Re: Optimizer oddness, possibly compounded in 8.1

Hannu Krosing <hannu@skype.net>

From: Hannu Krosing <hannu@skype.net>
To: Simon Riggs <simon@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, Philip Warner <pjw@rhyme.com.au>, pgsql-hackers@postgreSQL.org
Date: 2005-12-06T14:12:15Z
Lists: pgsql-hackers
Ühel kenal päeval, L, 2005-12-03 kell 09:21, kirjutas Simon Riggs:

> First off, I think we need to do some more work on partitioning so that
> some knowledge about the union set is understood by the optimizer. At
> the moment there is no concept of partition key, so its hard to spot
> when two union sets have the same key to allow pushdown.

One of the easier cases would be non-overlapping (exclusive) constraints
on union subtables on the joined column.

This could serve as a "partition key", or in case of many nonoverlapping
columns (ex.: table is partitioned by date and region), as many
partition keys.

-------------
Hannu