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store, config, session: Use system variables to enable async commit a…
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…nd 1PC (pingcap#21365)

* add a system variable for enabling async commit

Signed-off-by: ekexium <[email protected]>

* remove async commit enable config item

Signed-off-by: ekexium <[email protected]>

* add a system variable for enabling 1PC

Signed-off-by: ekexium <[email protected]>

* try to fix test

Signed-off-by: ekexium <[email protected]>

* remove 1pc item in config

Signed-off-by: ekexium <[email protected]>

* try to fix test

Signed-off-by: ekexium <[email protected]>

* correct the condition to enable 1pc

Signed-off-by: ekexium <[email protected]>

* do not enable 1pc/async commit on bootstrap if store is not tikv

Signed-off-by: ekexium <[email protected]>

* refactor checkAsyncCommit

Signed-off-by: ekexium <[email protected]>

* fix test: enable async commit or 1PC by setting txn options

Signed-off-by: ekexium <[email protected]>

* add a system variable for external consistency

Signed-off-by: ekexium <[email protected]>

* remove external consistency config item

Signed-off-by: ekexium <[email protected]>

* refactor: checkXXX does not need parameters

Signed-off-by: ekexium <[email protected]>

* refactor: add a helper function to pessimistic_test

Signed-off-by: ekexium <[email protected]>

* change allowed scope to global or session

Signed-off-by: ekexium <[email protected]>

* fix external consistency test

Signed-off-by: ekexium <[email protected]>

Co-authored-by: ti-srebot <[email protected]>
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@ekexium @ti-srebot
ekexium and ti-srebot authored Dec 2, 2020
1 parent 15ec9a6 commit 0e2f18d
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Showing 15 changed files with 332 additions and 362 deletions.
12 changes: 1 addition & 11 deletions config/config.go
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Original file line number Diff line number Diff line change
Expand Up @@ -509,8 +509,6 @@ type TiKVClient struct {
// CommitTimeout is the max time which command 'commit' will wait.
CommitTimeout string `toml:"commit-timeout" json:"commit-timeout"`
AsyncCommit AsyncCommit `toml:"async-commit" json:"async-commit"`
// Allow TiDB try to use 1PC protocol to commit transactions that involves only one region.
EnableOnePC bool `toml:"enable-one-pc" json:"enable-one-pc"`
// MaxBatchSize is the max batch size when calling batch commands API.
MaxBatchSize uint `toml:"max-batch-size" json:"max-batch-size"`
// If TiKV load is greater than this, TiDB will wait for a while to avoid little batch.
Expand All @@ -532,15 +530,10 @@ type TiKVClient struct {
CoprCache CoprocessorCache `toml:"copr-cache" json:"copr-cache"`
// TTLRefreshedTxnSize controls whether a transaction should update its TTL or not.
TTLRefreshedTxnSize int64 `toml:"ttl-refreshed-txn-size" json:"ttl-refreshed-txn-size"`
// Ensure external consistency when async commit or 1PC is enabled. When this option is enabled,
// TiDB needs to get a timestamp from PD before committing a transaction and thus latency is increased.
ExternalConsistency bool `toml:"external-consistency" json:"external-consistency"`
}

// AsyncCommit is the config for the async commit feature.
// AsyncCommit is the config for the async commit feature. The switch to enable it is a system variable.
type AsyncCommit struct {
// Whether to enable the async commit feature.
Enable bool `toml:"enable" json:"enable"`
// Use async commit only if the number of keys does not exceed KeysLimit.
KeysLimit uint `toml:"keys-limit" json:"keys-limit"`
// Use async commit only if the total size of keys does not exceed TotalKeySizeLimit.
Expand Down Expand Up @@ -728,15 +721,12 @@ var defaultConf = Config{
GrpcCompressionType: "none",
CommitTimeout: "41s",
AsyncCommit: AsyncCommit{
Enable: false,
// FIXME: Find an appropriate default limit.
KeysLimit: 256,
TotalKeySizeLimit: 4 * 1024, // 4 KiB
SafeWindow: 2 * time.Second,
AllowedClockDrift: 500 * time.Millisecond,
},
EnableOnePC: false,
ExternalConsistency: false,

