From: | CoL <col(at)mportal(dot)hu> |
---|---|
To: | pgsql-admin(at)postgresql(dot)org |
Subject: | Re: PostgreSQL: query optimizer: viewing query plans |
Date: | 2003-12-18 10:15:44 |
Message-ID: | brrunf$2j7n$1@news.hub.org |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-admin |
Hi,
Neil Zanella wrote:
> Hello,
>
> Several textbooks talk about query trees and query plans including the following
> relatively recent book <http://www.oreilly.com/catalog/sqltuning/> which covers
> how to apply performance tuning techniques by using knowledge about the query
> optimizer to rewrite SQL queries so that they get interpreted more efficiently.
>
> Unfortunately the book only shows how to view the query plan associated witht the
> given query for Oracle, IBM DB2, and MS SQL Server. I wonder whether PostgreSQL
> also has a way to let the user see the heuristically computed query plan created
> by the query optimizer. Is it possible to view query plans with PostgreSQL server
> and its related command line interfaces? How would I run such a command?
explain query
explain analyze query
and you can set logging in postgres.conf, and you can log
debug_print_XXX things (xxx like parse, rewritten query, the plan)
C.
From | Date | Subject | |
---|---|---|---|
Next Message | Eko Pranoto | 2003-12-18 10:35:10 | Problm Drop Table :: 748580 |
Previous Message | A.Bhuvaneswaran | 2003-12-18 09:26:27 | Re: system variable for update |