skip down stores

Signed-off-by: hehechen <[email protected]>

domain/infosync/tiflash_manager.go

@@ -31,6 +31,7 @@ import (
 
 	"github.com/gorilla/mux"
 	"github.com/pingcap/errors"
+	"github.com/pingcap/kvproto/pkg/metapb"
 	"github.com/pingcap/tidb/ddl/placement"
 	"github.com/pingcap/tidb/store/helper"
 	"github.com/pingcap/tidb/tablecodec"
@@ -92,7 +93,11 @@ func getTiFlashPeerWithoutLagCount(tiFlashStores map[int64]helper.StoreStat, tab
 		if err != nil {
 			logutil.BgLogger().Error("Fail to get peer status from TiFlash.",
 				zap.Int64("tableID", tableID))
-			return 0, err
+			// Just skip down or offline or tomestone stores, because PD will migrate regions from these stores.
+			if store.Store.State == int64(metapb.StoreState_Up) && store.Store.StateName != "Down" {
+				return 0, err
+			}
+			continue
 		}
 		flashPeerCount += len(regionReplica)
 	}