Re: hash index improving v3
Tom Lane <[email protected]> Thu, 04 Sep 2008 01:35:16 -0400
| Newsgroups | gmane.comp.db.postgresql.devel.patches |
|---|---|
| Message-ID | <[email protected]> |
Simon Riggs <[email protected]> writes: > Right now it seems strange that the index is larger than a btree, yet > the performance tests show that 3 times as much I/O was used accessing > the btree. Well, in an ideal world a hash index probe is O(1) while a btree probe is O(log N), so that result is exactly what hash proponents would hope for. Whether it's real or not is another question, but it could be. regards, tom lane -- Sent via pgsql-patches mailing list ([email protected]) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-patches