Re: Index AM change proposals, redux

From: Heikki Linnakangas <heikki(at)enterprisedb(dot)com>
To: Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com>
Cc: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgreSQL(dot)org
Subject: Re: Index AM change proposals, redux
Date: 2008-04-12 06:23:35
Message-ID: 48005567.3020304@enterprisedb.com
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Ron Mayer wrote:
> One use case that I think GIT would help a lot with are my
> large address tables that are clustered by zip-code but
> often queried by State, City, County, School District,
> Police Beat, etc.

Yep, GIT would shrink the index on zip-code tremendously...

> I imagine a GIT index on "state" would just occupy
> a couple pages at most regardless of how large the
> table gets.

.. Not quite that much, though. GIT still stores one index pointer per
heap page even on a fully clustered table. Otherwise it's not much good
for searches.

> And likewise, even an index on City
> would be orders of magnitude smaller than the existing
> ones; since all records for any given city are all
> on the same few disk pages.

Yep, it would help with that as well.

--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com

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