MaxBatchSize: 128,
OverloadThreshold: 200,
Expand Down
9 changes: 0 additions & 9 deletions config/config.toml.example
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Original file line number Diff line number Diff line change
Expand Up @@ -388,13 +388,6 @@ grpc-compression-type = "none"
# Max time for commit command, must be twice bigger than raft election timeout.
commit-timeout = "41s"

# Allow TiDB try to use 1PC protocol to commit transactions that involves only one region.
enable-one-pc = false

# Ensure external consistency when async commit or 1PC is enabled. When this option is enabled,
# TiDB needs to get a timestamp from PD before committing a transaction and thus latency is increased.
external-consistency = false

# Max batch size in gRPC.
max-batch-size = 128
# Overload threshold of TiKV.
Expand Down Expand Up @@ -424,8 +417,6 @@ store-liveness-timeout = "5s"
ttl-refreshed-txn-size = 33554432

[tikv-client.async-commit]
# Whether to enable the async commit feature. This feature reduces the latency of the two-phase commit.
enable = false
# The maximum allowed keys in an async commit transaction. Transactions with more keys than the limit
# will be committed with normal 2PC way.
keys-limit = 256
Expand Down
6 changes: 0 additions & 6 deletions config/config_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -203,10 +203,7 @@ max-batch-size=128
region-cache-ttl=6000
store-limit=0
ttl-refreshed-txn-size=8192
enable-one-pc=true
external-consistency=true
[tikv-client.async-commit]
enable=true
keys-limit=123
total-key-size-limit=1024
[stmt-summary]
Expand Down Expand Up @@ -242,15 +239,12 @@ spilled-file-encryption-method = "plaintext"
c.Assert(conf.AlterPrimaryKey, Equals, true)

c.Assert(conf.TiKVClient.CommitTimeout, Equals, "41s")
c.Assert(conf.TiKVClient.AsyncCommit.Enable, Equals, true)
c.Assert(conf.TiKVClient.AsyncCommit.KeysLimit, Equals, uint(123))
c.Assert(conf.TiKVClient.AsyncCommit.TotalKeySizeLimit, Equals, uint64(1024))
c.Assert(conf.TiKVClient.EnableOnePC, Equals, true)
c.Assert(conf.TiKVClient.MaxBatchSize, Equals, uint(128))
c.Assert(conf.TiKVClient.RegionCacheTTL, Equals, uint(6000))
c.Assert(conf.TiKVClient.StoreLimit, Equals, int64(0))
c.Assert(conf.TiKVClient.TTLRefreshedTxnSize, Equals, int64(8192))
c.Assert(conf.TiKVClient.ExternalConsistency, Equals, true)
c.Assert(conf.TokenLimit, Equals, uint(1000))
c.Assert(conf.EnableTableLock, IsTrue)
c.Assert(conf.DelayCleanTableLock, Equals, uint64(5))
Expand Down
6 changes: 6 additions & 0 deletions kv/kv.go
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Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,12 @@ const (
SampleStep
// CommitHook is a callback function called right after the transaction gets committed
CommitHook
// EnableAsyncCommit indicates whether async commit is enabled
EnableAsyncCommit
// Enable1PC indicates whether one-phase commit is enabled
Enable1PC
// GuaranteeExternalConsistency indicates whether to guarantee external consistency at the cost of an extra tso request before prewrite
GuaranteeExternalConsistency
)

// Priority value for transaction priority.
Expand Down
6 changes: 6 additions & 0 deletions session/bootstrap.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1335,6 +1335,12 @@ func doDMLWorks(s Session) {
vVal = string(variable.DynamicOnly)
}
}
if v.Name == variable.TiDBEnableAsyncCommit && config.GetGlobalConfig().Store == "tikv" {
vVal = variable.BoolOn
}
if v.Name == variable.TiDBEnable1PC && config.GetGlobalConfig().Store == "tikv" {
vVal = variable.BoolOn
}
value := fmt.Sprintf(`("%s", "%s")`, strings.ToLower(k), vVal)
values = append(values, value)
}
Expand Down
27 changes: 15 additions & 12 deletions session/pessimistic_test.go
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,12 @@ import (

var _ = SerialSuites(&testPessimisticSuite{})

