Horton

Re: First draft of PG 17 release notes

Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>

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From: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
To: Bruce Momjian <bruce@momjian.us>
Cc: PostgreSQL-development <pgsql-hackers@postgresql.org>
Date: 2024-05-13T07:16:38Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Revert support for ALTER TABLE ... MERGE/SPLIT PARTITION(S) commands

  2. When creating materialized views, use REFRESH to load data.

  3. Revert temporal primary keys and foreign keys

  4. Avoid needless large memcpys in libpq socket writing

  5. Enhance nbtree ScalarArrayOp execution.

  6. Introduce a non-recursive JSON parser

  7. Combine freezing and pruning steps in VACUUM

  8. Allow SIGINT to cancel psql database reconnections.

  9. Provide API for streaming relation data.

  10. Add hash support functions and hash opclass for contrib/ltree.

  11. Pull up ANY-SUBLINK with the necessary lateral support.

  12. Read WAL directly from WAL buffers.

  13. Introduce the dynamic shared memory registry.

  14. Add macros for looping through a List without a ListCell.

  15. Support +/- infinity in the interval data type.

  16. Extend ALTER OPERATOR to allow setting more optimization attributes.

  17. Consider cheap startup paths in add_paths_to_append_rel

On Fri, May 10, 2024 at 7:20 PM Bruce Momjian <bruce@momjian.us> wrote:
>
> > Thanks a lot for this work Bruce! It looks like commit
> > https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=91f2cae7a4e664e9c0472b364c7db29d755ab151
> > is missing from daft release notes. Just curious to know if it's
> > intentional or a miss out.
>
> I did not mention it because the commit didn't mention any performance
> benefit and it seemed more like an internal change than something people
> needed to know about.

Yes, it's an internal feature for someone not using Direct IO for WAL
and helps achieve things mentioned at
https://www.postgresql.org/message-id/flat/20230125211540.zylu74dj2uuh3k7w%40awork3.anarazel.de#0cac0a0d219129e32329831adea05db5
(I'm hoping to target them for PG18). It starts to show visible
benefits if someone enables direct IO for WAL (for whatever reasons)
https://www.postgresql.org/message-id/CALj2ACV6rS%2B7iZx5%2BoAvyXJaN4AG-djAQeM1mrM%3DYSDkVrUs7g%40mail.gmail.com
and https://www.postgresql.org/message-id/20230127061745.46yu4ksitzociwkt%40awork3.anarazel.de.

I'm okay if 91f2cae7 is left out for the reason that Direct IO for WAL
isn't something used in production and debug_io_direct is a developer
option.

> I could reword and merge it into this item, if
> you think I should:
>
>          Improve performance of heavily-contended WAL writes (Bharath Rupireddy)

I think both the commits are for different purposes - one is for WAL
wrties, another is for WAL reads.

--
Bharath Rupireddy
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com