Re: HOT pgbench results
От | Simon Riggs |
---|---|
Тема | Re: HOT pgbench results |
Дата | |
Msg-id | 1186515702.4192.63.camel@ebony.site обсуждение исходный текст |
Ответ на | Re: HOT pgbench results (Gregory Stark <stark@enterprisedb.com>) |
Список | pgsql-hackers |
On Tue, 2007-08-07 at 20:27 +0100, Gregory Stark wrote: > "Simon Riggs" <simon@2ndquadrant.com> writes: > > > On Tue, 2007-08-07 at 13:16 +0100, Heikki Linnakangas wrote: > >> I ran some CPU intensive pgbench tests on HOT. Results are not > >> surprising, HOT makes practically no difference on the total transaction > >> rate, but reduces the need to vacuum: > >> ... > > Nor would I expect anything else, on this test. > > I think the surprising thing was that it wasn't slower due to the extra cpu > spent pruning tuples. ...balanced by the extra time spent adding new blocks and doing block-spanning updates without HOT. For CPU bound situations, the real-world difference lies in the logical I/O we avoid by not doing index insertions. Larger tables have deeper index trees, so cause more block accesses to locate the block into which to insert. Small tables with few indexes aren't a real test of that, even if it does illustrate the basic CPU balance that HOT now offers in its latest incarnation (well done Heikki and Pavan). -- Simon Riggs EnterpriseDB http://www.enterprisedb.com
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