Add an improved "forward extremities" metric

Hopefully, N(extremities) * N(state_events) is a more realistic approximation
to "how big a problem is this room?".
This commit is contained in:
Richard van der Hoff 2020-09-29 22:30:00 +01:00
parent 6d2d42f8fb
commit 20e7c4de26

View file

@ -29,6 +29,18 @@ _extremities_collecter = GaugeBucketCollector(
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
@ -52,15 +64,26 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
def fetch(txn):
txn.execute(
"""
select count(*) c from event_forward_extremities
group by room_id
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.