On Thu, 2008-07-17 at 16:37 -0700, Dann Corbit wrote:
> Large table unique index equality search should be very fast with hashed
> index (and the only place where any advantage will be seen). Hashed
> indexes are useless for any search besides equality and gain more and
> more when the levels of the b-tree index increase.
I think a comparison with a btree using a functional index should be
shown.
> The only way to get better performance from hash based indexes is to
> read fewer index pages than if a tree-based index were used. So I think
> that the scheme used to create the index pages is the focus to make them
> worthwhile.
Agreed. Some math on that, plus a clear focus on making this faster than
a btree is critical to this project.
-- Simon Riggs www.2ndQuadrant.comPostgreSQL Training, Services and Support
