Horton

Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

Zhihong Yu <zyu@yugabyte.com>

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From: Zhihong Yu <zyu@yugabyte.com>
To: Dmitry Koval <d.koval@postgrespro.ru>
Cc: Matthias van de Meent <boekewurm+postgres@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2022-06-01T19:10:22Z
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 Wed, Jun 1, 2022 at 11:58 AM Dmitry Koval <d.koval@postgrespro.ru> wrote:

> Hi,
>
> 1)
> > For attachPartTable, the parameter wqueue is missing from comment.
> > The parameters of CloneRowTriggersToPartition are called parent and
> partition.
> > I think it is better to name the parameters to attachPartTable in a
> similar manner.
> >
> > For struct SplitPartContext, SplitPartitionContext would be better name.
> >
> > +       /* Store partition contect into list. */
> > contect -> context
>
> Thanks, changed.
>
> 2)
> > For transformPartitionCmdForMerge(), nested loop is used to detect
> duplicate names.
> > If the number of partitions in partcmd->partlist, we should utilize map
> to speed up the check.
>
> I'm not sure what we should utilize map in this case because chance that
> number of merging partitions exceed dozens is low.
> Is there a function example that uses a map for such a small number of
> elements?
>
> 3)
> > For check_parent_values_in_new_partitions():
> >
> > +           if (!find_value_in_new_partitions(&key->partsupfunc[0],
> > +                                             key->partcollation, parts,
> nparts, datum, false))
> > +               found = false;
> >
> > It seems we can break out of the loop when found is false.
>
> We have implicit "break" in "for" construction:
>
> +       for (i = 0; i < boundinfo->ndatums && found; i++)
>
> I'll change it to explicit "break;" to avoid confusion.
>
>
> Attached patch with the changes described above.
> --
> With best regards,
> Dmitry Koval
>
> Postgres Professional: http://postgrespro.com

Hi,
Thanks for your response.

w.r.t. #2, I think using nested loop is fine for now.
If, when this feature is merged, some user comes up with long merge list,
we can revisit this topic.

Cheers