*: modify GetGlobalConfig() to provide a thread safe API for unit test

config/config.go

@@ -14,6 +14,7 @@
 package config
 
 import (
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"encoding/base64"
@@ -693,10 +694,30 @@ func NewConfig() *Config {
 	return &conf
 }
 
+type ctxGlobalConfigKey struct{}
+
+var overrideConfigForTest ctxGlobalConfigKey
+
+// WithGlobalConfig provides a way for unit test to modify global config without DATA RACE.
+// The typical usage looks like this:
+//
+// ctx := context.Background()
+// cfg := *GetGlobalConfig(ctx)
+// cfg.XXX = XXX
+// ctx := config.WithGlobalConfig(ctx, &cfg)
+// tk.MustExecWithCtx(ctx, ...)
+//
+func WithGlobalConfig(ctx context.Context, cfg *Config) context.Context {
+	return context.WithValue(ctx, overrideConfigForTest, cfg)
+}
+
 // GetGlobalConfig returns the global configuration for this server.
 // It should store configuration from command line and configuration file.
 // Other parts of the system can read the global configuration use this function.
-func GetGlobalConfig() *Config {
+func GetGlobalConfig(ctx context.Context) *Config {
+	if raw := ctx.Value(overrideConfigForTest); raw != nil {
+		return raw.(*Config)
+	}
 	return globalConf.Load().(*Config)
 }
 
@@ -727,7 +748,7 @@ func isAllDeprecatedConfigItems(items []string) bool {
 // For example, if you start TiDB by the command "./tidb-server --port=3000", the port number should be
 // overwritten to 3000 and ignore the port number in the config file.
 func InitializeConfig(confPath string, configCheck, configStrict bool, reloadFunc ConfReloadFunc, enforceCmdArgs func(*Config)) {
-	cfg := GetGlobalConfig()
+	cfg := GetGlobalConfig(context.Background())
 	var err error
 	if confPath != "" {
 		if err = cfg.Load(confPath); err != nil {
@@ -885,13 +906,13 @@ func hasRootPrivilege() bool {
 }
 
 // TableLockEnabled uses to check whether enabled the table lock feature.
-func TableLockEnabled() bool {
-	return GetGlobalConfig().EnableTableLock
+func TableLockEnabled(ctx context.Context) bool {
+	return GetGlobalConfig(ctx).EnableTableLock
 }
 
 // TableLockDelayClean uses to get the time of delay clean table lock.
-var TableLockDelayClean = func() uint64 {
-	return GetGlobalConfig().DelayCleanTableLock
+var TableLockDelayClean = func(ctx context.Context) uint64 {
+	return GetGlobalConfig(ctx).DelayCleanTableLock
 }
 
 // ToLogConfig converts *Log to *logutil.LogConfig.

config/config_test.go

@@ -14,6 +14,7 @@
 package config
 
 import (
+	"context"
 	"encoding/json"
 	"os"
 	"os/user"
@@ -261,7 +262,7 @@ log-rotate = true`)
 	c.Assert(conf.Load(configFile), IsNil)
 
 	// Make sure the example config is the same as default config.
-	c.Assert(conf, DeepEquals, GetGlobalConfig())
+	c.Assert(conf, DeepEquals, GetGlobalConfig(context.Background()))
 
 	// Test for log config.
 	c.Assert(conf.Log.ToLogConfig(), DeepEquals, logutil.NewLogConfig("info", "text", "tidb-slow.log", conf.Log.File, false, func(config *zaplog.Config) { config.DisableErrorVerbose = conf.Log.getDisableErrorStack() }))
@@ -454,3 +455,15 @@ func (s *testConfigSuite) TestEncodeDefTempStorageDir(c *C) {
 		c.Assert(tempStorageDir, Equals, filepath.Join(dirPrefix, test.expect, "tmp-storage"))
 	}
 }
+
+func (s *testConfigSuite) TestWithGlobalConfig(c *C) {
+	cfg := NewConfig()
+	cfg.Binlog.Enable = true
+	cfg.EnableTableLock = true
+	ctx := WithGlobalConfig(context.Background(), cfg)
+
+	cfg1 := GetGlobalConfig(ctx)
+	c.Assert(cfg1, Equals, cfg)
+	c.Assert(cfg.Binlog.Enable, IsTrue)
+	c.Assert(cfg.EnableTableLock, IsTrue)
+}

