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tso_dispatcher.go
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tso_dispatcher.go
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// Copyright 2023 TiKV Project Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package pd
import (
"context"
"fmt"
"math/rand"
"runtime/trace"
"sync"
"time"
"github.com/opentracing/opentracing-go"
"github.com/pingcap/errors"
"github.com/pingcap/failpoint"
"github.com/pingcap/log"
"github.com/tikv/pd/client/errs"
"github.com/tikv/pd/client/grpcutil"
"github.com/tikv/pd/client/retry"
"github.com/tikv/pd/client/timerpool"
"github.com/tikv/pd/client/tsoutil"
"go.uber.org/zap"
"google.golang.org/grpc"
"google.golang.org/grpc/codes"
healthpb "google.golang.org/grpc/health/grpc_health_v1"
"google.golang.org/grpc/status"
)
type tsoDispatcher struct {
dispatcherCancel context.CancelFunc
tsoBatchController *tsoBatchController
}
type tsoInfo struct {
tsoServer string
reqKeyspaceGroupID uint32
respKeyspaceGroupID uint32
respReceivedAt time.Time
physical int64
logical int64
}
const (
tsLoopDCCheckInterval = time.Minute
defaultMaxTSOBatchSize = 10000 // should be higher if client is sending requests in burst
retryInterval = 500 * time.Millisecond
maxRetryTimes = 6
)
func (c *tsoClient) scheduleCheckTSODispatcher() {
select {
case c.checkTSODispatcherCh <- struct{}{}:
default:
}
}
func (c *tsoClient) scheduleUpdateTSOConnectionCtxs() {
select {
case c.updateTSOConnectionCtxsCh <- struct{}{}:
default:
}
}
func (c *tsoClient) dispatchRequest(dcLocation string, request *tsoRequest) error {
dispatcher, ok := c.tsoDispatcher.Load(dcLocation)
if !ok {
err := errs.ErrClientGetTSO.FastGenByArgs(fmt.Sprintf("unknown dc-location %s to the client", dcLocation))
log.Error("[tso] dispatch tso request error", zap.String("dc-location", dcLocation), errs.ZapError(err))
c.svcDiscovery.ScheduleCheckMemberChanged()
return err
}
defer trace.StartRegion(request.requestCtx, "tsoReqEnqueue").End()
dispatcher.(*tsoDispatcher).tsoBatchController.tsoRequestCh <- request
return nil
}
// TSFuture is a future which promises to return a TSO.
type TSFuture interface {
// Wait gets the physical and logical time, it would block caller if data is not available yet.
Wait() (int64, int64, error)
}
func (req *tsoRequest) Wait() (physical int64, logical int64, err error) {
// If tso command duration is observed very high, the reason could be it
// takes too long for Wait() be called.
start := time.Now()
cmdDurationTSOAsyncWait.Observe(start.Sub(req.start).Seconds())
select {
case err = <-req.done:
defer trace.StartRegion(req.requestCtx, "tsoReqDone").End()
err = errors.WithStack(err)
defer tsoReqPool.Put(req)
if err != nil {
cmdFailDurationTSO.Observe(time.Since(req.start).Seconds())
return 0, 0, err
}
physical, logical = req.physical, req.logical
now := time.Now()
cmdDurationWait.Observe(now.Sub(start).Seconds())
cmdDurationTSO.Observe(now.Sub(req.start).Seconds())
return
case <-req.requestCtx.Done():
return 0, 0, errors.WithStack(req.requestCtx.Err())
case <-req.clientCtx.Done():
return 0, 0, errors.WithStack(req.clientCtx.Err())
}
}
func (c *tsoClient) updateTSODispatcher() {
// Set up the new TSO dispatcher and batch controller.
