Re: Parallel Aggregate

On Tue, Mar 15, 2016 at 6:55 PM, David Rowley
 wrote:
> On 16 March 2016 at 11:00, Robert Haas  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.

...and why would one be true and the other false?

-- 
Robert Haas
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