scheduler: keep rank-formula-version at v1 when upgrading from a lowe…

…r version (#5699)

close #5698

Signed-off-by: HunDunDM <hundundm@gmail.com>

Co-authored-by: Ti Chi Robot <ti-community-prow-bot@tidb.io>

server/schedulers/hot_region.go

@@ -53,8 +53,12 @@ func init() {
 		}
 		if len(data) != 0 {
 			// After upgrading, use compatible config.
+
 			// For clusters with the initial version >= v5.2, it will be overwritten by the default config.
 			conf.applyPrioritiesConfig(compatiblePrioritiesConfig)
+			// For clusters with the initial version >= v6.4, it will be overwritten by the default config.
+			conf.SetRankFormulaVersion("")
+
 			if err := decoder(conf); err != nil {
 				return nil, err
 			}

server/schedulers/hot_region_test.go

@@ -67,6 +67,48 @@ func clearPendingInfluence(h *hotScheduler) {
 	h.regionPendings = make(map[uint64]*pendingInfluence)
 }
 
+func TestUpgrade(t *testing.T) {
+	re := require.New(t)
+	ctx, cancel := context.WithCancel(context.Background())
+	defer cancel()
+	opt := config.NewTestOptions()
+	tc := mockcluster.NewCluster(ctx, opt)
+	// new
+	sche, err := schedule.CreateScheduler(HotRegionType, schedule.NewOperatorController(ctx, tc, nil), storage.NewStorageWithMemoryBackend(), schedule.ConfigSliceDecoder(HotRegionType, nil))
+	re.NoError(err)
+	hb := sche.(*hotScheduler)
+	re.Equal([]string{statistics.QueryPriority, statistics.BytePriority}, hb.conf.GetReadPriorities())
+	re.Equal([]string{statistics.QueryPriority, statistics.BytePriority}, hb.conf.GetWriteLeaderPriorities())
+	re.Equal([]string{statistics.BytePriority, statistics.KeyPriority}, hb.conf.GetWritePeerPriorities())
+	re.Equal("v2", hb.conf.GetRankFormulaVersion())
+	// upgrade from json(null)
+	sche, err = schedule.CreateScheduler(HotRegionType, schedule.NewOperatorController(ctx, tc, nil), storage.NewStorageWithMemoryBackend(), schedule.ConfigJSONDecoder([]byte("null")))
+	re.NoError(err)
+	hb = sche.(*hotScheduler)
+	re.Equal([]string{statistics.QueryPriority, statistics.BytePriority}, hb.conf.GetReadPriorities())
+	re.Equal([]string{statistics.QueryPriority, statistics.BytePriority}, hb.conf.GetWriteLeaderPriorities())
+	re.Equal([]string{statistics.BytePriority, statistics.KeyPriority}, hb.conf.GetWritePeerPriorities())
+	re.Equal("v2", hb.conf.GetRankFormulaVersion())
+	// upgrade from < 5.2
+	config51 := `{"min-hot-byte-rate":100,"min-hot-key-rate":10,"min-hot-query-rate":10,"max-zombie-rounds":5,"max-peer-number":1000,"byte-rate-rank-step-ratio":0.05,"key-rate-rank-step-ratio":0.05,"query-rate-rank-step-ratio":0.05,"count-rank-step-ratio":0.01,"great-dec-ratio":0.95,"minor-dec-ratio":0.99,"src-tolerance-ratio":1.05,"dst-tolerance-ratio":1.05,"strict-picking-store":"true","enable-for-tiflash":"true"}`
+	sche, err = schedule.CreateScheduler(HotRegionType, schedule.NewOperatorController(ctx, tc, nil), storage.NewStorageWithMemoryBackend(), schedule.ConfigJSONDecoder([]byte(config51)))
+	re.NoError(err)
+	hb = sche.(*hotScheduler)
+	re.Equal([]string{statistics.BytePriority, statistics.KeyPriority}, hb.conf.GetReadPriorities())
+	re.Equal([]string{statistics.KeyPriority, statistics.BytePriority}, hb.conf.GetWriteLeaderPriorities())
+	re.Equal([]string{statistics.BytePriority, statistics.KeyPriority}, hb.conf.GetWritePeerPriorities())
+	re.Equal("v1", hb.conf.GetRankFormulaVersion())
+	// upgrade from < 6.4
+	config54 := `{"min-hot-byte-rate":100,"min-hot-key-rate":10,"min-hot-query-rate":10,"max-zombie-rounds":5,"max-peer-number":1000,"byte-rate-rank-step-ratio":0.05,"key-rate-rank-step-ratio":0.05,"query-rate-rank-step-ratio":0.05,"count-rank-step-ratio":0.01,"great-dec-ratio":0.95,"minor-dec-ratio":0.99,"src-tolerance-ratio":1.05,"dst-tolerance-ratio":1.05,"read-priorities":["query","byte"],"write-leader-priorities":["query","byte"],"write-peer-priorities":["byte","key"],"strict-picking-store":"true","enable-for-tiflash":"true","forbid-rw-type":"none"}`
+	sche, err = schedule.CreateScheduler(HotRegionType, schedule.NewOperatorController(ctx, tc, nil), storage.NewStorageWithMemoryBackend(), schedule.ConfigJSONDecoder([]byte(config54)))
+	re.NoError(err)
+	hb = sche.(*hotScheduler)
+	re.Equal([]string{statistics.QueryPriority, statistics.BytePriority}, hb.conf.GetReadPriorities())
+	re.Equal([]string{statistics.QueryPriority, statistics.BytePriority}, hb.conf.GetWriteLeaderPriorities())
+	re.Equal([]string{statistics.BytePriority, statistics.KeyPriority}, hb.conf.GetWritePeerPriorities())
+	re.Equal("v1", hb.conf.GetRankFormulaVersion())
+}
+
 func TestGCPendingOpInfos(t *testing.T) {
 	re := require.New(t)
 	ctx, cancel := context.WithCancel(context.Background())