c.GetTSOAllocators().Range(func(dcLocationKey, _ any) bool {
dcLocation := dcLocationKey.(string)
if !c.checkTSODispatcher(dcLocation) {
c.createTSODispatcher(dcLocation)
}
return true
})
// Clean up the unused TSO dispatcher
c.tsoDispatcher.Range(func(dcLocationKey, dispatcher any) bool {
dcLocation := dcLocationKey.(string)
// Skip the Global TSO Allocator
if dcLocation == globalDCLocation {
return true
}
if _, exist := c.GetTSOAllocators().Load(dcLocation); !exist {
log.Info("[tso] delete unused tso dispatcher", zap.String("dc-location", dcLocation))
dispatcher.(*tsoDispatcher).dispatcherCancel()
c.tsoDispatcher.Delete(dcLocation)
}
return true
})
}
type deadline struct {
timer *time.Timer
done chan struct{}
cancel context.CancelFunc
}
func newTSDeadline(
timeout time.Duration,
done chan struct{},
cancel context.CancelFunc,
) *deadline {
timer := timerpool.GlobalTimerPool.Get(timeout)
return &deadline{
timer: timer,
done: done,
cancel: cancel,
}
}
func (c *tsoClient) tsCancelLoop() {
defer c.wg.Done()
tsCancelLoopCtx, tsCancelLoopCancel := context.WithCancel(c.ctx)
defer tsCancelLoopCancel()
ticker := time.NewTicker(tsLoopDCCheckInterval)
defer ticker.Stop()
for {
// Watch every dc-location's tsDeadlineCh
c.GetTSOAllocators().Range(func(dcLocation, _ any) bool {
c.watchTSDeadline(tsCancelLoopCtx, dcLocation.(string))
return true
})
select {
case <-c.checkTSDeadlineCh:
continue
case <-ticker.C:
continue
case <-tsCancelLoopCtx.Done():
log.Info("exit tso requests cancel loop")
return
}
}
}
func (c *tsoClient) watchTSDeadline(ctx context.Context, dcLocation string) {
if _, exist := c.tsDeadline.Load(dcLocation); !exist {
tsDeadlineCh := make(chan *deadline, 1)
c.tsDeadline.Store(dcLocation, tsDeadlineCh)
go func(dc string, tsDeadlineCh <-chan *deadline) {
for {
select {
case d := <-tsDeadlineCh:
select {
case <-d.timer.C:
log.Error("[tso] tso request is canceled due to timeout", zap.String("dc-location", dc), errs.ZapError(errs.ErrClientGetTSOTimeout))
d.cancel()
timerpool.GlobalTimerPool.Put(d.timer)
case <-d.done:
timerpool.GlobalTimerPool.Put(d.timer)
case <-ctx.Done():
timerpool.GlobalTimerPool.Put(d.timer)
return
}
case <-ctx.Done():
return
}
}
}(dcLocation, tsDeadlineCh)
}
}
func (c *tsoClient) scheduleCheckTSDeadline() {
select {
case c.checkTSDeadlineCh <- struct{}{}:
default:
}
}
func (c *tsoClient) tsoDispatcherCheckLoop() {
defer c.wg.Done()
loopCtx, loopCancel := context.WithCancel(c.ctx)
defer loopCancel()
ticker := time.NewTicker(tsLoopDCCheckInterval)
defer ticker.Stop()
for {
c.updateTSODispatcher()
select {
case <-ticker.C:
case <-c.checkTSODispatcherCh:
case <-loopCtx.Done():
log.Info("exit tso dispatcher loop")
return
}
}
}
func (c *tsoClient) checkAllocator(
dispatcherCtx context.Context,
forwardCancel context.CancelFunc,
dc, forwardedHostTrim, addrTrim, url string,
updateAndClear func(newAddr string, connectionCtx *tsoConnectionContext)) {
defer func() {
// cancel the forward stream
forwardCancel()
requestForwarded.WithLabelValues(forwardedHostTrim, addrTrim).Set(0)
}()
cc, u := c.GetTSOAllocatorClientConnByDCLocation(dc)
var healthCli healthpb.HealthClient
ticker := time.NewTicker(time.Second)
defer ticker.Stop()
for {
