Re: allow partial union-all and improve parallel subquery costing

On 23-10-2020 07:51, Luc Vlaming wrote:
> On 14.10.20 09:38, Luc Vlaming wrote:
>> Hi,
>>
>> It seems I ran the wrong make checks to verify everything is correct 
>> (make check instead
>> of make installcheck-world) and this uncovered another regress test 
>> change. I also noticed
>> the statistics are sometimes giving different row count results so I 
>> increased the row
>> statistics target to make sure the regress output is stable. Updated 
>> patch attached which
>> now successfully runs installcheck-world for v13 and master.
>>
>> Kind regards,
>> Luc
>>
>> ________________________________________
>> From: Luc Vlaming <luc@swarm64.com>
>> Sent: Tuesday, October 13, 2020 10:57 AM
>> To: pgsql-hackers
>> Subject: allow partial union-all and improve parallel subquery costing
>>
>> 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
>>
> 
> Hi,
> 
> Created a commitfest entry assuming this is the right thing to do so 
> that someone can potentially pick it up during the commitfest.
> 
> Kind regards,
> Luc
> Swarm64

Hi,

Providing an updated patch based on latest master.

Cheers,
Luc