*: support global memory control for tidb

domain/domain.go

@@ -64,6 +64,7 @@ import (
 	"github.com/pingcap/tidb/util/engine"
 	"github.com/pingcap/tidb/util/expensivequery"
 	"github.com/pingcap/tidb/util/logutil"
+	"github.com/pingcap/tidb/util/servermemorylimit"
 	"github.com/pingcap/tidb/util/sqlexec"
 	"github.com/tikv/client-go/v2/txnkv/transaction"
 	pd "github.com/tikv/pd/client"
@@ -87,30 +88,31 @@ func NewMockDomain() *Domain {
 // Domain represents a storage space. Different domains can use the same database name.
 // Multiple domains can be used in parallel without synchronization.
 type Domain struct {
-	store                kv.Storage
-	infoCache            *infoschema.InfoCache
-	privHandle           *privileges.Handle
-	bindHandle           *bindinfo.BindHandle
-	statsHandle          unsafe.Pointer
-	statsLease           time.Duration
-	ddl                  ddl.DDL
-	info                 *infosync.InfoSyncer
-	globalCfgSyncer      *globalconfigsync.GlobalConfigSyncer
-	m                    sync.Mutex
-	SchemaValidator      SchemaValidator
-	sysSessionPool       *sessionPool
-	exit                 chan struct{}
-	etcdClient           *clientv3.Client
-	sysVarCache          sysVarCache // replaces GlobalVariableCache
-	slowQuery            *topNSlowQueries
-	expensiveQueryHandle *expensivequery.Handle
-	wg                   util.WaitGroupWrapper
-	statsUpdating        atomicutil.Int32
-	cancel               context.CancelFunc
-	indexUsageSyncLease  time.Duration
-	dumpFileGcChecker    *dumpFileGcChecker
-	expiredTimeStamp4PC  types.Time
-	logBackupAdvancer    *daemon.OwnerDaemon
+	store                   kv.Storage
+	infoCache               *infoschema.InfoCache
+	privHandle              *privileges.Handle
+	bindHandle              *bindinfo.BindHandle
+	statsHandle             unsafe.Pointer
+	statsLease              time.Duration
+	ddl                     ddl.DDL
+	info                    *infosync.InfoSyncer
+	globalCfgSyncer         *globalconfigsync.GlobalConfigSyncer
+	m                       sync.Mutex
+	SchemaValidator         SchemaValidator
+	sysSessionPool          *sessionPool
+	exit                    chan struct{}
+	etcdClient              *clientv3.Client
+	sysVarCache             sysVarCache // replaces GlobalVariableCache
+	slowQuery               *topNSlowQueries
+	expensiveQueryHandle    *expensivequery.Handle
+	serverMemoryLimitHandle *servermemorylimit.Handle
+	wg                      util.WaitGroupWrapper
+	statsUpdating           atomicutil.Int32
+	cancel                  context.CancelFunc
+	indexUsageSyncLease     time.Duration
+	dumpFileGcChecker       *dumpFileGcChecker
+	expiredTimeStamp4PC     types.Time
+	logBackupAdvancer       *daemon.OwnerDaemon
 
 	serverID             uint64
 	serverIDSession      *concurrency.Session
@@ -885,6 +887,7 @@ func NewDomain(store kv.Storage, ddlLease time.Duration, statsLease time.Duratio
 
 	do.SchemaValidator = NewSchemaValidator(ddlLease, do)
 	do.expensiveQueryHandle = expensivequery.NewExpensiveQueryHandle(do.exit)
+	do.serverMemoryLimitHandle = servermemorylimit.NewServerMemoryLimitHandle(do.exit)
 	do.sysProcesses = SysProcesses{mu: &sync.RWMutex{}, procMap: make(map[uint64]sessionctx.Context)}
 	variable.SetStatsCacheCapacity.Store(do.SetStatsCacheCapacity)
 	return do
@@ -1818,6 +1821,11 @@ func (do *Domain) ExpensiveQueryHandle() *expensivequery.Handle {
 	return do.expensiveQueryHandle
 }
 
+// ServerMemoryLimitHandle returns the expensive query handle.
+func (do *Domain) ServerMemoryLimitHandle() *servermemorylimit.Handle {
+	return do.serverMemoryLimitHandle
+}
+
 const (
 	privilegeKey   = "/tidb/privilege"
 	sysVarCacheKey = "/tidb/sysvars"

executor/executor.go

@@ -1943,6 +1943,7 @@ func ResetContextOfStmt(ctx sessionctx.Context, s ast.StmtNode) (err error) {
 	} else {
 		sc.InitMemTracker(memory.LabelForSQLText, vars.MemQuotaQuery)
 		sc.MemTracker.AttachToGlobalTracker(GlobalMemoryUsageTracker)
+		sc.MemTracker.IsRootTrackerOfSess, sc.MemTracker.SessionID = true, vars.ConnectionID
 	}
 