ddl/db_change_test.go

@@ -92,7 +92,7 @@ func (s *testStateChangeSuiteBase) TearDownSuite(c *C) {
 
 // TestShowCreateTable tests the result of "show create table" when we are running "add index" or "add column".
 func (s *serialTestStateChangeSuite) TestShowCreateTable(c *C) {
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = true
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = true
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 	tk.MustExec("create table t (id int)")
@@ -858,7 +858,7 @@ func (s *testStateChangeSuite) TestParallelAlterAddIndex(c *C) {
 }
 
 func (s *serialTestStateChangeSuite) TestParallelAlterAddExpressionIndex(c *C) {
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = true
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = true
 	sql1 := "ALTER TABLE t add index expr_index_b((b+1));"
 	sql2 := "CREATE INDEX expr_index_b ON t ((c+1));"
 	f := func(c *C, err1, err2 error) {

ddl/db_integration_test.go

@@ -1705,15 +1705,15 @@ func (s *testIntegrationSuite1) TestTreatOldVersionUTF8AsUTF8MB4(c *C) {
 	}
 	updateTableInfo(tblInfo)
 	s.tk.MustExec("alter table t add column c varchar(10) character set utf8;") // load latest schema.
-	c.Assert(config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4, IsTrue)
+	c.Assert(config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4, IsTrue)
 	s.tk.MustExec("insert into t set a= x'f09f8c80'")
 	s.tk.MustQuery("show create table t").Check(testkit.Rows("t CREATE TABLE `t` (\n" +
 		"  `a` varchar(10) DEFAULT NULL,\n" +
 		"  `b` varchar(10) CHARACTER SET ascii COLLATE ascii_bin DEFAULT NULL,\n" +
 		"  `c` varchar(10) CHARACTER SET utf8 COLLATE utf8_bin DEFAULT NULL\n" +
 		") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
 
-	config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4 = false
+	config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4 = false
 	s.tk.MustExec("alter table t drop column c;") //  reload schema.
 	s.tk.MustGetErrCode("insert into t set a= x'f09f8c80'", errno.ErrTruncatedWrongValueForField)
 	s.tk.MustQuery("show create table t").Check(testkit.Rows("t CREATE TABLE `t` (\n" +
@@ -1730,7 +1730,7 @@ func (s *testIntegrationSuite1) TestTreatOldVersionUTF8AsUTF8MB4(c *C) {
 	tblInfo.Columns[0].Version = model.ColumnInfoVersion0
 	updateTableInfo(tblInfo)
 
-	config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4 = true
+	config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4 = true
 	s.tk.MustExec("alter table t add column c varchar(10);") //  load latest schema.
 	s.tk.MustExec("insert into t set a= x'f09f8c80'")
 	s.tk.MustQuery("show create table t").Check(testkit.Rows("t CREATE TABLE `t` (\n" +
@@ -1739,7 +1739,7 @@ func (s *testIntegrationSuite1) TestTreatOldVersionUTF8AsUTF8MB4(c *C) {
 		"  `c` varchar(10) DEFAULT NULL\n" +
 		") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
 
-	config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4 = false
+	config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4 = false
 	s.tk.MustExec("alter table t drop column c;") //  reload schema.
 	s.tk.MustGetErrCode("insert into t set a= x'f09f8c80'", errno.ErrTruncatedWrongValueForField)
 	s.tk.MustQuery("show create table t").Check(testkit.Rows("t CREATE TABLE `t` (\n" +
@@ -1748,7 +1748,7 @@ func (s *testIntegrationSuite1) TestTreatOldVersionUTF8AsUTF8MB4(c *C) {
 		") ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin"))
 
