Re: Calculation of unused columns - Mailing list pgsql-performance

From Robert Haas
Subject Re: Calculation of unused columns
Date
Msg-id 603c8f070910171853l5f2a81ai71f00417f8a2e959@mail.gmail.com
Whole thread Raw
In response to Re: Calculation of unused columns  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Calculation of unused columns  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
On Sat, Oct 17, 2009 at 9:41 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> I've been thinking about this since your earlier mail, and I think it
> would probably be possible to suppress unused columns in a non-flattened
> subquery.  I remain unconvinced that it's worth the trouble though.
> A real (not handwavy) example would help make the case here.

Are there any situations where this would enable join removal that
otherwise wouldn't be possible?  Maybe a query involving an
unflattenable VIEW?

...Robert

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