func (s *testPessimisticSuite) newAsyncCommitTestKitWithInit(c *C) *testkit.TestKit {
tk := testkit.NewTestKitWithInit(c, s.store)
tk.Se.GetSessionVars().EnableAsyncCommit = true
return tk
}

type testPessimisticSuite struct {
testSessionSuiteBase
}
Expand Down Expand Up @@ -1962,17 +1968,16 @@ func (s *testPessimisticSuite) TestSelectForUpdateWaitSeconds(c *C) {
func (s *testPessimisticSuite) TestSelectForUpdateConflictRetry(c *C) {
defer config.RestoreFunc()()
config.UpdateGlobal(func(conf *config.Config) {
conf.TiKVClient.AsyncCommit.Enable = true
conf.TiKVClient.AsyncCommit.SafeWindow = 500 * time.Millisecond
conf.TiKVClient.AsyncCommit.AllowedClockDrift = 0
})

tk := testkit.NewTestKitWithInit(c, s.store)
tk := s.newAsyncCommitTestKitWithInit(c)
tk.MustExec("drop table if exists tk")
tk.MustExec("create table tk (c1 int primary key, c2 int)")
tk.MustExec("insert into tk values(1,1),(2,2)")
tk2 := testkit.NewTestKitWithInit(c, s.store)
tk3 := testkit.NewTestKitWithInit(c, s.store)
tk2 := s.newAsyncCommitTestKitWithInit(c)
tk3 := s.newAsyncCommitTestKitWithInit(c)

tk2.MustExec("begin pessimistic")
tk3.MustExec("begin pessimistic")
Expand Down Expand Up @@ -2008,7 +2013,6 @@ func (s *testPessimisticSuite) TestAsyncCommitWithSchemaChange(c *C) {

defer config.RestoreFunc()()
config.UpdateGlobal(func(conf *config.Config) {
conf.TiKVClient.AsyncCommit.Enable = true
conf.TiKVClient.AsyncCommit.SafeWindow = time.Second
conf.TiKVClient.AsyncCommit.AllowedClockDrift = 0
})
Expand All @@ -2017,12 +2021,12 @@ func (s *testPessimisticSuite) TestAsyncCommitWithSchemaChange(c *C) {
c.Assert(failpoint.Disable("github.com/pingcap/tidb/store/tikv/beforeSchemaCheck"), IsNil)
}()

tk := testkit.NewTestKitWithInit(c, s.store)
tk := s.newAsyncCommitTestKitWithInit(c)
tk.MustExec("drop table if exists tk")
tk.MustExec("create table tk (c1 int primary key, c2 int, c3 int)")
tk.MustExec("insert into tk values(1, 1, 1)")
tk2 := testkit.NewTestKitWithInit(c, s.store)
tk3 := testkit.NewTestKitWithInit(c, s.store)
tk2 := s.newAsyncCommitTestKitWithInit(c)
tk3 := s.newAsyncCommitTestKitWithInit(c)

// The txn tk writes something but with failpoint the primary key is not committed.
tk.MustExec("begin pessimistic")
Expand Down Expand Up @@ -2079,14 +2083,13 @@ func (s *testPessimisticSuite) Test1PCWithSchemaChange(c *C) {

defer config.RestoreFunc()()
config.UpdateGlobal(func(conf *config.Config) {
conf.TiKVClient.EnableOnePC = true
conf.TiKVClient.AsyncCommit.SafeWindow = time.Second
conf.TiKVClient.AsyncCommit.AllowedClockDrift = 0
})

tk := testkit.NewTestKitWithInit(c, s.store)
tk2 := testkit.NewTestKitWithInit(c, s.store)
tk3 := testkit.NewTestKitWithInit(c, s.store)
tk := s.newAsyncCommitTestKitWithInit(c)
tk2 := s.newAsyncCommitTestKitWithInit(c)
tk3 := s.newAsyncCommitTestKitWithInit(c)