 	sc.InitDiskTracker(memory.LabelForSQLText, -1)

executor/executor_test.go

@@ -6063,3 +6063,66 @@ func TestTableLockPrivilege(t *testing.T) {
 	tk2.MustExec("LOCK TABLE test.t WRITE, test2.t2 WRITE")
 	tk.MustExec("LOCK TABLE test.t WRITE, test2.t2 WRITE")
 }
+
+func TestGlobalMemoryControl(t *testing.T) {
+	store, dom := testkit.CreateMockStoreAndDomain(t)
+
+	tk0 := testkit.NewTestKit(t, store)
+	tk0.MustExec("set global tidb_mem_oom_action = 'cancel'")
+	tk0.MustExec("set global tidb_server_memory_limit = 512 << 20")
+	tk0.MustExec("set global tidb_server_memory_limit_sess_min_size = 128")
+
+	tk1 := testkit.NewTestKit(t, store)
+	tracker1 := tk1.Session().GetSessionVars().StmtCtx.MemTracker
+
+	tk2 := testkit.NewTestKit(t, store)
+	tracker2 := tk2.Session().GetSessionVars().StmtCtx.MemTracker
+
+	tk3 := testkit.NewTestKit(t, store)
+	tracker3 := tk3.Session().GetSessionVars().StmtCtx.MemTracker
+
+	sm := &testkit.MockSessionManager{
+		PS: []*util.ProcessInfo{tk1.Session().ShowProcess(), tk2.Session().ShowProcess(), tk3.Session().ShowProcess()},
+	}
+	dom.ServerMemoryLimitHandle().SetSessionManager(sm)
+	go dom.ServerMemoryLimitHandle().Run()
+
+	tracker1.Consume(100 << 20) // 100 MB
+	tracker2.Consume(200 << 20) // 200 MB
+	tracker3.Consume(300 << 20) // 300 MB
+
+	test := make([]int, 128<<20) // Keep 1GB HeapInUse
+	time.Sleep(500 * time.Millisecond)
+
+	// Kill Top1
+	require.False(t, tracker1.NeedKill.Load())
+	require.False(t, tracker2.NeedKill.Load())
+	require.True(t, tracker3.NeedKill.Load())
+	require.Equal(t, memory.MemUsageTop1Tracker.Load(), tracker3)
+	util.WithRecovery( // Next Consume() will panic and cancel the SQL
+		func() {
+			tracker3.Consume(1)
+		}, func(r interface{}) {
+			require.True(t, strings.Contains(r.(string), "Out Of Memory Quota!"))
+		})
+	tracker2.Consume(300 << 20) // Sum 500MB, Not Panic, Waiting t3 cancel finish.
+	time.Sleep(500 * time.Millisecond)
+	require.False(t, tracker2.NeedKill.Load())
+	// Kill Finished
+	tracker3.Consume(-(300 << 20))
+	// Simulated SQL is Canceled and the time is updated
+	sm.PSMu.Lock()
+	ps := *sm.PS[2]
+	ps.Time = time.Now()
+	sm.PS[2] = &ps
+	sm.PSMu.Unlock()
+	time.Sleep(500 * time.Millisecond)
+	// Kill the Next SQL
+	util.WithRecovery( // Next Consume() will panic and cancel the SQL
+		func() {
+			tracker2.Consume(1)
+		}, func(r interface{}) {
+			require.True(t, strings.Contains(r.(string), "Out Of Memory Quota!"))
+		})
+	require.Equal(t, test[0], 0) // Keep 1GB HeapInUse
+}

