Provide GetMinTS API to solve the compatibility issue brought by mult…

…i-timeline tso (tikv#6421)

ref tikv#6142

1. Import kvproto change to introduce GetMinTS rpc in the TSO service.
6. Add server side implementation for GetMinTS rpc.
7. Add client side implementation for GetMinTS rpc.
8. Add unit test

Signed-off-by: Bin Shi <binshi.bing@gmail.com>

client/client.go

@@ -252,20 +252,20 @@ type serviceModeKeeper struct {
 	// triggering service mode switching concurrently.
 	sync.RWMutex
 	serviceMode     pdpb.ServiceMode
-	tsoClient       atomic.Value // *tsoClient
+	tsoClient       *tsoClient
 	tsoSvcDiscovery ServiceDiscovery
 }
 
-func (smk *serviceModeKeeper) close() {
-	smk.Lock()
-	defer smk.Unlock()
-	switch smk.serviceMode {
+func (k *serviceModeKeeper) close() {
+	k.Lock()
+	defer k.Unlock()
+	switch k.serviceMode {
 	case pdpb.ServiceMode_API_SVC_MODE:
-		smk.tsoSvcDiscovery.Close()
+		k.tsoSvcDiscovery.Close()
 		fallthrough
 	case pdpb.ServiceMode_PD_SVC_MODE:
-		if tsoCli := smk.tsoClient.Load(); tsoCli != nil {
-			tsoCli.(*tsoClient).Close()
+		if k.tsoClient != nil {
+			k.tsoClient.Close()
 		}
 	case pdpb.ServiceMode_UNKNOWN_SVC_MODE:
 	}
@@ -486,8 +486,8 @@ func (c *client) setServiceMode(newMode pdpb.ServiceMode) {
 	}
 	newTSOCli.Setup()
 	// Replace the old TSO client.
-	oldTSOClient := c.getTSOClient()
-	c.tsoClient.Store(newTSOCli)
+	oldTSOClient := c.tsoClient
+	c.tsoClient = newTSOCli
 	oldTSOClient.Close()
 	// Replace the old TSO service discovery if needed.
 	oldTSOSvcDiscovery := c.tsoSvcDiscovery
@@ -506,11 +506,10 @@ func (c *client) setServiceMode(newMode pdpb.ServiceMode) {
 		zap.String("new-mode", newMode.String()))
 }
 
-func (c *client) getTSOClient() *tsoClient {
-	if tsoCli := c.tsoClient.Load(); tsoCli != nil {
-		return tsoCli.(*tsoClient)
-	}
-	return nil
+func (c *client) getServiceClientProxy() (*tsoClient, pdpb.ServiceMode) {
+	c.RLock()
+	defer c.RUnlock()
+	return c.tsoClient, c.serviceMode
 }
 
 func (c *client) scheduleUpdateTokenConnection() {
@@ -675,7 +674,7 @@ func (c *client) GetLocalTSAsync(ctx context.Context, dcLocation string) TSFutur
 	req := tsoReqPool.Get().(*tsoRequest)
 	req.requestCtx = ctx
 	req.clientCtx = c.ctx
-	tsoClient := c.getTSOClient()
+	tsoClient, _ := c.getServiceClientProxy()
 	req.start = time.Now()
 	req.dcLocation = dcLocation
 
@@ -704,6 +703,26 @@ func (c *client) GetLocalTS(ctx context.Context, dcLocation string) (physical in
 	return resp.Wait()
 }
 
+func (c *client) GetMinTS(ctx context.Context) (physical int64, logical int64, err error) {
+	tsoClient, serviceMode := c.getServiceClientProxy()
+	if tsoClient == nil {
+		return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs("tso client is nil")
+	}
+
+	switch serviceMode {
+	case pdpb.ServiceMode_UNKNOWN_SVC_MODE:
+		return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs("unknown service mode")
+	case pdpb.ServiceMode_PD_SVC_MODE:
+		// If the service mode is switched to API during GetTS() call, which happens during migration,
+		// returning the default timeline should be fine.
+		return c.GetTS(ctx)
+	case pdpb.ServiceMode_API_SVC_MODE:
+		return tsoClient.getMinTS(ctx)
+	default:
+		return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs("undefined service mode")
+	}
+}
+
 func handleRegionResponse(res *pdpb.GetRegionResponse) *Region {
 	if res.Region == nil {
 		return nil
@@ -1395,7 +1414,7 @@ func (c *client) respForErr(observer prometheus.Observer, start time.Time, err e
 // GetTSOAllocators returns {dc-location -> TSO allocator leader URL} connection map
 // For test only.
 func (c *client) GetTSOAllocators() *sync.Map {
-	tsoClient := c.getTSOClient()
+	tsoClient, _ := c.getServiceClientProxy()
 	if tsoClient == nil {
 		return nil
 	}

