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Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

Alexander Korotkov <aekorotkov@gmail.com>

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From: Alexander Korotkov <aekorotkov@gmail.com>
To: Pavel Borisov <pashkin.elfe@gmail.com>
Cc: Justin Pryzby <pryzby@telsasoft.com>, 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: 2026-06-16T12:22:02Z
Lists: pgsql-hackers 
Hi, Pavel!

On Tue, Jun 16, 2026 at 12:57 AM Pavel Borisov <pashkin.elfe@gmail.com> wrote:
> I looked into the patch. It's simple enough and looks good to me.
> I have one question: is it correct to pass 0 reloptions to
> NewRelationCreateToastTable or we need to use transformRelOptions +
> heap_reloptions pair to derive toast_reloptions as it is done in
> ProcessUtilitySlow() and create_ctas_internal()?

Yes, (Datum) 0 is correct here.  MERGE/SPLIT PARTITION grammar
provides no syntactic way for the user to specify reloptions for the
new partitions, so there is nothing to extract via
transformRelOptions.  This matches createPartitionTable() itself,
which already calls heap_create_with_catalog(... reloptions=(Datum) 0
...) for the main relation a few lines above; the TOAST table just
inherits that choice.

Extending the syntax to accept WITH (...) on new partitions would be a
separate, larger feature.  Out of scope for this bug fix.

------
Regards,
Alexander Korotkov
Supabase

Commits

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

  1. doc: clarify MERGE PARTITIONS adjacency requirement

  2. Take into account default_tablespace during MERGE/SPLIT PARTITION(S)

  3. Create TOAST table for partitions made by MERGE/SPLIT PARTITION

  4. Adjust errcode in checkPartition()

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

  6. Implement ALTER TABLE ... SPLIT PARTITION ... command

  7. Implement ALTER TABLE ... MERGE PARTITIONS ... command

  8. Calculate agglevelsup correctly when Aggref contains a CTE.

  9. Use PqMsg_* macros in applyparallelworker.c.

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

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

  12. Use specific collation where needed in new test

  13. Expand virtual generated columns in the planner

  14. Virtual generated columns

  15. Define PG_LOGICAL_DIR for path pg_logical/ in data folder

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

  17. Avoid repeated table name lookups in createPartitionTable()

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

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

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

  21. Fix regression tests conflict in 3ca43dbbb6

  22. Add permission check for MERGE/SPLIT partition operations

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

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

  25. Add tab completion for partition MERGE/SPLIT operations

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

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

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

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

  30. Grammar fixes for split/merge partitions code

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

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

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

  34. Support identity columns in partitioned tables

  35. Fix indentation in twophase.c

  36. Fix corner-case planner failure for MERGE.

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

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