Log number of events fetched from DB

When we finish processing a request, log the number of events we fetched from
the database to handle it.

[I'm trying to figure out which requests are responsible for large amounts of
event cache churn. It may turn out to be more helpful to add counts to the
prometheus per-request/block metrics, but that is an extension to this code
anyway.]
This commit is contained in:
Richard van der Hoff 2018-06-21 06:15:03 +01:00
parent aff3d76920
commit b088aafcae
3 changed files with 12 additions and 1 deletions

View file

@ -99,16 +99,18 @@ class SynapseRequest(Request):
db_txn_count = context.db_txn_count
db_txn_duration_sec = context.db_txn_duration_sec
db_sched_duration_sec = context.db_sched_duration_sec
evt_db_fetch_count = context.evt_db_fetch_count
except Exception:
ru_utime, ru_stime = (0, 0)
db_txn_count, db_txn_duration_sec = (0, 0)
evt_db_fetch_count = 0
end_time = time.time()
self.site.access_logger.info(
"%s - %s - {%s}"
" Processed request: %.3fsec (%.3fsec, %.3fsec) (%.3fsec/%.3fsec/%d)"
" %sB %s \"%s %s %s\" \"%s\"",
" %sB %s \"%s %s %s\" \"%s\" [%d dbevts]",
self.getClientIP(),
self.site.site_tag,
self.authenticated_entity,
@ -124,6 +126,7 @@ class SynapseRequest(Request):
self.get_redacted_uri(),
self.clientproto,
self.get_user_agent(),
evt_db_fetch_count,
)
try:

View file

@ -21,6 +21,7 @@ from synapse.events.utils import prune_event
from synapse.util.logcontext import (
PreserveLoggingContext, make_deferred_yieldable, run_in_background,
LoggingContext,
)
from synapse.util.metrics import Measure
from synapse.api.errors import SynapseError
@ -145,6 +146,9 @@ class EventsWorkerStore(SQLBaseStore):
missing_events_ids = [e for e in event_ids if e not in event_entry_map]
if missing_events_ids:
log_ctx = LoggingContext.current_context()
log_ctx.evt_db_fetch_count += len(missing_events_ids)
missing_events = yield self._enqueue_events(
missing_events_ids,
check_redacted=check_redacted,

View file

@ -60,6 +60,7 @@ class LoggingContext(object):
__slots__ = [
"previous_context", "name", "ru_stime", "ru_utime",
"db_txn_count", "db_txn_duration_sec", "db_sched_duration_sec",
"evt_db_fetch_count",
"usage_start",
"main_thread", "alive",
"request", "tag",
@ -109,6 +110,9 @@ class LoggingContext(object):
# sec spent waiting for db txns to be scheduled
self.db_sched_duration_sec = 0
# number of events this thread has fetched from the db
self.evt_db_fetch_count = 0
# If alive has the thread resource usage when the logcontext last
# became active.
self.usage_start = None