diff --git a/synapse/storage/databases/main/metrics.py b/synapse/storage/databases/main/metrics.py
new file mode 100644
index 0000000000..92099f95ce
--- /dev/null
+++ b/synapse/storage/databases/main/metrics.py
@@ -0,0 +1,139 @@
+# -*- coding: utf-8 -*-
+# Copyright 2020 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.
+
+from synapse.metrics import GaugeBucketCollector
+from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.storage._base import SQLBaseStore
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.event_push_actions import (
+ EventPushActionsWorkerStore,
+)
+
+# Collect metrics on the number of forward extremities that exist.
+_extremities_collecter = GaugeBucketCollector(
+ "synapse_forward_extremities",
+ "Number of rooms on the server with the given number of forward extremities"
+ " or fewer",
+ buckets=[1, 2, 3, 5, 7, 10, 15, 20, 50, 100, 200, 500],
+)
+
+# we also expose metrics on the "number of excess extremity events", which is
+# (E-1)*N, where E is the number of extremities and N is the number of state
+# events in the room. This is an approximation to the number of state events
+# we could remove from state resolution by reducing the graph to a single
+# forward extremity.
+_excess_state_events_collecter = GaugeBucketCollector(
+ "synapse_excess_extremity_events",
+ "Number of rooms on the server with the given number of excess extremity "
+ "events, or fewer",
+ buckets=[0] + [1 << n for n in range(12)],
+)
+
+
+class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
+ """Functions to pull various metrics from the DB, for e.g. phone home
+ stats and prometheus metrics.
+ """
+
+ def __init__(self, database: DatabasePool, db_conn, hs):
+ super().__init__(database, db_conn, hs)
+
+ # Read the extrems every 60 minutes
+ def read_forward_extremities():
+ # run as a background process to make sure that the database transactions
+ # have a logcontext to report to
+ return run_as_background_process(
+ "read_forward_extremities", self._read_forward_extremities
+ )
+
+ hs.get_clock().looping_call(read_forward_extremities, 60 * 60 * 1000)
+
+ async def _read_forward_extremities(self):
+ def fetch(txn):
+ txn.execute(
+ """
+ SELECT t1.c, t2.c
+ FROM (
+ SELECT room_id, COUNT(*) c FROM event_forward_extremities
+ GROUP BY room_id
+ ) t1 LEFT JOIN (
+ SELECT room_id, COUNT(*) c FROM current_state_events
+ GROUP BY room_id
+ ) t2 ON t1.room_id = t2.room_id
+ """
+ )
+ return txn.fetchall()
+
+ res = await self.db_pool.runInteraction("read_forward_extremities", fetch)
+
+ _extremities_collecter.update_data(x[0] for x in res)
+
+ _excess_state_events_collecter.update_data(
+ (x[0] - 1) * x[1] for x in res if x[1]
+ )
+
+ async def count_daily_messages(self):
+ """
+ Returns an estimate of the number of messages sent in the last day.
+
+ If it has been significantly less or more than one day since the last
+ call to this function, it will return None.
+ """
+
+ def _count_messages(txn):
+ sql = """
+ SELECT COALESCE(COUNT(*), 0) FROM events
+ WHERE type = 'm.room.message'
+ AND stream_ordering > ?
+ """
+ txn.execute(sql, (self.stream_ordering_day_ago,))
+ (count,) = txn.fetchone()
+ return count
+
+ return await self.db_pool.runInteraction("count_messages", _count_messages)
+
+ async def count_daily_sent_messages(self):
+ def _count_messages(txn):
+ # This is good enough as if you have silly characters in your own
+ # hostname then thats your own fault.
+ like_clause = "%:" + self.hs.hostname
+
+ sql = """
+ SELECT COALESCE(COUNT(*), 0) FROM events
+ WHERE type = 'm.room.message'
+ AND sender LIKE ?
+ AND stream_ordering > ?
+ """
+
+ txn.execute(sql, (like_clause, self.stream_ordering_day_ago))
+ (count,) = txn.fetchone()
+ return count
+
+ return await self.db_pool.runInteraction(
+ "count_daily_sent_messages", _count_messages
+ )
+
+ async def count_daily_active_rooms(self):
+ def _count(txn):
+ sql = """
+ SELECT COALESCE(COUNT(DISTINCT room_id), 0) FROM events
+ WHERE type = 'm.room.message'
+ AND stream_ordering > ?
+ """
+ txn.execute(sql, (self.stream_ordering_day_ago,))
+ (count,) = txn.fetchone()
+ return count
+
+ return await self.db_pool.runInteraction("count_daily_active_rooms", _count)
|
