From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Joel Jacobson <joel(at)trustly(dot)com> |
Cc: | Pg Hackers <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: pg_stat_activity.waiting_start |
Date: | 2016-12-24 02:00:59 |
Message-ID: | 8779.1482544859@sss.pgh.pa.us |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Joel Jacobson <joel(at)trustly(dot)com> writes:
> We already have xact_start, query_start and backend_start
> to get the timestamptz for when different things happened.
> I would like to propose adding a fourth such column, "waiting_start",
> which would tell how long time a backend has been waiting.
The difficulty with that is it'd require a gettimeofday() call for
every wait start. Even on platforms where those are relatively cheap,
the overhead would be nasty --- and on some platforms, it'd be
astonishingly bad. We sweated quite a lot to get the overhead of
pg_stat_activity wait monitoring down to the point where it would be
tolerable for non-heavyweight locks, but I'm afraid this would push
it back into the not-tolerable range.
regards, tom lane
From | Date | Subject | |
---|---|---|---|
Next Message | Stephen Frost | 2016-12-24 02:05:40 | Re: pg_stat_activity.waiting_start |
Previous Message | Joel Jacobson | 2016-12-24 01:37:15 | Re: pg_stat_activity.waiting_start |