diff --git a/src/backend/storage/buffer/bufmgr.c b/src/backend/storage/buffer/bufmgr.c
index 9b0283fa518..c60158d675f 100644
--- a/src/backend/storage/buffer/bufmgr.c
+++ b/src/backend/storage/buffer/bufmgr.c
@@ -2474,6 +2474,7 @@ SetBufferCommitInfoNeedsSave(Buffer buffer)
 		{
 			/* Do vacuum cost accounting */
 			VacuumPageDirty++;
+			pgBufferUsage.shared_blks_dirtied++;
 			if (VacuumCostActive)
 				VacuumCostBalance += VacuumCostPageDirty;
 		}