Thread

[PATCH 2/2] Fix MakeTransitionCaptureState to return a consistent result

Kyotaro Horiguchi <horikyota.ntt@gmail.com> — 2025-02-07T05:12:18Z

When both an UPDATE trigger referencing NEW TABLE and a DELETE trigger
referencing OLD TABLE are present, the function returns an
inconsistent result for UPDATE command between reference flags and
tuplestores.  This causes a crash in version 14 and earlier during
cross-partition UPDATEs on a partitioned table.

This commit fixes the function so that it returns a consistent state
by incorporating part of the changes made in commit 7103ebb7aae in
version 15 as part of its own fix, thereby reducing the code
differences with version 15 and later versions.
---
 src/backend/commands/trigger.c | 36 +++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 16 deletions(-)

diff --git a/src/backend/commands/trigger.c b/src/backend/commands/trigger.c
index d04b4beed91..10cfd59aa52 100644
--- a/src/backend/commands/trigger.c
+++ b/src/backend/commands/trigger.c
@@ -4511,8 +4511,10 @@ TransitionCaptureState *
 MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
 {
 	TransitionCaptureState *state;
-	bool		need_old,
-				need_new;
+	bool		need_old_upd,
+				need_new_upd,
+				need_old_del,
+				need_new_ins;
 	AfterTriggersTableData *table;
 	MemoryContext oldcxt;
 	ResourceOwner saveResourceOwner;
@@ -4524,23 +4526,25 @@ MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
 	switch (cmdType)
 	{
 		case CMD_INSERT:
-			need_old = false;
-			need_new = trigdesc->trig_insert_new_table;
+			need_old_upd = need_old_del = need_new_upd = false;
+			need_new_ins = trigdesc->trig_insert_new_table;
 			break;
 		case CMD_UPDATE:
-			need_old = trigdesc->trig_update_old_table;
-			need_new = trigdesc->trig_update_new_table;
+			need_old_upd = trigdesc->trig_update_old_table;
+			need_new_upd = trigdesc->trig_update_new_table;
+			need_old_del = need_new_ins = false;
 			break;
 		case CMD_DELETE:
-			need_old = trigdesc->trig_delete_old_table;
-			need_new = false;
+			need_old_del = trigdesc->trig_delete_old_table;
+			need_old_upd = need_new_upd = need_new_ins = false;
 			break;
 		default:
 			elog(ERROR, "unexpected CmdType: %d", (int) cmdType);
-			need_old = need_new = false;	/* keep compiler quiet */
+			/* keep compiler quiet */
+			need_old_upd = need_new_upd = need_old_del = need_new_ins = false;
 			break;
 	}
-	if (!need_old && !need_new)
+	if (!need_old_upd && !need_new_upd && !need_new_ins && !need_old_del)
 		return NULL;
 
 	/* Check state, like AfterTriggerSaveEvent. */
@@ -4570,9 +4574,9 @@ MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
 	saveResourceOwner = CurrentResourceOwner;
 	CurrentResourceOwner = CurTransactionResourceOwner;
 
-	if (need_old && table->old_tuplestore == NULL)
+	if ((need_old_upd || need_old_del) && table->old_tuplestore == NULL)
 		table->old_tuplestore = tuplestore_begin_heap(false, false, work_mem);
-	if (need_new && table->new_tuplestore == NULL)
+	if ((need_new_upd || need_new_ins) && table->new_tuplestore == NULL)
 		table->new_tuplestore = tuplestore_begin_heap(false, false, work_mem);
 
 	CurrentResourceOwner = saveResourceOwner;
@@ -4580,10 +4584,10 @@ MakeTransitionCaptureState(TriggerDesc *trigdesc, Oid relid, CmdType cmdType)
 
 	/* Now build the TransitionCaptureState struct, in caller's context */
 	state = (TransitionCaptureState *) palloc0(sizeof(TransitionCaptureState));
-	state->tcs_delete_old_table = trigdesc->trig_delete_old_table;
-	state->tcs_update_old_table = trigdesc->trig_update_old_table;
-	state->tcs_update_new_table = trigdesc->trig_update_new_table;
-	state->tcs_insert_new_table = trigdesc->trig_insert_new_table;
+	state->tcs_delete_old_table = need_old_del;
+	state->tcs_update_old_table = need_old_upd;
+	state->tcs_update_new_table = need_new_upd;
+	state->tcs_insert_new_table = need_new_ins;
 	state->tcs_private = table;
 
 	return state;
-- 
2.43.5


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