Re: Parallel Aggregate - Mailing list pgsql-hackers

From David Rowley
Subject Re: Parallel Aggregate
Date
Msg-id CAKJS1f96XQLMLjSG=sk=TRCVWmnxJuRNNnRt0voSPsVhB0BVAQ@mail.gmail.com
Whole thread Raw
In response to Re: Parallel Aggregate  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: Parallel Aggregate
List pgsql-hackers
On 16 March 2016 at 11:00, Robert Haas <robertmhaas@gmail.com> wrote:
> I don't see why we would need to leave aggpartial out of the equals()
> check.  I must be missing something.

See fix_combine_agg_expr_mutator()

This piece of code:

/*
* Aggrefs for partial aggregates are wrapped up in a PartialAggref,
* we need to look into the PartialAggref to find the Aggref within.
*/
foreach(lc, context->subplan_itlist->tlist)
{
PartialAggref *paggref;
tle = (TargetEntry *) lfirst(lc);
paggref = (PartialAggref *) tle->expr;

if (IsA(paggref, PartialAggref) &&
equal(paggref->aggref, aggref))
break;
}

if equals() compared the aggpartial then this code would fail to find
the Aggref in the subnode due to the aggpartial field being true on
one and false on the other Aggref.


-- David Rowley                   http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training & Services



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