Re: Add SPLIT PARTITION/MERGE PARTITIONS commands

FWIW, I also proposed a patch earlier that fixes error messages and
comments in the split partition code

Sorry, I thought all the fixes you suggested were already included in v1-0002-Fixes-for-english-text.patch (but they are not).
Added missing lines to v2-0002-Fixes-for-english-text.patch.

It seems to me that v2-0001-Fix-for-SPLIT-MERGE-partitions-of-temporary-table.patch
is not complete either.
Take a look, please:
CREATE TABLE t (i int) PARTITION BY RANGE (i);
SET search_path = pg_temp, public;
CREATE TABLE tp_0_1 PARTITION OF t
  FOR VALUES FROM (0) TO (1);
-- fails with:
ERROR:  cannot create a temporary relation as partition of permanent relation "t"

But:
CREATE TABLE t (i int) PARTITION BY RANGE (i);
CREATE TABLE tp_0_1 PARTITION OF t
  FOR VALUES FROM (0) TO (1);
CREATE TABLE tp_1_2 PARTITION OF t
  FOR VALUES FROM (1) TO (2);
INSERT INTO t VALUES(0), (1);
SELECT * FROM t;
-- the expected result is:
 i
---
 0
 1
(2 rows)

SET search_path = pg_temp, public;
ALTER TABLE t
MERGE PARTITIONS (tp_0_1, tp_1_2) INTO tp_0_2;
-- succeeds, and
\c -
SELECT * FROM t;
-- gives:
 i
---
(0 rows)

Please also ask your tech writers to check contents of src/test/sql/*, if
possible (perhaps, they'll fix "salesmans" and improve grammar).

Best regards,
Alexander