Re: RFC: replace pg_stat_activity.waiting with something more descriptive

> 14 нояб. 2015 г., в 10:50, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> написал(а):
>
> On Wed, Sep 16, 2015 at 11:22 PM, Robert Haas <robertmhaas(at)gmail(dot)com <mailto:robertmhaas(at)gmail(dot)com>> wrote:
> > On Wed, Sep 16, 2015 at 12:29 PM, Alexander Korotkov
> > <aekorotkov(at)gmail(dot)com <mailto:aekorotkov(at)gmail(dot)com>> wrote:
> >
> > >> I think it's reasonable to consider reporting this data in the PGPROC
> > >> using a 4-byte integer rather than reporting it through a singe byte
> > >> in the backend status structure. I believe that addresses the
> > >> concerns about reporting from auxiliary processes, and it also allows
> > >> a little more data to be reported. For anything in excess of that, I
> > >> think we should think rather harder. Most likely, such addition
> > >> detail should be reported only for certain types of wait events, or on
> > >> a delay, or something like that, so that the core mechanism remains
> > >> really, really fast.
> > >
> > > That sounds reasonable. There are many pending questions, but it seems like
> > > step forward to me.
> >
> > Great, let's do it. I think we should probably do the work to
> > separate the non-individual lwlocks into tranches first, though.
> >
>
> One thing that occurred to me in this context is that if we store the wait
> event information in PGPROC, then can we think of providing the info
> about wait events in a separate view pg_stat_waits (or pg_stat_wait_info or
> any other better name) where we can display wait information about
> all-processes rather than only backends? This will avoid the confusion
> about breaking the backward compatibility for the current 'waiting' column
> in pg_stat_activity.
>
> pg_stat_waits can have columns:
> pid - Process Id
> wait_class_name - Name of the wait class
> wait class_event - name of the wait event
>
> We can extend it later with the information about timing for wait event.
>
> Also, if we follow this approach, I think we don't need to store this
> information in PgBackendStatus.

Sounds like exactly the same that was proposed by Ildus in this thead [0]. Great to be thinking in the same direction. And on the rights of advertisements I’ve somehow described using all those views here [1].

[0] http://www.postgresql.org/message-id/559D4729.9080704@postgrespro.ru
[1] https://simply.name/pg-stat-wait.html

>
>
> With Regards,
> Amit Kapila.
> EnterpriseDB: http://www.enterprisedb.com <http://www.enterprisedb.com/>

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