Unfortunately
I'm still seeing a very slow
query which is affecting our tests. It's happening with
roughly the same frequency as the previous error.
In the log, it looks like an INSERT on the users table
takes about 23 seconds. This query is connecting from
_javascript_ to a Postgres server on the same machine. After 18
seconds, the test performing the INSERT times out, we try to
clear the database, and then the next test runs. The next test
also attempts to INSERT a record, but is blocked on the first
INSERT. After 5 more seconds, the first INSERT completes, and
the second INSERT is allowed to run.
2016-04-14 00:46:54.649 UTC 2016-04-14 00:46:34 UTC
[14308-570ee86a.37e4-42] 00000 ubuntu@circle_test LOG:
process 14308 still waiting for ExclusiveLock on extension
of relation 17215 of database 16387 after 1000.104 ms
2016-04-14 00:46:54.649 UTC 2016-04-14 00:46:34 UTC
[14308-570ee86a.37e4-43] 00000 ubuntu@circle_test DETAIL:
Process holding the lock: 14260. Wait queue: 14308.
2016-04-14 00:46:58.979 UTC 2016-04-14 00:46:34 UTC
[14308-570ee86a.37e4-45] 00000 ubuntu@circle_test LOG:
process 14308 acquired ExclusiveLock on extension of
relation 17215 of database 16387 after 5330.117 ms
Between the last time I emailed and now, I also disabled
autovacuum on the server; it seemed unnecessary if we are
issuing ~10k queries tops, and generating ~100k records tops,
in the course of a test run. However, I didn't see any other
queries or log messages (e.g. "kicking off autovacuum") that
would have indicated a problem.
Any ideas why an INSERT on an empty table, to a low-load
server running on the same machine, with no other queries
being generated during that time, could take 23 seconds to
complete? The server is running Postgres 9.4.6.
What other information do I/you need to figure out what's
going on?
