Get rid of ReferentialIntegritySnapshotOverride by extending Executor API

to allow es_snapshot to be set to SnapshotNow rather than a query snapshot.
This solves a bug reported by Wade Klaver, wherein triggers fired as a
result of RI cascade updates could misbehave.

2 files changed, 9 insertions, 36 deletions

diff --git a/src/backend/utils/adt/ri_triggers.c b/src/backend/utils/adt/ri_triggers.c
index 877034519c1..6250995e1b8 100644
--- a/src/backend/utils/adt/ri_triggers.c
+++ b/src/backend/utils/adt/ri_triggers.c
@@ -17,7 +17,7 @@
  *
  * Portions Copyright (c) 1996-2003, PostgreSQL Global Development Group
  *
- * $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.57 2003/09/25 06:58:04 petere Exp $
+ * $Header: /cvsroot/pgsql/src/backend/utils/adt/ri_triggers.c,v 1.58 2003/09/25 18:58:35 tgl Exp $
  *
  * ----------
  */
@@ -187,8 +187,6 @@ RI_FKey_check(PG_FUNCTION_ARGS)
 	int			i;
 	int			match_type;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -627,8 +625,6 @@ RI_FKey_noaction_del(PG_FUNCTION_ARGS)
 	int			i;
 	int			match_type;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -807,8 +803,6 @@ RI_FKey_noaction_upd(PG_FUNCTION_ARGS)
 	int			i;
 	int			match_type;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -995,8 +989,6 @@ RI_FKey_cascade_del(PG_FUNCTION_ARGS)
 	void	   *qplan;
 	int			i;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -1159,8 +1151,6 @@ RI_FKey_cascade_upd(PG_FUNCTION_ARGS)
 	int			i;
 	int			j;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -1349,8 +1339,6 @@ RI_FKey_restrict_del(PG_FUNCTION_ARGS)
 	void	   *qplan;
 	int			i;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -1520,8 +1508,6 @@ RI_FKey_restrict_upd(PG_FUNCTION_ARGS)
 	void	   *qplan;
 	int			i;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -1694,8 +1680,6 @@ RI_FKey_setnull_del(PG_FUNCTION_ARGS)
 	void	   *qplan;
 	int			i;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -1868,8 +1852,6 @@ RI_FKey_setnull_upd(PG_FUNCTION_ARGS)
 	int			match_type;
 	bool		use_cached_query;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -2083,8 +2065,6 @@ RI_FKey_setdefault_del(PG_FUNCTION_ARGS)
 	RI_QueryKey qkey;
 	void	   *qplan;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -2296,8 +2276,6 @@ RI_FKey_setdefault_upd(PG_FUNCTION_ARGS)
 	void	   *qplan;
 	int			match_type;
 
-	ReferentialIntegritySnapshotOverride = true;
-
 	/*
 	 * Check that this is a valid trigger call on the right time and
 	 * event.
@@ -2936,15 +2914,19 @@ ri_PerformCheck(RI_QueryKey *qkey, void *qplan,
 	 */
 	limit = (expect_OK == SPI_OK_SELECT) ? 1 : 0;
 
-	/* Run the plan */
-	spi_result = SPI_execp(qplan, vals, nulls, limit);
+	/*
+	 * Run the plan, using SnapshotNow time qual rules so that we can see
+	 * all committed tuples, even those committed after our own transaction
+	 * or query started.
+	 */
+	spi_result = SPI_execp_now(qplan, vals, nulls, limit);
 
 	/* Restore UID */
 	SetUserId(save_uid);
 
 	/* Check result */
 	if (spi_result < 0)
-		elog(ERROR, "SPI_execp failed");
+		elog(ERROR, "SPI_execp_now returned %d", spi_result);
 
 	if (expect_OK >= 0 && spi_result != expect_OK)
 		ri_ReportViolation(qkey, constrname ? constrname : "",
diff --git a/src/backend/utils/time/tqual.c b/src/backend/utils/time/tqual.c
index 6a1ab38d14a..5b594fcf680 100644
--- a/src/backend/utils/time/tqual.c
+++ b/src/backend/utils/time/tqual.c
@@ -16,7 +16,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.68 2003/09/22 00:47:23 tgl Exp $
+ *	  $Header: /cvsroot/pgsql/src/backend/utils/time/tqual.c,v 1.69 2003/09/25 18:58:35 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -39,8 +39,6 @@ Snapshot	SerializableSnapshot = NULL;
 TransactionId RecentXmin = InvalidTransactionId;
 TransactionId RecentGlobalXmin = InvalidTransactionId;
 
-bool		ReferentialIntegritySnapshotOverride = false;
-
 
 /*
  * HeapTupleSatisfiesItself
@@ -665,10 +663,6 @@ HeapTupleSatisfiesDirty(HeapTupleHeader tuple)
 bool
 HeapTupleSatisfiesSnapshot(HeapTupleHeader tuple, Snapshot snapshot)
 {
-	/* XXX this is horribly ugly: */
-	if (ReferentialIntegritySnapshotOverride)
-		return HeapTupleSatisfiesNow(tuple);
-
 	if (!(tuple->t_infomask & HEAP_XMIN_COMMITTED))
 	{
 		if (tuple->t_infomask & HEAP_XMIN_INVALID)
@@ -978,9 +972,6 @@ HeapTupleSatisfiesVacuum(HeapTupleHeader tuple, TransactionId OldestXmin)
 void
 SetQuerySnapshot(void)
 {
-	/* Initialize snapshot overriding to false */
-	ReferentialIntegritySnapshotOverride = false;
-
 	/* 1st call in xaction? */
 	if (SerializableSnapshot == NULL)
 	{