// the pd/allocator leader change, we need to re-establish the stream
if u != url {
log.Info("[tso] the leader of the allocator leader is changed", zap.String("dc", dc), zap.String("origin", url), zap.String("new", u))
return
}
if healthCli == nil && cc != nil {
healthCli = healthpb.NewHealthClient(cc)
}
if healthCli != nil {
healthCtx, healthCancel := context.WithTimeout(dispatcherCtx, c.option.timeout)
resp, err := healthCli.Check(healthCtx, &healthpb.HealthCheckRequest{Service: ""})
failpoint.Inject("unreachableNetwork", func() {
resp.Status = healthpb.HealthCheckResponse_UNKNOWN
})
healthCancel()
if err == nil && resp.GetStatus() == healthpb.HealthCheckResponse_SERVING {
// create a stream of the original allocator
cctx, cancel := context.WithCancel(dispatcherCtx)
stream, err := c.tsoStreamBuilderFactory.makeBuilder(cc).build(cctx, cancel, c.option.timeout)
if err == nil && stream != nil {
log.Info("[tso] recover the original tso stream since the network has become normal", zap.String("dc", dc), zap.String("url", url))
updateAndClear(url, &tsoConnectionContext{url, stream, cctx, cancel})
return
}
}
}
select {
case <-dispatcherCtx.Done():
return
case <-ticker.C:
// To ensure we can get the latest allocator leader
// and once the leader is changed, we can exit this function.
cc, u = c.GetTSOAllocatorClientConnByDCLocation(dc)
}
}
}
func (c *tsoClient) checkTSODispatcher(dcLocation string) bool {
dispatcher, ok := c.tsoDispatcher.Load(dcLocation)
if !ok || dispatcher == nil {
return false
}
return true
}
func (c *tsoClient) createTSODispatcher(dcLocation string) {
dispatcherCtx, dispatcherCancel := context.WithCancel(c.ctx)
dispatcher := &tsoDispatcher{
dispatcherCancel: dispatcherCancel,
tsoBatchController: newTSOBatchController(
make(chan *tsoRequest, defaultMaxTSOBatchSize*2),
defaultMaxTSOBatchSize),
}
if _, ok := c.tsoDispatcher.LoadOrStore(dcLocation, dispatcher); !ok {
// Successfully stored the value. Start the following goroutine.
// Each goroutine is responsible for handling the tso stream request for its dc-location.
// The only case that will make the dispatcher goroutine exit
// is that the loopCtx is done, otherwise there is no circumstance
// this goroutine should exit.
c.wg.Add(1)
go c.handleDispatcher(dispatcherCtx, dcLocation, dispatcher.tsoBatchController)
log.Info("[tso] tso dispatcher created", zap.String("dc-location", dcLocation))
} else {
dispatcherCancel()
}
}
func (c *tsoClient) handleDispatcher(
dispatcherCtx context.Context,
dc string,
tbc *tsoBatchController) {
var (
err error
streamAddr string
stream tsoStream
streamCtx context.Context
cancel context.CancelFunc
// addr -> connectionContext
connectionCtxs sync.Map
opts []opentracing.StartSpanOption
)
defer func() {
log.Info("[tso] exit tso dispatcher", zap.String("dc-location", dc))
// Cancel all connections.
connectionCtxs.Range(func(_, cc any) bool {
cc.(*tsoConnectionContext).cancel()
return true
})
c.wg.Done()
}()
// Call updateTSOConnectionCtxs once to init the connectionCtxs first.
c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs)
// Only the Global TSO needs to watch the updateTSOConnectionCtxsCh to sense the
// change of the cluster when TSO Follower Proxy is enabled.
