sessionctx, executor: add session var to control explicit insertion on auto_random column

ddl/serial_test.go

@@ -940,6 +940,23 @@ func (s *testSerialSuite) TestAutoRandom(c *C) {
 	assertShowWarningCorrect("create table t (a bigint auto_random(15) primary key)", 281474976710655)
 	assertShowWarningCorrect("create table t (a bigint unsigned auto_random(15) primary key)", 562949953421311)
 
+	// Test insert into auto_random column explicitly is not allowed by default.
+	assertExplicitInsertDisallowed := func(sql string) {
+		assertInvalidAutoRandomErr(sql, autoid.AutoRandomExplicitInsertDisabledErrMsg)
+	}
+	tk.MustExec("set @@allow_auto_random_explicit_insert = false")
+	mustExecAndDrop("create table t (a bigint auto_random primary key)", func() {
+		assertExplicitInsertDisallowed("insert into t values (1)")
+		assertExplicitInsertDisallowed("insert into t values (3)")
+		tk.MustExec("insert into t values()")
+	})
+	tk.MustExec("set @@allow_auto_random_explicit_insert = true")
+	mustExecAndDrop("create table t (a bigint auto_random primary key)", func() {
+		tk.MustExec("insert into t values(1)")
+		tk.MustExec("insert into t values(3)")
+		tk.MustExec("insert into t values()")
+	})
+
 	// Disallow using it when allow-auto-random is not enabled.
 	config.GetGlobalConfig().Experimental.AllowAutoRandom = false
 	assertExperimentDisabled("create table auto_random_table (a int primary key auto_random(3))")

executor/ddl_test.go

@@ -844,6 +844,7 @@ func (s *testAutoRandomSuite) TestAutoRandomBitsData(c *C) {
 
 	testutil.ConfigTestUtils.SetupAutoRandomTestConfig()
 	defer testutil.ConfigTestUtils.RestoreAutoRandomTestConfig()
+	tk.MustExec("set @@allow_auto_random_explicit_insert = true")
 
 	tk.MustExec("create table t (a bigint primary key auto_random(15), b int)")
 	for i := 0; i < 100; i++ {

executor/insert_common.go

@@ -22,6 +22,7 @@ import (
 	"github.com/pingcap/parser/model"
 	"github.com/pingcap/parser/mysql"
 	"github.com/pingcap/tidb/config"
+	"github.com/pingcap/tidb/ddl"
 	"github.com/pingcap/tidb/expression"
 	"github.com/pingcap/tidb/kv"
 	"github.com/pingcap/tidb/meta/autoid"
@@ -847,6 +848,9 @@ func (e *InsertValues) adjustAutoRandomDatum(ctx context.Context, d types.Datum,
 	}
 	// Use the value if it's not null and not 0.
 	if recordID != 0 {
+		if !e.ctx.GetSessionVars().AllowAutoRandExplicitInsert {
+			return types.Datum{}, ddl.ErrInvalidAutoRandom.GenWithStackByArgs(autoid.AutoRandomExplicitInsertDisabledErrMsg)
+		}
 		err = e.rebaseAutoRandomID(recordID, &c.FieldType)
 		if err != nil {
 			return types.Datum{}, err

executor/insert_test.go

@@ -1106,6 +1106,8 @@ func (s *testSuite9) TestAutoRandomIDExplicit(c *C) {
 	}
 
 	tk := testkit.NewTestKit(c, s.store)
+	tk.MustExec("set @@allow_auto_random_explicit_insert = true")
+
 	tk.MustExec(`use test`)
 	tk.MustExec(`drop table if exists ar`)
 	tk.MustExec(`create table ar (id bigint key auto_random, name char(10))`)

executor/seqtest/seq_executor_test.go

@@ -832,6 +832,7 @@ func HelperTestAdminShowNextID(c *C, s *seqTestSuite, str string) {
 
 	oldAutoRandom := config.GetGlobalConfig().Experimental.AllowAutoRandom
 	config.GetGlobalConfig().Experimental.AllowAutoRandom = true
+	tk.MustExec("set @@allow_auto_random_explicit_insert = true")
 	defer func() {
 		config.GetGlobalConfig().Experimental.AllowAutoRandom = oldAutoRandom
 	}()

meta/autoid/errors.go

@@ -47,6 +47,8 @@ const (
 	AutoRandomNonPositive = "the value of auto_random should be positive"
 	// AutoRandomAvailableAllocTimesNote is reported when a table containing auto_random is created.
 	AutoRandomAvailableAllocTimesNote = "Available implicit allocation times: %d"
+	// AutoRandomExplicitInsertDisabledErrMsg is reported when auto_random column value is explicitly specified, but the session var 'allow_auto_random_explicit_insert' is false.
+	AutoRandomExplicitInsertDisabledErrMsg = "Explicit insertion on auto_random column is disabled. Try to set @@allow_auto_random_explicit_insert = true."
 	// AutoRandomOnNonBigIntColumn is reported when define auto random to non bigint column
 	AutoRandomOnNonBigIntColumn = "auto_random option must be defined on `bigint` column, but not on `%s` column"
 )

session/session.go

@@ -2053,6 +2053,7 @@ var builtinGlobalVariable = []string{
 	variable.TiDBEvolvePlanBaselines,
 	variable.TiDBIsolationReadEngines,
 	variable.TiDBStoreLimit,
+	variable.TiDBAllowAutoRandExplicitInsert,
 }
 
 var (

sessionctx/variable/session.go

@@ -396,6 +396,9 @@ type SessionVars struct {
 	// If value is set to 2 , which means to force to send batch cop for any query. Value is set to 0 means never use batch cop.
 	AllowBatchCop int
 
