config: enable user configuration for retry strategy. (#1055)

Signed-off-by: Smityz <[email protected]>
Co-authored-by: disksing <[email protected]>

config/retry/config.go

@@ -0,0 +1,207 @@
+// Copyright 2021 TiKV 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.
+
+// NOTE: The code in this file is based on code from the
+// TiDB project, licensed under the Apache License v 2.0
+//
+// https://github.com/pingcap/tidb/tree/cc5e161ac06827589c4966674597c137cc9e809c/store/tikv/retry/config.go
+//
+
+// Copyright 2021 PingCAP, Inc.
+//
+// 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 retry
+
+import (
+	"context"
+	"math"
+	"math/rand"
+	"strings"
+	"time"
+
+	"github.com/prometheus/client_golang/prometheus"
+	tikverr "github.com/tikv/client-go/v2/error"
+	"github.com/tikv/client-go/v2/internal/logutil"
+	"github.com/tikv/client-go/v2/kv"
+	"github.com/tikv/client-go/v2/metrics"
+	"go.uber.org/zap"
+)
+
+// Config is the configuration of the Backoff function.
+type Config struct {
+	name   string
+	metric *prometheus.Observer
+	fnCfg  *BackoffFnCfg
+	err    error
+}
+
+// backoffFn is the backoff function which compute the sleep time and do sleep.
+type backoffFn func(ctx context.Context, maxSleepMs int) int
+
+func (c *Config) createBackoffFn(vars *kv.Variables) backoffFn {
+	if strings.EqualFold(c.name, txnLockFastName) {
+		return newBackoffFn(vars.BackoffLockFast, c.fnCfg.cap, c.fnCfg.jitter)
+	}
+	return newBackoffFn(c.fnCfg.base, c.fnCfg.cap, c.fnCfg.jitter)
+}
+
+// BackoffFnCfg is the configuration for the backoff func which implements exponential backoff with
+// optional jitters.
+// See http://www.awsarchitectureblog.com/2015/03/backoff.html
+type BackoffFnCfg struct {
+	base   int
+	cap    int
+	jitter int
+}
+
+// NewBackoffFnCfg creates the config for BackoffFn.
+func NewBackoffFnCfg(base, cap, jitter int) *BackoffFnCfg {
+	return &BackoffFnCfg{
+		base,
+		cap,
+		jitter,
+	}
+}
+
+// NewConfig creates a new Config for the Backoff operation.
+func NewConfig(name string, metric *prometheus.Observer, backoffFnCfg *BackoffFnCfg, err error) *Config {
+	return &Config{
+		name:   name,
+		metric: metric,
+		fnCfg:  backoffFnCfg,
+		err:    err,
+	}
+}
+
+func (c *Config) String() string {
+	return c.name
+}
+
+// SetErrors sets a more detailed error instead of the default bo config.
+func (c *Config) SetErrors(err error) {
+	c.err = err
+}
+
+func (c *Config) SetBackoffFnCfg(fnCfg *BackoffFnCfg) {
+	c.fnCfg = fnCfg
+}
+
+const txnLockFastName = "txnLockFast"
+
+// Backoff Config variables.
+var (
+	// TODO: distinguish tikv and tiflash in metrics
+	BoTiKVRPC    = NewConfig("tikvRPC", &metrics.BackoffHistogramRPC, NewBackoffFnCfg(100, 2000, EqualJitter), tikverr.ErrTiKVServerTimeout)
+	BoTiFlashRPC = NewConfig("tiflashRPC", &metrics.BackoffHistogramRPC, NewBackoffFnCfg(100, 2000, EqualJitter), tikverr.ErrTiFlashServerTimeout)
+	BoTxnLock    = NewConfig("txnLock", &metrics.BackoffHistogramLock, NewBackoffFnCfg(100, 3000, EqualJitter), tikverr.ErrResolveLockTimeout)
+	BoPDRPC      = NewConfig("pdRPC", &metrics.BackoffHistogramPD, NewBackoffFnCfg(500, 3000, EqualJitter), tikverr.NewErrPDServerTimeout(""))
+	// change base time to 2ms, because it may recover soon.
+	BoRegionMiss               = NewConfig("regionMiss", &metrics.BackoffHistogramRegionMiss, NewBackoffFnCfg(2, 500, NoJitter), tikverr.ErrRegionUnavailable)
+	BoRegionScheduling         = NewConfig("regionScheduling", &metrics.BackoffHistogramRegionScheduling, NewBackoffFnCfg(2, 500, NoJitter), tikverr.ErrRegionUnavailable)
+	BoTiKVServerBusy           = NewConfig("tikvServerBusy", &metrics.BackoffHistogramServerBusy, NewBackoffFnCfg(2000, 10000, EqualJitter), tikverr.ErrTiKVServerBusy)
+	BoTiKVDiskFull             = NewConfig("tikvDiskFull", &metrics.BackoffHistogramTiKVDiskFull, NewBackoffFnCfg(500, 5000, NoJitter), tikverr.ErrTiKVDiskFull)
+	BoRegionRecoveryInProgress = NewConfig("regionRecoveryInProgress", &metrics.BackoffHistogramRegionRecoveryInProgress, NewBackoffFnCfg(100, 10000, EqualJitter), tikverr.ErrRegionRecoveryInProgress)
+	BoTiFlashServerBusy        = NewConfig("tiflashServerBusy", &metrics.BackoffHistogramServerBusy, NewBackoffFnCfg(2000, 10000, EqualJitter), tikverr.ErrTiFlashServerBusy)
+	BoTxnNotFound              = NewConfig("txnNotFound", &metrics.BackoffHistogramEmpty, NewBackoffFnCfg(2, 500, NoJitter), tikverr.ErrResolveLockTimeout)
+	BoStaleCmd                 = NewConfig("staleCommand", &metrics.BackoffHistogramStaleCmd, NewBackoffFnCfg(2, 1000, NoJitter), tikverr.ErrTiKVStaleCommand)
+	BoMaxTsNotSynced           = NewConfig("maxTsNotSynced", &metrics.BackoffHistogramEmpty, NewBackoffFnCfg(2, 500, NoJitter), tikverr.ErrTiKVMaxTimestampNotSynced)
+	BoMaxDataNotReady          = NewConfig("dataNotReady", &metrics.BackoffHistogramDataNotReady, NewBackoffFnCfg(2, 2000, NoJitter), tikverr.ErrRegionDataNotReady)
+	BoMaxRegionNotInitialized  = NewConfig("regionNotInitialized", &metrics.BackoffHistogramEmpty, NewBackoffFnCfg(2, 1000, NoJitter), tikverr.ErrRegionNotInitialized)
+	BoIsWitness                = NewConfig("isWitness", &metrics.BackoffHistogramIsWitness, NewBackoffFnCfg(1000, 10000, EqualJitter), tikverr.ErrIsWitness)
+	// TxnLockFast's `base` load from vars.BackoffLockFast when create BackoffFn.
+	BoTxnLockFast = NewConfig(txnLockFastName, &metrics.BackoffHistogramLockFast, NewBackoffFnCfg(2, 3000, EqualJitter), tikverr.ErrResolveLockTimeout)
+)
+
+var isSleepExcluded = map[string]int{
+	BoTiKVServerBusy.name: 600000, // The max excluded limit is 10min.
+	// add BoTiFlashServerBusy if appropriate
+}
+
+// setBackoffExcluded is used for test only.
+func setBackoffExcluded(name string, maxVal int) {
+	if _, ok := isSleepExcluded[name]; ok {
+		isSleepExcluded[name] = maxVal
+	}
+}
+
+const (
+	// NoJitter makes the backoff sequence strict exponential.
+	NoJitter = 1 + iota
+	// FullJitter applies random factors to strict exponential.
+	FullJitter
+	// EqualJitter is also randomized, but prevents very short sleeps.
+	EqualJitter
+	// DecorrJitter increases the maximum jitter based on the last random value.
+	DecorrJitter
+)
+
+// newBackoffFn creates a backoff func which implements exponential backoff with
+// optional jitters.
+// See http://www.awsarchitectureblog.com/2015/03/backoff.html
+func newBackoffFn(base, cap, jitter int) backoffFn {
+	if base < 2 {
+		// Top prevent panic in 'rand.Intn'.
+		base = 2
+	}
+	attempts := 0
+	lastSleep := base
+	return func(ctx context.Context, maxSleepMs int) int {
+		var sleep int
+		switch jitter {
+		case NoJitter:
+			sleep = expo(base, cap, attempts)
+		case FullJitter:
+			v := expo(base, cap, attempts)
+			sleep = rand.Intn(v)
+		case EqualJitter:
+			v := expo(base, cap, attempts)
+			sleep = v/2 + rand.Intn(v/2)
+		case DecorrJitter:
+			sleep = int(math.Min(float64(cap), float64(base+rand.Intn(lastSleep*3-base))))
+		}
+		logutil.BgLogger().Debug("backoff",
+			zap.Int("base", base),
+			zap.Int("sleep", sleep),
+			zap.Int("attempts", attempts))
+
+		realSleep := sleep
+		// when set maxSleepMs >= 0 in `tikv.BackoffWithMaxSleep` will force sleep maxSleepMs milliseconds.
+		if maxSleepMs >= 0 && realSleep > maxSleepMs {
+			realSleep = maxSleepMs
+		}
+		select {
+		case <-time.After(time.Duration(realSleep) * time.Millisecond):
+			attempts++
+			lastSleep = sleep
+			return realSleep
+		case <-ctx.Done():
+			return 0
+		}
+	}
+}
+
+func expo(base, cap, n int) int {
+	return int(math.Min(float64(cap), float64(base)*math.Pow(2.0, float64(n))))
+}

