Re: HeapTuple header changes cause core dumps in CVS tip

On Mon, 15 Jul 2002 16:46:44 -0400, Tom Lane 
wrote:
>regression=# update foo set f1 = 'qq';
>server closed the connection unexpectedly

Same with DELETE FROM foo;

>I am not sure if this is a bug introduced by the patch, or if it's
>exposed a previously lurking bug.

I suspect the former :-(

>It seems that the HEAP_MOVED bits
>should be cleared before re-using cmax for something else, but I have
>not dug through the old logic to see how it was done before.

AFAICS from a quick look at tqual it didn't matter before.  Once the
vacuum transaction had committed, on the next access to the tuple
MOVED_IN caused XMIN_COMMITTED to be set, and after that the MOVED
bits were never looked at again.  MOVED_OFF is not an issue.

I'll take a closer look at tqual and the vacuum source code tomorrow.
For now the attached patch cures both symptoms (UPDATE and DELETE) and
passes all regression tests.  A regression test for this case will
follow.

Servus
 Manfred
diff -ruN ../base/src/backend/access/heap/heapam.c src/backend/access/heap/heapam.c
--- ../base/src/backend/access/heap/heapam.c	2002-07-15 22:22:28.000000000 +0200
+++ src/backend/access/heap/heapam.c	2002-07-16 00:16:59.000000000 +0200
@@ -1123,11 +1123,11 @@
 			CheckMaxObjectId(HeapTupleGetOid(tup));
 	}
 
+	tup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
 	HeapTupleHeaderSetXmin(tup->t_data, GetCurrentTransactionId());
 	HeapTupleHeaderSetCmin(tup->t_data, cid);
 	HeapTupleHeaderSetXmaxInvalid(tup->t_data);
-	HeapTupleHeaderSetCmax(tup->t_data, FirstCommandId);
-	tup->t_data->t_infomask &= ~(HEAP_XACT_MASK);
+	/* HeapTupleHeaderSetCmax(tup->t_data, FirstCommandId); */
 	tup->t_data->t_infomask |= HEAP_XMAX_INVALID;
 	tup->t_tableOid = relation->rd_id;
 
@@ -1321,7 +1321,7 @@
 
 	START_CRIT_SECTION();
 	/* store transaction information of xact deleting the tuple */
-	tp.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
+	tp.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_MOVED |
 							 HEAP_XMAX_INVALID | HEAP_MARKED_FOR_UPDATE);
 	HeapTupleHeaderSetXmax(tp.t_data, GetCurrentTransactionId());
 	HeapTupleHeaderSetCmax(tp.t_data, cid);
@@ -1554,7 +1554,7 @@
 		_locked_tuple_.tid = oldtup.t_self;
 		XactPushRollback(_heap_unlock_tuple, (void *) &_locked_tuple_);
 
-		oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
+		oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_MOVED |
 									   HEAP_XMAX_INVALID |
 									   HEAP_MARKED_FOR_UPDATE);
 		oldtup.t_data->t_infomask |= HEAP_XMAX_UNLOGGED;
@@ -1645,7 +1645,7 @@
 	}
 	else
 	{
-		oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED |
+		oldtup.t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_MOVED |
 									   HEAP_XMAX_INVALID |
 									   HEAP_MARKED_FOR_UPDATE);
 		HeapTupleHeaderSetXmax(oldtup.t_data, GetCurrentTransactionId());
@@ -1816,7 +1816,7 @@
 	((PageHeader) BufferGetPage(*buffer))->pd_sui = ThisStartUpID;
 
 	/* store transaction information of xact marking the tuple */
-	tuple->t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID);
+	tuple->t_data->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_XMAX_INVALID | HEAP_MOVED);
 	tuple->t_data->t_infomask |= HEAP_MARKED_FOR_UPDATE;
 	HeapTupleHeaderSetXmax(tuple->t_data, GetCurrentTransactionId());
 	HeapTupleHeaderSetCmax(tuple->t_data, cid);
@@ -2147,7 +2147,7 @@
 
 	if (redo)
 	{
-		htup->t_infomask &= ~(HEAP_XMAX_COMMITTED |
+		htup->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_MOVED |
 							  HEAP_XMAX_INVALID | HEAP_MARKED_FOR_UPDATE);
 		HeapTupleHeaderSetXmax(htup, record->xl_xid);
 		HeapTupleHeaderSetCmax(htup, FirstCommandId);
@@ -2320,7 +2320,7 @@
 		}
 		else
 		{
-			htup->t_infomask &= ~(HEAP_XMAX_COMMITTED |
+			htup->t_infomask &= ~(HEAP_XMAX_COMMITTED | HEAP_MOVED |
 							 HEAP_XMAX_INVALID | HEAP_MARKED_FOR_UPDATE);
 			HeapTupleHeaderSetXmax(htup, record->xl_xid);
 			HeapTupleHeaderSetCmax(htup, FirstCommandId);