Re: Tracking last scan time

Hi

On Fri, 30 Sept 2022 at 18:58, Andres Freund <andres(at)anarazel(dot)de> wrote:

> Hi,
>
> On 2022-09-30 17:58:31 +0200, Vik Fearing wrote:
> > On 9/7/22 12:03, Dave Page wrote:
> > > Here's a v4 patch. This reverts to using
> > > GetCurrentTransactionStopTimestamp() for the last_scan times, and will
> > > set xactStopTimestamp the first time
> GetCurrentTransactionStopTimestamp()
> > > is called, thus avoiding multiple gettimeofday() calls.
> > > SetCurrentTransactionStopTimestamp() is removed, as is use
> > > of xactStopTimestamp (except when resetting it to 0).
> >
> > This patch looks good to me and has much saner behavior than what it
> > replaces.
>
> I agree. However, it seems like a significant enough behavioural change
> that
> I'd rather commit it as a separate patch. I agree with Vik's judgement
> that
> the patch otherwise is otherwise ready. Happy to do that split myself, or
> you
> can do it...
>

Thanks. It's just the changes in xact.c, so it doesn't seem like it would
cause you any more work either way, in which case, I'll leave it to you :-)

FYI, the OID I chose was simply the closest single value to those used for
the other related functions (e.g. pg_stat_get_numscans). Seemed like a good
way to use up one more random unused value, but I don't care if it gets
changed to the 8000+ range.

--
Dave Page
Blog: https://pgsnake.blogspot.com
Twitter: @pgsnake

EDB: https://www.enterprisedb.com