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tso: improve skipping sync condition and add more logs (#7139)
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close #7138

Only skip the sync if the following conditions are met:

1. The timestamp in memory has been initialized.
2. The last saved timestamp in etcd is not zero.
3. The last saved timestamp in memory is not zero.
4. The last saved timestamp in etcd is equal to the last saved timestamp in memory.

Signed-off-by: JmPotato <ghzpotato@gmail.com>

Co-authored-by: ti-chi-bot[bot] <108142056+ti-chi-bot[bot]@users.noreply.github.com>
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@JmPotato @ti-chi-bot
JmPotato and ti-chi-bot[bot] authored Sep 25, 2023
1 parent 3c632b1 commit 7e6cd0a
Showing 1 changed file with 34 additions and 10 deletions.
44 changes: 34 additions & 10 deletions pkg/tso/tso.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -27,6 +27,7 @@ import (
"github.com/tikv/pd/pkg/election"
"github.com/tikv/pd/pkg/errs"
"github.com/tikv/pd/pkg/storage/endpoint"
"github.com/tikv/pd/pkg/utils/logutil"
"github.com/tikv/pd/pkg/utils/syncutil"
"github.com/tikv/pd/pkg/utils/tsoutil"
"github.com/tikv/pd/pkg/utils/typeutil"
Expand Down Expand Up @@ -156,6 +157,7 @@ func (t *timestampOracle) GetTimestampPath() string {

// SyncTimestamp is used to synchronize the timestamp.
func (t *timestampOracle) SyncTimestamp(leadership *election.Leadership) error {
log.Info("start to sync timestamp", logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0))
t.metrics.syncEvent.Inc()

failpoint.Inject("delaySyncTimestamp", func() {
Expand All @@ -167,9 +169,20 @@ func (t *timestampOracle) SyncTimestamp(leadership *election.Leadership) error {
return err
}
lastSavedTime := t.getLastSavedTime()
// If `lastSavedTime` is not zero, it means that the `timestampOracle` has already been initialized
// before, so we could safely skip the sync if `lastSavedTime` is equal to `last`.
if lastSavedTime != typeutil.ZeroTime && typeutil.SubRealTimeByWallClock(lastSavedTime, last) == 0 {
// We could skip the synchronization if the following conditions are met:
// 1. The timestamp in memory has been initialized.
// 2. The last saved timestamp in etcd is not zero.
// 3. The last saved timestamp in memory is not zero.
// 4. The last saved timestamp in etcd is equal to the last saved timestamp in memory.
// 1 is to ensure the timestamp in memory could always be initialized. 2-4 are to ensure
// the synchronization could be skipped safely.
if t.isInitialized() &&
last != typeutil.ZeroTime &&
lastSavedTime != typeutil.ZeroTime &&
typeutil.SubRealTimeByWallClock(last, lastSavedTime) == 0 {
log.Info("skip sync timestamp",
logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0),
zap.Time("last", last), zap.Time("last-saved", lastSavedTime))
t.metrics.skipSyncEvent.Inc()
return nil
}
Expand All @@ -185,7 +198,10 @@ func (t *timestampOracle) SyncTimestamp(leadership *election.Leadership) error {
// the timestamp allocation will start from the saved etcd timestamp temporarily.
if typeutil.SubRealTimeByWallClock(next, last) < UpdateTimestampGuard {
log.Warn("system time may be incorrect",
zap.Time("last", last), zap.Time("next", next), errs.ZapError(errs.ErrIncorrectSystemTime))
logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0),
zap.Time("last", last), zap.Time("last-saved", lastSavedTime),
zap.Time("next", next),
errs.ZapError(errs.ErrIncorrectSystemTime))
next = last.Add(UpdateTimestampGuard)
}
failpoint.Inject("failedToSaveTimestamp", func() {
Expand All @@ -197,11 +213,14 @@ func (t *timestampOracle) SyncTimestamp(leadership *election.Leadership) error {
t.metrics.errSaveSyncTSEvent.Inc()
return err
}
t.metrics.syncSaveDuration.Observe(time.Since(start).Seconds())
t.lastSavedTime.Store(save)
t.metrics.syncSaveDuration.Observe(time.Since(start).Seconds())

