Repair problems occurring when multiple RI updates have to be done to the same

row within one query: we were firing check triggers before all the updates
were done, leading to bogus failures.  Fix by making the triggers queued by
an RI update go at the end of the outer query's trigger event list, thereby
effectively making the processing "breadth-first".  This was indeed how it
worked pre-8.0, so the bug does not occur in the 7.x branches.
Per report from Pavel Stehule.

1 files changed, 22 insertions, 15 deletions

diff --git a/src/backend/executor/spi.c b/src/backend/executor/spi.c
index 71e40ed25b4..77e2cafb109 100644
--- a/src/backend/executor/spi.c
+++ b/src/backend/executor/spi.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.133.4.2 2007/03/17 03:16:03 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/spi.c,v 1.133.4.3 2007/08/15 19:16:12 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -39,9 +39,9 @@ static void _SPI_prepare_plan(const char *src, _SPI_plan *plan);
 static int _SPI_execute_plan(_SPI_plan *plan,
 							 Datum *Values, const char *Nulls,
 							 Snapshot snapshot, Snapshot crosscheck_snapshot,
-							 bool read_only, int tcount);
+							 bool read_only, bool fire_triggers, int tcount);
 
-static int _SPI_pquery(QueryDesc *queryDesc, int tcount);
+static int _SPI_pquery(QueryDesc *queryDesc, bool fire_triggers, int tcount);
 
 static void _SPI_error_callback(void *arg);
 
@@ -301,7 +301,7 @@ SPI_execute(const char *src, bool read_only, int tcount)
 
 	res = _SPI_execute_plan(&plan, NULL, NULL,
 							InvalidSnapshot, InvalidSnapshot,
-							read_only, tcount);
+							read_only, true, tcount);
 
 	_SPI_end_call(true);
 	return res;
@@ -334,7 +334,7 @@ SPI_execute_plan(void *plan, Datum *Values, const char *Nulls,
 	res = _SPI_execute_plan((_SPI_plan *) plan,
 							Values, Nulls,
 							InvalidSnapshot, InvalidSnapshot,
-							read_only, tcount);
+							read_only, true, tcount);
 
 	_SPI_end_call(true);
 	return res;
@@ -349,9 +349,12 @@ SPI_execp(void *plan, Datum *Values, const char *Nulls, int tcount)
 
 /*
  * SPI_execute_snapshot -- identical to SPI_execute_plan, except that we allow
- * the caller to specify exactly which snapshots to use.  This is currently
- * not documented in spi.sgml because it is only intended for use by RI
- * triggers.
+ * the caller to specify exactly which snapshots to use.  Also, the caller
+ * may specify that AFTER triggers should be queued as part of the outer
+ * query rather than being fired immediately at the end of the command.
+ *
+ * This is currently not documented in spi.sgml because it is only intended
+ * for use by RI triggers.
  *
  * Passing snapshot == InvalidSnapshot will select the normal behavior of
  * fetching a new snapshot for each query.
@@ -360,7 +363,7 @@ int
 SPI_execute_snapshot(void *plan,
 					 Datum *Values, const char *Nulls,
 					 Snapshot snapshot, Snapshot crosscheck_snapshot,
-					 bool read_only, int tcount)
+					 bool read_only, bool fire_triggers, int tcount)
 {
 	int			res;
 
@@ -377,7 +380,7 @@ SPI_execute_snapshot(void *plan,
 	res = _SPI_execute_plan((_SPI_plan *) plan,
 							Values, Nulls,
 							snapshot, crosscheck_snapshot,
-							read_only, tcount);
+							read_only, fire_triggers, tcount);
 
 	_SPI_end_call(true);
 	return res;
@@ -1317,12 +1320,14 @@ _SPI_prepare_plan(const char *src, _SPI_plan *plan)
  *		behavior of taking a new snapshot for each query.
  * crosscheck_snapshot: for RI use, all others pass InvalidSnapshot
  * read_only: TRUE for read-only execution (no CommandCounterIncrement)
+ * fire_triggers: TRUE to fire AFTER triggers at end of query (normal case);
+ *		FALSE means any AFTER triggers are postponed to end of outer query
  * tcount: execution tuple-count limit, or 0 for none
  */
 static int
 _SPI_execute_plan(_SPI_plan *plan, Datum *Values, const char *Nulls,
 				  Snapshot snapshot, Snapshot crosscheck_snapshot,
-				  bool read_only, int tcount)
+				  bool read_only, bool fire_triggers, int tcount)
 {
 	volatile int res = 0;
 	Snapshot	saveActiveSnapshot;
@@ -1473,7 +1478,7 @@ _SPI_execute_plan(_SPI_plan *plan, Datum *Values, const char *Nulls,
 											crosscheck_snapshot,
 											dest,
 											paramLI, false);
-					res = _SPI_pquery(qdesc,
+					res = _SPI_pquery(qdesc, fire_triggers,
 									  queryTree->canSetTag ? tcount : 0);
 					FreeQueryDesc(qdesc);
 				}
@@ -1506,7 +1511,7 @@ fail:
 }
 
 static int
-_SPI_pquery(QueryDesc *queryDesc, int tcount)
+_SPI_pquery(QueryDesc *queryDesc, bool fire_triggers, int tcount)
 {
 	int			operation = queryDesc->operation;
 	int			res;
@@ -1540,7 +1545,8 @@ _SPI_pquery(QueryDesc *queryDesc, int tcount)
 		ResetUsage();
 #endif
 
-	AfterTriggerBeginQuery();
+	if (fire_triggers)
+		AfterTriggerBeginQuery();
 
 	ExecutorStart(queryDesc, false);
 
@@ -1558,7 +1564,8 @@ _SPI_pquery(QueryDesc *queryDesc, int tcount)
 	ExecutorEnd(queryDesc);
 
 	/* Take care of any queued AFTER triggers */
-	AfterTriggerEndQuery();
+	if (fire_triggers)
+		AfterTriggerEndQuery();
 
 	if (queryDesc->dest->mydest == SPI)
 	{