Re: Execution plan changed after upgrade from 7.3.9 to 8.2.3 - Mailing list pgsql-performance

From Alvaro Herrera
Subject Re: Execution plan changed after upgrade from 7.3.9 to 8.2.3
Date
Msg-id 20070313130945.GB4490@alvh.no-ip.org
Whole thread Raw
In response to Re: Execution plan changed after upgrade from 7.3.9 to 8.2.3  (<vincent.moreau@leroymerlin.fr>)
Responses Re: Execution plan changed after upgrade from 7.3.9 to 8.2.3
List pgsql-performance
vincent.moreau@leroymerlin.fr wrote:
> I have attached the requested information.
>
> You will see that the query is quite messy and could be easily improved.
> Unfortunately, it came from a third party application and we do not have
> access to the source code.

There are only nested loops and hash joins, while the other plan seems
to be more elaborate -- I wonder if you have disabled bitmap scan, merge
joins, in 8.2?   Try a SHOW enable_mergejoin in psql.

--
Alvaro Herrera                                http://www.CommandPrompt.com/
The PostgreSQL Company - Command Prompt, Inc.

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