t.metrics.syncOKEvent.Inc()
log.Info("sync and save timestamp", zap.Time("last", last), zap.Time("save", save), zap.Time("next", next))
log.Info("sync and save timestamp",
logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0),
zap.Time("last", last), zap.Time("last-saved", lastSavedTime),
zap.Time("save", save), zap.Time("next", next))
// save into memory
t.setTSOPhysical(next, true)
return nil
Expand Down Expand Up @@ -267,8 +286,8 @@ func (t *timestampOracle) resetUserTimestampInner(leadership *election.Leadershi
t.metrics.errSaveResetTSEvent.Inc()
return err
}
t.metrics.resetSaveDuration.Observe(time.Since(start).Seconds())
t.lastSavedTime.Store(save)
t.metrics.resetSaveDuration.Observe(time.Since(start).Seconds())
}
// save into memory only if nextPhysical or nextLogical is greater.
t.tsoMux.physical = nextPhysical
Expand Down Expand Up @@ -313,6 +332,7 @@ func (t *timestampOracle) UpdateTimestamp(leadership *election.Leadership) error
jetLag := typeutil.SubRealTimeByWallClock(now, prevPhysical)
if jetLag > 3*t.updatePhysicalInterval && jetLag > jetLagWarningThreshold {
log.Warn("clock offset",
logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0),
zap.Duration("jet-lag", jetLag),
zap.Time("prev-physical", prevPhysical),
zap.Time("now", now),
Expand All @@ -331,7 +351,9 @@ func (t *timestampOracle) UpdateTimestamp(leadership *election.Leadership) error
} else if prevLogical > maxLogical/2 {
// The reason choosing maxLogical/2 here is that it's big enough for common cases.
// Because there is enough timestamp can be allocated before next update.
log.Warn("the logical time may be not enough", zap.Int64("prev-logical", prevLogical))
log.Warn("the logical time may be not enough",
logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0),
zap.Int64("prev-logical", prevLogical))
next = prevPhysical.Add(time.Millisecond)
} else {
// It will still use the previous physical time to alloc the timestamp.
Expand All @@ -346,14 +368,15 @@ func (t *timestampOracle) UpdateTimestamp(leadership *election.Leadership) error
start := time.Now()
if err := t.storage.SaveTimestamp(t.GetTimestampPath(), save); err != nil {
log.Warn("save timestamp failed",
logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0),
zap.String("dc-location", t.dcLocation),
zap.String("timestamp-path", t.GetTimestampPath()),
zap.Error(err))
t.metrics.errSaveUpdateTSEvent.Inc()
return err
}
t.metrics.updateSaveDuration.Observe(time.Since(start).Seconds())
t.lastSavedTime.Store(save)
t.metrics.updateSaveDuration.Observe(time.Since(start).Seconds())
}
// save into memory
t.setTSOPhysical(next, false)
Expand Down Expand Up @@ -388,6 +411,7 @@ func (t *timestampOracle) getTS(ctx context.Context, leadership *election.Leader
}
if resp.GetLogical() >= maxLogical {
log.Warn("logical part outside of max logical interval, please check ntp time, or adjust config item `tso-update-physical-interval`",
logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0),
zap.Reflect("response", resp),
zap.Int("retry-count", i), errs.ZapError(errs.ErrLogicOverflow))
t.metrics.logicalOverflowEvent.Inc()
Expand All @@ -409,7 +433,7 @@ func (t *timestampOracle) getTS(ctx context.Context, leadership *election.Leader
func (t *timestampOracle) ResetTimestamp() {
t.tsoMux.Lock()
defer t.tsoMux.Unlock()
log.Info("reset the timestamp in memory")
log.Info("reset the timestamp in memory", logutil.CondUint32("keyspace-group-id", t.keyspaceGroupID, t.keyspaceGroupID > 0))
t.tsoMux.physical = typeutil.ZeroTime
t.tsoMux.logical = 0
t.tsoMux.updateTime = typeutil.ZeroTime
Expand Down

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