Re: Calculated view fields (8.1 != 8.2) - Mailing list pgsql-hackers

From Gaetano Mendola
Subject Re: Calculated view fields (8.1 != 8.2)
Date
Msg-id 45F05773.6000607@bigfoot.com
Whole thread Raw
In response to Re: Calculated view fields (8.1 != 8.2)  (Tom Lane <tgl@sss.pgh.pa.us>)
Responses Re: Calculated view fields (8.1 != 8.2)  (Gaetano Mendola <mendola@bigfoot.com>)
List pgsql-hackers
Tom Lane wrote:
> Gaetano Mendola <mendola@bigfoot.com> writes:
>> [ 8.2 evaluates volatile functions in the targetlist of a view ]
>> If I mark the function as STABLE or IMMUTABLE then even with version
>> 8.2 the function is not evaluated. Is this the intended behavior?
> 
> Yes; people complained that we needed to be more careful about the
> number of times volatile functions get evaluated.

I suspect that functions are evaluated also for record discarded due to
joins. Is that the case?

Like:

SELECT * FROM ta JOIN tb USING (id) where tb.foo = 4;

If ta is a view with some calculated fields are the function on ta
evaluated only for record matching the filters or in some case (
like a full scan on ta ) also for the records discarded due to the join?


Regards
Gaetano Mendola


pgsql-hackers by date:

Previous
From: Doug Knight
Date:
Subject: Re: [PATCHES] pg_standby
Next
From: "Simon Riggs"
Date:
Subject: Re: [PATCHES] pg_standby