config: introduce the dc-location config

server/config/config.go

@@ -31,6 +31,7 @@ import (
 	"github.com/tikv/pd/pkg/metricutil"
 	"github.com/tikv/pd/pkg/typeutil"
 	"github.com/tikv/pd/server/schedule/storelimit"
+	"github.com/tikv/pd/server/tso"
 	"github.com/tikv/pd/server/versioninfo"
 
 	"github.com/BurntSushi/toml"
@@ -82,8 +83,8 @@ type Config struct {
 	LogFileDeprecated  string `toml:"log-file" json:"log-file,omitempty"`
 	LogLevelDeprecated string `toml:"log-level" json:"log-level,omitempty"`
 
-	// TsoSaveInterval is the interval to save timestamp.
-	TsoSaveInterval typeutil.Duration `toml:"tso-save-interval" json:"tso-save-interval"`
+	// Tso service related configuration.
+	Tso TsoConfig `toml:"tso" json:"tso"`
 
 	Metric metricutil.MetricConfig `toml:"metric" json:"metric"`
 
@@ -492,7 +493,9 @@ func (c *Config) Adjust(meta *toml.MetaData) error {
 
 	adjustInt64(&c.LeaderLease, defaultLeaderLease)
 
-	adjustDuration(&c.TsoSaveInterval, time.Duration(defaultLeaderLease)*time.Second)
+	if err := c.Tso.adjust(); err != nil {
+		return err
+	}
 
 	if c.nextRetryDelay == 0 {
 		c.nextRetryDelay = defaultNextRetryDelay
@@ -1319,3 +1322,32 @@ func (c *DRAutoSyncReplicationConfig) adjust(meta *configMetaData) {
 		c.WaitSyncTimeout = typeutil.Duration{Duration: defaultDRWaitSyncTimeout}
 	}
 }
+
+// TsoConfig is the configuration for Tso service.
+type TsoConfig struct {
+	// TsoSaveInterval is the interval to save timestamp.
+	TsoSaveInterval typeutil.Duration `toml:"tso-save-interval" json:"tso-save-interval"`
+	// EnableLocalTso is used to enable the Local TSO Allocator feature,
+	// which allows the PD server to generate local Tso for certain DC-level transactions.
+	// To make this feature meaningful, user has to set the dc-location configuration for
+	// each PD server.
+	EnableLocalTso bool `toml:"enable-local-tso" json:"enable-local-tso"`
+	// DCLocation indicates that which data center a PD server is in. According to it,
+	// the PD cluster can elect a TSO allocator to generate local Tso for
+	// DC-level transactions.
+	DCLocation string `toml:"dc-location" json:"dc-location"`
+}
+
+// Validate is used to validate if some Tso configurations are right.
+func (c *TsoConfig) Validate() error {
+	if c.DCLocation == tso.GlobalDCLocation {
+		errMsg := fmt.Sprintf("dc-location %s is the PD reserved label to represent the PD leader, please try another one.", tso.GlobalDCLocation)
+		return errors.New(errMsg)
+	}
+	return nil
+}
+
+func (c *TsoConfig) adjust() error {
+	adjustDuration(&c.TsoSaveInterval, time.Duration(defaultLeaderLease)*time.Second)
+	return c.Validate()
+}

server/server.go

@@ -349,7 +349,7 @@ func (s *Server) startServer(ctx context.Context) error {
 	s.member.SetMemberGitHash(s.member.ID(), versioninfo.PDGitHash)
 	s.idAllocator = id.NewAllocatorImpl(s.client, s.rootPath, s.member.MemberValue())
 	s.tsoAllocatorManager = tso.NewAllocatorManager(
-		s.member.Etcd(), s.client, s.rootPath, s.cfg.TsoSaveInterval.Duration,
+		s.member.Etcd(), s.client, s.rootPath, s.cfg.Tso.TsoSaveInterval.Duration,
 		func() time.Duration { return s.persistOptions.GetMaxResetTSGap() },
 	)
 	kvBase := kv.NewEtcdKVBase(s.client, s.rootPath)

server/testutil.go

@@ -70,8 +70,10 @@ func NewTestSingleConfig(c *check.C) *config.Config {
 
 		InitialClusterState: embed.ClusterStateFlagNew,
 
-		LeaderLease:     1,
-		TsoSaveInterval: typeutil.NewDuration(200 * time.Millisecond),
+		LeaderLease: 1,
+		Tso: config.TsoConfig{
+			TsoSaveInterval: typeutil.NewDuration(200 * time.Millisecond),
+		},
 	}
 
 	cfg.AdvertiseClientUrls = cfg.ClientUrls

tools/pd-simulator/simulator/config.go

@@ -88,7 +88,7 @@ func (sc *SimConfig) Adjust() error {
 	adjustInt64(&sc.StoreIOMBPerSecond, defaultStoreIOMBPerSecond)
 	adjustString(&sc.StoreVersion, defaultStoreVersion)
 	adjustInt64(&sc.ServerConfig.LeaderLease, defaultLeaderLease)
-	adjustDuration(&sc.ServerConfig.TsoSaveInterval, defaultTsoSaveInterval)
+	adjustDuration(&sc.ServerConfig.Tso.TsoSaveInterval, defaultTsoSaveInterval)
 	adjustDuration(&sc.ServerConfig.TickInterval, defaultTickInterval)
 	adjustDuration(&sc.ServerConfig.ElectionInterval, defaultElectionInterval)
 	adjustDuration(&sc.ServerConfig.LeaderPriorityCheckInterval, defaultLeaderPriorityCheckInterval)