// TODO: support TSO Follower Proxy for the Local TSO.
if dc == globalDCLocation {
go func() {
var updateTicker = &time.Ticker{}
setNewUpdateTicker := func(ticker *time.Ticker) {
if updateTicker.C != nil {
updateTicker.Stop()
}
updateTicker = ticker
}
// Set to nil before returning to ensure that the existing ticker can be GC.
defer setNewUpdateTicker(nil)
for {
select {
case <-dispatcherCtx.Done():
return
case <-c.option.enableTSOFollowerProxyCh:
enableTSOFollowerProxy := c.option.getEnableTSOFollowerProxy()
log.Info("[tso] tso follower proxy status changed",
zap.String("dc-location", dc),
zap.Bool("enable", enableTSOFollowerProxy))
if enableTSOFollowerProxy && updateTicker.C == nil {
// Because the TSO Follower Proxy is enabled,
// the periodic check needs to be performed.
setNewUpdateTicker(time.NewTicker(memberUpdateInterval))
} else if !enableTSOFollowerProxy && updateTicker.C != nil {
// Because the TSO Follower Proxy is disabled,
// the periodic check needs to be turned off.
setNewUpdateTicker(&time.Ticker{})
} else {
// The status of TSO Follower Proxy does not change, and updateTSOConnectionCtxs is not triggered
continue
}
case <-updateTicker.C:
case <-c.updateTSOConnectionCtxsCh:
}
c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs)
}
}()
}
// Loop through each batch of TSO requests and send them for processing.
streamLoopTimer := time.NewTimer(c.option.timeout)
defer streamLoopTimer.Stop()
bo := retry.InitialBackoffer(updateMemberBackOffBaseTime, updateMemberTimeout, updateMemberBackOffBaseTime)
tsoBatchLoop:
for {
select {
case <-dispatcherCtx.Done():
return
default:
}
// Start to collect the TSO requests.
maxBatchWaitInterval := c.option.getMaxTSOBatchWaitInterval()
if err = tbc.fetchPendingRequests(dispatcherCtx, maxBatchWaitInterval); err != nil {
if err == context.Canceled {
log.Info("[tso] stop fetching the pending tso requests due to context canceled",
zap.String("dc-location", dc))
} else {
log.Error("[tso] fetch pending tso requests error",
zap.String("dc-location", dc),
errs.ZapError(errs.ErrClientGetTSO, err))
}
return
}
if maxBatchWaitInterval >= 0 {
tbc.adjustBestBatchSize()
}
// Stop the timer if it's not stopped.
if !streamLoopTimer.Stop() {
select {
case <-streamLoopTimer.C: // try to drain from the channel
default:
}
}
// We need be careful here, see more details in the comments of Timer.Reset.
// https://pkg.go.dev/time@master#Timer.Reset
streamLoopTimer.Reset(c.option.timeout)
// Choose a stream to send the TSO gRPC request.
streamChoosingLoop:
for {
connectionCtx := c.chooseStream(&connectionCtxs)
if connectionCtx != nil {
streamAddr, stream, streamCtx, cancel = connectionCtx.streamAddr, connectionCtx.stream, connectionCtx.ctx, connectionCtx.cancel
}
// Check stream and retry if necessary.
if stream == nil {
log.Info("[tso] tso stream is not ready", zap.String("dc", dc))
if c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs) {
continue streamChoosingLoop
}
timer := time.NewTimer(retryInterval)
select {
case <-dispatcherCtx.Done():
timer.Stop()
return
case <-streamLoopTimer.C:
err = errs.ErrClientCreateTSOStream.FastGenByArgs(errs.RetryTimeoutErr)
log.Error("[tso] create tso stream error", zap.String("dc-location", dc), errs.ZapError(err))
c.svcDiscovery.ScheduleCheckMemberChanged()
c.finishRequest(tbc.getCollectedRequests(), 0, 0, 0, errors.WithStack(err))
timer.Stop()
continue tsoBatchLoop
case <-timer.C:
timer.Stop()
continue streamChoosingLoop
}
}
select {
case <-streamCtx.Done():
log.Info("[tso] tso stream is canceled", zap.String("dc", dc), zap.String("stream-addr", streamAddr))
// Set `stream` to nil and remove this stream from the `connectionCtxs` due to being canceled.
