Re: Parallel Aggregate

On 17 March 2016 at 01:29, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> On Wed, Mar 16, 2016 at 8:19 AM, Amit Kapila <amit(dot)kapila16(at)gmail(dot)com> wrote:
>> Isn't it better to call it as Parallel Aggregate instead of Partial
>> Aggregate. Initialy, we have kept Partial for seqscan, but later on we
>> changed to Parallel Seq Scan, so I am not able to think why it is better to
>> call Partial incase of Aggregates.
>
> I think partial is the right terminology. Unlike a parallel
> sequential scan, a partial aggregate isn't parallel-aware and could be
> used in contexts having nothing to do with parallelism. It's just
> that it outputs transition values instead of a finalized value.

+1 the reason the partial aggregate patches have been kept separate
from the parallel aggregate patches is that partial aggregate will
serve for many other purposes. Parallel Aggregate is just one of many
possible use cases for this, so it makes little sense to give it a
name according to a single use case.

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David Rowley http://www.2ndQuadrant.com/
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