pg.ddx.io  pgsql-performance@postgresql.org mailing list archive  
help / color / mirror / Atom feed
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ronaldo Maia <romaia@async.com.br>
Cc: pgsql-performance@postgresql.org
Subject: Re: Possible regression (slow query on 9.2/9.3 when compared to 9.1)
Date: Sun, 29 Dec 2013 17:32:20 -0500
Message-ID: <30316.1388356340@sss.pgh.pa.us> (raw)
In-Reply-To: <CAJMy52gS=RgMxk6FBjyQMeLL2vDLT5Jvhv8cw-X=CV44jZNaYQ@mail.gmail.com>
References: <CAJMy52gS=RgMxk6FBjyQMeLL2vDLT5Jvhv8cw-X=CV44jZNaYQ@mail.gmail.com>
List-Unsubscribe:  <mailto:majordomo@postgresql.org?body=unsub%20pgsql-performance>

Ronaldo Maia <romaia@async.com.br> writes:
> Recently I have tried to upgrade our postgres instalation from 9.1 to 9.3,
> but one query in particular got extremelly slow.

FWIW, this test case doesn't reproduce any problem for me --- I get
identical plans and indistinguishable timings (about 450ms on my machine)
from 9.1 and 9.3 branch tips.  This is with all-default settings and
a VACUUM ANALYZE after loading the data.  I had to guess at the definition
of stoq_normalize_string(), too, so I used

create function stoq_normalize_string(text) returns text language sql
  strict immutable as 'select unaccent($1)';

I speculate that you forgot to analyze the data after loading, or there's
some performance-relevant setting that you didn't carry forward from the
9.1 database.

			regards, tom lane


-- 
Sent via pgsql-performance mailing list (pgsql-performance@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-performance



view thread (2+ messages)

Message-ID: <30316.1388356340@sss.pgh.pa.us>
Permalink:  ../30316.1388356340@sss.pgh.pa.us/
Also on:    postgresql.org/message-id/30316.1388356340@sss.pgh.pa.us

 · 

reply

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: tgl@sss.pgh.pa.us, romaia@async.com.br
  Subject: Re: Possible regression (slow query on 9.2/9.3 when compared to 9.1)
  In-Reply-To: <30316.1388356340@sss.pgh.pa.us>

* 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