Re: Domain check taking place unnecessarily? - Mailing list pgsql-performance

From Tom Lane
Subject Re: Domain check taking place unnecessarily?
Date
Msg-id 3893890.1675955401@sss.pgh.pa.us
Whole thread Raw
In response to Re: Domain check taking place unnecessarily?  (Mark Hills <mark@xwax.org>)
Responses Re: Domain check taking place unnecessarily?  (Mark Hills <mark@xwax.org>)
List pgsql-performance
Mark Hills <mark@xwax.org> writes:
> On Wed, 8 Feb 2023, Laurenz Albe wrote:
>> It takes 30 seconds to schan the table and determine that all existing 
>> rows satisky the constraint.

> But there's no existing data (note this is adding column, not constraint)

> Existing rows are guaranteed to satisfy the domain check, because the 
> domain check is guaranteed to be immutable (per [1] in my original mail)

immutable != "will accept null".

There could be some more optimizations here, perhaps, but there aren't.

            regards, tom lane



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