tk.MustExec("drop table if exists tk")
tk.MustExec("create table tk (c1 int primary key, c2 int)")
Expand Down
6 changes: 6 additions & 0 deletions session/session.go
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Original file line number Diff line number Diff line change
Expand Up @@ -466,6 +466,9 @@ func (s *session) doCommit(ctx context.Context) error {
if s.GetSessionVars().EnableAmendPessimisticTxn {
s.txn.SetOption(kv.SchemaAmender, NewSchemaAmenderForTikvTxn(s))
}
s.txn.SetOption(kv.EnableAsyncCommit, s.GetSessionVars().EnableAsyncCommit)
s.txn.SetOption(kv.Enable1PC, s.GetSessionVars().Enable1PC)
s.txn.SetOption(kv.GuaranteeExternalConsistency, s.GetSessionVars().GuaranteeExternalConsistency)

return s.txn.Commit(sessionctx.SetCommitCtx(ctx, s))
}
Expand Down Expand Up @@ -2284,6 +2287,9 @@ var builtinGlobalVariable = []string{
variable.TiDBEnableAmendPessimisticTxn,
variable.TiDBMemoryUsageAlarmRatio,
variable.TiDBEnableRateLimitAction,
variable.TiDBEnableAsyncCommit,
variable.TiDBEnable1PC,
variable.TiDBGuaranteeExternalConsistency,
}

var (
Expand Down
155 changes: 86 additions & 69 deletions sessionctx/variable/session.go
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Original file line number Diff line number Diff line change
Expand Up @@ -756,6 +756,14 @@ type SessionVars struct {

// EnabledRateLimitAction indicates whether enabled ratelimit action during coprocessor
EnabledRateLimitAction bool

// EnableAsyncCommit indicates whether to enable the async commit feature.
EnableAsyncCommit bool

// Enable1PC indicates whether to enable the one-phase commit feature.
Enable1PC bool

