-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Shreya Bhargava wrote: > "Note that the bottom line for the problems with hash indexes is that the > current implementation doesn't offer any advantages over btree indexes. Hash > indexes need to be not only as good of a choice as btree indexes but > significantly better a significantly better choice at least for some > specific circumstances." Oh it does. I recently used a hash index to speed up my database. Namely I found it improved performance when indexing a non-integer column containing english words.
I don't know how much of that data was cached, according to the sound of my harddrive it wasn't all of it. Consider this anecdotical evidence, but the speedup was noticeable. > We performed some probe tests on our patch on > hash index and the original btree index to compare the > performance between the two. We used a 80 million tuple table. > The table contained single integer attribute and the data > range was 0 - 100000000. (generated by a random generator). I'd be interested how much difference is there between non-integer index behaviour. I at least had the impression that in my case the sorted strings in the btree pages didn't compare too well. > */Gregory Stark <[EMAIL PROTECTED]>/* wrote: > "Kenneth Marshall" writes: > > On Thu, Sep 20, 2007 at 05:12:45PM -0700, Tom Raney wrote: > >> Using our implementation, build times and index sizes are > >> comparable with btree index build times and index sizes. Way to go! Currently building hash indices is no fun. Regards, Jens-W. Schicke -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFHMErXzhchXT4RR5ARAh7pAKCZIZFJFa7Oq25GvwDhiZJFsrtwgACbBC1F otwhIZVlNgUGlroePIafi1c= =N1f7 -----END PGP SIGNATURE----- ---------------------------(end of broadcast)--------------------------- TIP 7: You can help support the PostgreSQL project by donating at http://www.postgresql.org/about/donate