From: Alexander Korotkov <akorotkov@postgresql.org>
To: pgsql-committers@lists.postgresql.org
Subject: pgsql: Implement ALTER TABLE ... MERGE PARTITIONS ... command
Date: Sat, 06 Apr 2024 22:19:06 +0000
Message-ID: <E1rtENN-000rrU-RZ@gemulon.postgresql.org> (raw)
Implement ALTER TABLE ... MERGE PARTITIONS ... command
This new DDL command merges several partitions into the one partition of the
target table. The target partition is created using new
createPartitionTable() function with parent partition as the template.
This commit comprises quite naive implementation which works in single process
and holds the ACCESS EXCLUSIVE LOCK on the parent table during all the
operations including the tuple routing. This is why this new DDL command
can't be recommended for large partitioned tables under a high load. However,
this implementation come in handy in certain cases even as is.
Also, it could be used as a foundation for future implementations with lesser
locking and possibly parallel.
Discussion: https://postgr.es/m/c73a1746-0cd0-6bdd-6b23-3ae0b7c0c582%40postgrespro.ru
Author: Dmitry Koval
Reviewed-by: Matthias van de Meent, Laurenz Albe, Zhihong Yu, Justin Pryzby
Reviewed-by: Alvaro Herrera, Robert Haas, Stephane Tachoires
Branch
------
master
Details
-------
https://git.postgresql.org/pg/commitdiff/1adf16b8fba45f77056d91573cd7138ed9da4ebf
Modified Files
--------------
doc/src/sgml/ddl.sgml | 19 +
doc/src/sgml/ref/alter_table.sgml | 77 ++-
src/backend/commands/tablecmds.c | 354 +++++++++-
src/backend/parser/gram.y | 22 +-
src/backend/parser/parse_utilcmd.c | 89 +++
src/backend/partitioning/partbounds.c | 207 ++++++
src/include/nodes/parsenodes.h | 14 +
src/include/parser/kwlist.h | 1 +
src/include/partitioning/partbounds.h | 6 +
src/test/isolation/expected/partition-merge.out | 199 ++++++
src/test/isolation/isolation_schedule | 1 +
src/test/isolation/specs/partition-merge.spec | 54 ++
.../modules/test_ddl_deparse/test_ddl_deparse.c | 3 +
src/test/regress/expected/partition_merge.out | 732 +++++++++++++++++++++
src/test/regress/parallel_schedule | 2 +-
src/test/regress/sql/partition_merge.sql | 430 ++++++++++++
src/tools/pgindent/typedefs.list | 1 +
17 files changed, 2189 insertions(+), 22 deletions(-)
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To: pgsql-committers@postgresql.org
Cc: akorotkov@postgresql.org, pgsql-committers@lists.postgresql.org
Subject: Re: pgsql: Implement ALTER TABLE ... MERGE PARTITIONS ... command
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