 	// Test modify column charset.
-	config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4 = true
+	config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4 = true
 	s.tk.MustExec("alter table t modify column a varchar(10) character set utf8mb4") //  change column charset.
 	tbl = testGetTableByName(c, s.ctx, "test", "t")
 	c.Assert(tbl.Meta().Columns[0].Charset, Equals, charset.CharsetUTF8MB4)
@@ -1776,15 +1776,15 @@ func (s *testIntegrationSuite1) TestTreatOldVersionUTF8AsUTF8MB4(c *C) {
 	tblInfo.Columns[0].Charset = charset.CharsetUTF8
 	tblInfo.Columns[0].Collate = charset.CollationUTF8
 	updateTableInfo(tblInfo)
-	c.Assert(config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4, IsTrue)
+	c.Assert(config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4, IsTrue)
 	s.tk.MustExec("alter table t change column b b varchar(20) character set ascii") // reload schema.
 	s.tk.MustExec("insert into t set a= x'f09f8c80'")
 	s.tk.MustQuery("show create table t").Check(testkit.Rows("t CREATE TABLE `t` (\n" +
 		"  `a` varchar(20) DEFAULT NULL,\n" +
 		"  `b` varchar(20) CHARACTER SET ascii COLLATE ascii_bin DEFAULT NULL\n" +
 		") ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin"))
 
-	config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4 = false
+	config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4 = false
 	s.tk.MustExec("alter table t change column b b varchar(30) character set ascii") // reload schema.
 	s.tk.MustGetErrCode("insert into t set a= x'f09f8c80'", errno.ErrTruncatedWrongValueForField)
 	s.tk.MustQuery("show create table t").Check(testkit.Rows("t CREATE TABLE `t` (\n" +
@@ -1793,11 +1793,11 @@ func (s *testIntegrationSuite1) TestTreatOldVersionUTF8AsUTF8MB4(c *C) {
 		") ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin"))
 
 	// Test for alter table convert charset
-	config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4 = true
+	config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4 = true
 	s.tk.MustExec("alter table t drop column b") // reload schema.
 	s.tk.MustExec("alter table t convert to charset utf8mb4;")
 
-	config.GetGlobalConfig().TreatOldVersionUTF8AsUTF8MB4 = false
+	config.GetGlobalConfig(context.Background()).TreatOldVersionUTF8AsUTF8MB4 = false
 	s.tk.MustExec("alter table t add column b varchar(50);") // reload schema.
 	s.tk.MustQuery("show create table t").Check(testkit.Rows("t CREATE TABLE `t` (\n" +
 		"  `a` varchar(20) DEFAULT NULL,\n" +
@@ -2044,7 +2044,7 @@ func (s *testIntegrationSuite3) TestParserIssue284(c *C) {
 }
 
 func (s *testIntegrationSuite7) TestAddExpressionIndex(c *C) {
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = true
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = true
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 	tk.MustExec("drop table if exists t;")
@@ -2096,12 +2096,12 @@ func (s *testIntegrationSuite7) TestAddExpressionIndex(c *C) {
 	tk.MustExec("alter table t1 alter index ei_ab invisible;")
 
 	// Test experiment switch.
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = false
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = false
 	tk.MustGetErrMsg("create index d on t((a+1))", "[ddl:8200]Unsupported creating expression index without allow-expression-index in config")
 }
 
 func (s *testIntegrationSuite7) TestCreateExpressionIndexError(c *C) {
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = true
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = true
 
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
@@ -2263,7 +2263,7 @@ func (s *testIntegrationSuite3) TestCreateTableWithAutoIdCache(c *C) {
 }
 
 func (s *testIntegrationSuite4) TestAlterIndexVisibility(c *C) {
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = true
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = true
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("create database if not exists alter_index_test")
 	tk.MustExec("USE alter_index_test;")

ddl/db_partition_test.go

@@ -1138,7 +1138,7 @@ func (s *testIntegrationSuite4) TestExchangePartitionTableCompatiable(c *C) {
 }
 
 func (s *testIntegrationSuite7) TestExchangePartitionExpressIndex(c *C) {
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = true
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = true
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 	tk.MustExec("drop table if exists pt1;")

ddl/db_test.go

@@ -264,7 +264,7 @@ func (s *testDBSuite2) TestAddUniqueIndexRollback(c *C) {
 }
 
 func (s *testSerialDBSuite) TestAddExpressionIndexRollback(c *C) {
-	config.GetGlobalConfig().Experimental.AllowsExpressionIndex = true
+	config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex = true
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test_db")
 	tk.MustExec("drop table if exists t1")
@@ -4454,7 +4454,7 @@ func (s *testDBSuite2) TestTablesLockDelayClean(c *C) {
 
