| From: | Leonardo Francalanci <m_lists(at)yahoo(dot)it> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Peter Geoghegan <peter(at)2ndquadrant(dot)com> |
| Cc: | Stefan Keller <sfkeller(at)gmail(dot)com>, "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Hash index use presently(?) discouraged since 2005: revive or bury it? |
| Date: | 2011-09-14 09:43:27 |
| Message-ID: | 1315993407.43414.YahooMailNeo@web29009.mail.ird.yahoo.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
>> Hash indexes have been improved since 2005 - their performance was
>> improved quite a bit in 9.0. Here's a more recent analysis:
>
>> http://www.depesz.com/index.php/2010/06/28/should-you-use-hash-index/
>
> The big picture though is that we're not going to remove hash indexes,
> even if they're nearly useless in themselves
Well, if they provide 3x the performance of btree indexes on index creation,
I wouldn't call them "useless" just because they're not logged or they can't
be unique. In fact, I think the docs should specify that in index creation
they're actually better than btree (if, in fact, they are and the "depesz" test
is not a corner case).
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