Skip site navigation (1) Skip section navigation (2)

Re: Poor performance problem with Materialize, 8.4 -> 9.1 (enable_material)

From: Claudio Freire <klaussfreire(at)gmail(dot)com>
To: Eoghan Murray <eoghan(at)qatano(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Poor performance problem with Materialize, 8.4 -> 9.1 (enable_material)
Date: 2012-07-13 18:56:50
Message-ID: CAGTBQpbeJo1+UwT_fNA1KJ1sTxeJfLZOzP0gti2MNw-aAysBsQ@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-performance
On Fri, Jul 13, 2012 at 3:22 PM, Eoghan Murray <eoghan(at)qatano(dot)com> wrote:
> This is with `enable_material=off`, with `enable_material=on` it also
> doesn't go for the Merge Join, but the Materialize step pushes it up to over
> 7,000ms.

I think this one could stem from what Tom observed, that the rowcount
estimate is way off.

It usually helps a great deal if you can get PG to estimate correctly,
be it by doing analyze, incrementing statistics or simply formulating
your query in a way that's friendlier for PG's estimator.

In response to

pgsql-performance by date

Next:From: Robert KlemmeDate: 2012-07-13 20:06:55
Subject: Re: Any tool/script available which can be used to measure scalability of an application's database.
Previous:From: Sergey KonoplevDate: 2012-07-13 18:37:15
Subject: Re: Any tool/script available which can be used to measure scalability of an application's database.

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group