Re: cached plans and enable_partition_pruning - Mailing list pgsql-hackers

From Alvaro Herrera
Subject Re: cached plans and enable_partition_pruning
Date
Msg-id 20180723160332.5hawct6hxda6tw4q@alvherre.pgsql
Whole thread Raw
In response to Re: cached plans and enable_partition_pruning  (Amit Langote <amitlangote09@gmail.com>)
Responses Re: cached plans and enable_partition_pruning  (Andres Freund <andres@anarazel.de>)
List pgsql-hackers
On 2018-Jul-24, Amit Langote wrote:

> On Mon, Jul 23, 2018 at 11:20 PM, Andres Freund <andres@anarazel.de> wrote:

> > I think it's correct to check the plan time value, rather than the
> > execution time value. Other enable_* GUCs also take effect there, and I
> > don't see a problem with that?
> 
> Ah, so that may have been intentional.  Although, I wonder if
> enable_partition_pruning could be made to work differently than other
> enable_* settings, because we *can* perform pruning which is an
> optimization function even during execution, whereas we cannot modify
> the plan in other cases?

Well, let's discuss the use-case for doing that.  We introduced the GUC
to cover for the case of bugs in the pruning code (and even then there
was people saying we should remove it.)  Why would you have the GUC
turned on during planning but off during execution?

-- 
Álvaro Herrera                https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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