Re: Joins on over 10 tables returns unreliable results

Peter Eisentraut <peter_e@gmx.net>

From: Peter Eisentraut <peter_e@gmx.net>
To: jeffery.l.seaman@intel.com, pgsql-bugs@postgresql.org
Date: 2000-10-31T14:27:23Z
Lists: pgsql-bugs
pgsql-bugs@postgresql.org writes:

> Running Postgres version 7.01 on Redhat linux 6.2.  When joining on
> more than 10 tables not all of the expected results are returned.  
> The query can be repeated several times, with different result sets
> when the data itself is static.  The most common result is the return
> of only one record.  11 tables seems to be the magic limit.  Joins on
> 10 tables works without a hitch.  This join was based on a column id
> that exists in all of the tables.

This seems to be a problem in the genetic query optimizer.  But to examine
closer we'd really need to get sample data and queries to reproduce this.

For now you can SET geqo TO 'off'; to disable this.

-- 
Peter Eisentraut      peter_e@gmx.net       http://yi.org/peter-e/