tidb collector 源码
tidb collector 代码
文件路径：/br/pkg/streamhelper/collector.go
// Copyright 2022 PingCAP, Inc. Licensed under Apache-2.0.
package streamhelper
import (
"context"
"fmt"
"strconv"
"strings"
"sync"
"sync/atomic"
"github.com/pingcap/errors"
logbackup "github.com/pingcap/kvproto/pkg/logbackuppb"
"github.com/pingcap/log"
"github.com/pingcap/tidb/br/pkg/logutil"
"github.com/pingcap/tidb/br/pkg/utils"
"github.com/pingcap/tidb/kv"
"github.com/pingcap/tidb/metrics"
"go.uber.org/zap"
)
const (
defaultBatchSize = 1024
)
type onSuccessHook = func(uint64, kv.KeyRange)
// storeCollector collects the region checkpoints from some store.
// it receives requests from the input channel, batching the requests, and send them to the store.
// because the server supports batching, the range of request regions can be discrete.
// note this is a temporary struct, its lifetime is shorter that the tick of advancer.
type storeCollector struct {
storeID uint64
batchSize int
service LogBackupService
input chan RegionWithLeader
// the oneshot error reporter.
err *atomic.Value
// whether the recv and send loop has exited.
doneMessenger chan struct{}
onSuccess onSuccessHook
// concurrency safety:
// those fields should only be write on the goroutine running `recvLoop`.
// Once it exits, we can read those fields.
currentRequest logbackup.GetLastFlushTSOfRegionRequest
checkpoint uint64
inconsistent []kv.KeyRange
regionMap map[uint64]kv.KeyRange
}
func newStoreCollector(storeID uint64, srv LogBackupService) *storeCollector {
return &storeCollector{
storeID: storeID,
batchSize: defaultBatchSize,
service: srv,
input: make(chan RegionWithLeader, defaultBatchSize),
err: new(atomic.Value),
doneMessenger: make(chan struct{}),
regionMap: make(map[uint64]kv.KeyRange),
}
}
func (c *storeCollector) reportErr(err error) {
if oldErr := c.Err(); oldErr != nil {
log.Warn("reporting error twice, ignoring", logutil.AShortError("old", err), logutil.AShortError("new", oldErr))
return
}
c.err.Store(err)
}
func (c *storeCollector) Err() error {
err, ok := c.err.Load().(error)
if !ok {
return nil
}
return err
}
func (c *storeCollector) setOnSuccessHook(hook onSuccessHook) {
c.onSuccess = hook
}
func (c *storeCollector) begin(ctx context.Context) {
err := c.recvLoop(ctx)
if err != nil {
log.Warn("collector loop meet error", logutil.ShortError(err))
c.reportErr(err)
}
close(c.doneMessenger)
}
func (c *storeCollector) recvLoop(ctx context.Context) (err error) {
defer utils.PanicToErr(&err)
log.Debug("Begin recv loop", zap.Uint64("store", c.storeID))
for {
select {
case <-ctx.Done():
return ctx.Err()
case r, ok := <-c.input:
if !ok {
return c.sendPendingRequests(ctx)
}
if r.Leader.StoreId != c.storeID {
log.Warn("trying to request to store which isn't the leader of region.",
zap.Uint64("region", r.Region.Id),
zap.Uint64("target-store", c.storeID),
zap.Uint64("leader", r.Leader.StoreId),
)
}
c.appendRegionMap(r)
c.currentRequest.Regions = append(c.currentRequest.Regions, &logbackup.RegionIdentity{
Id: r.Region.GetId(),
EpochVersion: r.Region.GetRegionEpoch().GetVersion(),
})
if len(c.currentRequest.Regions) >= c.batchSize {
err := c.sendPendingRequests(ctx)
if err != nil {
return err
}
}
}
}
}
func (c *storeCollector) appendRegionMap(r RegionWithLeader) {
c.regionMap[r.Region.GetId()] = kv.KeyRange{StartKey: r.Region.StartKey, EndKey: r.Region.EndKey}
}
type StoreCheckpoints struct {
HasCheckpoint bool
Checkpoint uint64
FailureSubRanges []kv.KeyRange
}
func (s *StoreCheckpoints) merge(other StoreCheckpoints) {
if other.HasCheckpoint && (other.Checkpoint < s.Checkpoint || !s.HasCheckpoint) {
s.Checkpoint = other.Checkpoint
s.HasCheckpoint = true
}
s.FailureSubRanges = append(s.FailureSubRanges, other.FailureSubRanges...)