connectionCtxs.Delete(streamAddr)
cancel()
stream = nil
continue
default:
break streamChoosingLoop
}
}
done := make(chan struct{})
dl := newTSDeadline(c.option.timeout, done, cancel)
tsDeadlineCh, ok := c.tsDeadline.Load(dc)
for !ok || tsDeadlineCh == nil {
c.scheduleCheckTSDeadline()
time.Sleep(time.Millisecond * 100)
tsDeadlineCh, ok = c.tsDeadline.Load(dc)
}
select {
case <-dispatcherCtx.Done():
return
case tsDeadlineCh.(chan *deadline) <- dl:
}
opts = extractSpanReference(tbc, opts[:0])
err = c.processRequests(stream, dc, tbc, opts)
close(done)
// If error happens during tso stream handling, reset stream and run the next trial.
if err != nil {
select {
case <-dispatcherCtx.Done():
return
default:
}
c.svcDiscovery.ScheduleCheckMemberChanged()
log.Error("[tso] getTS error after processing requests",
zap.String("dc-location", dc),
zap.String("stream-addr", streamAddr),
errs.ZapError(errs.ErrClientGetTSO, err))
// Set `stream` to nil and remove this stream from the `connectionCtxs` due to error.
connectionCtxs.Delete(streamAddr)
cancel()
stream = nil
// Because ScheduleCheckMemberChanged is asynchronous, if the leader changes, we better call `updateMember` ASAP.
if IsLeaderChange(err) {
if err := bo.Exec(dispatcherCtx, c.svcDiscovery.CheckMemberChanged); err != nil {
select {
case <-dispatcherCtx.Done():
return
default:
}
}
// Because the TSO Follower Proxy could be configured online,
// If we change it from on -> off, background updateTSOConnectionCtxs
// will cancel the current stream, then the EOF error caused by cancel()
// should not trigger the updateTSOConnectionCtxs here.
// So we should only call it when the leader changes.
c.updateTSOConnectionCtxs(dispatcherCtx, dc, &connectionCtxs)
}
}
}
}
// TSO Follower Proxy only supports the Global TSO proxy now.
func (c *tsoClient) allowTSOFollowerProxy(dc string) bool {
return dc == globalDCLocation && c.option.getEnableTSOFollowerProxy()
}
// chooseStream uses the reservoir sampling algorithm to randomly choose a connection.
// connectionCtxs will only have only one stream to choose when the TSO Follower Proxy is off.
func (c *tsoClient) chooseStream(connectionCtxs *sync.Map) (connectionCtx *tsoConnectionContext) {
idx := 0
connectionCtxs.Range(func(_, cc any) bool {
j := rand.Intn(idx + 1)
if j < 1 {
connectionCtx = cc.(*tsoConnectionContext)
}
idx++
return true
})
return connectionCtx
}
type tsoConnectionContext struct {
streamAddr string
// Current stream to send gRPC requests, pdpb.PD_TsoClient for a leader/follower in the PD cluster,
// or tsopb.TSO_TsoClient for a primary/secondary in the TSO cluster
stream tsoStream
ctx context.Context
cancel context.CancelFunc
}
func (c *tsoClient) updateTSOConnectionCtxs(updaterCtx context.Context, dc string, connectionCtxs *sync.Map) bool {
// Normal connection creating, it will be affected by the `enableForwarding`.
createTSOConnection := c.tryConnectToTSO
if c.allowTSOFollowerProxy(dc) {
createTSOConnection = c.tryConnectToTSOWithProxy
}
if err := createTSOConnection(updaterCtx, dc, connectionCtxs); err != nil {
log.Error("[tso] update connection contexts failed", zap.String("dc", dc), errs.ZapError(err))
return false
}
return true
}
// tryConnectToTSO will try to connect to the TSO allocator leader. If the connection becomes unreachable
// and enableForwarding is true, it will create a new connection to a follower to do the forwarding,
// while a new daemon will be created also to switch back to a normal leader connection ASAP the
// connection comes back to normal.
