Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

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