Re: Session WAL activity

On Thu, Dec 05, 2019 at 12:23:40PM +0300, Konstantin Knizhnik wrote:
> Concerning keeping PGPROC size as small as possible, I agree that it is
> reasonable argument.
> But even now it is very large (816 bytes) and adding extra 8 bytes will
> increase it on less than 1%.

It does not mean that we should add all kind of things to PGPROC as
that's a structure sensitive enough already. By the way, why do you
assume that 8-byte reads are always safe and atomic in the patch?

> Right now pg_stat_activity also accessing PGPROC to obtain wait event
> information and also not taking any locks.
> So it can wrongly report backend status. But I never heard that somebody
> complains about it.

Please see pgstat.h, close to pgstat_report_wait_start().
--
Michael