Re: Difference between explain analyze and real execution time

From: Robert Haas <robertmhaas(at)gmail(dot)com>
To: Artur Zając <azajac(at)ang(dot)com(dot)pl>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Difference between explain analyze and real execution time
Date: 2010-11-15 19:39:03
Message-ID: AANLkTim=wpohtfWkNx-=22jcagXndrfTwjvogNt9=f0D@mail.gmail.com
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

2010/11/15 Artur Zając <azajac(at)ang(dot)com(dot)pl>:
> Why there is so big difference between explain analyze (0.710 ms) and real
> execution time (3309 ms)? Any suggestions?

Could it be that it takes a long time to plan for some reason? How
fast is a plain EXPLAIN?

What happens if you start up psql, turn on \timing, and then run
EXPLAIN ANALYZE from within an interactive session? That's usually a
better way to test, as it avoids counting the session-startup
overhead.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company

In response to

Responses

Browse pgsql-performance by date

  From Date Subject
Next Message Humair Mohammed 2010-11-15 20:14:26
Previous Message Robert Haas 2010-11-15 19:36:38 Re: Running PostgreSQL as fast as possible no matter the consequences