Re: pg14b1 stuck in lazy_scan_prune/heap_page_prune of pg_statistic

On 2021-Jun-08, Justin Pryzby wrote:

> On Tue, Jun 08, 2021 at 12:06:02PM -0400, Alvaro Herrera wrote:
> > On 2021-Jun-06, Justin Pryzby wrote:
> >
> > > However, I also found an autovacuum chewing 100% CPU, and it appears the
> > > problem is actually because autovacuum has locked a page of pg-statistic, and
> > > every other process then gets stuck waiting in the planner. I checked a few
> > > and found these:
> >
> > Hmm ... I wonder if this could be related to commits d9d076222f5b,
> > c98763bf51bf, etc. I don't have any connecting thoughts other than the
> > tuple visibility code being involved. Do you see any procs with the
> > PROC_IN_SAFE_IC flag set?
>
> Can you give me a hint how to do that from a corefile ?

(gdb) set $i=0
(gdb) set $total = ProcGlobal->allProcCount
(gdb) while($i<$total)
>print ProcGlobal->allProcs[$i++]->statusFlags
>end

--
Álvaro Herrera Valdivia, Chile
"In fact, the basic problem with Perl 5's subroutines is that they're not
crufty enough, so the cruft leaks out into user-defined code instead, by
the Conservation of Cruft Principle." (Larry Wall, Apocalypse 6)