client/client_test.go

@@ -24,6 +24,7 @@ import (
 	"github.com/stretchr/testify/require"
 	"github.com/tikv/pd/client/testutil"
 	"github.com/tikv/pd/client/tlsutil"
+	"github.com/tikv/pd/client/tsoutil"
 	"go.uber.org/goleak"
 	"google.golang.org/grpc"
 )
@@ -32,13 +33,13 @@ func TestMain(m *testing.M) {
 	goleak.VerifyTestMain(m, testutil.LeakOptions...)
 }
 
-func TestTsLessEqual(t *testing.T) {
+func TestTSLessEqual(t *testing.T) {
 	re := require.New(t)
-	re.True(tsLessEqual(9, 9, 9, 9))
-	re.True(tsLessEqual(8, 9, 9, 8))
-	re.False(tsLessEqual(9, 8, 8, 9))
-	re.False(tsLessEqual(9, 8, 9, 6))
-	re.True(tsLessEqual(9, 6, 9, 8))
+	re.True(tsoutil.TSLessEqual(9, 9, 9, 9))
+	re.True(tsoutil.TSLessEqual(8, 9, 9, 8))
+	re.False(tsoutil.TSLessEqual(9, 8, 8, 9))
+	re.False(tsoutil.TSLessEqual(9, 8, 9, 6))
+	re.True(tsoutil.TSLessEqual(9, 6, 9, 8))
 }
 
 func TestUpdateURLs(t *testing.T) {

client/errs/errno.go

@@ -43,6 +43,7 @@ var (
 	ErrClientTSOStreamClosed       = errors.Normalize("encountered TSO stream being closed unexpectedly", errors.RFCCodeText("PD:client:ErrClientTSOStreamClosed"))
 	ErrClientGetTSOTimeout         = errors.Normalize("get TSO timeout", errors.RFCCodeText("PD:client:ErrClientGetTSOTimeout"))
 	ErrClientGetTSO                = errors.Normalize("get TSO failed, %v", errors.RFCCodeText("PD:client:ErrClientGetTSO"))
+	ErrClientGetMinTSO             = errors.Normalize("get min TSO failed, %v", errors.RFCCodeText("PD:client:ErrClientGetMinTSO"))
 	ErrClientGetLeader             = errors.Normalize("get leader failed, %v", errors.RFCCodeText("PD:client:ErrClientGetLeader"))
 	ErrClientGetMember             = errors.Normalize("get member failed", errors.RFCCodeText("PD:client:ErrClientGetMember"))
 	ErrClientGetClusterInfo        = errors.Normalize("get cluster info failed", errors.RFCCodeText("PD:client:ErrClientGetClusterInfo"))

client/go.mod

@@ -8,7 +8,7 @@ require (
 	github.com/opentracing/opentracing-go v1.2.0
 	github.com/pingcap/errors v0.11.5-0.20211224045212-9687c2b0f87c
 	github.com/pingcap/failpoint v0.0.0-20210918120811-547c13e3eb00
-	github.com/pingcap/kvproto v0.0.0-20230426023724-d90a321b46be
+	github.com/pingcap/kvproto v0.0.0-20230511011722-6e0e8a7deaa1
 	github.com/pingcap/log v1.1.1-0.20221110025148-ca232912c9f3
 	github.com/prometheus/client_golang v1.11.1
 	github.com/stretchr/testify v1.8.2

