From: Sergey Burladyan <eshkinkot@gmail.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Jeff Janes <jeff.janes@gmail.com>
Cc: pgsql-performance\@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: Looks like merge join planning time is too big, 55 seconds
Date: Fri, 02 Aug 2013 20:20:22 +0400
Message-ID: <878v0kuks9.fsf@seb.koffice.internal> (raw)
In-Reply-To: <1899.1375458648@sss.pgh.pa.us>
References: <CAJ2ymdjK-+LZHFY+cskRq98c_4F1PEfveOVNbNGpWL0Pczy5Ew@mail.gmail.com>
<8761vpwid4.fsf@seb.koffice.internal>
<CAMkU=1zyWZEC0YfQ0D4obWWHZqcLoLApUzf-f2+LOVH2ib=s_g@mail.gmail.com>
<87li4lusvd.fsf@seb.koffice.internal>
<CAMkU=1zuaFU7-DBJGawX+P+e4HjXmL+R_sxOLoB4Q18B5fRPHw@mail.gmail.com>
<87li4l9j34.fsf@home.progtech.ru>
<87k3k5kkup.fsf@home.progtech.ru>
<CAMkU=1x51iVmUcLewMUBLB3fKW9tkpfsL0iYQuXp33aTAiQVPA@mail.gmail.com>
<1899.1375458648@sss.pgh.pa.us>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>
Tom Lane <tgl@sss.pgh.pa.us> writes:
> Jeff Janes <jeff.janes@gmail.com> writes:
> > On Thu, Aug 1, 2013 at 5:16 PM, Sergey Burladyan <eshkinkot@gmail.com> wrote:
> >> If I not mistaken, may be two code paths like this here:
> >> (1) mergejoinscansel -> scalarineqsel-> ineq_histogram_selectivity -> get_actual_variable_range -> index_getnext
> >> (2) scalargtsel -> scalarineqsel -> ineq_histogram_selectivity -> get_actual_variable_range -> index_getnext
>
> > Yeah, I think you are correct.
>
> mergejoinscansel does *not* call scalarineqsel, nor get_actual_variable_range.
> It calls get_variable_range, which only looks at the pg_statistic
> entries.
Hmm, I speak about 9.2.2 but in current HEAD this call still exist,
please see: http://doxygen.postgresql.org/selfuncs_8c_source.html#l02976> I think we need to see the actual stack traces, not incomplete versions.
> It's possible that the situation here involves bloat in pg_statistic, but
> we're just leaping to conclusions if we assume that that's where the index
> fetches are occurring.
I found debug symbols and send stack trace to mail list, but it blocked
by size, try again with zip
--
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performanceAttachments:
gdb.log.gz (application/x-gzip, 3.3K) download
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-performance@postgresql.org
Cc: eshkinkot@gmail.com, tgl@sss.pgh.pa.us, jeff.janes@gmail.com
Subject: Re: Looks like merge join planning time is too big, 55 seconds
In-Reply-To: <878v0kuks9.fsf@seb.koffice.internal>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox