Horton

Re: exposing wait events for non-backends (was: Tracking wait event for latches)

Michael Paquier <michael.paquier@gmail.com>

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From: Michael Paquier <michael.paquier@gmail.com>
To: Craig Ringer <craig@2ndquadrant.com>
Cc: Kevin Grittner <kgrittn@gmail.com>, Andres Freund <andres@anarazel.de>, Alvaro Herrera <alvherre@2ndquadrant.com>, Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, Alexander Korotkov <a.korotkov@postgrespro.ru>, PostgreSQL mailing lists <pgsql-hackers@postgresql.org>
Date: 2016-12-13T01:13:17Z
Lists: pgsql-hackers 
On Tue, Dec 13, 2016 at 10:05 AM, Craig Ringer <craig@2ndquadrant.com> wrote:
> We should probably expose a proc_type or something, with types:
>
> * client_backend
> * bgworker
> * walsender
> * autovacuum
> * checkpointer
> * bgwriter

A text field is adapted then, more than a single character.

> for simpler filtering.
>
> I don't think existing user code is likely to get upset by more
> processes appearing in pg_stat_activity, and it'll be very handy.

Indeed, for WAL senders now abusing of the query field is definitely
not consistent. Even if having this information is useful, adding such
a column would make sense. Still, one thing that is important to keep
with pg_stat_activity is the ability to count the number of
connections that are part of max_connections for monitoring purposes.
The docs definitely would need an example of such a query counting
only client_backend and WAL senders and tell users that this can be
used to count how many active connections there are.
-- 
Michael

Commits

  1. Show more processes in pg_stat_activity.