Fix dependency handling of partitions and inheritance for ON COMMIT

Enterprise / PostgreSQL - Michael Paquier [paquier.xyz] - 9 November 2018 01:03 EST

This commit fixes a set of issues with ON COMMIT actions when used on partitioned tables and tables with inheritance children:- Applying ON COMMIT DROP on a partitioned table with partitions or on a table with inheritance children caused a failure at commit time, with complains about the children being already dropped as all relations are dropped one at the same time.- Applying ON COMMIT DELETE on a partition relying on a partitioned table which uses ON COMMIT DROP would cause the partition truncation to fail as the parent is removed first.

The solution to the first problem is to handle the removal of all the dependencies in one go instead of dropping relations one-by-one, based on a suggestion from Álvaro Herrera. So instead all the relation OIDs to remove are gathered and then processed in one round of multiple deletions.

The solution to the second problem is to reorder the actions, with truncation happening first and relation drop done after. Even if it means that a partition could be first truncated, then immediately dropped if its partitioned table is dropped, this has the merit to keep the code simple as there is no need to do existence checks on the relations to drop.

Contrary to a manual TRUNCATE on a partitioned table, ON COMMIT DELETE does not cascade to its partitions. The ON COMMIT action defined on each partition gets the priority.

Author: Michael Paquier

319a810180 Fix dependency handling of partitions and inheritance for ON COMMIT
doc/src/sgml/ref/create_table.sgml | 7 +++-
src/backend/commands/tablecmds.c | 77 +++++++++++++++++++++++-----------
src/test/regress/expected/temp.out | 85 ++++++++++++++++++++++++++++++++++++++
src/test/regress/sql/temp.sql | 59 ++++++++++++++++++++++++++
4 files changed, 203 insertions(+), 25 deletions(-)

Upstream: git.postgresql.org


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