client/go.sum

@@ -82,8 +82,8 @@ github.com/pingcap/errors v0.11.5-0.20211224045212-9687c2b0f87c h1:xpW9bvK+HuuTm
 github.com/pingcap/errors v0.11.5-0.20211224045212-9687c2b0f87c/go.mod h1:X2r9ueLEUZgtx2cIogM0v4Zj5uvvzhuuiu7Pn8HzMPg=
 github.com/pingcap/failpoint v0.0.0-20210918120811-547c13e3eb00 h1:C3N3itkduZXDZFh4N3vQ5HEtld3S+Y+StULhWVvumU0=
 github.com/pingcap/failpoint v0.0.0-20210918120811-547c13e3eb00/go.mod h1:4qGtCB0QK0wBzKtFEGDhxXnSnbQApw1gc9siScUl8ew=
-github.com/pingcap/kvproto v0.0.0-20230426023724-d90a321b46be h1:eHtwHgPzzm8aIZ4x8o7zg1b23cjUl0AikW+SDLpqf3E=
-github.com/pingcap/kvproto v0.0.0-20230426023724-d90a321b46be/go.mod h1:guCyM5N+o+ru0TsoZ1hi9lDjUMs2sIBjW3ARTEpVbnk=
+github.com/pingcap/kvproto v0.0.0-20230511011722-6e0e8a7deaa1 h1:VXQ6Du/nKZ9IQnI9NWMzKbftWu8NV5pQkSLKIRzzGN4=
+github.com/pingcap/kvproto v0.0.0-20230511011722-6e0e8a7deaa1/go.mod h1:guCyM5N+o+ru0TsoZ1hi9lDjUMs2sIBjW3ARTEpVbnk=
 github.com/pingcap/log v1.1.1-0.20221110025148-ca232912c9f3 h1:HR/ylkkLmGdSSDaD8IDP+SZrdhV1Kibl9KrHxJ9eciw=
 github.com/pingcap/log v1.1.1-0.20221110025148-ca232912c9f3/go.mod h1:DWQW5jICDR7UJh4HtxXSM20Churx4CQL0fwL/SoOSA4=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=

client/tso_client.go

@@ -22,23 +22,29 @@ import (
 	"time"
 
 	"github.com/pingcap/errors"
+	"github.com/pingcap/kvproto/pkg/pdpb"
+	"github.com/pingcap/kvproto/pkg/tsopb"
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/client/errs"
+	"github.com/tikv/pd/client/tsoutil"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
 	healthpb "google.golang.org/grpc/health/grpc_health_v1"
 )
 
 // TSOClient is the client used to get timestamps.
 type TSOClient interface {
-	// GetTS gets a timestamp from PD.
+	// GetTS gets a timestamp from PD or TSO microservice.
 	GetTS(ctx context.Context) (int64, int64, error)
-	// GetTSAsync gets a timestamp from PD, without block the caller.
+	// GetTSAsync gets a timestamp from PD or TSO microservice, without block the caller.
 	GetTSAsync(ctx context.Context) TSFuture
-	// GetLocalTS gets a local timestamp from PD.
+	// GetLocalTS gets a local timestamp from PD or TSO microservice.
 	GetLocalTS(ctx context.Context, dcLocation string) (int64, int64, error)
-	// GetLocalTSAsync gets a local timestamp from PD, without block the caller.
+	// GetLocalTSAsync gets a local timestamp from PD or TSO microservice, without block the caller.
 	GetLocalTSAsync(ctx context.Context, dcLocation string) TSFuture
+	// GetMinTS gets a timestamp from PD or the minimal timestamp across all keyspace groups from
+	// the TSO microservice.
+	GetMinTS(ctx context.Context) (int64, int64, error)
 }
 
