Re: [HACKERS] Parallel Aggregation support for aggregate functionsthat use transitions not implemented for array_agg - Mailing list pgsql-hackers

From Peter Eisentraut
Subject Re: [HACKERS] Parallel Aggregation support for aggregate functionsthat use transitions not implemented for array_agg
Date
Msg-id f24345e8-4f7a-a4ac-69a9-68700a4872d7@2ndquadrant.com
Whole thread Raw
In response to [HACKERS] Parallel Aggregation support for aggregate functions that use transitions not implemented for array_agg  ("Regina Obe" <lr@pcorp.us>)
Responses Re: [HACKERS] Parallel Aggregation support for aggregate functionsthat use transitions not implemented for array_agg
Re: [HACKERS] Parallel Aggregation support for aggregate functions that use transitions not implemented for array_agg
List pgsql-hackers
On 6/6/17 13:52, Regina Obe wrote:
> It seems CREATE  AGGREGATE was expanded in 9.6 to support parallelization of
> aggregate functions using transitions, with the addition of serialfunc and
> deserialfunc to the aggregate definitions.
> 
> https://www.postgresql.org/docs/10/static/sql-createaggregate.html
> 
> I was looking at the PostgreSQL 10 source code for some example usages of
> this and was hoping that array_agg and string_agg would support the feature.

I'm not sure how you would parallelize these, since in most uses you
want to have a deterministic output order.

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services



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