+	// TiDBAllowAutoRandExplicitInsert indicates whether explicit insertion on auto_random column is allowed.
+	AllowAutoRandExplicitInsert bool
+
 	// CorrelationThreshold is the guard to enable row count estimation using column order correlation.
 	CorrelationThreshold float64
 
@@ -690,6 +693,7 @@ func NewSessionVars() *SessionVars {
 		WindowingUseHighPrecision:   true,
 		PrevFoundInPlanCache:        DefTiDBFoundInPlanCache,
 		FoundInPlanCache:            DefTiDBFoundInPlanCache,
+		AllowAutoRandExplicitInsert: DefTiDBAllowAutoRandExplicitInsert,
 	}
 	vars.KVVars = kv.NewVariables(&vars.Killed)
 	vars.Concurrency = Concurrency{
@@ -1290,6 +1294,8 @@ func (s *SessionVars) SetSystemVar(name string, val string) error {
 		s.FoundInPlanCache = TiDBOptOn(val)
 	case TiDBEnableCollectExecutionInfo:
 		config.GetGlobalConfig().EnableCollectExecutionInfo = TiDBOptOn(val)
+	case TiDBAllowAutoRandExplicitInsert:
+		s.AllowAutoRandExplicitInsert = TiDBOptOn(val)
 	}
 	s.systems[name] = val
 	return nil

sessionctx/variable/sysvar.go

@@ -721,6 +721,7 @@ var defaultSysVars = []*SysVar{
 	{ScopeSession, TiDBCheckMb4ValueInUTF8, BoolToIntStr(config.GetGlobalConfig().CheckMb4ValueInUTF8)},
 	{ScopeSession, TiDBFoundInPlanCache, BoolToIntStr(DefTiDBFoundInPlanCache)},
 	{ScopeSession, TiDBEnableCollectExecutionInfo, BoolToIntStr(logutil.DefaultTiDBEnableSlowLog)},
+	{ScopeSession, TiDBAllowAutoRandExplicitInsert, boolToOnOff(DefTiDBAllowAutoRandExplicitInsert)},
 }
 
 // SynonymsSysVariables is synonyms of system variables.

sessionctx/variable/tidb_vars.go

@@ -171,6 +171,9 @@ const (
 
 	// TiDBFoundInPlanCache indicates whether the last statement was found in plan cache
 	TiDBFoundInPlanCache = "last_plan_from_cache"
+
+	// TiDBAllowAutoRandExplicitInsert indicates whether explicit insertion on auto_random column is allowed.
+	TiDBAllowAutoRandExplicitInsert = "allow_auto_random_explicit_insert"
 )
 
 // TiDB system variable names that both in session and global scope.
@@ -487,6 +490,7 @@ const (
 	DefTiDBMetricSchemaRangeDuration   = 60 // 60s
 	DefTiDBFoundInPlanCache            = false
 	DefTidbEnableCollectExecutionInfo  = false
+	DefTiDBAllowAutoRandExplicitInsert = false
 )
 
 // Process global variables.

sessionctx/variable/varsutil.go

@@ -440,7 +440,8 @@ func ValidateSetSystemVar(vars *SessionVars, name string, value string, scope Sc
 		TiDBLowResolutionTSO, TiDBEnableIndexMerge, TiDBEnableNoopFuncs,
 		TiDBCheckMb4ValueInUTF8, TiDBEnableSlowLog, TiDBRecordPlanInSlowLog,
 		TiDBScatterRegion, TiDBGeneralLog, TiDBConstraintCheckInPlace,
-		TiDBEnableVectorizedExpression, TiDBFoundInPlanCache, TiDBEnableCollectExecutionInfo:
+		TiDBEnableVectorizedExpression, TiDBFoundInPlanCache, TiDBEnableCollectExecutionInfo,
+		TiDBAllowAutoRandExplicitInsert:
 		fallthrough
 	case GeneralLog, AvoidTemporalUpgrade, BigTables, CheckProxyUsers, LogBin,
 		CoreFile, EndMakersInJSON, SQLLogBin, OfflineMode, PseudoSlaveMode, LowPriorityUpdates,

sessionctx/variable/varsutil_test.go

@@ -85,6 +85,7 @@ func (s *testVarsutilSuite) TestNewSessionVars(c *C) {
 	c.Assert(vars.TiDBOptJoinReorderThreshold, Equals, DefTiDBOptJoinReorderThreshold)
 	c.Assert(vars.EnableFastAnalyze, Equals, DefTiDBUseFastAnalyze)
 	c.Assert(vars.FoundInPlanCache, Equals, DefTiDBFoundInPlanCache)
+	c.Assert(vars.AllowAutoRandExplicitInsert, Equals, DefTiDBAllowAutoRandExplicitInsert)
 
 	assertFieldsGreaterThanZero(c, reflect.ValueOf(vars.Concurrency))
 	assertFieldsGreaterThanZero(c, reflect.ValueOf(vars.MemQuota))