| 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: | 2007-04-28 22:47:10 |
| Message-ID: | 1177800430.6440.182.camel@localhost.localdomain |
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| Thread: | |
| Lists: | 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
| Attachment | Content-Type | Size |
|---|---|---|
| numeric_hash_func-3.patch | text/x-patch | 8.1 KB |
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