func (t *leaseTest) node(nodeID uint32) *csql.LeaseManager {
	mgr := t.nodes[nodeID]
	if mgr == nil {
		mgr = csql.NewLeaseManager(nodeID, *t.server.DB(), t.server.Clock())
		t.nodes[nodeID] = mgr
	}
	return mgr
}

func (t *leaseTest) node(nodeID uint32) *csql.LeaseManager {
	mgr := t.nodes[nodeID]
	if mgr == nil {
		mgr = csql.NewLeaseManager(
			nodeID, *t.kvDB,
			t.server.Clock(),
			t.leaseManagerTestingKnobs,
			t.server.Stopper(),
		)
		t.nodes[nodeID] = mgr
	}
	return mgr
}

// NewServer creates a Server from a server.Context.
func NewServer(ctx *Context, stopper *stop.Stopper) (*Server, error) {
	if ctx == nil {
		return nil, util.Errorf("ctx must not be null")
	}

	if _, err := net.ResolveTCPAddr("tcp", ctx.Addr); err != nil {
		return nil, util.Errorf("unable to resolve RPC address %q: %v", ctx.Addr, err)
	}

	if ctx.Insecure {
		log.Warning("running in insecure mode, this is strongly discouraged. See --insecure and --certs.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := ctx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := ctx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		ctx:     ctx,
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

	s.rpcContext = crpc.NewContext(&ctx.Context, s.clock, stopper)
	stopper.RunWorker(func() {
		s.rpcContext.RemoteClocks.MonitorRemoteOffsets(stopper)
	})

	s.rpc = crpc.NewServer(s.rpcContext)

	s.gossip = gossip.New(s.rpcContext, s.ctx.GossipBootstrapResolvers)
	s.storePool = storage.NewStorePool(s.gossip, s.clock, ctx.TimeUntilStoreDead, stopper)

	feed := util.NewFeed(stopper)
	tracer := tracer.NewTracer(feed, ctx.Addr)

	ds := kv.NewDistSender(&kv.DistSenderContext{Clock: s.clock, RPCContext: s.rpcContext}, s.gossip)
	sender := kv.NewTxnCoordSender(ds, s.clock, ctx.Linearizable, tracer, s.stopper)
	s.db = client.NewDB(sender)

	var err error
	s.raftTransport, err = newRPCTransport(s.gossip, s.rpc, s.rpcContext)
	if err != nil {
		return nil, err
	}
	s.stopper.AddCloser(s.raftTransport)

	s.kvDB = kv.NewDBServer(&s.ctx.Context, sender)
	if err := s.kvDB.RegisterRPC(s.rpc); err != nil {
		return nil, err
	}

	leaseMgr := sql.NewLeaseManager(0, *s.db, s.clock)
	leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)
	s.sqlServer = sql.MakeServer(&s.ctx.Context, *s.db, s.gossip, leaseMgr)
	if err := s.sqlServer.RegisterRPC(s.rpc); err != nil {
		return nil, err
	}

	s.pgServer = pgwire.NewServer(&pgwire.Context{
		Context:  &s.ctx.Context,
		Executor: s.sqlServer.Executor,
		Stopper:  stopper,
	})

	// TODO(bdarnell): make StoreConfig configurable.
	nCtx := storage.StoreContext{
		Clock:           s.clock,
		DB:              s.db,
		Gossip:          s.gossip,
		Transport:       s.raftTransport,
		ScanInterval:    s.ctx.ScanInterval,
		ScanMaxIdleTime: s.ctx.ScanMaxIdleTime,
		EventFeed:       feed,
		Tracer:          tracer,
		StorePool:       s.storePool,
		AllocatorOptions: storage.AllocatorOptions{
			AllowRebalance: true,
			Mode:           s.ctx.BalanceMode,
		},
	}
	s.node = NewNode(nCtx)
	s.admin = newAdminServer(s.db, s.stopper)
	s.status = newStatusServer(s.db, s.gossip, ctx)
	s.tsDB = ts.NewDB(s.db)
	s.tsServer = ts.NewServer(s.tsDB)

	return s, nil
}

// NewServer creates a Server from a server.Context.
func NewServer(ctx *Context, stopper *stop.Stopper) (*Server, error) {
	if ctx == nil {
		return nil, util.Errorf("ctx must not be null")
	}

