Re: Less than ideal error reporting in pg_stat_statements

From: Peter Geoghegan <pg(at)heroku(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Jim Nasby <Jim(dot)Nasby(at)bluetreble(dot)com>, Pg Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Less than ideal error reporting in pg_stat_statements
Date: 2015-10-02 21:04:59
Message-ID: CAM3SWZTJEPY7A5HBJMB-s6rhZxk8LXiaxZPAMDytBpLs3P60Tw@mail.gmail.com
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On Tue, Sep 22, 2015 at 6:01 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
> On Tue, Sep 22, 2015 at 5:01 PM, Peter Geoghegan <pg(at)heroku(dot)com> wrote:
>> My guess is that this very large query involved a very large number of
>> constants, possibly contained inside an " IN ( )". Slight variants of
>> the same query, that a human would probably consider to be equivalent
>> have caused artificial pressure on garbage collection.
>
> I could write a patch to do compaction in-place.

In the end, I decided on a simpler approach to fixing this general
sort of problem with the attached patch. See commit message for
details.

I went this way not because compaction in-place was necessarily a bad
idea, but because I think that a minimal approach will work just as
well in real world cases.

It would be nice to get this committed before the next point releases
are tagged, since I've now heard a handful of complaints like this.

--
Peter Geoghegan

Attachment Content-Type Size
0001-Fix-pg_stat_statements-garbage-collection-bugs.patch text/x-patch 7.2 KB

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