Re: Hash function for numeric (WIP) - Mailing list pgsql-patches

From Neil Conway
Subject Re: Hash function for numeric (WIP)
Date
Msg-id 1177800430.6440.182.camel@localhost.localdomain
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In response to Re: Hash function for numeric (WIP)  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Hash function for numeric (WIP)  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-patches
Sorry for fat-fingering the previous reply -- I wanted to add:

On Fri, 2007-04-27 at 10:02 -0400, Tom Lane wrote:
> Perhaps a sufficiently robust way would be to form the hash as the
> XOR of each supplied digit, circular-shifted by say 3 times the
> digit's weight.

The only objection I have to this is that it means we need to have
another hash function in the backend. The Jenkins hash we use in
hash_any() has been studied and we can have at least some confidence in
its collision-resistance, etc.

Anyway, attached is a revised version of the hash_any()-based patch.

-Neil


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