diff --git a/src/jrd/DatabaseSnapshot.cpp b/src/jrd/DatabaseSnapshot.cpp
index 22d23c0270..b27e036245 100644
--- a/src/jrd/DatabaseSnapshot.cpp
+++ b/src/jrd/DatabaseSnapshot.cpp
@@ -423,7 +423,7 @@ DatabaseSnapshot::DatabaseSnapshot(thread_db* tdbb, MemoryPool& pool)
 	}
 
 	// Signal other processes to dump their data
-	Lock temp_lock(tdbb, sizeof(SLONG), LCK_monitor), *lock = &temp_lock;
+	Lock temp_lock(tdbb, 0, LCK_monitor), *lock = &temp_lock;
 
 	if (LCK_lock(tdbb, lock, LCK_EX, LCK_WAIT))
 		LCK_release(tdbb, lock);