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


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