Horton

Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

Alexander Korotkov <aekorotkov@gmail.com>

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From: Alexander Korotkov <aekorotkov@gmail.com>
To: Dmitry Koval <d.koval@postgrespro.ru>
Cc: jian he <jian.universality@gmail.com>, pgsql-hackers@lists.postgresql.org
Date: 2025-06-05T01:41:47Z
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.

Hi Dmitry!

On Wed, Jun 4, 2025 at 10:44 PM Dmitry Koval <d.koval@postgrespro.ru> wrote:
> Thank you very much for review.

Thank you for your work on this patch.  I have some additional notes on
this patch.

Why don't you use *existing_relation_id argument of
RangeVarGetAndCheckCreationNamespace(), when it is called from
createPartitionTable() and ATExecSplitPartition()?  This argument provide
an elegant way to find a duplicate table with the same name.

It also seems that 0002 patch has the following error message, which aren't
experienced in the regression tests.

+                   datum = list_nth(spec->upperdatums, abs(cmpval) - 1);
+                   ereport(ERROR,
+                           errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+                           errmsg("upper bound of partition \"%s\" is not
equal to upper bound of split partition",
+                                  relname),
+                           parser_errposition(pstate, datum->location));


+               ereport(ERROR,
+                       errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+                       errmsg("new partition \"%s\" cannot have this value
because split partition does not have",
+                              relname),
+                       parser_errposition(pstate, overlap_location));


+       ereport(ERROR,
+               errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+               errmsg("new partitions do not have value %s but split
partition does",
+                      searchNull ? "NULL" :
get_list_partvalue_string(notFoundVal)));


+                           ereport(ERROR,
+
errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+                                   errmsg("DEFAULT partition should be
one"),
+                                   parser_errposition(pstate,
sps->name->location));

+       ereport(ERROR,
+               errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+               errmsg("one partition in the list should be DEFAULT because
split partition is DEFAULT"),
+               parser_errposition(pstate, ((SinglePartitionSpec *)
linitial(partlist))->name->location));


+       ereport(ERROR,
+               errcode(ERRCODE_INVALID_OBJECT_DEFINITION),
+               errmsg("new partition cannot be DEFAULT because DEFAULT
partition already exists"),
+               parser_errposition(pstate, spsDef->name->location));

+               ereport(ERROR,
+                       errcode(ERRCODE_CHECK_VIOLATION),
+                       errmsg("can not find partition for split partition
row"),
+                       errtable(splitRel));

------
Regards,
Alexander Korotkov
Supabase