Fix trigger transition table capture for MERGE in CTE queries. When executing a data-modifying CTE query containing MERGE and some other DML operation on a table with statement-level AFTER triggers, the transition tables passed to the triggers would fail to include the rows affected by the MERGE.
The reason is that, when initializing a ModifyTable node for MERGE, MakeTransitionCaptureState() would create a TransitionCaptureState structure with a single "tcs_private" field pointing to an AfterTriggersTableData structure with cmdType == CMD_MERGE. Tuples captured there would then not be included in the sets of tuples captured when executing INSERT/UPDATE/DELETE ModifyTable nodes in the same query. Since there are no MERGE triggers, we should only create AfterTriggersTableData structures for INSERT/UPDATE/DELETE. Individual MERGE actions should then use those, thereby sharing the same capture tuplestores as any other DML commands executed in the same query. This requires changing the TransitionCaptureState structure, replacing "tcs_private" with 3 separate pointers to AfterTriggersTableData structures, one for each of INSERT, UPDATE, and DELETE. Nominally, this is an ABI break to a public structure in commands/trigger.h. However, since this is a private field pointing to an opaque data structure, the only way to create a valid TransitionCaptureState is by calling MakeTransitionCaptureState(), and no extensions appear to be doing that anyway, so it seems safe for back-patching. Backpatch to v15, where MERGE was introduced. Bug: #19380 Reported-by: Daniel Woelfel <[email protected]> Author: Dean Rasheed <[email protected]> Reviewed-by: Tom Lane <[email protected]> Discussion: https://postgr.es/m/19380-4e293be2b4007248%40postgresql.org Backpatch-through: 15 Branch ------ REL_16_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/e7391bbf14db94afee1fd3c011314f7b8ee493e9 Modified Files -------------- src/backend/commands/trigger.c | 148 +++++++++++++++++++++------------ src/include/commands/trigger.h | 4 +- src/test/regress/expected/triggers.out | 8 +- src/test/regress/sql/triggers.sql | 4 + 4 files changed, 107 insertions(+), 57 deletions(-)
