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allow partial union-all and improve parallel subquery costing - Mailing list pgsql-hackers

From Luc Vlaming
Subject allow partial union-all and improve parallel subquery costing
Date
Msg-id FRXPR01MB09021F98988B057A636AA4EEB7040@FRXPR01MB0902.DEUPRD01.PROD.OUTLOOK.DE
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Responses Re: allow partial union-all and improve parallel subquery costing
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Hi,

While developing some improvements for TPC-DS queries I found out that with 
UNION ALL partial paths are not emitted. Whilst fixing that I also came across
the subquery costing which does not seem to consider parallelism when doing 
the costing.

I added a simplified testcase in pg-regress to show this goes wrong, and 
attached also a before and after explain output of tpc-ds SF100 query 5
based on version 12.4.

I hope I followed all etiquette and these kind of improvements are welcome.

Kind regards,
Luc
Swarm64
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