Re: hung backends stuck in spinlock heavy endless loop

On 2015-01-13 19:05:10 -0500, Tom Lane wrote:
> Merlin Moncure <mmoncure(at)gmail(dot)com> writes:
> > On Tue, Jan 13, 2015 at 5:54 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
> >> In case it isn't clear, I think that the proximate cause here may well
> >> be either one (or both) of commits
> >> efada2b8e920adfdf7418862e939925d2acd1b89 and/or
> >> 40dae7ec537c5619fc93ad602c62f37be786d161. Probably the latter. I think
> >> that the profile is roughly consistent with that, although I may well
> >> be wrong.
>
> > I'm out of time for the day, but I'm fairly confident I can reproduce.
> > I'll see if I can reverse those commits tomorrow and retest (I'm on
> > development box).
>
> I'm not convinced that Peter is barking up the right tree. I'm noticing
> that the profiles seem rather skewed towards parser/planner work; so I
> suspect the contention is probably on access to system catalogs. No
> idea exactly why though.

The plan contains plpgsql and exec_stmt_dynexecute(). So it might just
be executing crazy amounts of dynamic statements.

I'm still wondering if this isn'ta different issue to the first one, the
plans do look different.

Greetings,

Andres Freund

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Andres Freund http://www.2ndQuadrant.com/
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