internal/client/client_batch.go

@@ -48,9 +48,9 @@ import (
 	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/tikv/client-go/v2/config"
+	"github.com/tikv/client-go/v2/config/retry"
 	tikverr "github.com/tikv/client-go/v2/error"
 	"github.com/tikv/client-go/v2/internal/logutil"
-	"github.com/tikv/client-go/v2/internal/retry"
 	"github.com/tikv/client-go/v2/metrics"
 	"github.com/tikv/client-go/v2/tikvrpc"
 	"github.com/tikv/client-go/v2/util"

internal/client/main_test.go

@@ -25,8 +25,8 @@ func TestMain(m *testing.M) {
 	util.EnableFailpoints()
 	opts := []goleak.Option{
 		goleak.IgnoreTopFunction("google.golang.org/grpc.(*ClientConn).WaitForStateChange"),
-		goleak.IgnoreTopFunction("github.com/tikv/client-go/v2/internal/retry.newBackoffFn.func1"),
-		goleak.IgnoreTopFunction("github.com/tikv/client-go/v2/internal/retry.(*Config).createBackoffFn.newBackoffFn.func2"),
+		goleak.IgnoreTopFunction("github.com/tikv/client-go/v2/config/retry.newBackoffFn.func1"),
+		goleak.IgnoreTopFunction("github.com/tikv/client-go/v2/config/retry.(*Config).createBackoffFn.newBackoffFn.func2"),
 	}
 	goleak.VerifyTestMain(m, opts...)
 }