sessionctx/variable/sysvar.go

@@ -716,6 +716,54 @@ var defaultSysVars = []*SysVar{
 			return nil
 		},
 	},
+	{Scope: ScopeGlobal, Name: TiDBServerMemoryLimit, Value: strconv.FormatUint(DefTiDBServerMemoryLimit, 10), Type: TypeUnsigned, MinValue: 0, MaxValue: math.MaxUint64,
+		GetGlobal: func(s *SessionVars) (string, error) {
+			return memory.ServerMemoryLimit.String(), nil
+		},
+		Validation: func(s *SessionVars, normalizedValue string, originalValue string, scope ScopeFlag) (string, error) {
+			intVal, err := strconv.ParseUint(normalizedValue, 10, 64)
+			if err != nil {
+				return "", err
+			}
+			if intVal > 0 && intVal < (512<<20) { // 512 MB
+				s.StmtCtx.AppendWarning(ErrTruncatedWrongValue.GenWithStackByArgs(TiDBServerMemoryLimit, originalValue))
+				intVal = 512 << 20
+			}
+			return strconv.FormatUint(intVal, 10), nil
+		},
+		SetGlobal: func(s *SessionVars, val string) error {
+			intVal, err := strconv.ParseUint(val, 10, 64)
+			if err != nil {
+				return err
+			}
+			memory.ServerMemoryLimit.Store(intVal)
+			return nil
+		},
+	},
+	{Scope: ScopeGlobal, Name: TiDBServerMemoryLimitSessMinSize, Value: strconv.FormatUint(DefTiDBServerMemoryLimitSessMinSize, 10), Type: TypeUnsigned, MinValue: 0, MaxValue: math.MaxUint64,
+		GetGlobal: func(s *SessionVars) (string, error) {
+			return memory.ServerMemoryLimitSessMinSize.String(), nil
+		},
+		Validation: func(s *SessionVars, normalizedValue string, originalValue string, scope ScopeFlag) (string, error) {
+			intVal, err := strconv.ParseUint(normalizedValue, 10, 64)
+			if err != nil {
+				return "", err
+			}
+			if intVal > 0 && intVal < 128 { // 128 Bytes
+				s.StmtCtx.AppendWarning(ErrTruncatedWrongValue.GenWithStackByArgs(TiDBServerMemoryLimitSessMinSize, originalValue))
+				intVal = 128
+			}
+			return strconv.FormatUint(intVal, 10), nil
+		},
+		SetGlobal: func(s *SessionVars, val string) error {
+			intVal, err := strconv.ParseUint(val, 10, 64)
+			if err != nil {
+				return err
+			}
+			memory.ServerMemoryLimitSessMinSize.Store(intVal)
+			return nil
+		},
+	},
 	{Scope: ScopeGlobal, Name: TiDBEnableColumnTracking, Value: BoolToOnOff(DefTiDBEnableColumnTracking), Type: TypeBool, GetGlobal: func(s *SessionVars) (string, error) {
 		return BoolToOnOff(EnableColumnTracking.Load()), nil
 	}, SetGlobal: func(s *SessionVars, val string) error {

sessionctx/variable/sysvar_test.go

@@ -17,6 +17,7 @@ package variable
 import (
 	"encoding/json"
 	"fmt"
+	"math"
 	"strconv"
 	"sync/atomic"
 	"testing"
@@ -746,3 +747,80 @@ func TestSetTIDBDiskQuota(t *testing.T) {
 	require.NoError(t, err)
 	require.Equal(t, strconv.FormatInt(pb, 10), val)
 }
+
+func TestTiDBServerMemoryLimit(t *testing.T) {
+	vars := NewSessionVars()
+	mock := NewMockGlobalAccessor4Tests()
+	mock.SessionVars = vars
+	vars.GlobalVarsAccessor = mock
+	var (
+		mb  uint64 = 1 << 20
+		err error
+		val string
+	)
+	// Test tidb_server_memory_limit
+	serverMemoryLimit := GetSysVar(TiDBServerMemoryLimit)
+	// Check default value
+	require.Equal(t, serverMemoryLimit.Value, strconv.FormatUint(DefTiDBServerMemoryLimit, 10))
+
+	// MinValue is 512 MB
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimit, strconv.FormatUint(100*mb, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimit)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(512*mb, 10), val)
+
+	// Test Close
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimit, strconv.FormatUint(0, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimit)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(0, 10), val)
+
+	// Test MaxValue
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimit, strconv.FormatUint(math.MaxUint64, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimit)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(math.MaxUint64, 10), val)
+
+	// Test Normal Value
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimit, strconv.FormatUint(1024*mb, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimit)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(1024*mb, 10), val)
+
+	// Test tidb_server_memory_limit_sess_min_size
+	serverMemoryLimitSessMinSize := GetSysVar(TiDBServerMemoryLimitSessMinSize)
+	// Check default value
+	require.Equal(t, serverMemoryLimitSessMinSize.Value, strconv.FormatUint(DefTiDBServerMemoryLimitSessMinSize, 10))
+
+	// MinValue is 128 Bytes
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimitSessMinSize, strconv.FormatUint(100, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimitSessMinSize)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(128, 10), val)
+
+	// Test Close
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimitSessMinSize, strconv.FormatUint(0, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimitSessMinSize)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(0, 10), val)
+
+	// Test MaxValue
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimitSessMinSize, strconv.FormatUint(math.MaxUint64, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimitSessMinSize)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(math.MaxUint64, 10), val)
+
+	// Test Normal Value
+	err = mock.SetGlobalSysVar(TiDBServerMemoryLimitSessMinSize, strconv.FormatUint(200*mb, 10))
+	require.NoError(t, err)
+	val, err = mock.GetGlobalSysVar(TiDBServerMemoryLimitSessMinSize)
+	require.NoError(t, err)
+	require.Equal(t, strconv.FormatUint(200*mb, 10), val)
+}