 type tsoRequest struct {
@@ -275,3 +281,116 @@ func (c *tsoClient) backupClientConn() (*grpc.ClientConn, string) {
 	}
 	return nil, ""
 }
+
+// getMinTS gets a timestamp from PD or the minimal timestamp across all keyspace groups from the TSO microservice.
+func (c *tsoClient) getMinTS(ctx context.Context) (physical, logical int64, err error) {
+	// Immediately refresh the TSO server/pod list
+	addrs, err := c.svcDiscovery.DiscoverMicroservice(tsoService)
+	if err != nil {
+		return 0, 0, errs.ErrClientGetMinTSO.Wrap(err).GenWithStackByCause()
+	}
+	if len(addrs) == 0 {
+		return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs("no tso servers/pods discovered")
+	}
+
+	// Get the minimal timestamp from the TSO servers/pods
+	var mutex sync.Mutex
+	resps := make([]*tsopb.GetMinTSResponse, 0)
+	wg := sync.WaitGroup{}
+	wg.Add(len(addrs))
+	for _, addr := range addrs {
+		go func(addr string) {
+			defer wg.Done()
+			resp, err := c.getMinTSFromSingleServer(ctx, addr, c.option.timeout)
+			if err != nil || resp == nil {
+				log.Warn("[tso] failed to get min ts from tso server",
+					zap.String("address", addr), zap.Error(err))
+				return
+			}
+			mutex.Lock()
+			defer mutex.Unlock()
+			resps = append(resps, resp)
+		}(addr)
+	}
+	wg.Wait()
+
+	// Check the results. The returned minimal timestamp is valid if all the conditions are met:
+	// 1. The number of responses is equal to the number of TSO servers/pods.
+	// 2. The number of keyspace groups asked is equal to the number of TSO servers/pods.
+	// 3. The minimal timestamp is not zero.
+	var (
+		minTS               *pdpb.Timestamp
+		keyspaceGroupsAsked uint32
+	)
+	if len(resps) == 0 {
+		return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs("none of tso server/pod responded")
+	}
+	emptyTS := &pdpb.Timestamp{}
+	keyspaceGroupsTotal := resps[0].KeyspaceGroupsTotal
+	for _, resp := range resps {
+		if resp.KeyspaceGroupsTotal == 0 {
+			return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs("the tso service has no keyspace group")
+		}
+		if resp.KeyspaceGroupsTotal != keyspaceGroupsTotal {
+			return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs(
+				"the tso service has inconsistent keyspace group total count")
+		}
+		keyspaceGroupsAsked += resp.KeyspaceGroupsServing
+		if tsoutil.CompareTimestamp(resp.Timestamp, emptyTS) > 0 &&
+			(minTS == nil || tsoutil.CompareTimestamp(resp.Timestamp, minTS) < 0) {
+			minTS = resp.Timestamp
+		}
+	}
+
+	if keyspaceGroupsAsked != keyspaceGroupsTotal {
+		return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs(
+			fmt.Sprintf("can't query all the tso keyspace groups. Asked %d, expected %d",
+				keyspaceGroupsAsked, keyspaceGroupsTotal))
+	}
+
+	if minTS == nil {
+		return 0, 0, errs.ErrClientGetMinTSO.FastGenByArgs("the tso service is not ready")
+	}
+
+	return minTS.Physical, tsoutil.AddLogical(minTS.Logical, 0, minTS.SuffixBits), nil
+}
+
+func (c *tsoClient) getMinTSFromSingleServer(
+	ctx context.Context, tsoSrvAddr string, timeout time.Duration,
+) (*tsopb.GetMinTSResponse, error) {
+	cc, err := c.svcDiscovery.GetOrCreateGRPCConn(tsoSrvAddr)
+	if err != nil {
+		return nil, errs.ErrClientGetMinTSO.FastGenByArgs(
+			fmt.Sprintf("can't connect to tso server %s", tsoSrvAddr))
+	}
+
+	cctx, cancel := context.WithTimeout(ctx, timeout)
+	defer cancel()
+
+	resp, err := tsopb.NewTSOClient(cc).GetMinTS(
+		cctx, &tsopb.GetMinTSRequest{
+			Header: &tsopb.RequestHeader{
+				ClusterId:       c.svcDiscovery.GetClusterID(),
+				KeyspaceId:      c.svcDiscovery.GetKeyspaceID(),
+				KeyspaceGroupId: c.svcDiscovery.GetKeyspaceGroupID(),
+			},
+			DcLocation: globalDCLocation,
+		})
+	if err != nil {
+		attachErr := errors.Errorf("error:%s target:%s status:%s",
+			err, cc.Target(), cc.GetState().String())
+		return nil, errs.ErrClientGetMinTSO.Wrap(attachErr).GenWithStackByCause()
+	}
+	if resp == nil {
+		attachErr := errors.Errorf("error:%s target:%s status:%s",
+			"no min ts info collected", cc.Target(), cc.GetState().String())
+		return nil, errs.ErrClientGetMinTSO.Wrap(attachErr).GenWithStackByCause()
+	}
+	if resp.GetHeader().GetError() != nil {
+		attachErr := errors.Errorf("error:%s target:%s status:%s",
+			resp.GetHeader().GetError().String(), cc.Target(), cc.GetState().String())
+		return nil, errs.ErrClientGetMinTSO.Wrap(attachErr).GenWithStackByCause()
+	}
+
+	return resp, nil
+}

