Re: Rewritten rows on unchanged values - Mailing list pgsql-general

Hi folks,


On 2013-03-22 13:32, Bertrand Janin wrote:
 >    UPDATE demo
 >    SET value = value
 >    WHERE id = 1;


On 2013-03-22 14:55, Tom Lane wrote:
 >
> It's not *necessary* to do so.  However, avoiding it would require
> sitting there and comparing the old and new tuples,


But in this case, no tuples would need to be compared: just by looking
at the query is becomes clear that it is a no-op.
Isn't this something the planner is or could be aware of?

Betrand, out of curiosity: is this a synthentic test case or do you
really have an application that generates queries like this?


Best regards,

    -hannes