Re: proposal: add 'waiting for replication' to pg_stat_activity.state

On 3 December 2015 at 09:32, Peter Eisentraut <peter_e(at)gmx(dot)net> wrote:

> On 12/2/15 7:00 PM, Craig Ringer wrote:
> > I notice that you don't set the 'waiting' flag. 'waiting' is presently
> > documented as:
> >
> > <entry>True if this backend is currently waiting on a lock</entry>
> >
> > ... but I'm inclined to just widen its definition and set it here, since
> > we most certainly are waiting, and the column isn't named
> > 'waiting_on_a_lock'. It shouldn't upset various canned lock monitoring
> > queries people have since they generally do an inner join on pg_locks
> > anyway.
>
> I'm not so sure about that assumption.
>

Even if it's an outer join, the worst that'll happen is that they'll get
entries with nulls in pg_locks. I don't think it's worth worrying about too
much.

We could always mitigate it by adding a pg_lock_status view to the system
catalogs with a decent canned query over pg_stat_activity and pg_locks, so
people can stop copying & pasting from the wiki or using buggy homebrew
queries ;)

--
Craig Ringer http://www.2ndQuadrant.com/
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