	if _, err := net.ResolveTCPAddr("tcp", ctx.Addr); err != nil {
		return nil, util.Errorf("unable to resolve RPC address %q: %v", ctx.Addr, err)
	}

	if ctx.Insecure {
		log.Warning("running in insecure mode, this is strongly discouraged. See --insecure and --certs.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := ctx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := ctx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		Tracer:  tracing.NewTracer(),
		ctx:     ctx,
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

	s.rpcContext = crpc.NewContext(&ctx.Context, s.clock, stopper)
	stopper.RunWorker(func() {
		s.rpcContext.RemoteClocks.MonitorRemoteOffsets(stopper)
	})

	s.rpc = crpc.NewServer(s.rpcContext)

	s.gossip = gossip.New(s.rpcContext, s.ctx.GossipBootstrapResolvers, stopper)
	s.storePool = storage.NewStorePool(s.gossip, s.clock, ctx.TimeUntilStoreDead, stopper)

	feed := util.NewFeed(stopper)

	// A custom RetryOptions is created which uses stopper.ShouldDrain() as
	// the Closer. This prevents infinite retry loops from occurring during
	// graceful server shutdown
	//
	// Such a loop loop occurs with the DistSender attempts a connection to the
	// local server during shutdown, and receives an internal server error (HTTP
	// Code 5xx). This is the correct error for a server to return when it is
	// shutting down, and is normally retryable in a cluster environment.
	// However, on a single-node setup (such as a test), retries will never
	// succeed because the only server has been shut down; thus, thus the
	// DistSender needs to know that it should not retry in this situation.
	retryOpts := kv.GetDefaultDistSenderRetryOptions()
	retryOpts.Closer = stopper.ShouldDrain()
	ds := kv.NewDistSender(&kv.DistSenderContext{
		Clock:           s.clock,
		RPCContext:      s.rpcContext,
		RPCRetryOptions: &retryOpts,
	}, s.gossip)
	txnRegistry := metric.NewRegistry()
	txnMetrics := kv.NewTxnMetrics(txnRegistry)
	sender := kv.NewTxnCoordSender(ds, s.clock, ctx.Linearizable, s.Tracer, s.stopper, txnMetrics)
	s.db = client.NewDB(sender)

	s.grpc = grpc.NewServer()
	s.raftTransport = storage.NewRaftTransport(storage.GossipAddressResolver(s.gossip), s.grpc, s.rpcContext)

	s.kvDB = kv.NewDBServer(&s.ctx.Context, sender, stopper)
	if err := s.kvDB.RegisterRPC(s.rpc); err != nil {
		return nil, err
	}

	s.leaseMgr = sql.NewLeaseManager(0, *s.db, s.clock)
	s.leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)
	sqlRegistry := metric.NewRegistry()
	s.sqlExecutor = sql.NewExecutor(*s.db, s.gossip, s.leaseMgr, s.stopper, sqlRegistry)

	s.pgServer = pgwire.MakeServer(&s.ctx.Context, s.sqlExecutor, sqlRegistry)

	// TODO(bdarnell): make StoreConfig configurable.
	nCtx := storage.StoreContext{
		Clock:           s.clock,
		DB:              s.db,
		Gossip:          s.gossip,
		Transport:       s.raftTransport,
		ScanInterval:    s.ctx.ScanInterval,
		ScanMaxIdleTime: s.ctx.ScanMaxIdleTime,
		EventFeed:       feed,
		Tracer:          s.Tracer,
		StorePool:       s.storePool,
		SQLExecutor: sql.InternalExecutor{
			LeaseManager: s.leaseMgr,
		},
		LogRangeEvents: true,
		AllocatorOptions: storage.AllocatorOptions{
			AllowRebalance: true,
			Mode:           s.ctx.BalanceMode,
		},
	}
//.........这里部分代码省略.........