GuaranteeExternalConsistency bool
}

// UseDynamicPartitionPrune indicates whether use new dynamic partition prune.
Expand Down Expand Up @@ -826,75 +834,78 @@ type ConnectionInfo struct {
// NewSessionVars creates a session vars object.
func NewSessionVars() *SessionVars {
vars := &SessionVars{
Users: make(map[string]types.Datum),
UserVarTypes: make(map[string]*types.FieldType),
systems: make(map[string]string),
stmtVars: make(map[string]string),
PreparedStmts: make(map[uint32]interface{}),
PreparedStmtNameToID: make(map[string]uint32),
PreparedParams: make([]types.Datum, 0, 10),
TxnCtx: &TransactionContext{},
RetryInfo: &RetryInfo{},
ActiveRoles: make([]*auth.RoleIdentity, 0, 10),
StrictSQLMode: true,
AutoIncrementIncrement: DefAutoIncrementIncrement,
AutoIncrementOffset: DefAutoIncrementOffset,
Status: mysql.ServerStatusAutocommit,
StmtCtx: new(stmtctx.StatementContext),
AllowAggPushDown: false,
AllowBCJ: false,
OptimizerSelectivityLevel: DefTiDBOptimizerSelectivityLevel,
RetryLimit: DefTiDBRetryLimit,
DisableTxnAutoRetry: DefTiDBDisableTxnAutoRetry,
DDLReorgPriority: kv.PriorityLow,
allowInSubqToJoinAndAgg: DefOptInSubqToJoinAndAgg,
preferRangeScan: DefOptPreferRangeScan,
CorrelationThreshold: DefOptCorrelationThreshold,
CorrelationExpFactor: DefOptCorrelationExpFactor,
CPUFactor: DefOptCPUFactor,
CopCPUFactor: DefOptCopCPUFactor,
CopTiFlashConcurrencyFactor: DefOptTiFlashConcurrencyFactor,
NetworkFactor: DefOptNetworkFactor,
ScanFactor: DefOptScanFactor,
DescScanFactor: DefOptDescScanFactor,
SeekFactor: DefOptSeekFactor,
MemoryFactor: DefOptMemoryFactor,
DiskFactor: DefOptDiskFactor,
ConcurrencyFactor: DefOptConcurrencyFactor,
EnableRadixJoin: false,
EnableVectorizedExpression: DefEnableVectorizedExpression,
L2CacheSize: cpuid.CPU.Cache.L2,
CommandValue: uint32(mysql.ComSleep),
TiDBOptJoinReorderThreshold: DefTiDBOptJoinReorderThreshold,
SlowQueryFile: config.GetGlobalConfig().Log.SlowQueryFile,
WaitSplitRegionFinish: DefTiDBWaitSplitRegionFinish,
WaitSplitRegionTimeout: DefWaitSplitRegionTimeout,
enableIndexMerge: false,
EnableNoopFuncs: DefTiDBEnableNoopFuncs,
replicaRead: kv.ReplicaReadLeader,
AllowRemoveAutoInc: DefTiDBAllowRemoveAutoInc,
UsePlanBaselines: DefTiDBUsePlanBaselines,
EvolvePlanBaselines: DefTiDBEvolvePlanBaselines,
IsolationReadEngines: make(map[kv.StoreType]struct{}),
LockWaitTimeout: DefInnodbLockWaitTimeout * 1000,
MetricSchemaStep: DefTiDBMetricSchemaStep,
MetricSchemaRangeDuration: DefTiDBMetricSchemaRangeDuration,
SequenceState: NewSequenceState(),
WindowingUseHighPrecision: true,
PrevFoundInPlanCache: DefTiDBFoundInPlanCache,
FoundInPlanCache: DefTiDBFoundInPlanCache,
PrevFoundInBinding: DefTiDBFoundInBinding,
FoundInBinding: DefTiDBFoundInBinding,
SelectLimit: math.MaxUint64,
AllowAutoRandExplicitInsert: DefTiDBAllowAutoRandExplicitInsert,
EnableClusteredIndex: DefTiDBEnableClusteredIndex,
EnableParallelApply: DefTiDBEnableParallelApply,
ShardAllocateStep: DefTiDBShardAllocateStep,
EnableChangeColumnType: DefTiDBChangeColumnType,
EnableAmendPessimisticTxn: DefTiDBEnableAmendPessimisticTxn,
PartitionPruneMode: *atomic2.NewString(DefTiDBPartitionPruneMode),
TxnScope: config.GetGlobalConfig().TxnScope,
EnabledRateLimitAction: DefTiDBEnableRateLimitAction,
Users: make(map[string]types.Datum),
UserVarTypes: make(map[string]*types.FieldType),
systems: make(map[string]string),
stmtVars: make(map[string]string),
PreparedStmts: make(map[uint32]interface{}),
PreparedStmtNameToID: make(map[string]uint32),
PreparedParams: make([]types.Datum, 0, 10),
TxnCtx: &TransactionContext{},
RetryInfo: &RetryInfo{},
ActiveRoles: make([]*auth.RoleIdentity, 0, 10),
StrictSQLMode: true,
AutoIncrementIncrement: DefAutoIncrementIncrement,
AutoIncrementOffset: DefAutoIncrementOffset,
Status: mysql.ServerStatusAutocommit,
StmtCtx: new(stmtctx.StatementContext),
AllowAggPushDown: false,
AllowBCJ: false,
OptimizerSelectivityLevel: DefTiDBOptimizerSelectivityLevel,
RetryLimit: DefTiDBRetryLimit,
