Check that partitions are not in use when dropping constraints
If the user creates a deferred constraint in a partition, and in a
transaction they cause the constraint's trigger execution to be deferred
until commit time *and* drop the constraint, then when commit time comes
the queued trigger will fail to run because the trigger object will have
been dropped.
This is explained because when a constraint gets dropped in a
partitioned table, the recursion to drop the ones in partitions is done
by the dependency mechanism, not by ALTER TABLE traversing the recursion
tree as in all other cases. In the non-partitioned case, this problem
is avoided by checking that the table is not "in use" by alter-table;
other alter-table subcommands that recurse to partitions do that check
for each partition. But the dependency mechanism doesn't have a way to
do that. Fix the problem by applying the same check to all partitions
during ALTER TABLE's "prep" phase, which correctly raises the necessary
error.
Reported-by: Rajkumar Raghuwanshi <rajkumar.raghuwanshi@enterprisedb.com>
Discussion: https://postgr.es/m/CAKcux6nZiO9-eEpr1ZD84bT1mBoVmeZkfont8iSpcmYrjhGWgA@mail.gmail.com
Branch
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REL_12_STABLE
Details
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https://git.postgresql.org/pg/commitdiff/3ffe655c0af03cb4d5aab18da2aaa7022d207bf3
Modified Files
--------------
src/backend/commands/tablecmds.c | 56 +++++++++++++++++++++++++------
src/test/regress/expected/foreign_key.out | 15 +++++++++
src/test/regress/sql/foreign_key.sql | 12 +++++++
3 files changed, 72 insertions(+), 11 deletions(-)