On 14 September 2011 00:04, Stefan Keller <sfkeller(at)gmail(dot)com> wrote:
> Has this been verified on a recent release? I can't believe that hash
> performs so bad over all these points. Theory tells me otherwise and
> http://en.wikipedia.org/wiki/Hash_table seems to be a success.
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/
--
Peter Geoghegan http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training and Services