 	tk.MustExec("lock tables t1 write")
 	checkTableLock(c, tk.Se, "test", "t1", model.TableLockWrite)
-	config.GetGlobalConfig().DelayCleanTableLock = 100
+	config.GetGlobalConfig(context.Background()).DelayCleanTableLock = 100
 	var wg sync.WaitGroup
 	wg.Add(1)
 	var startTime time.Time
@@ -4468,7 +4468,7 @@ func (s *testDBSuite2) TestTablesLockDelayClean(c *C) {
 	wg.Wait()
 	c.Assert(time.Since(startTime).Seconds() > 0.1, IsTrue)
 	checkTableLock(c, tk.Se, "test", "t1", model.TableLockNone)
-	config.GetGlobalConfig().DelayCleanTableLock = 0
+	config.GetGlobalConfig(context.Background()).DelayCleanTableLock = 0
 }
 
 // TestConcurrentLockTables test concurrent lock/unlock tables.

ddl/ddl_api.go

@@ -193,7 +193,7 @@ func (d *ddl) DropSchema(ctx sessionctx.Context, schema model.CIStr) (err error)
 	if err != nil {
 		return errors.Trace(err)
 	}
-	if !config.TableLockEnabled() {
+	if !config.TableLockEnabled(context.Background()) {
 		return nil
 	}
 	// Clear table locks hold by the session.
@@ -1266,7 +1266,7 @@ func buildTableInfo(
 			if err != nil {
 				return nil, err
 			}
-			if !config.GetGlobalConfig().AlterPrimaryKey {
+			if !config.GetGlobalConfig(context.Background()).AlterPrimaryKey {
 				singleIntPK := isSingleIntPK(constr, lastCol)
 				clusteredIdx := ctx.GetSessionVars().EnableClusteredIndex
 				if singleIntPK || clusteredIdx {
@@ -4018,7 +4018,7 @@ func (d *ddl) DropTable(ctx sessionctx.Context, ti ast.Ident) (err error) {
 	if err != nil {
 		return errors.Trace(err)
 	}
-	if !config.TableLockEnabled() {
+	if !config.TableLockEnabled(context.Background()) {
 		return nil
 	}
 	if ok, _ := ctx.CheckTableLocked(tb.Meta().ID); ok {
@@ -4072,7 +4072,7 @@ func (d *ddl) TruncateTable(ctx sessionctx.Context, ti ast.Ident) error {
 		BinlogInfo: &model.HistoryInfo{},
 		Args:       []interface{}{newTableID},
 	}
-	if ok, _ := ctx.CheckTableLocked(tb.Meta().ID); ok && config.TableLockEnabled() {
+	if ok, _ := ctx.CheckTableLocked(tb.Meta().ID); ok && config.TableLockEnabled(context.Background()) {
 		// AddTableLock here to avoid this ddl job was executed successfully but the session was been kill before return.
 		// The session will release all table locks it holds, if we don't add the new locking table id here,
 		// the session may forget to release the new locked table id when this ddl job was executed successfully
@@ -4082,7 +4082,7 @@ func (d *ddl) TruncateTable(ctx sessionctx.Context, ti ast.Ident) error {
 	err = d.doDDLJob(ctx, job)
 	err = d.callHookOnChanged(err)
 	if err != nil {
-		if config.TableLockEnabled() {
+		if config.TableLockEnabled(context.Background()) {
 			ctx.ReleaseTableLockByTableIDs([]int64{newTableID})
 		}
 		return errors.Trace(err)
@@ -4094,7 +4094,7 @@ func (d *ddl) TruncateTable(ctx sessionctx.Context, ti ast.Ident) error {
 		}
 	}
 