func TestSchemaChangeProcess(t *testing.T) {
	defer leaktest.AfterTest(t)
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()
	// Disable external processing of mutations.
	defer csql.TestDisableAsyncSchemaChangeExec()()
	server, sqlDB, kvDB := setup(t)
	defer cleanup(server, sqlDB)
	var id = csql.ID(keys.MaxReservedDescID + 2)
	var node = roachpb.NodeID(2)
	db := server.DB()
	leaseMgr := csql.NewLeaseManager(0, *db, hlc.NewClock(hlc.UnixNano))
	changer := csql.NewSchemaChangerForTesting(id, 0, node, *db, leaseMgr)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, INDEX foo(v));
INSERT INTO t.test VALUES ('a', 'b'), ('c', 'd');
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor for version.
	nameKey := csql.MakeNameMetadataKey(keys.MaxReservedDescID+1, "test")
	gr, err := kvDB.Get(nameKey)
	if err != nil {
		t.Fatal(err)
	}
	if !gr.Exists() {
		t.Fatalf("Name entry %q does not exist", nameKey)
	}
	descKey := csql.MakeDescMetadataKey(csql.ID(gr.ValueInt()))
	desc := &csql.Descriptor{}

	// Check that MaybeIncrementVersion doesn't increment the version
	// when the up_version bit is not set.
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	expectedVersion := desc.GetTable().Version

	if err := changer.MaybeIncrementVersion(); err != nil {
		t.Fatal(err)
	}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	newVersion := desc.GetTable().Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err := changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", desc.GetTable())
	}

	// Check that MaybeIncrementVersion increments the version
	// correctly.
	expectedVersion++
	desc.GetTable().UpVersion = true
	if err := kvDB.Put(descKey, desc); err != nil {
		t.Fatal(err)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if isDone {
		t.Fatalf("table expected to have an outstanding schema change: %v", desc.GetTable())
	}
	if err := changer.MaybeIncrementVersion(); err != nil {
		t.Fatal(err)
	}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
	newVersion = desc.GetTable().Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", desc.GetTable())
	}

	// Check that RunStateMachineBeforeBackfill doesn't do anything
	// if there are no mutations queued.
	if err := changer.RunStateMachineBeforeBackfill(); err != nil {
		t.Fatal(err)
	}
	if err := kvDB.GetProto(descKey, desc); err != nil {
		t.Fatal(err)
	}
//.........这里部分代码省略.........

func TestSchemaChangeProcess(t *testing.T) {
	defer leaktest.AfterTest(t)()
	// The descriptor changes made must have an immediate effect
	// so disable leases on tables.
	defer csql.TestDisableTableLeases()()

	params, _ := createTestServerParams()
	// Disable external processing of mutations.
	params.Knobs.SQLSchemaChangeManager = &csql.SchemaChangeManagerTestingKnobs{
		AsyncSchemaChangerExecNotification: schemaChangeManagerDisabled,
	}
	s, sqlDB, kvDB := serverutils.StartServer(t, params)
	defer s.Stopper().Stop()

	var id = sqlbase.ID(keys.MaxReservedDescID + 2)
	var node = roachpb.NodeID(2)
	stopper := stop.NewStopper()
	leaseMgr := csql.NewLeaseManager(0, *kvDB, hlc.NewClock(hlc.UnixNano), csql.LeaseManagerTestingKnobs{}, stopper)
	defer stopper.Stop()
	changer := csql.NewSchemaChangerForTesting(id, 0, node, *kvDB, leaseMgr)

	if _, err := sqlDB.Exec(`
CREATE DATABASE t;
CREATE TABLE t.test (k CHAR PRIMARY KEY, v CHAR, INDEX foo(v));
INSERT INTO t.test VALUES ('a', 'b'), ('c', 'd');
`); err != nil {
		t.Fatal(err)
	}

	// Read table descriptor for version.
	tableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")

	expectedVersion := tableDesc.Version

	desc, err := changer.MaybeIncrementVersion()
	if err != nil {
		t.Fatal(err)
	}
	tableDesc = desc.GetTable()
	newVersion := tableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err := changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", tableDesc)
	}

	// Check that MaybeIncrementVersion increments the version
	// correctly.
	expectedVersion++
	tableDesc.UpVersion = true
	if err := kvDB.Put(
		sqlbase.MakeDescMetadataKey(tableDesc.ID),
		sqlbase.WrapDescriptor(tableDesc),
	); err != nil {
		t.Fatal(err)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if isDone {
		t.Fatalf("table expected to have an outstanding schema change: %v", desc.GetTable())
	}
	desc, err = changer.MaybeIncrementVersion()
	if err != nil {
		t.Fatal(err)
	}
	tableDesc = desc.GetTable()
	savedTableDesc := sqlbase.GetTableDescriptor(kvDB, "t", "test")
	newVersion = tableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version in returned desc; e = %d, v = %d", expectedVersion, newVersion)
	}
	newVersion = savedTableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version in saved desc; e = %d, v = %d", expectedVersion, newVersion)
	}
	isDone, err = changer.IsDone()
	if err != nil {
		t.Fatal(err)
	}
	if !isDone {
		t.Fatalf("table expected to not have an outstanding schema change: %v", tableDesc)
	}

