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