client/tso_dispatcher.go

@@ -27,6 +27,7 @@ import (
 	"github.com/pingcap/log"
 	"github.com/tikv/pd/client/errs"
 	"github.com/tikv/pd/client/grpcutil"
+	"github.com/tikv/pd/client/tsoutil"
 	"go.uber.org/zap"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
@@ -715,19 +716,14 @@ func (c *tsoClient) processRequests(
 		return err
 	}
 	// `logical` is the largest ts's logical part here, we need to do the subtracting before we finish each TSO request.
-	firstLogical := addLogical(logical, -count+1, suffixBits)
+	firstLogical := tsoutil.AddLogical(logical, -count+1, suffixBits)
 	c.compareAndSwapTS(dcLocation, physical, firstLogical, suffixBits, count)
 	c.finishRequest(requests, physical, firstLogical, suffixBits, nil)
 	return nil
 }
 
-// Because of the suffix, we need to shift the count before we add it to the logical part.
-func addLogical(logical, count int64, suffixBits uint32) int64 {
-	return logical + count<<suffixBits
-}
-
 func (c *tsoClient) compareAndSwapTS(dcLocation string, physical, firstLogical int64, suffixBits uint32, count int64) {
-	largestLogical := addLogical(firstLogical, count-1, suffixBits)
+	largestLogical := tsoutil.AddLogical(firstLogical, count-1, suffixBits)
 	lastTSOInterface, loaded := c.lastTSMap.LoadOrStore(dcLocation, &lastTSO{
 		physical: physical,
 		// Save the largest logical part here
@@ -742,7 +738,7 @@ func (c *tsoClient) compareAndSwapTS(dcLocation string, physical, firstLogical i
 	// The TSO we get is a range like [largestLogical-count+1, largestLogical], so we save the last TSO's largest logical
 	// to compare with the new TSO's first logical. For example, if we have a TSO resp with logical 10, count 5, then
 	// all TSOs we get will be [6, 7, 8, 9, 10].
-	if tsLessEqual(physical, firstLogical, lastPhysical, lastLogical) {
+	if tsoutil.TSLessEqual(physical, firstLogical, lastPhysical, lastLogical) {
 		panic(errors.Errorf("%s timestamp fallback, newly acquired ts (%d, %d) is less or equal to last one (%d, %d)",
 			dcLocation, physical, firstLogical, lastPhysical, lastLogical))
 	}
@@ -751,19 +747,12 @@ func (c *tsoClient) compareAndSwapTS(dcLocation string, physical, firstLogical i
 	lastTSOPointer.logical = largestLogical
 }
 
-func tsLessEqual(physical, logical, thatPhysical, thatLogical int64) bool {
-	if physical == thatPhysical {
-		return logical <= thatLogical
-	}
-	return physical < thatPhysical
-}
-
 func (c *tsoClient) finishRequest(requests []*tsoRequest, physical, firstLogical int64, suffixBits uint32, err error) {
 	for i := 0; i < len(requests); i++ {
 		if span := opentracing.SpanFromContext(requests[i].requestCtx); span != nil {
 			span.Finish()
 		}
-		requests[i].physical, requests[i].logical = physical, addLogical(firstLogical, int64(i), suffixBits)
+		requests[i].physical, requests[i].logical = physical, tsoutil.AddLogical(firstLogical, int64(i), suffixBits)
 		requests[i].done <- err
 	}
 }

client/tso_service_discovery.go

@@ -98,10 +98,11 @@ type tsoServerDiscovery struct {
 	failureCount int
 }
 
-func (t *tsoServerDiscovery) countFailure() {
+func (t *tsoServerDiscovery) countFailure() bool {
 	t.Lock()
 	defer t.Unlock()
 	t.failureCount++
+	return t.failureCount >= len(t.addrs)
 }
 
 func (t *tsoServerDiscovery) resetFailure() {
@@ -414,8 +415,9 @@ func (c *tsoServiceDiscovery) updateMember() error {
 	}
 	keyspaceGroup, err := c.findGroupByKeyspaceID(c.keyspaceID, tsoServerAddr, updateMemberTimeout)
 	if err != nil {
-		c.tsoServerDiscovery.countFailure()
-		log.Error("[tso] failed to find the keyspace group", errs.ZapError(err))
+		if c.tsoServerDiscovery.countFailure() {
+			log.Error("[tso] failed to find the keyspace group", errs.ZapError(err))
+		}
 		return err
 	}
 	c.tsoServerDiscovery.resetFailure()