Re: Compression and on-disk sorting - Mailing list pgsql-hackers

From Simon Riggs
Subject Re: Compression and on-disk sorting
Date
Msg-id 1148674904.2755.254.camel@localhost.localdomain
Whole thread Raw
In response to Re: Compression and on-disk sorting  ("Jim C. Nasby" <jnasby@pervasive.com>)
Responses Re: Compression and on-disk sorting
Re: Compression and on-disk sorting
List pgsql-hackers
On Fri, 2006-05-26 at 14:47 -0500, Jim C. Nasby wrote:

> But the meat is:
>                                         -- work_mem --
>                         Scale           2000    20000
> not compressed          150             805.7   797.7
> not compressed          3000            17820   17436
> compressed              150             371.4   400.1
> compressed              3000            8152    8537
> compressed, no headers  3000            7325    7876

Since Tom has committed the header-removing patch, we need to test
not compressed, no headers v compressed, no headers

There is a noticeable rise in sort time with increasing work_mem, but
that needs to be offset from the benefit that in-general comes from
using a large Heap for the sort. With the data you're using that always
looks like a loss, but that isn't true with all input data orderings.

--  Simon Riggs EnterpriseDB          http://www.enterprisedb.com



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