Added hint bits horizon

Author: homper

src/backend/access/heap/heapam_visibility.c

@@ -78,6 +78,8 @@
 #include "utils/builtins.h"
 #include "utils/snapmgr.h"
 
+static TransactionId hint_bit_horizon = InvalidTransactionId;
+
 
 /*
  * SetHintBits()
@@ -127,6 +129,11 @@ SetHintBits(HeapTupleHeader tuple, Buffer buffer,
 		}
 	}
 
+	if (TransactionIdIsValid(hint_bit_horizon) &&
+		TransactionIdIsValid(xid) &&
+		TransactionIdFollows(xid, hint_bit_horizon))
+		return;
+
 	tuple->t_infomask |= infomask;
 	MarkBufferDirtyHint(buffer, true);
 }
@@ -1786,3 +1793,9 @@ HeapTupleSatisfiesVisibility(HeapTuple htup, Snapshot snapshot, Buffer buffer)
 
 	return false;				/* keep compiler quiet */
 }
+
+void
+SetHintBitsHorizon(TransactionId new_horizon)
+{
+	hint_bit_horizon = new_horizon;
+}

src/include/access/heapam.h

@@ -412,6 +412,8 @@ extern bool HeapTupleHeaderIsOnlyLocked(HeapTupleHeader tuple);
 extern bool HeapTupleIsSurelyDead(HeapTuple htup,
 								  struct GlobalVisState *vistest);
 
+extern void SetHintBitsHorizon(TransactionId new_horizon);
+
 /*
  * To avoid leaking too much knowledge about reorderbuffer implementation
  * details this is implemented in reorderbuffer.c not heapam_visibility.c