Re: Unused index influencing sequential scan plan - Mailing list pgsql-performance

From Tom Lane
Subject Re: Unused index influencing sequential scan plan
Date
Msg-id 603.1350579992@sss.pgh.pa.us
Whole thread Raw
In response to Re: Unused index influencing sequential scan plan  (Peter Geoghegan <peter@2ndquadrant.com>)
List pgsql-performance
Peter Geoghegan <peter@2ndquadrant.com> writes:
> Is there a case to be made for a index access method whose
> pseudo-indexes costs essentially nothing to maintain, and simply
> represent an ongoing obligation for ANALYZE to provide statistics for
> an expression?

If we were going to support it, I think we'd be better off exposing such
a feature as DDL having nothing to do with indexes.  Not sure it's worth
the trouble though.  The ANALYZE wart to compute stats for index
expressions has been there a long time, and there's been essentially
zero field demand for another way to do it.  What people really seem to
care about is more intelligence about making use of expression indexes
to avoid recalculation of the expression --- something you'd not get
from a stats-only feature.

            regards, tom lane


pgsql-performance by date:

Previous
From: Thom Brown
Date:
Subject: Re: Unused index influencing sequential scan plan
Next
From: Jeff Janes
Date:
Subject: Re: shared_buffers/effective_cache_size on 96GB server