	// Check that RunStateMachineBeforeBackfill doesn't do anything
	// if there are no mutations queued.
	if err := changer.RunStateMachineBeforeBackfill(); err != nil {
		t.Fatal(err)
	}

	tableDesc = sqlbase.GetTableDescriptor(kvDB, "t", "test")
	newVersion = tableDesc.Version
	if newVersion != expectedVersion {
		t.Fatalf("bad version; e = %d, v = %d", expectedVersion, newVersion)
//.........这里部分代码省略.........

//.........这里部分代码省略.........
	// Such a loop loop occurs with the DistSender attempts a connection to the
	// local server during shutdown, and receives an internal server error (HTTP
	// Code 5xx). This is the correct error for a server to return when it is
	// shutting down, and is normally retryable in a cluster environment.
	// However, on a single-node setup (such as a test), retries will never
	// succeed because the only server has been shut down; thus, thus the
	// DistSender needs to know that it should not retry in this situation.
	retryOpts := base.DefaultRetryOptions()
	retryOpts.Closer = s.stopper.ShouldQuiesce()
	distSenderCfg := kv.DistSenderConfig{
		Ctx:             s.Ctx(),
		Clock:           s.clock,
		RPCContext:      s.rpcContext,
		RPCRetryOptions: &retryOpts,
	}
	s.distSender = kv.NewDistSender(&distSenderCfg, s.gossip)

	txnMetrics := kv.MakeTxnMetrics()
	s.registry.AddMetricStruct(txnMetrics)
	s.txnCoordSender = kv.NewTxnCoordSender(s.Ctx(), s.distSender, s.clock, srvCtx.Linearizable,
		s.stopper, txnMetrics)
	s.db = client.NewDB(s.txnCoordSender)

	s.raftTransport = storage.NewRaftTransport(storage.GossipAddressResolver(s.gossip), s.grpc, s.rpcContext)

	s.kvDB = kv.NewDBServer(s.ctx.Context, s.txnCoordSender, s.stopper)
	roachpb.RegisterExternalServer(s.grpc, s.kvDB)

	// Set up Lease Manager
	var lmKnobs sql.LeaseManagerTestingKnobs
	if srvCtx.TestingKnobs.SQLLeaseManager != nil {
		lmKnobs = *srvCtx.TestingKnobs.SQLLeaseManager.(*sql.LeaseManagerTestingKnobs)
	}
	s.leaseMgr = sql.NewLeaseManager(0, *s.db, s.clock, lmKnobs, s.stopper)
	s.leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)

	// Set up the DistSQL server
	distSQLCfg := distsql.ServerConfig{
		Context:    s.Ctx(),
		DB:         s.db,
		RPCContext: s.rpcContext,
	}
	s.distSQLServer = distsql.NewServer(distSQLCfg)
	distsql.RegisterDistSQLServer(s.grpc, s.distSQLServer)

	// Set up Executor
	execCfg := sql.ExecutorConfig{
		Context:      s.Ctx(),
		DB:           s.db,
		Gossip:       s.gossip,
		LeaseManager: s.leaseMgr,
		Clock:        s.clock,
		DistSQLSrv:   s.distSQLServer,
	}
	if srvCtx.TestingKnobs.SQLExecutor != nil {
		execCfg.TestingKnobs = srvCtx.TestingKnobs.SQLExecutor.(*sql.ExecutorTestingKnobs)
	} else {
		execCfg.TestingKnobs = &sql.ExecutorTestingKnobs{}
	}

	s.sqlExecutor = sql.NewExecutor(execCfg, s.stopper)
	s.registry.AddMetricStruct(s.sqlExecutor)

	s.pgServer = pgwire.MakeServer(s.ctx.Context, s.sqlExecutor)
	s.registry.AddMetricStruct(s.pgServer.Metrics())

