Re: BUG #5226: Limit operator slows down - Mailing list pgsql-bugs

On 2/12/2009 10:35 PM, aftab wrote:
>
> The following bug has been logged online:
>
> Bug reference:      5226
> Logged by:          aftab
> Email address:      akhangd@hotmail.co.uk
> PostgreSQL version: 8.3.8
> Operating system:   Centos 5
> Description:        Limit operator slows down
> Details:
>
> S1="SELECT *
> FROM position WHERE
> position.POSITION_STATE_ID=2 AND
> position.TARGET_ID=18
> ORDER BY position.ID DESC
> ";
> S2="SELECT *
> FROM position WHERE
> position.POSITION_STATE_ID=2 AND
> position.TARGET_ID=18
> ORDER BY position.ID DESC
> LIMIT 1
> ";
>
> S1 takes 0.16ms compared to S2 which takes 5 secs. Both S1 and S2 are same
> except "LIMIT 1 " is added to S2.

Please read this:

   http://wiki.postgresql.org/wiki/Guide_to_reporting_problems

then re-post your question to the pgsql-general mailing list, including
appropriate EXPLAIN ANALYZE output for both queries, etc.

--
Craig Ringer