Andres Freund wrote:
> static void
> heap_xlog_lock(XLogRecPtr lsn, XLogRecord *record)
> {
> ...
> HeapTupleHeaderClearHotUpdated(htup);
> HeapTupleHeaderSetXmax(htup, xlrec->locking_xid);
> HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
> /* Make sure there is no forward chain link in t_ctid */
> htup->t_ctid = xlrec->target.tid;
> ...
> }
I think the fix is to reset HOT_UPDATED and t_ctid only if the infomask
says the tuple is LOCKED_ONLY, per the attached patch. This matches
what heap_lock_tuple is doing originally:
if (HEAP_XMAX_IS_LOCKED_ONLY(new_infomask))
HeapTupleHeaderClearHotUpdated(tuple->t_data);
HeapTupleHeaderSetXmax(tuple->t_data, xid);
/*
* Make sure there is no forward chain link in t_ctid. Note that in the
* cases where the tuple has been updated, we must not overwrite t_ctid,
* because it was set by the updater. Moreover, if the tuple has been
* updated, we need to follow the update chain to lock the new versions
of
* the tuple as well.
*/
if (HEAP_XMAX_IS_LOCKED_ONLY(new_infomask))
tuple->t_data->t_ctid = *tid;
--
Álvaro Herrera http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Training & Services
diff --git a/src/backend/access/heap/heapam.c b/src/backend/access/heap/heapam.c
index a771ccb..6d1f9e0 100644
--- a/src/backend/access/heap/heapam.c
+++ b/src/backend/access/heap/heapam.c
@@ -8016,11 +8016,14 @@ heap_xlog_lock(XLogRecPtr lsn, XLogRecord *record)
fix_infomask_from_infobits(xlrec->infobits_set, &htup->t_infomask,
&htup->t_infomask2);
- HeapTupleHeaderClearHotUpdated(htup);
+ if (HEAP_XMAX_IS_LOCKED_ONLY(htup->t_infomask))
+ {
+ HeapTupleHeaderClearHotUpdated(htup);
+ /* Make sure there is no forward chain link in t_ctid */
+ htup->t_ctid = xlrec->target.tid;
+ }
HeapTupleHeaderSetXmax(htup, xlrec->locking_xid);
HeapTupleHeaderSetCmax(htup, FirstCommandId, false);
- /* Make sure there is no forward chain link in t_ctid */
- htup->t_ctid = xlrec->target.tid;
PageSetLSN(page, lsn);
MarkBufferDirty(buffer);
UnlockReleaseBuffer(buffer);
--
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