Re: Index AM change proposals, redux - Mailing list pgsql-hackers

From Heikki Linnakangas
Subject Re: Index AM change proposals, redux
Date
Msg-id 48005567.3020304@enterprisedb.com
Whole thread Raw
In response to Re: Index AM change proposals, redux  (Ron Mayer <rm_pg@cheapcomplexdevices.com>)
Responses Re: Index AM change proposals, redux  (Ron Mayer <rm_pg@cheapcomplexdevices.com>)
List pgsql-hackers
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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