diff --git a/src/backend/access/transam/multixact.c b/src/backend/access/transam/multixact.c
index 675affe4f76..c601ff98a14 100644
--- a/src/backend/access/transam/multixact.c
+++ b/src/backend/access/transam/multixact.c
@@ -3050,7 +3050,8 @@ PerformMembersTruncation(MultiXactOffset oldestOffset, MultiXactOffset newOldest
 	 */
 	while (segment != endsegment)
 	{
-		elog(DEBUG2, "truncating multixact members segment %x", segment);
+		elog(DEBUG2, "truncating multixact members segment %llx",
+			 (unsigned long long) segment);
 		SlruDeleteSegment(MultiXactMemberCtl, segment);
 
 		/* move to next segment, handling wraparound correctly */
@@ -3201,14 +3202,14 @@ TruncateMultiXact(MultiXactId newOldestMulti, Oid newOldestMultiDB)
 	}
 
 	elog(DEBUG1, "performing multixact truncation: "
-		 "offsets [%u, %u), offsets segments [%x, %x), "
-		 "members [%u, %u), members segments [%x, %x)",
+		 "offsets [%u, %u), offsets segments [%llx, %llx), "
+		 "members [%u, %u), members segments [%llx, %llx)",
 		 oldestMulti, newOldestMulti,
-		 MultiXactIdToOffsetSegment(oldestMulti),
-		 MultiXactIdToOffsetSegment(newOldestMulti),
+		 (unsigned long long) MultiXactIdToOffsetSegment(oldestMulti),
+		 (unsigned long long) MultiXactIdToOffsetSegment(newOldestMulti),
 		 oldestOffset, newOldestOffset,
-		 MXOffsetToMemberSegment(oldestOffset),
-		 MXOffsetToMemberSegment(newOldestOffset));
+		 (unsigned long long) MXOffsetToMemberSegment(oldestOffset),
+		 (unsigned long long) MXOffsetToMemberSegment(newOldestOffset));
 
 	/*
 	 * Do truncation, and the WAL logging of the truncation, in a critical
@@ -3461,14 +3462,14 @@ multixact_redo(XLogReaderState *record)
 			   SizeOfMultiXactTruncate);
 
 		elog(DEBUG1, "replaying multixact truncation: "
-			 "offsets [%u, %u), offsets segments [%x, %x), "
-			 "members [%u, %u), members segments [%x, %x)",
+			 "offsets [%u, %u), offsets segments [%llx, %llx), "
+			 "members [%u, %u), members segments [%llx, %llx)",
 			 xlrec.startTruncOff, xlrec.endTruncOff,
-			 MultiXactIdToOffsetSegment(xlrec.startTruncOff),
-			 MultiXactIdToOffsetSegment(xlrec.endTruncOff),
+			 (unsigned long long) MultiXactIdToOffsetSegment(xlrec.startTruncOff),
+			 (unsigned long long) MultiXactIdToOffsetSegment(xlrec.endTruncOff),
 			 xlrec.startTruncMemb, xlrec.endTruncMemb,
-			 MXOffsetToMemberSegment(xlrec.startTruncMemb),
-			 MXOffsetToMemberSegment(xlrec.endTruncMemb));
+			 (unsigned long long) MXOffsetToMemberSegment(xlrec.startTruncMemb),
+			 (unsigned long long) MXOffsetToMemberSegment(xlrec.endTruncMemb));
 
 		/* should not be required, but more than cheap enough */
 		LWLockAcquire(MultiXactTruncationLock, LW_EXCLUSIVE);