Horton

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

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Richard Guo <guofenglinux@gmail.com>
Cc: tender wang <tndrwang@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2023-09-07T19:14:50Z
Lists: pgsql-hackers 
On Tue, Sep 5, 2023 at 8:07 AM Richard Guo <guofenglinux@gmail.com> wrote:
> Yeah, this seems an omission in commit 45be99f8.

It's been a while, but I think I omitted this deliberately because I
didn't really understand the value of it and wanted to keep the
planning cost down.

The example query provided here seems rather artificial. Surely few
people write a join clause that references neither of the tables being
joined. Is there a more realistic case where this makes a big
difference?

-- 
Robert Haas
EDB: http://www.enterprisedb.com

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.