func (c *tsoClient) tryConnectToTSO(
dispatcherCtx context.Context,
dc string,
connectionCtxs *sync.Map,
) error {
var (
networkErrNum uint64
err error
stream tsoStream
url string
cc *grpc.ClientConn
)
updateAndClear := func(newAddr string, connectionCtx *tsoConnectionContext) {
if cc, loaded := connectionCtxs.LoadOrStore(newAddr, connectionCtx); loaded {
// If the previous connection still exists, we should close it first.
cc.(*tsoConnectionContext).cancel()
connectionCtxs.Store(newAddr, connectionCtx)
}
connectionCtxs.Range(func(addr, cc any) bool {
if addr.(string) != newAddr {
cc.(*tsoConnectionContext).cancel()
connectionCtxs.Delete(addr)
}
return true
})
}
// retry several times before falling back to the follower when the network problem happens
ticker := time.NewTicker(retryInterval)
defer ticker.Stop()
for i := 0; i < maxRetryTimes; i++ {
c.svcDiscovery.ScheduleCheckMemberChanged()
cc, url = c.GetTSOAllocatorClientConnByDCLocation(dc)
if cc != nil {
cctx, cancel := context.WithCancel(dispatcherCtx)
stream, err = c.tsoStreamBuilderFactory.makeBuilder(cc).build(cctx, cancel, c.option.timeout)
failpoint.Inject("unreachableNetwork", func() {
stream = nil
err = status.New(codes.Unavailable, "unavailable").Err()
})
if stream != nil && err == nil {
updateAndClear(url, &tsoConnectionContext{url, stream, cctx, cancel})
return nil
}
if err != nil && c.option.enableForwarding {
// The reason we need to judge if the error code is equal to "Canceled" here is that
// when we create a stream we use a goroutine to manually control the timeout of the connection.
// There is no need to wait for the transport layer timeout which can reduce the time of unavailability.
// But it conflicts with the retry mechanism since we use the error code to decide if it is caused by network error.
// And actually the `Canceled` error can be regarded as a kind of network error in some way.
if rpcErr, ok := status.FromError(err); ok && (isNetworkError(rpcErr.Code()) || rpcErr.Code() == codes.Canceled) {
networkErrNum++
}
}
cancel()
} else {
networkErrNum++
}
select {
case <-dispatcherCtx.Done():
return err
case <-ticker.C:
}
}
if networkErrNum == maxRetryTimes {
// encounter the network error
backupClientConn, addr := c.backupClientConn()
if backupClientConn != nil {
log.Info("[tso] fall back to use follower to forward tso stream", zap.String("dc", dc), zap.String("addr", addr))
forwardedHost, ok := c.GetTSOAllocatorServingAddrByDCLocation(dc)
if !ok {
return errors.Errorf("cannot find the allocator leader in %s", dc)
}
// create the follower stream
cctx, cancel := context.WithCancel(dispatcherCtx)
cctx = grpcutil.BuildForwardContext(cctx, forwardedHost)
stream, err = c.tsoStreamBuilderFactory.makeBuilder(backupClientConn).build(cctx, cancel, c.option.timeout)
if err == nil {
forwardedHostTrim := trimHTTPPrefix(forwardedHost)
addrTrim := trimHTTPPrefix(addr)
// the goroutine is used to check the network and change back to the original stream
go c.checkAllocator(dispatcherCtx, cancel, dc, forwardedHostTrim, addrTrim, url, updateAndClear)
requestForwarded.WithLabelValues(forwardedHostTrim, addrTrim).Set(1)
updateAndClear(addr, &tsoConnectionContext{addr, stream, cctx, cancel})
return nil
}
cancel()
}
}
return err
}
// getAllTSOStreamBuilders returns a TSO stream builder for every service endpoint of TSO leader/followers
// or of keyspace group primary/secondaries.
