         if ratelimit:
             # We check if this is a room admin redacting an event so that we
diff --git a/synapse/server_notices/resource_limits_server_notices.py b/synapse/server_notices/resource_limits_server_notices.py
index d97166351e..73f2cedb5c 100644
--- a/synapse/server_notices/resource_limits_server_notices.py
+++ b/synapse/server_notices/resource_limits_server_notices.py
@@ -48,6 +48,12 @@ class ResourceLimitsServerNotices(object):
 
         self._notifier = hs.get_notifier()
 
+        self._enabled = (
+            hs.config.limit_usage_by_mau
+            and self._server_notices_manager.is_enabled()
+            and not hs.config.hs_disabled
+        )
+
     async def maybe_send_server_notice_to_user(self, user_id):
         """Check if we need to send a notice to this user, this will be true in
         two cases.
@@ -61,14 +67,7 @@ class ResourceLimitsServerNotices(object):
         Returns:
             Deferred
         """
-        if self._config.hs_disabled is True:
-            return
-
-        if self._config.limit_usage_by_mau is False:
-            return
-
-        if not self._server_notices_manager.is_enabled():
-            # Don't try and send server notices unless they've been enabled
+        if not self._enabled:
             return
 
         timestamp = await self._store.user_last_seen_monthly_active(user_id)
diff --git a/synapse/storage/data_stores/main/monthly_active_users.py b/synapse/storage/data_stores/main/monthly_active_users.py
index 925bc5691b..a42c52f323 100644
--- a/synapse/storage/data_stores/main/monthly_active_users.py
+++ b/synapse/storage/data_stores/main/monthly_active_users.py
@@ -122,6 +122,10 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
     def __init__(self, database: Database, db_conn, hs):
         super(MonthlyActiveUsersStore, self).__init__(database, db_conn, hs)
 
+        self._limit_usage_by_mau = hs.config.limit_usage_by_mau
+        self._mau_stats_only = hs.config.mau_stats_only
+        self._max_mau_value = hs.config.max_mau_value
+
         # Do not add more reserved users than the total allowable number
         # cur = LoggingTransaction(
         self.db.new_transaction(
@@ -130,7 +134,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             [],
             [],
             self._initialise_reserved_users,
-            hs.config.mau_limits_reserved_threepids[: self.hs.config.max_mau_value],
+            hs.config.mau_limits_reserved_threepids[: self._max_mau_value],
         )
 
     def _initialise_reserved_users(self, txn, threepids):
@@ -142,6 +146,15 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             threepids (list[dict]): List of threepid dicts to reserve
         """
 
+        # XXX what is this function trying to achieve?  It upserts into
+        # monthly_active_users for each *registered* reserved mau user, but why?
+        #
+        #  - shouldn't there already be an entry for each reserved user (at least
+        #    if they have been active recently)?
+        #
+        #  - if it's important that the timestamp is kept up to date, why do we only
+        #    run this at startup?
+
         for tp in threepids:
             user_id = self.get_user_id_by_threepid_txn(txn, tp["medium"], tp["address"])
 
@@ -191,8 +204,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
 
             txn.execute(sql, query_args)
 
-            max_mau_value = self.hs.config.max_mau_value
-            if self.hs.config.limit_usage_by_mau:
+            if self._limit_usage_by_mau:
                 # If MAU user count still exceeds the MAU threshold, then delete on
                 # a least recently active basis.
                 # Note it is not possible to write this query using OFFSET due to
@@ -210,13 +222,13 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
                             LIMIT ?
                         )
                         """
-                    txn.execute(sql, (max_mau_value,))
+                    txn.execute(sql, ((self._max_mau_value),))
                 # Need if/else since 'AND user_id NOT IN ({})' fails on Postgres
                 # when len(reserved_users) == 0. Works fine on sqlite.
                 else:
                     # Must be >= 0 for postgres
                     num_of_non_reserved_users_to_remove = max(
-                        max_mau_value - len(reserved_users), 0
+                        self._max_mau_value - len(reserved_users), 0
                     )
 
                     # It is important to filter reserved users twice to guard
@@ -335,7 +347,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
         Args:
             user_id(str): the user_id to query
         """
-        if self.hs.config.limit_usage_by_mau or self.hs.config.mau_stats_only:
+        if self._limit_usage_by_mau or self._mau_stats_only:
             # Trial users and guests should not be included as part of MAU group
             is_guest = yield self.is_guest(user_id)
             if is_guest:
@@ -356,11 +368,11 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
                 # In the case where mau_stats_only is True and limit_usage_by_mau is
                 # False, there is no point in checking get_monthly_active_count - it
                 # adds no value and will break the logic if max_mau_value is exceeded.
-                if not self.hs.config.limit_usage_by_mau:
+                if not self._limit_usage_by_mau:
                     yield self.upsert_monthly_active_user(user_id)
                 else:
                     count = yield self.get_monthly_active_count()
-                    if count < self.hs.config.max_mau_value:
+                    if count < self._max_mau_value:
                         yield self.upsert_monthly_active_user(user_id)
             elif now - last_seen_timestamp > LAST_SEEN_GRANULARITY:
                 yield self.upsert_monthly_active_user(user_id)