}
func (s *StoreCheckpoints) String() string {
sb := new(strings.Builder)
sb.WriteString("StoreCheckpoints:")
if s.HasCheckpoint {
sb.WriteString(strconv.Itoa(int(s.Checkpoint)))
} else {
sb.WriteString("none")
}
fmt.Fprintf(sb, ":(remaining %d ranges)", len(s.FailureSubRanges))
return sb.String()
}
func (c *storeCollector) spawn(ctx context.Context) func(context.Context) (StoreCheckpoints, error) {
go c.begin(ctx)
return func(cx context.Context) (StoreCheckpoints, error) {
close(c.input)
select {
case <-cx.Done():
return StoreCheckpoints{}, cx.Err()
case <-c.doneMessenger:
}
if err := c.Err(); err != nil {
return StoreCheckpoints{}, err
}
sc := StoreCheckpoints{
HasCheckpoint: c.checkpoint != 0,
Checkpoint: c.checkpoint,
FailureSubRanges: c.inconsistent,
}
return sc, nil
}
}
func (c *storeCollector) sendPendingRequests(ctx context.Context) error {
log.Debug("sending batch", zap.Int("size", len(c.currentRequest.Regions)), zap.Uint64("store", c.storeID))
defer log.Debug("sending batch done", zap.Uint64("store", c.storeID))
cli, err := c.service.GetLogBackupClient(ctx, c.storeID)
if err != nil {
return err
}
cps, err := cli.GetLastFlushTSOfRegion(ctx, &c.currentRequest)
if err != nil {
return err
}
metrics.GetCheckpointBatchSize.WithLabelValues("checkpoint").Observe(float64(len(c.currentRequest.GetRegions())))
c.currentRequest = logbackup.GetLastFlushTSOfRegionRequest{}
for _, checkpoint := range cps.Checkpoints {
if checkpoint.Err != nil {
log.Debug("failed to get region checkpoint", zap.Stringer("err", checkpoint.Err))
if checkpoint.Err.EpochNotMatch != nil {
metrics.RegionCheckpointFailure.WithLabelValues("epoch-not-match").Inc()
}
if checkpoint.Err.NotLeader != nil {
metrics.RegionCheckpointFailure.WithLabelValues("not-leader").Inc()
}
metrics.RegionCheckpointRequest.WithLabelValues("fail").Inc()
c.inconsistent = append(c.inconsistent, c.regionMap[checkpoint.Region.Id])
} else {
metrics.RegionCheckpointRequest.WithLabelValues("success").Inc()
if c.onSuccess != nil {
c.onSuccess(checkpoint.Checkpoint, c.regionMap[checkpoint.Region.Id])
}
// assuming the checkpoint would never be zero, use it as the placeholder. (1970 is so far away...)
if checkpoint.Checkpoint < c.checkpoint || c.checkpoint == 0 {
c.checkpoint = checkpoint.Checkpoint
}
}
}
return nil
}
type runningStoreCollector struct {
collector *storeCollector
wait func(context.Context) (StoreCheckpoints, error)
}
// clusterCollector is the controller for collecting region checkpoints for the cluster.
// It creates multi store collectors.
/*
┌──────────────────────┐ Requesting ┌────────────┐
┌─►│ StoreCollector[id=1] ├─────────────►│ TiKV[id=1] │
│ └──────────────────────┘ └────────────┘
│
│Owns
┌──────────────────┐ │ ┌──────────────────────┐ Requesting ┌────────────┐
│ ClusterCollector ├─────┼─►│ StoreCollector[id=4] ├─────────────►│ TiKV[id=4] │
└──────────────────┘ │ └──────────────────────┘ └────────────┘
│
│
│ ┌──────────────────────┐ Requesting ┌────────────┐
└─►│ StoreCollector[id=5] ├─────────────►│ TiKV[id=5] │
└──────────────────────┘ └────────────┘
*/
type clusterCollector struct {
mu sync.Mutex
collectors map[uint64]runningStoreCollector
noLeaders []kv.KeyRange
onSuccess onSuccessHook
// The context for spawning sub collectors.
// Because the collectors are running lazily,
// keep the initial context for all subsequent goroutines,
// so we can make sure we can cancel all subtasks.
masterCtx context.Context
cancel context.CancelFunc
srv LogBackupService
}
// NewClusterCollector creates a new cluster collector.
// collectors are the structure transform region information to checkpoint information,
// by requesting the checkpoint of regions in the store.
func NewClusterCollector(ctx context.Context, srv LogBackupService) *clusterCollector {
cx, cancel := context.WithCancel(ctx)
return &clusterCollector{
collectors: map[uint64]runningStoreCollector{},
masterCtx: cx,
cancel: cancel,
srv: srv,
}
}
// setOnSuccessHook sets the hook when getting checkpoint of some region.
func (c *clusterCollector) setOnSuccessHook(hook onSuccessHook) {
c.onSuccess = hook
}
// collectRegion adds a region to the collector.
func (c *clusterCollector) collectRegion(r RegionWithLeader) error {
c.mu.Lock()
defer c.mu.Unlock()
if c.masterCtx.Err() != nil {
return nil
}
if r.Leader.GetStoreId() == 0 {
log.Warn("there are regions without leader", zap.Uint64("region", r.Region.GetId()))
c.noLeaders = append(c.noLeaders, kv.KeyRange{StartKey: r.Region.StartKey, EndKey: r.Region.EndKey})
return nil
}
leader := r.Leader.StoreId
_, ok := c.collectors[leader]
if !ok {
coll := newStoreCollector(leader, c.srv)
if c.onSuccess != nil {
coll.setOnSuccessHook(c.onSuccess)
}
c.collectors[leader] = runningStoreCollector{
collector: coll,
wait: coll.spawn(c.masterCtx),
}
}
sc := c.collectors[leader].collector
select {
case sc.input <- r:
return nil
case <-sc.doneMessenger:
err := sc.Err()
if err != nil {
c.cancel()
}
return err
}
}
// Finish finishes collecting the region checkpoints, wait and returning the final result.
// Note this takes the ownership of this collector, you may create a new collector for next use.
func (c *clusterCollector) Finish(ctx context.Context) (StoreCheckpoints, error) {
defer c.cancel()
result := StoreCheckpoints{FailureSubRanges: c.noLeaders}
for id, coll := range c.collectors {
r, err := coll.wait(ctx)
if err != nil {
return StoreCheckpoints{}, errors.Annotatef(err, "store %d", id)
}
result.merge(r)
log.Debug("get checkpoint", zap.Stringer("checkpoint", &r), zap.Stringer("merged", &result))
}
return result, nil
}
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