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:


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.


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