On Thu, Sep 06, 2007 at 11:56:25PM -0700, Neil Conway wrote: > On Sun, 2007-02-09 at 13:04 -0500, Kenneth Marshall wrote: > > 2. Evaluate the performance of different hash index implementations > > and/or changes to the current implementation. My current plan is > > to keep the implementation as simple as possible and still provide > > the desired performance. Several hash index suggestions deal with > > changing the layout of the keys on a page to improve lookup > > performance, including reducing the bucket size to a fraction of > > a page or only storing the hash value on the page, instead of > > the index value itself. > > You might find this patch useful: > > http://archives.postgresql.org/pgsql-patches/2005-05/msg00164.php > > It implements the "just store the hash in the index" idea; it also sorts > the entries in a bucket by the hash value, which allows binary search to > be used to locate candidate matches. > > I was surprised that this didn't result in a performance improvement for > the benchmarks that I ran, but I never got around to investigating > further (either running more benchmarks or checking whether there was a > bug in the implementation). > > Unfortunately, the patch doesn't apply cleanly to HEAD, but I can merge > it up to HEAD if you'd like. > > -Neil > I have another question. Did the scan code at this time use the heap-order scanning? Could that have had an impact on the patch performance?
Ken ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org