reduce compare

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

Author: HuSharp

tikv/kv.go

@@ -547,7 +547,7 @@ func (s *KVStore) updateSafeTS(ctx context.Context) {
 	tikvClient := s.GetTiKVClient()
 	wg := &sync.WaitGroup{}
 	wg.Add(len(stores))
-	safeTS, txnScopeMap, err := s.buildTxnScopeMap(ctx)
+	safeTS, txnScopeMap, err := s.buildTxnScopeMap(ctx, stores)
 	for _, store := range stores {
 		storeID := store.StoreID()
 		storeAddr := store.GetAddr()
@@ -591,19 +591,22 @@ func (s *KVStore) updateSafeTS(ctx context.Context) {
 		}(ctx, wg, storeID, storeAddr)
 	}
 
-	for txnScope, storeIDs := range txnScopeMap {
-		s.updateMinSafeTS(txnScope, storeIDs)
+	if safeTS != 0 && err == nil {
+		s.minSafeTS.Store(oracle.GlobalTxnScope, safeTS)
+	} else {
+		for txnScope, storeIDs := range txnScopeMap {
+			s.updateMinSafeTS(txnScope, storeIDs)
+		}
 	}
 	wg.Wait()
 }
 
 // build txnScopeMap and judge whether it is needed to get safeTS from PD.
 // - if stores label are global, return get cluster min resolved ts from pd.
 // - if contains dc label store, return try to get it from TiKV.
-func (s *KVStore) buildTxnScopeMap(ctx context.Context) (safeTS uint64, txnScopeMap map[string][]uint64, err error) {
+func (s *KVStore) buildTxnScopeMap(ctx context.Context, stores []*Store) (safeTS uint64, txnScopeMap map[string][]uint64, err error) {
 	isGlobal := true
 	txnScopeMap = make(map[string][]uint64)
-	stores := s.regionCache.GetStoresByType(tikvrpc.TiKV)
 	for _, store := range stores {
 		txnScopeMap[oracle.GlobalTxnScope] = append(txnScopeMap[oracle.GlobalTxnScope], store.StoreID())