Re: Constraint exclusion can't process simple constant expressions? - Mailing list pgsql-performance

From Josh Berkus
Subject Re: Constraint exclusion can't process simple constant expressions?
Date
Msg-id 4DAF92B3.60806@agliodbs.com
Whole thread Raw
In response to Re: Constraint exclusion can't process simple constant expressions?  (Brendan Jurd <direvus@gmail.com>)
Responses Re: Constraint exclusion can't process simple constant expressions?  (Brendan Jurd <direvus@gmail.com>)
List pgsql-performance
> Emphasis on "always".  If the result of the function, given the same
> argument values, can be different after a SET, then it doesn't qualify
> for immutability.  At least, that's my understanding.

Hmmmm.  But within the context of the query plan itself, the results of
that expression are going to be constant.  That is, for a given query
execution, it's always going to be the same comparison.

So this goes back to my original assertion that CE can't be fixed ...

--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com

pgsql-performance by date:

Previous
From: Brendan Jurd
Date:
Subject: Re: Constraint exclusion can't process simple constant expressions?
Next
From: "mark"
Date:
Subject: rant ? check the BBWC