Horton

Re: First draft of the PG 15 release notes

Amit Langote <amitlangote09@gmail.com>

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From: Amit Langote <amitlangote09@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: David Rowley <dgrowleyml@gmail.com>, PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2022-05-25T03:00:47Z
Lists: pgsql-hackers

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On Wed, May 25, 2022 at 8:36 AM Bruce Momjian <bruce@momjian.us> wrote:
> On Thu, May 19, 2022 at 06:13:28PM +0900, Amit Langote wrote:
> > Or maybe we could mention that but use a wording that doesn't make it
> > sound like an implementation detail, like:
> >
> > +Previously, an ordered partition scan could not be used for a
> > LIST-partitioned table with any partition containing multiple values,
> > nor for partitioned tables with DEFAULT partition.  Now it can be used
> > in those cases at least for queries in which such partitions are
> > pruned.
>
> Sorry, I just don't see this as an improvement because it starts with a
> complex term "an ordered partition scan" rather than simply "a
> partitioned table".

The headline says "Allow ordered scans of partitions to avoid sorting
in more cases", so I proposed starting the description too with "an
ordered scan".  Also, not sure about going with:

"previously, <table-with-limiting-properties> could not be used for
<scan-method>, but now it can be provided <conditions>"

instead of:

"previously, <scan-method> could not be used for
<table-with-limiting-properties>, but now it can be provided
<conditions>"

as in my proposed wording, but maybe that's just me.

Anyway, I still think it would be better to fix the description such
that the cases in which ordered scans will continue to not be usable
are clear.  The existing text doesn't make clear, for example, that a
DEFAULT partition if present must have been pruned for an ordered scan
to be used. So I propose:

+Previously, a partitioned table with DEFAULT partition or a LIST
partition containing multiple values could not be used for ordered
partition scans. Now it can be used at least in the cases where such
partitions are pruned.


--
Thanks, Amit Langote
EDB: http://www.enterprisedb.com

Commits

  1. Doc: last minute adjustment to the release notes

  2. Doc: more tweaking of v15 release notes.

  3. Doc: further adjust notes about pg_upgrade_output.d.

  4. Doc: add list of major features to the v15 release notes.

  5. relnotes: update item about public schema permission change

  6. relnotes: update ordered partition scan item

  7. relnotes: add Heikki to UTF8 item

  8. relnotes: improve UTF8 text item in relation to ASCII

  9. relnotes: add null logical replication item

  10. relnotes: adjust several logical replication items and FK text

  11. relnotes: mention non-exclusive backup mode was deprecated

  12. relnotes: add author to in-memory sorts item

  13. relnotes: update for non-exclusive backup mode removal

  14. relnote: improve sorting entries

  15. relnotes: adjustments from Álvaro Herrera

  16. relnotes: update foreign key partition and add sort items

  17. relnotes: more adjustments

  18. relnotes: logical replication permissions checked by subscrib.

  19. relnotes: adjustments

  20. relnotes: remove sequence replication and update 'postgres -C'

  21. relnote: extensive updates

  22. relnotes: "training" -> "trailing"

  23. Standardize references to Zstandard as <productname>

  24. pgstat: Update docs to match the shared memory stats reality.

  25. Raise a WARNING for missing publications.

  26. Skip empty transactions for logical replication.

  27. Optionally disable subscriptions on error.

  28. Allow root-owned SSL private keys in libpq, not only the backend.

  29. Use COPY FREEZE in pgbench for faster benchmark table population.