Re: bad JIT decision - Mailing list pgsql-general

From Scott Ribe
Subject Re: bad JIT decision
Date
Msg-id 690D93FA-4A30-422D-94C3-18A089B8AEFE@elevated-dev.com
Whole thread Raw
In response to Re: bad JIT decision  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Responses Re: bad JIT decision
List pgsql-general
> On Jul 27, 2020, at 4:00 PM, Alvaro Herrera <alvherre@2ndquadrant.com> wrote:
>
> I don't quite understand why is it that a table with 1000 partitions
> means that JIT compiles the thing 1000 times.  Sure, it is possible that
> some partitions have a different column layout, but it seems an easy bet
> that most cases are going to have identical column layout, and so tuple
> deforming can be shared.  (I'm less sure about sharing a compile of an
> expression, since the varno would vary. But presumably there's a way to
> take the varno as an input value for the compiled expr too?)  Now I
> don't actually know how this works so please correct if I misunderstand
> it.

I'm guessing it's because of inlining. You could optimize a function that takes parameters, no problem. But what's
happeningis inlining, with parameters, then optimizing. 




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