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commit    b8a606e21b0619ac378558bdd258c54aee7cb4ed
Author:   Heikki Linnakangas <heikki.linnakangas@iki.fi>
Date:     Tue Nov 28 09:59:09 2023 +0000
First released in: 17.0, 12.18, 13.14, 14.11, 15.6, 16.2

    Fix assertions with RI triggers in heap_update and heap_delete.
    
    If the tuple being updated is not visible to the crosscheck snapshot,
    we return TM_Updated but the assertions would not hold in that case.
    Move them to before the cross-check.
    
    Fixes bug #17893. Backpatch to all supported versions.
    
    Author: Alexander Lakhin
    Backpatch-through: 12
    Discussion: https://www.postgresql.org/message-id/17893-35847009eec517b5%40postgresql.org


 src/backend/access/heap/heapam.c | 41 +++++++++++++++++++++++-----------------
 src/include/access/tableam.h     |  4 ++--
 2 files changed, 26 insertions(+), 19 deletions(-)

diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index 657af12a399..e1e54a265cf 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -2677,13 +2677,7 @@ l1:
 			result = TM_Deleted;
 	}
 
-	if (crosscheck != InvalidSnapshot && result == TM_Ok)
-	{
-		/* Perform additional check for transaction-snapshot mode RI updates */
-		if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
-			result = TM_Updated;
-	}
-
+	/* sanity check the result HeapTupleSatisfiesUpdate() and the logic above */
 	if (result != TM_Ok)
 	{
 		Assert(result == TM_SelfModified ||
@@ -2693,6 +2687,17 @@ l1:
 		Assert(!(tp.t_data->t_infomask & HEAP_XMAX_INVALID));
 		Assert(result != TM_Updated ||
 			   !ItemPointerEquals(&tp.t_self, &tp.t_data->t_ctid));
+	}
+
+	if (crosscheck != InvalidSnapshot && result == TM_Ok)
+	{
+		/* Perform additional check for transaction-snapshot mode RI updates */
+		if (!HeapTupleSatisfiesVisibility(&tp, crosscheck, buffer))
+			result = TM_Updated;
+	}
+
+	if (result != TM_Ok)
+	{
 		tmfd->ctid = tp.t_data->t_ctid;
 		tmfd->xmax = HeapTupleHeaderGetUpdateXid(tp.t_data);
 		if (result == TM_SelfModified)
@@ -3320,16 +3325,7 @@ l2:
 			result = TM_Deleted;
 	}
 
-	if (crosscheck != InvalidSnapshot && result == TM_Ok)
-	{
-		/* Perform additional check for transaction-snapshot mode RI updates */
-		if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
-		{
-			result = TM_Updated;
-			Assert(!ItemPointerEquals(&oldtup.t_self, &oldtup.t_data->t_ctid));
-		}
-	}
-
+	/* Sanity check the result HeapTupleSatisfiesUpdate() and the logic above */
 	if (result != TM_Ok)
 	{
 		Assert(result == TM_SelfModified ||
@@ -3339,6 +3335,17 @@ l2:
 		Assert(!(oldtup.t_data->t_infomask & HEAP_XMAX_INVALID));
 		Assert(result != TM_Updated ||
 			   !ItemPointerEquals(&oldtup.t_self, &oldtup.t_data->t_ctid));
+	}
+
+	if (crosscheck != InvalidSnapshot && result == TM_Ok)
+	{
+		/* Perform additional check for transaction-snapshot mode RI updates */
+		if (!HeapTupleSatisfiesVisibility(&oldtup, crosscheck, buffer))
+			result = TM_Updated;
+	}
+
+	if (result != TM_Ok)
+	{
 		tmfd->ctid = oldtup.t_data->t_ctid;
 		tmfd->xmax = HeapTupleHeaderGetUpdateXid(oldtup.t_data);
 		if (result == TM_SelfModified)
diff --git a/src/include/access/tableam.h b/src/include/access/tableam.h
index 5933012d183..29f67d51535 100644
--- a/src/include/access/tableam.h
+++ b/src/include/access/tableam.h
@@ -1220,8 +1220,8 @@ table_multi_insert(Relation rel, TupleTableSlot **slots, int nslots,
  * TM_BeingModified (the last only possible if wait == false).
  *
  * In the failure cases, the routine fills *tmfd with the tuple's t_ctid,
- * t_xmax, and, if possible, and, if possible, t_cmax.  See comments for
- * struct TM_FailureData for additional info.
+ * t_xmax, and, if possible, t_cmax.  See comments for struct
+ * TM_FailureData for additional info.
  */
 static inline TM_Result
 table_tuple_delete(Relation rel, ItemPointer tid, CommandId cid,


[parent: a5e95ff46f58]