Horton

Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

Alexander Korotkov <aekorotkov@gmail.com>

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From: Alexander Korotkov <aekorotkov@gmail.com>
To: Justin Pryzby <pryzby@telsasoft.com>
Cc: Dmitry Koval <d.koval@postgrespro.ru>, Alexander Lakhin <exclusion@gmail.com>, pgsql-hackers@lists.postgresql.org, Tomas Vondra <tomas.vondra@enterprisedb.com>, Alvaro Herrera <alvherre@alvh.no-ip.org>
Date: 2024-05-08T21:51:32Z
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. Adjust errcode in checkPartition()

  2. Fix usage of palloc() in MERGE/SPLIT PARTITION(s) code

  3. Implement ALTER TABLE ... SPLIT PARTITION ... command

  4. Implement ALTER TABLE ... MERGE PARTITIONS ... command

  5. Calculate agglevelsup correctly when Aggref contains a CTE.

  6. Use PqMsg_* macros in applyparallelworker.c.

  7. Restrict psql meta-commands in plain-text dumps.

  8. Ensure we have a snapshot when updating various system catalogs.

  9. Use specific collation where needed in new test

  10. Expand virtual generated columns in the planner

  11. Virtual generated columns

  12. Define PG_LOGICAL_DIR for path pg_logical/ in data folder

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

  14. Avoid repeated table name lookups in createPartitionTable()

  15. Provide deterministic order for catalog queries in partition_split.sql

  16. Don't copy extended statistics during MERGE/SPLIT partition operations

  17. Fix the name collision detection in MERGE/SPLIT partition operations

  18. Fix regression tests conflict in 3ca43dbbb6

  19. Add permission check for MERGE/SPLIT partition operations

  20. Fix one more portability shortcoming in new test_pg_dump test.

  21. Inherit parent's AM for partition MERGE/SPLIT operations

  22. Add tab completion for partition MERGE/SPLIT operations

  23. Rename tables in tests of partition MERGE/SPLIT operations

  24. Make new partitions with parent's persistence during MERGE/SPLIT

  25. Document the way partition MERGE/SPLIT operations create new partitions

  26. Change the way ATExecMergePartitions() handles the name collision

  27. Grammar fixes for split/merge partitions code

  28. Checks for ALTER TABLE ... SPLIT/MERGE PARTITIONS ... commands

  29. Fix some grammer errors from error messages and codes comments

  30. Support TZ and OF format codes in to_timestamp().

  31. Support identity columns in partitioned tables

  32. Fix indentation in twophase.c

  33. Fix corner-case planner failure for MERGE.

  34. Doc: fix documentation example for bytea hex output format.

  35. Avoid repeated name lookups during table and index DDL.

On Thu, May 9, 2024 at 12:37 AM Justin Pryzby <pryzby@telsasoft.com> wrote:
>
> On Wed, May 08, 2024 at 09:00:10PM +0300, Alexander Korotkov wrote:
> > On Fri, May 3, 2024 at 4:32 PM Alexander Korotkov <aekorotkov@gmail.com> wrote:
> > > On Fri, May 3, 2024 at 4:23 PM Justin Pryzby <pryzby@telsasoft.com> wrote:
> > > > On Wed, May 01, 2024 at 10:51:24PM +0300, Dmitry Koval wrote:
> > > > > 30.04.2024 23:15, Justin Pryzby пишет:
> > > > > > Is this issue already fixed ?
> > > > > > I wasn't able to reproduce it.  Maybe it only happened with earlier
> > > > > > patch versions applied ?
> > > > >
> > > > > I think this was fixed in commit [1].
> > > > >
> > > > > [1] https://github.com/postgres/postgres/commit/fcf80c5d5f0f3787e70fca8fd029d2e08a923f91
> > > >
> > > > I tried to reproduce it at fcf80c5d5f~, but couldn't.
> > > > I don't see how that patch would fix it anyway.
> > > > I'm hoping Alexander can confirm what happened.
> > >
> > > This problem is only relevant for an old version of fix [1], which
> > > overrides schemas for new partitions.  That version was never
> > > committed.
> >
> > Here are the patches.
> > 0002 Skips copying extended statistics while creating new partitions in MERGE/SPLIT
> >
> > For 0002 I'd like to hear some feedback on wordings used in docs and comments.
>
> commit message:
>
> Currenlty => Currently
> partiions => partitios
> copying => by copying


Thank you!

>
> > However, parent's table extended statistics already covers all its
> > children.
>
> => That's the wrong explanation.  It's not that "stats on the parent
> table cover its children".  It's that there are two types of stats:
> stats for the "table hierarchy" and stats for the individual table.
> That's true for single-column stats as well as for extended stats.
> In both cases, that's indicated by the inh flag in the code and in the
> catalog.
>
> The right explanation is that extended stats on partitioned tables are
> not similar to indexes.  Indexes on parent table are nothing other than
> a mechanism to create indexes on the child tables.  That's not true for
> stats.
>
> See also my prior messages
> ZiJW1g2nbQs9ekwK@pryzbyj2023
> Zi5Msg74C61DjJKW@pryzbyj2023

Yes, I understand that parents pg_statistic entry with stainherit ==
true includes statistics for the children.  I tried to express this by
word "covers".  But you're right, this is the wrong explanation.

Can I, please, ask you to revise the patch?

> I think EXCLUDE IDENTITY can/should now also be removed - see 509199587.
> I'm not able to reproduce that problem anyway, even before that...

I will check this.

------
Regards,
Alexander Korotkov
Supabase