Re: What needs to be done for real Partitioning?

Tom Lane <tgl@sss.pgh.pa.us>

From: Tom Lane <tgl@sss.pgh.pa.us>
To: "Stacy White" <harsh@computer.org>
Cc: "Alvaro Herrera" <alvherre@dcc.uchile.cl>, "PFC" <lists@boutiquenumerique.com>, "Josh Berkus" <josh@agliodbs.com>, pgsql-performance@postgresql.org
Date: 2005-03-20T23:01:49Z
Lists: pgsql-performance
"Stacy White" <harsh@computer.org> writes:
> FWIW, we see large benefits from partitioning other than the ability to
> easily drop data, for example:

> - We can vacuum only the active portions of a table
> - Postgres automatically keeps related records clustered together on disk,
> which makes it more likely that the blocks used by common queries can be
> found in cache
> - The query engine uses full table scans on the relevant sections of data,
> and quickly skips over the irrelevant sections
> - 'CLUSTER'ing a single partition is likely to be significantly more
> performant than clustering a large table

Global indexes would seriously reduce the performance of both vacuum and
cluster for a single partition, and if you want seq scans you don't need
an index for that at all.  So the above doesn't strike me as a strong
argument for global indexes ...

			regards, tom lane