Horton

RE: Should consider materializing the cheapest inner path in consider_parallel_nestloop()

Fujii.Yuki@df.MitsubishiElectric.co.jp <fujii.yuki@df.mitsubishielectric.co.jp>

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From: "Fujii.Yuki@df.MitsubishiElectric.co.jp" <Fujii.Yuki@df.MitsubishiElectric.co.jp>
To: Tender Wang <tndrwang@gmail.com>, Tomasz Rybak <tomasz.rybak@post.pl>
Cc: "pgsql-hackers@lists.postgresql.org" <pgsql-hackers@lists.postgresql.org>, "robertmhaas@gmail.com" <robertmhaas@gmail.com>, Richard Guo <guofenglinux@gmail.com>, David Rowley <dgrowleyml@gmail.com>, "Fujii.Yuki@df.MitsubishiElectric.co.jp" <Fujii.Yuki@df.MitsubishiElectric.co.jp>
Date: 2024-06-05T01:26:30Z
Lists: pgsql-hackers 
Hi. Tender.

Thank you for modification.

> From: Tender Wang <tndrwang@gmail.com>
> Sent: Tuesday, June 4, 2024 7:51 PM
> 	Please add more tests.  Especially please add some negative tests;
> 	current patch checks that it is safe to apply materialization. It would
> 	be helpful to add tests checking that materialization is not applied
> 	in both checked cases:
> 	1. when inner join path is not parallel safe
> 	2. when matpath is not parallel safe
> 
> 
> 
> I added a test case that inner rel is not parallel safe. Actually, 
> matpath will not create if inner rel is not parallel safe. So I didn't add test case for the second  scenario.
Is there case in which matpath is not parallel safe and inner rel is parallel safe?
If right, I think that it would be suitable to add a negative test in a such case.

Sincerely yours,
Yuuki Fujii

--
Yuuki Fujii
Information Technology R&D Center Mitsubishi Electric Corporation

Commits

  1. Fix unstable test in select_parallel.sql

  2. Consider materializing the cheapest inner path in parallel nestloop

  3. doc PG 17 relnotes: adjust IN wording

  4. Support parallel joins, and make related improvements.