func (c *tsoClient) getAllTSOStreamBuilders() map[string]tsoStreamBuilder {
var (
addrs = c.svcDiscovery.GetServiceURLs()
streamBuilders = make(map[string]tsoStreamBuilder, len(addrs))
cc *grpc.ClientConn
err error
)
for _, addr := range addrs {
if len(addrs) == 0 {
continue
}
if cc, err = c.svcDiscovery.GetOrCreateGRPCConn(addr); err != nil {
continue
}
healthCtx, healthCancel := context.WithTimeout(c.ctx, c.option.timeout)
resp, err := healthpb.NewHealthClient(cc).Check(healthCtx, &healthpb.HealthCheckRequest{Service: ""})
healthCancel()
if err == nil && resp.GetStatus() == healthpb.HealthCheckResponse_SERVING {
streamBuilders[addr] = c.tsoStreamBuilderFactory.makeBuilder(cc)
}
}
return streamBuilders
}
// tryConnectToTSOWithProxy will create multiple streams to all the service endpoints to work as
// a TSO proxy to reduce the pressure of the main serving service endpoint.
func (c *tsoClient) tryConnectToTSOWithProxy(dispatcherCtx context.Context, dc string, connectionCtxs *sync.Map) error {
tsoStreamBuilders := c.getAllTSOStreamBuilders()
leaderAddr := c.svcDiscovery.GetServingAddr()
forwardedHost, ok := c.GetTSOAllocatorServingAddrByDCLocation(dc)
if !ok {
return errors.Errorf("cannot find the allocator leader in %s", dc)
}
// GC the stale one.
connectionCtxs.Range(func(addr, cc any) bool {
addrStr := addr.(string)
if _, ok := tsoStreamBuilders[addrStr]; !ok {
log.Info("[tso] remove the stale tso stream",
zap.String("dc", dc),
zap.String("addr", addrStr))
cc.(*tsoConnectionContext).cancel()
connectionCtxs.Delete(addr)
}
return true
})
// Update the missing one.
for addr, tsoStreamBuilder := range tsoStreamBuilders {
if _, ok = connectionCtxs.Load(addr); ok {
continue
}
log.Info("[tso] try to create tso stream",
zap.String("dc", dc), zap.String("addr", addr))
cctx, cancel := context.WithCancel(dispatcherCtx)
// Do not proxy the leader client.
if addr != leaderAddr {
log.Info("[tso] use follower to forward tso stream to do the proxy",
zap.String("dc", dc), zap.String("addr", addr))
cctx = grpcutil.BuildForwardContext(cctx, forwardedHost)
}
// Create the TSO stream.
stream, err := tsoStreamBuilder.build(cctx, cancel, c.option.timeout)
if err == nil {
if addr != leaderAddr {
forwardedHostTrim := trimHTTPPrefix(forwardedHost)
addrTrim := trimHTTPPrefix(addr)
requestForwarded.WithLabelValues(forwardedHostTrim, addrTrim).Set(1)
}
connectionCtxs.Store(addr, &tsoConnectionContext{addr, stream, cctx, cancel})
continue
}
log.Error("[tso] create the tso stream failed",
zap.String("dc", dc), zap.String("addr", addr), errs.ZapError(err))
cancel()
}
return nil
}
func extractSpanReference(tbc *tsoBatchController, opts []opentracing.StartSpanOption) []opentracing.StartSpanOption {
for _, req := range tbc.getCollectedRequests() {
if span := opentracing.SpanFromContext(req.requestCtx); span != nil {
opts = append(opts, opentracing.ChildOf(span.Context()))
}
}
return opts
}
func (c *tsoClient) processRequests(
stream tsoStream, dcLocation string, tbc *tsoBatchController, opts []opentracing.StartSpanOption,
) error {
if len(opts) > 0 {
span := opentracing.StartSpan("pdclient.processRequests", opts...)
