worker, utils: show same master status

dm/worker/server.go

@@ -15,6 +15,7 @@ package worker
 
 import (
 	"context"
+	"github.com/pingcap/dm/pkg/utils"
 	"io"
 	"net"
 	"sync"
@@ -250,12 +251,14 @@ func (s *Server) QueryTaskOperation(ctx context.Context, req *pb.QueryTaskOperat
 func (s *Server) QueryStatus(ctx context.Context, req *pb.QueryStatusRequest) (*pb.QueryStatusResponse, error) {
 	log.L().Info("", zap.String("request", "QueryStatus"), zap.Stringer("payload", req))
 
+	utils.EnableMasterStatusCache()
 	resp := &pb.QueryStatusResponse{
 		Result:        true,
 		SubTaskStatus: s.worker.QueryStatus(req.Name),
 		RelayStatus:   s.worker.relayHolder.Status(),
 		SourceID:      s.worker.cfg.SourceID,
 	}
+	utils.DisableMasterStatusCache()
 
 	if len(resp.SubTaskStatus) == 0 {
 		resp.Msg = "no sub task started"

pkg/utils/db.go

@@ -19,6 +19,7 @@ import (
 	"fmt"
 	"strconv"
 	"strings"
+	"sync"
 
 	"github.com/pingcap/dm/pkg/gtid"
 	"github.com/pingcap/dm/pkg/log"
@@ -135,8 +136,36 @@ func GetSlaveServerID(ctx context.Context, db *sql.DB) (map[uint32]struct{}, err
 	return serverIDs, nil
 }
 
+var (
+	useMasterStatusCache bool
+	masterMu             sync.Mutex
+	masterStatusCached bool
+	masterPosCache  gmysql.Position
+	masterGTIDCache gtid.Set
+)
+
+func EnableMasterStatusCache() {
+	masterMu.Lock()
+	defer masterMu.Unlock()
+	useMasterStatusCache = true
+	masterStatusCached = false
+}
+
+func DisableMasterStatusCache() {
+	masterMu.Lock()
+	defer masterMu.Unlock()
+	useMasterStatusCache = false
+}
+
 // GetMasterStatus gets status from master
 func GetMasterStatus(db *sql.DB, flavor string) (gmysql.Position, gtid.Set, error) {
+	masterMu.Lock()
+	defer masterMu.Unlock()
+
+	if useMasterStatusCache && masterStatusCached {
+		return masterPosCache, masterGTIDCache, nil
+	}
+
 	var (
 		binlogPos gmysql.Position
 		gs        gtid.Set
@@ -199,6 +228,12 @@ func GetMasterStatus(db *sql.DB, flavor string) (gmysql.Position, gtid.Set, erro
 		}
 	}
 
+	if useMasterStatusCache {
+		masterStatusCached = true
+		masterPosCache = binlogPos
+		masterGTIDCache = gs
+	}
+
 	return binlogPos, gs, nil
 }