-	if !config.TableLockEnabled() {
+	if !config.TableLockEnabled(context.Background()) {
 		return nil
 	}
 	if ok, _ := ctx.CheckTableLocked(tb.Meta().ID); ok {
@@ -4178,7 +4178,7 @@ func getAnonymousIndex(t table.Table, colName model.CIStr) model.CIStr {
 
 func (d *ddl) CreatePrimaryKey(ctx sessionctx.Context, ti ast.Ident, indexName model.CIStr,
 	indexPartSpecifications []*ast.IndexPartSpecification, indexOption *ast.IndexOption) error {
-	if !config.GetGlobalConfig().AlterPrimaryKey {
+	if !config.GetGlobalConfig(context.Background()).AlterPrimaryKey {
 		return ErrUnsupportedModifyPrimaryKey.GenWithStack("Unsupported add primary key, alter-primary-key is false")
 	}
 
@@ -4356,7 +4356,7 @@ func (d *ddl) CreateIndex(ctx sessionctx.Context, ti ast.Ident, keyType ast.Inde
 	if err != nil {
 		return err
 	}
-	if len(hiddenCols) > 0 && !config.GetGlobalConfig().Experimental.AllowsExpressionIndex {
+	if len(hiddenCols) > 0 && !config.GetGlobalConfig(context.Background()).Experimental.AllowsExpressionIndex {
 		return ErrUnsupportedExpressionIndex
 	}
 	if err = checkAddColumnTooManyColumns(len(t.Cols()) + len(hiddenCols)); err != nil {
@@ -4552,7 +4552,7 @@ func (d *ddl) DropIndex(ctx sessionctx.Context, ti ast.Ident, indexName model.CI
 		isPK = true
 	}
 	if isPK {
-		if !config.GetGlobalConfig().AlterPrimaryKey {
+		if !config.GetGlobalConfig(context.Background()).AlterPrimaryKey {
 			return ErrUnsupportedModifyPrimaryKey.GenWithStack("Unsupported drop primary key when alter-primary-key is false")
 
 		}

ddl/ddl_test.go

@@ -94,7 +94,7 @@ func TestT(t *testing.T) {
 	ReorgWaitTimeout = 30 * time.Millisecond
 	batchInsertDeleteRangeSize = 2
 
-	cfg := config.GetGlobalConfig()
+	cfg := config.GetGlobalConfig(context.Background())
 	newCfg := *cfg
 	// Test for table lock.
 	newCfg.EnableTableLock = true

ddl/index.go

@@ -78,8 +78,9 @@ func buildIndexColumns(columns []*model.ColumnInfo, indexPartSpecifications []*a
 		sumLength += indexColumnLength
 
 		// The sum of all lengths must be shorter than the max length for prefix.
-		if sumLength > config.GetGlobalConfig().MaxIndexLength {
-			return nil, errTooLongKey.GenWithStackByArgs(config.GetGlobalConfig().MaxIndexLength)
+		maxIndexLengthConfig := config.GetGlobalConfig(context.Background()).MaxIndexLength
+		if sumLength > maxIndexLengthConfig {
+			return nil, errTooLongKey.GenWithStackByArgs(maxIndexLengthConfig)
 		}
 
 		idxParts = append(idxParts, &model.IndexColumn{
@@ -123,8 +124,9 @@ func checkIndexPrefixLength(columns []*model.ColumnInfo, idxColumns []*model.Ind
 		}
 		sumLength += indexColumnLength
 		// The sum of all lengths must be shorter than the max length for prefix.
-		if sumLength > config.GetGlobalConfig().MaxIndexLength {
-			return errTooLongKey.GenWithStackByArgs(config.GetGlobalConfig().MaxIndexLength)
+		maxIndexLengthConfig := config.GetGlobalConfig(context.Background()).MaxIndexLength
+		if sumLength > maxIndexLengthConfig {
+			return errTooLongKey.GenWithStackByArgs(maxIndexLengthConfig)
 		}
 	}
 	return nil
@@ -168,8 +170,9 @@ func checkIndexColumn(col *model.ColumnInfo, ic *ast.IndexPartSpecification) err
 	}
 
 	// Specified length must be shorter than the max length for prefix.
-	if ic.Length > config.GetGlobalConfig().MaxIndexLength {
-		return errTooLongKey.GenWithStackByArgs(config.GetGlobalConfig().MaxIndexLength)
+	maxIndexLength := config.GetGlobalConfig(context.Background()).MaxIndexLength
+	if ic.Length > maxIndexLength {
+		return errTooLongKey.GenWithStackByArgs(maxIndexLength)
 	}
 	return nil
 }