sessionctx/variable/tidb_vars.go

@@ -20,6 +20,8 @@ import (
 	"github.com/pingcap/tidb/config"
 	"github.com/pingcap/tidb/parser/mysql"
 	"github.com/pingcap/tidb/sessionctx/variable/featuretag/concurrencyddl"
+	"github.com/pingcap/tidb/util/mathutil"
+	"github.com/pingcap/tidb/util/memory"
 	"github.com/pingcap/tidb/util/paging"
 	"go.uber.org/atomic"
 )
@@ -837,6 +839,10 @@ const (
 	TiDBDDLEnableFastReorg = "tidb_ddl_enable_fast_reorg"
 	// TiDBDDLDiskQuota used to set disk quota for lightning add index.
 	TiDBDDLDiskQuota = "tidb_ddl_disk_quota"
+	// TiDBServerMemoryLimit indicates the memory limit of the tidb-server instance.
+	TiDBServerMemoryLimit = "tidb_server_memory_limit"
+	// TiDBServerMemoryLimitSessMinSize indicates the minimal memory used of a session, that becomes a candidate for session kill.
+	TiDBServerMemoryLimitSessMinSize = "tidb_server_memory_limit_sess_min_size"
 )
 
 // TiDB intentional limits
@@ -1072,6 +1078,7 @@ const (
 	DefTiDBForeignKeyChecks                         = false
 	DefTiDBOptRangeMaxSize                          = 0
 	DefTiDBCostModelVer                             = 1
+	DefTiDBServerMemoryLimitSessMinSize             = 128 << 20
 )
 
 // Process global variables.
@@ -1123,6 +1130,10 @@ var (
 	// EnableForeignKey indicates whether to enable foreign key feature.
 	EnableForeignKey    = atomic.NewBool(false)
 	EnableRCReadCheckTS = atomic.NewBool(false)
+
+	// DefTiDBServerMemoryLimit indicates the default value of TiDBServerMemoryLimit(TotalMem * 80%).
+	// It should be a const and shouldn't be modified after tidb is started.
+	DefTiDBServerMemoryLimit = mathutil.Max(memory.GetMemTotalIgnoreErr()/10*8, 512<<20)
 )
 
 var (

testkit/mocksessionmanager.go

@@ -26,6 +26,7 @@ import (
 // MockSessionManager is a mocked session manager which is used for test.
 type MockSessionManager struct {
 	PS      []*util.ProcessInfo
+	PSMu    sync.RWMutex
 	SerID   uint64
 	TxnInfo []*txninfo.TxnInfo
 	conn    map[uint64]session.Session
@@ -51,6 +52,8 @@ func (msm *MockSessionManager) ShowTxnList() []*txninfo.TxnInfo {
 
 // ShowProcessList implements the SessionManager.ShowProcessList interface.
 func (msm *MockSessionManager) ShowProcessList() map[uint64]*util.ProcessInfo {
+	msm.PSMu.RLock()
+	defer msm.PSMu.RUnlock()
 	ret := make(map[uint64]*util.ProcessInfo)
 	if len(msm.PS) > 0 {
 		for _, item := range msm.PS {
@@ -68,6 +71,8 @@ func (msm *MockSessionManager) ShowProcessList() map[uint64]*util.ProcessInfo {
 
 // GetProcessInfo implements the SessionManager.GetProcessInfo interface.
 func (msm *MockSessionManager) GetProcessInfo(id uint64) (*util.ProcessInfo, bool) {
+	msm.PSMu.RLock()
+	defer msm.PSMu.RUnlock()
 	for _, item := range msm.PS {
 		if item.ID == id {
 			return item, true

tidb-server/main.go

@@ -746,6 +746,7 @@ func createServer(storage kv.Storage, dom *domain.Domain) *server.Server {
 	svr.SetDomain(dom)
 	svr.InitGlobalConnID(dom.ServerID)
 	go dom.ExpensiveQueryHandle().SetSessionManager(svr).Run()
+	go dom.ServerMemoryLimitHandle().SetSessionManager(svr).Run()
 	dom.InfoSyncer().SetSessionManager(svr)
 	return svr
 }

util/memory/meminfo.go

@@ -30,6 +30,14 @@ var MemTotal func() (uint64, error)
 // MemUsed returns the total used amount of RAM on this system
 var MemUsed func() (uint64, error)
 
+// GetMemTotalIgnoreErr returns the total amount of RAM on this system/container. If error occurs, return 0.
+func GetMemTotalIgnoreErr() uint64 {
+	if memTotal, err := MemTotal(); err == nil {
+		return memTotal
+	}
+	return 0
+}
+
 // MemTotalNormal returns the total amount of RAM on this system in non-container environment.
 func MemTotalNormal() (uint64, error) {
 	total, t := memLimit.get()