Horton

Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

Justin Pryzby <pryzby@telsasoft.com>

View thread
From: Justin Pryzby <pryzby@telsasoft.com>
To: Alexander Korotkov <aekorotkov@gmail.com>
Cc: Dmitry Koval <d.koval@postgrespro.ru>, Alexander Lakhin <exclusion@gmail.com>, Robert Haas <robertmhaas@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2024-04-24T20:26:47Z
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 Mon, Apr 22, 2024 at 01:31:48PM +0300, Alexander Korotkov wrote:
> Hi!
> 
> On Fri, Apr 19, 2024 at 4:29 PM Alexander Korotkov <aekorotkov@gmail.com> wrote:
> > On Fri, Apr 19, 2024 at 2:26 AM Dmitry Koval <d.koval@postgrespro.ru> wrote:
> > > 18.04.2024 19:00, Alexander Lakhin wrote:
> > > > leaves a strange constraint:
> > > > \d+ t*
> > > >                                            Table "public.tp_0"
> > > > ...
> > > > Not-null constraints:
> > > >      "merge-16385-26BCB0-tmp_i_not_null" NOT NULL "i"
> > >
> > > Thanks!
> > > Attached fix (with test) for this case.
> > > The patch should be applied after patches
> > > v6-0001- ... .patch ... v6-0004- ... .patch
> >
> > I've incorporated this fix with 0001 patch.
> >
> > Also added to the patchset
> > 005 – tab completion by Dagfinn [1]
> > 006 – draft fix for table AM issue spotted by Alexander Lakhin [2]
> > 007 – doc review by Justin [3]
> >
> > I'm continuing work on this.
> >
> > Links
> > 1. https://www.postgresql.org/message-id/87plumiox2.fsf%40wibble.ilmari.org
> > 2. https://www.postgresql.org/message-id/84ada05b-be5c-473e-6d1c-ebe5dd21b190%40gmail.com
> > 3. https://www.postgresql.org/message-id/ZiGH0xc1lxJ71ZfB%40pryzbyj2023
> 
> 0001
> The way we handle name collisions during MERGE PARTITIONS operation is
> reworked by integration of patch [3].  This makes note about commit in
> [2] not relevant.

This patch also/already fixes the schema issue I reported.  Thanks.

If you wanted to include a test case for that:

begin;
CREATE SCHEMA s;
CREATE SCHEMA t;
CREATE TABLE p(i int) PARTITION BY RANGE(i);
CREATE TABLE s.c1 PARTITION OF p FOR VALUES FROM (1)TO(2);
CREATE TABLE s.c2 PARTITION OF p FOR VALUES FROM (2)TO(3);
ALTER TABLE p MERGE PARTITIONS (s.c1, s.c2) INTO s.c1; -- misbehaves if merging into the same name as an existing partition
\d+ p
...
Partitions: c1 FOR VALUES FROM (1) TO (3)

> 0002
> The persistence of the new partition is copied as suggested in [1].
> But the checks are in-place, because search_path could influence new
> table persistence.  Per review [2], commit message typos are fixed,
> documentation is revised, revised tests to cover schema-qualification,
> usage of search_path.

Subject: [PATCH v8 2/7] Make new partitions with parent's persistence during MERGE/SPLIT operations

This patch adds documentation saying:
+      Any indexes, constraints and user-defined row-level triggers that exist
+      in the parent table are cloned on new partitions [...]

Which is good to say, and addresses part of my message [0]
[0] ZiJW1g2nbQs9ekwK@pryzbyj2023

But it doesn't have anything to do with "creating new partitions with
parent's persistence".  Maybe there was a merge conflict and the docs
ended up in the wrong patch ?

Also, defaults, storage options, compression are also copied.  As will
be anything else from LIKE.  And since anything added in the future will
also be copied, maybe it's better to just say that the tables will be
created the same way as "LIKE .. INCLUDING ALL EXCLUDING ..", or
similar.  Otherwise, the next person who adds a new option for LIKE
would have to remember to update this paragraph...

Also, extended stats objects are currently cloned to new child tables.
But I suggested in [0] that they probably shouldn't be.

> 007 – doc review by Justin [3]

I suggest to drop this patch for now.  I'll send some more minor fixes to
docs and code comments once the other patches are settled.

-- 
Justin