There was an interesting presentation at PG Con from a guy at Sun who
did a series of load tests on 8.3 vs 8.4
http://www.pgcon.org/2009/schedule/events/124.en.html
There is a link to the video from that page so you can watch it. But
he found a strange "corner case" where 8.4 performed way worse. After
he did a bit of digging he found a couple of default settings that
had changed in 8.4, and when he set them back to their old 8.3 values
and re-ran the tests, there was a huge difference in outcome.
On Wed, Jun 17, 2009 at 10:50 AM, Todd A.
Cook<tcook@blackducksoftware.com> wrote:
> Hi,
>
> First, the numbers:
>
> PG Version Load time pg_database_size autovac
> ----------------------------------------------------------
> 8.2.13 179 min 92,807,992,820 on
> 8.3.7 180 min 84,048,744,044 on (defaults)
> 8.4b2 206 min 84,028,995,344 on (defaults)
> 8.4b2 183 min 84,028,839,696 off
>
> The bulk of the data is in 16 tables, each having about 55 million rows of
> the form (int, int, smallint, smallint, int, int, int). Each table has a
> single partial index on one of the integer columns. The dump file was 14GB
> compressed.
>
> The loads were all done on the same machine, with the DB going on a pair
> of SATA drives in a RAID-0 stripe. The machine has 2 non-HT Xeons and
> 8GB RAM. maintenance_work_mem was set to 512MB in all three cases.
>
> -- todd
>
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