diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 49637284f91..a6f1df11066 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -1355,6 +1355,7 @@ WaitReadBuffers(ReadBuffersOperation *operation)
 	IOContext	io_context;
 	IOObject	io_object;
 	char		persistence;
+	static int  double_counts = 0;
 
 	/*
 	 * Currently operations are only allowed to include a read of some range,
@@ -1426,6 +1427,7 @@ WaitReadBuffers(ReadBuffersOperation *operation)
 											  operation->smgr->smgr_rlocator.locator.relNumber,
 											  operation->smgr->smgr_rlocator.backend,
 											  true);
+			double_counts++;
 			continue;
 		}
 
@@ -1523,6 +1525,7 @@ WaitReadBuffers(ReadBuffersOperation *operation)
 		if (VacuumCostActive)
 			VacuumCostBalance += VacuumCostPageMiss * io_buffers_len;
 	}
+	elog(LOG, "Double counts = %d", double_counts);
 }
 
 /*