DisableTxnAutoRetry: DefTiDBDisableTxnAutoRetry,
DDLReorgPriority: kv.PriorityLow,
allowInSubqToJoinAndAgg: DefOptInSubqToJoinAndAgg,
preferRangeScan: DefOptPreferRangeScan,
CorrelationThreshold: DefOptCorrelationThreshold,
CorrelationExpFactor: DefOptCorrelationExpFactor,
CPUFactor: DefOptCPUFactor,
CopCPUFactor: DefOptCopCPUFactor,
CopTiFlashConcurrencyFactor: DefOptTiFlashConcurrencyFactor,
NetworkFactor: DefOptNetworkFactor,
ScanFactor: DefOptScanFactor,
DescScanFactor: DefOptDescScanFactor,
SeekFactor: DefOptSeekFactor,
MemoryFactor: DefOptMemoryFactor,
DiskFactor: DefOptDiskFactor,
ConcurrencyFactor: DefOptConcurrencyFactor,
EnableRadixJoin: false,
EnableVectorizedExpression: DefEnableVectorizedExpression,
L2CacheSize: cpuid.CPU.Cache.L2,
CommandValue: uint32(mysql.ComSleep),
TiDBOptJoinReorderThreshold: DefTiDBOptJoinReorderThreshold,
SlowQueryFile: config.GetGlobalConfig().Log.SlowQueryFile,
WaitSplitRegionFinish: DefTiDBWaitSplitRegionFinish,
WaitSplitRegionTimeout: DefWaitSplitRegionTimeout,
enableIndexMerge: false,
EnableNoopFuncs: DefTiDBEnableNoopFuncs,
replicaRead: kv.ReplicaReadLeader,
AllowRemoveAutoInc: DefTiDBAllowRemoveAutoInc,
UsePlanBaselines: DefTiDBUsePlanBaselines,
EvolvePlanBaselines: DefTiDBEvolvePlanBaselines,
IsolationReadEngines: make(map[kv.StoreType]struct{}),
LockWaitTimeout: DefInnodbLockWaitTimeout * 1000,
MetricSchemaStep: DefTiDBMetricSchemaStep,
MetricSchemaRangeDuration: DefTiDBMetricSchemaRangeDuration,
SequenceState: NewSequenceState(),
WindowingUseHighPrecision: true,
PrevFoundInPlanCache: DefTiDBFoundInPlanCache,
FoundInPlanCache: DefTiDBFoundInPlanCache,
PrevFoundInBinding: DefTiDBFoundInBinding,
FoundInBinding: DefTiDBFoundInBinding,
SelectLimit: math.MaxUint64,
AllowAutoRandExplicitInsert: DefTiDBAllowAutoRandExplicitInsert,
EnableClusteredIndex: DefTiDBEnableClusteredIndex,
EnableParallelApply: DefTiDBEnableParallelApply,
ShardAllocateStep: DefTiDBShardAllocateStep,
EnableChangeColumnType: DefTiDBChangeColumnType,
EnableAmendPessimisticTxn: DefTiDBEnableAmendPessimisticTxn,
PartitionPruneMode: *atomic2.NewString(DefTiDBPartitionPruneMode),
TxnScope: config.GetGlobalConfig().TxnScope,
EnabledRateLimitAction: DefTiDBEnableRateLimitAction,
EnableAsyncCommit: DefTiDBEnableAsyncCommit,
Enable1PC: DefTiDBEnable1PC,
GuaranteeExternalConsistency: DefTiDBGuaranteeExternalConsistency,
}
vars.KVVars = kv.NewVariables(&vars.Killed)
vars.Concurrency = Concurrency{
Expand Down Expand Up @@ -1605,6 +1616,12 @@ func (s *SessionVars) SetSystemVar(name string, val string) error {
MemoryUsageAlarmRatio.Store(tidbOptFloat64(val, 0.8))
case TiDBEnableRateLimitAction:
s.EnabledRateLimitAction = TiDBOptOn(val)
case TiDBEnableAsyncCommit:
s.EnableAsyncCommit = TiDBOptOn(val)
case TiDBEnable1PC:
s.Enable1PC = TiDBOptOn(val)
case TiDBGuaranteeExternalConsistency:
s.GuaranteeExternalConsistency = TiDBOptOn(val)
}
s.systems[name] = val
return nil
Expand Down
3 changes: 3 additions & 0 deletions sessionctx/variable/sysvar.go
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Original file line number Diff line number Diff line change
Expand Up @@ -1153,6 +1153,9 @@ var defaultSysVars = []*SysVar{
{Scope: ScopeGlobal, Name: "rpl_semi_sync_master_wait_no_slave", Value: BoolOn, Type: TypeBool},
{Scope: ScopeGlobal, Name: "slave_rows_search_algorithms", Value: "TABLE_SCAN,INDEX_SCAN"},
{Scope: ScopeGlobal, Name: SlaveAllowBatching, Value: BoolOff, Type: TypeBool},
{Scope: ScopeGlobal | ScopeSession, Name: TiDBEnableAsyncCommit, Value: BoolToOnOff(DefTiDBEnableAsyncCommit), Type: TypeBool},
{Scope: ScopeGlobal | ScopeSession, Name: TiDBEnable1PC, Value: BoolToOnOff(DefTiDBEnable1PC), Type: TypeBool},
{Scope: ScopeGlobal | ScopeSession, Name: TiDBGuaranteeExternalConsistency, Value: BoolToOnOff(DefTiDBGuaranteeExternalConsistency), Type: TypeBool},
}

// SynonymsSysVariables is synonyms of system variables.
Expand Down
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