[schedulers]: get stores only once

server/cluster/coordinator.go

@@ -23,6 +23,8 @@ import (
 	"sync/atomic"
 	"time"
 
+	"github.com/tikv/pd/server/schedule/opt"
+
 	"github.com/pingcap/errors"
 	"github.com/pingcap/failpoint"
 	"github.com/pingcap/log"
@@ -821,8 +823,9 @@ func (s *scheduleController) Stop() {
 
 func (s *scheduleController) Schedule() []*operator.Operator {
 	for i := 0; i < maxScheduleRetries; i++ {
+		cacheCluster := opt.NewCacheCluster(s.cluster)
 		// If we have schedule, reset interval to the minimal interval.
-		if op := s.Scheduler.Schedule(s.cluster); op != nil {
+		if op := s.Scheduler.Schedule(cacheCluster); op != nil {
 			s.nextInterval = s.Scheduler.GetMinInterval()
 			return op
 		}

server/schedule/opt/opts.go

@@ -47,6 +47,25 @@ type Cluster interface {
 	AddSuspectRegions(ids ...uint64)
 }
 
+// cacheCluster include cache info
+type cacheCluster struct {
+	Cluster
+	stores []*core.StoreInfo
+}
+
+// GetStores returns store infos from cache
+func (c *cacheCluster) GetStores() []*core.StoreInfo {
+	return c.stores
+}
+
+// NewCacheCluster constructor for cache
+func NewCacheCluster(c Cluster) Cluster {
+	return &cacheCluster{
+		Cluster: c,
+		stores:  c.GetStores(),
+	}
+}
+
 // HeartbeatStream is an interface.
 type HeartbeatStream interface {
 	Send(*pdpb.RegionHeartbeatResponse) error