Re: Hash function for numeric (WIP)

From: Neil Conway <neilc(at)samurai(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: pgsql-patches <pgsql-patches(at)postgresql(dot)org>
Subject: Re: Hash function for numeric (WIP)
Date: 2007-05-08 19:00:49
Message-ID: 1178650849.6034.17.camel@goldbach
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On Sun, 2007-06-05 at 21:30 -0400, Tom Lane wrote:
> It'd be a good idea if you repeat the previous number-of-collisions
> experiment on this code.

I repeated the same experiment, and got essentially the same number of
collisions (829 collisions on ~2 million randomly generated numerics,
with 273 duplicates). Since the modified hash still uses hash_any() and
really only differs when there are leading/trailing zeros, this is
consistent with what I'd expect.

Patch applied to HEAD.

-Neil

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