defer span.Finish()
}
requests := tbc.getCollectedRequests()
for _, req := range requests {
defer trace.StartRegion(req.requestCtx, "tsoReqSend").End()
}
count := int64(len(requests))
reqKeyspaceGroupID := c.svcDiscovery.GetKeyspaceGroupID()
respKeyspaceGroupID, physical, logical, suffixBits, err := stream.processRequests(
c.svcDiscovery.GetClusterID(), c.svcDiscovery.GetKeyspaceID(), reqKeyspaceGroupID,
dcLocation, requests, tbc.batchStartTime)
if err != nil {
c.finishRequest(requests, 0, 0, 0, err)
return err
}
// `logical` is the largest ts's logical part here, we need to do the subtracting before we finish each TSO request.
firstLogical := tsoutil.AddLogical(logical, -count+1, suffixBits)
curTSOInfo := &tsoInfo{
tsoServer: stream.getServerAddr(),
reqKeyspaceGroupID: reqKeyspaceGroupID,
respKeyspaceGroupID: respKeyspaceGroupID,
respReceivedAt: time.Now(),
physical: physical,
logical: tsoutil.AddLogical(firstLogical, count-1, suffixBits),
}
c.compareAndSwapTS(dcLocation, curTSOInfo, physical, firstLogical)
c.finishRequest(requests, physical, firstLogical, suffixBits, nil)
return nil
}
func (c *tsoClient) compareAndSwapTS(
dcLocation string,
curTSOInfo *tsoInfo,
physical, firstLogical int64,
) {
val, loaded := c.lastTSOInfoMap.LoadOrStore(dcLocation, curTSOInfo)
if !loaded {
return
}
lastTSOInfo := val.(*tsoInfo)
if lastTSOInfo.respKeyspaceGroupID != curTSOInfo.respKeyspaceGroupID {
log.Info("[tso] keyspace group changed",
zap.String("dc-location", dcLocation),
zap.Uint32("old-group-id", lastTSOInfo.respKeyspaceGroupID),
zap.Uint32("new-group-id", curTSOInfo.respKeyspaceGroupID))
}
// 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]. lastTSOInfo.logical stores the logical part of the largest ts returned
// last time.
if tsoutil.TSLessEqual(physical, firstLogical, lastTSOInfo.physical, lastTSOInfo.logical) {
log.Panic("[tso] timestamp fallback",
zap.String("dc-location", dcLocation),
zap.Uint32("keyspace", c.svcDiscovery.GetKeyspaceID()),
zap.String("last-ts", fmt.Sprintf("(%d, %d)", lastTSOInfo.physical, lastTSOInfo.logical)),
zap.String("cur-ts", fmt.Sprintf("(%d, %d)", physical, firstLogical)),
zap.String("last-tso-server", lastTSOInfo.tsoServer),
zap.String("cur-tso-server", curTSOInfo.tsoServer),
zap.Uint32("last-keyspace-group-in-request", lastTSOInfo.reqKeyspaceGroupID),
zap.Uint32("cur-keyspace-group-in-request", curTSOInfo.reqKeyspaceGroupID),
zap.Uint32("last-keyspace-group-in-response", lastTSOInfo.respKeyspaceGroupID),
zap.Uint32("cur-keyspace-group-in-response", curTSOInfo.respKeyspaceGroupID),
zap.Time("last-response-received-at", lastTSOInfo.respReceivedAt),
zap.Time("cur-response-received-at", curTSOInfo.respReceivedAt))
}
lastTSOInfo.tsoServer = curTSOInfo.tsoServer
lastTSOInfo.reqKeyspaceGroupID = curTSOInfo.reqKeyspaceGroupID
lastTSOInfo.respKeyspaceGroupID = curTSOInfo.respKeyspaceGroupID
lastTSOInfo.respReceivedAt = curTSOInfo.respReceivedAt
lastTSOInfo.physical = curTSOInfo.physical
lastTSOInfo.logical = curTSOInfo.logical
}
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, tsoutil.AddLogical(firstLogical, int64(i), suffixBits)
defer trace.StartRegion(requests[i].requestCtx, "tsoReqDequeue").End()
requests[i].done <- err
}
}