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Re: Hash index

From: "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com>
To: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Cc: Scott Marlowe <smarlowe(at)g2switchworks(dot)com>,RAJU kumar <raju_19db(at)rediffmail(dot)com>, pgsql-admin(at)postgresql(dot)org
Subject: Re: Hash index
Date: 2005-08-30 20:17:38
Message-ID: (view raw, whole thread or download thread mbox)
Lists: pgsql-admin
On Tue, Aug 30, 2005 at 03:32:26PM -0400, Tom Lane wrote:
> That leaves hash.  I'm hoping someone will step up and do WAL logging
> for hash in the near future.  Unlike rtree, I'm not expecting that we
> might get rid of hash indexes.  Even if the performance problems never
> get fixed, we use hash index opclasses to manage datatype-specific
> hashing for hash joins, hash aggregation, etc, so if we removed hash
> indexes we'd need to find some other representation for all that.

So does that mean a hash index could (theoretically) improve the
performance of a hash join or hash aggregation?
Jim C. Nasby, Sr. Engineering Consultant      jnasby(at)pervasive(dot)com
Pervasive Software        512-569-9461

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