// NewServer creates a Server from a server.Context.
func NewServer(ctx Context, stopper *stop.Stopper) (*Server, error) {
	if _, err := net.ResolveTCPAddr("tcp", ctx.Addr); err != nil {
		return nil, errors.Errorf("unable to resolve RPC address %q: %v", ctx.Addr, err)
	}

	if ctx.Insecure {
		log.Warning(context.TODO(), "running in insecure mode, this is strongly discouraged. See --insecure.")
	}
	// Try loading the TLS configs before anything else.
	if _, err := ctx.GetServerTLSConfig(); err != nil {
		return nil, err
	}
	if _, err := ctx.GetClientTLSConfig(); err != nil {
		return nil, err
	}

	s := &Server{
		Tracer:  tracing.NewTracer(),
		ctx:     ctx,
		mux:     http.NewServeMux(),
		clock:   hlc.NewClock(hlc.UnixNano),
		stopper: stopper,
	}
	s.clock.SetMaxOffset(ctx.MaxOffset)

	s.rpcContext = rpc.NewContext(ctx.Context, s.clock, s.stopper)
	s.rpcContext.HeartbeatCB = func() {
		if err := s.rpcContext.RemoteClocks.VerifyClockOffset(); err != nil {
			log.Fatal(context.TODO(), err)
		}
	}
	s.grpc = rpc.NewServer(s.rpcContext)

	s.registry = metric.NewRegistry()
	s.gossip = gossip.New(s.rpcContext, s.grpc, s.ctx.GossipBootstrapResolvers, s.stopper, s.registry)
	s.storePool = storage.NewStorePool(
		s.gossip,
		s.clock,
		s.rpcContext,
		ctx.ReservationsEnabled,
		ctx.TimeUntilStoreDead,
		s.stopper,
	)

	// A custom RetryOptions is created which uses stopper.ShouldQuiesce() as
	// the Closer. This prevents infinite retry loops from occurring during
	// graceful server shutdown
	//
	// Such a loop loop occurs with the DistSender attempts a connection to the
	// local server during shutdown, and receives an internal server error (HTTP
	// Code 5xx). This is the correct error for a server to return when it is
	// shutting down, and is normally retryable in a cluster environment.
	// However, on a single-node setup (such as a test), retries will never
	// succeed because the only server has been shut down; thus, thus the
	// DistSender needs to know that it should not retry in this situation.
	retryOpts := base.DefaultRetryOptions()
	retryOpts.Closer = s.stopper.ShouldQuiesce()
	s.distSender = kv.NewDistSender(&kv.DistSenderContext{
		Clock:           s.clock,
		RPCContext:      s.rpcContext,
		RPCRetryOptions: &retryOpts,
	}, s.gossip)
	txnMetrics := kv.NewTxnMetrics(s.registry)
	sender := kv.NewTxnCoordSender(s.distSender, s.clock, ctx.Linearizable, s.Tracer,
		s.stopper, txnMetrics)
	s.db = client.NewDB(sender)

	s.raftTransport = storage.NewRaftTransport(storage.GossipAddressResolver(s.gossip), s.grpc, s.rpcContext)

	s.kvDB = kv.NewDBServer(s.ctx.Context, sender, s.stopper)
	roachpb.RegisterExternalServer(s.grpc, s.kvDB)

	// Set up Lease Manager
	var lmKnobs sql.LeaseManagerTestingKnobs
	if ctx.TestingKnobs.SQLLeaseManager != nil {
		lmKnobs = *ctx.TestingKnobs.SQLLeaseManager.(*sql.LeaseManagerTestingKnobs)
	}
	s.leaseMgr = sql.NewLeaseManager(0, *s.db, s.clock, lmKnobs, s.stopper)
	s.leaseMgr.RefreshLeases(s.stopper, s.db, s.gossip)

	// Set up the DistSQL server
	distSQLCtx := distsql.ServerContext{
		Context:    context.Background(),
		DB:         s.db,
		RPCContext: s.rpcContext,
	}
	s.distSQLServer = distsql.NewServer(distSQLCtx)
	distsql.RegisterDistSQLServer(s.grpc, s.distSQLServer)

	// Set up Executor
	eCtx := sql.ExecutorContext{
		Context:      context.Background(),
		DB:           s.db,
		Gossip:       s.gossip,
		LeaseManager: s.leaseMgr,
		Clock:        s.clock,
		DistSQLSrv:   s.distSQLServer,
	}
	if ctx.TestingKnobs.SQLExecutor != nil {
//.........这里部分代码省略.........