*: improve performance of show variables

context/context.go

@@ -86,7 +86,7 @@ func (t basicCtxType) String() string {
 const (
 	// QueryString is the key for original query string.
 	QueryString basicCtxType = 1
-	// Initing is the key for indicating if the server is running bootstrap or upgrad job.
+	// Initing is the key for indicating if the server is running bootstrap or upgrade job.
 	Initing basicCtxType = 2
 	// LastExecuteDDL is the key for whether the session execute a ddl command last time.
 	LastExecuteDDL basicCtxType = 3

ddl/foreign_key_test.go

@@ -38,12 +38,14 @@ type testForeighKeySuite struct {
 }
 
 func (s *testForeighKeySuite) SetUpSuite(c *C) {
+	testleak.BeforeTest()
 	s.store = testCreateStore(c, "test_foreign")
 }
 
 func (s *testForeighKeySuite) TearDownSuite(c *C) {
 	err := s.store.Close()
 	c.Assert(err, IsNil)
+	testleak.AfterTest(c)()
 }
 
 func (s *testForeighKeySuite) testCreateForeignKey(c *C, tblInfo *model.TableInfo, fkName string, keys []string, refTable string, refKeys []string, onDelete ast.ReferOptionType, onUpdate ast.ReferOptionType) *model.Job {
@@ -110,7 +112,6 @@ func getForeignKey(t table.Table, name string) *model.FKInfo {
 }
 
 func (s *testForeighKeySuite) TestForeignKey(c *C) {
-	defer testleak.AfterTest(c)()
 	d := testNewDDL(goctx.Background(), nil, s.store, nil, nil, testLease)
 	defer d.Stop()
 	s.d = d

executor/show.go

@@ -358,23 +358,50 @@ func (e *ShowExec) fetchShowCharset() error {
 	return nil
 }
 
-func (e *ShowExec) fetchShowVariables() error {
-	sessionVars := e.ctx.GetSessionVars()
+func (e *ShowExec) fetchShowVariables() (err error) {
+	var (
+		value         string
+		ok            bool
+		sessionVars   = e.ctx.GetSessionVars()
+		unreachedVars = make([]string, 0, len(variable.SysVars))
+	)
 	for _, v := range variable.SysVars {
-		var err error
-		var value string
 		if !e.GlobalScope {
-			// Try to get Session Scope variable value first.
-			value, err = varsutil.GetSessionSystemVar(sessionVars, v.Name)
+			// For a session scope variable,
+			// 1. try to fetch value from SessionVars.Systems;
+			// 2. if this variable is session-only, fetch value from SysVars
+			//		otherwise, fetch the value from table `mysql.Global_Variables`.
+			value, ok, err = varsutil.GetSessionOnlySysVars(sessionVars, v.Name)
 		} else {
-			value, err = varsutil.GetGlobalSystemVar(sessionVars, v.Name)
+			// If the scope of a system variable is ScopeNone,
+			// it's a read-only variable, so we return the default value of it.
+			// Otherwise, we have to fetch the values from table `mysql.Global_Variables` for global variable names.
+			value, ok, err = varsutil.GetScopeNoneSystemVar(v.Name)
 		}
 		if err != nil {
 			return errors.Trace(err)
 		}
+		if !ok {
+			unreachedVars = append(unreachedVars, v.Name)
+			continue
+		}
 		row := types.MakeDatums(v.Name, value)
 		e.rows = append(e.rows, row)
 	}
+	if len(unreachedVars) != 0 {
+		systemVars, err := sessionVars.GlobalVarsAccessor.GetAllSysVars()
+		if err != nil {
+			return errors.Trace(err)
+		}
+		for _, varName := range unreachedVars {
+			varValue, ok := systemVars[varName]
+			if !ok {
+				varValue = variable.SysVars[varName].Value
+			}
+			row := types.MakeDatums(varName, varValue)
+			e.rows = append(e.rows, row)
+		}
+	}
 	return nil
 }
 

expression/integration_test.go

@@ -59,6 +59,7 @@ func (s *testIntegrationSuite) cleanEnv(c *C) {
 
 func (s *testIntegrationSuite) SetUpSuite(c *C) {
 	var err error
+	testleak.BeforeTest()
 	s.store, s.dom, err = newStoreWithBootstrap()
 	c.Assert(err, IsNil)
 	s.ctx = mock.NewContext()
@@ -67,14 +68,12 @@ func (s *testIntegrationSuite) SetUpSuite(c *C) {
 func (s *testIntegrationSuite) TearDownSuite(c *C) {
 	s.dom.Close()
 	s.store.Close()
+	testleak.AfterTest(c)()
 }
 
 func (s *testIntegrationSuite) TestFuncREPEAT(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk.MustExec("USE test;")
 	tk.MustExec("DROP TABLE IF EXISTS table_string;")
 	tk.MustExec("CREATE TABLE table_string(a CHAR(20), b VARCHAR(20), c TINYTEXT, d TEXT(20), e MEDIUMTEXT, f LONGTEXT, g BIGINT);")
@@ -108,10 +107,7 @@ func (s *testIntegrationSuite) TestFuncREPEAT(c *C) {
 
 func (s *testIntegrationSuite) TestFuncLpadAndRpad(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk.MustExec(`USE test;`)
 	tk.MustExec(`DROP TABLE IF EXISTS t;`)
 	tk.MustExec(`CREATE TABLE t(a BINARY(10), b CHAR(10));`)
@@ -131,10 +127,7 @@ func (s *testIntegrationSuite) TestFuncLpadAndRpad(c *C) {
 }
 
 func (s *testIntegrationSuite) TestMiscellaneousBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
@@ -213,10 +206,7 @@ func (s *testIntegrationSuite) TestMiscellaneousBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestConvertToBit(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 	tk.MustExec("drop table if exists t, t1")
@@ -242,10 +232,7 @@ func (s *testIntegrationSuite) TestConvertToBit(c *C) {
 }
 
 func (s *testIntegrationSuite) TestMathBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -531,10 +518,7 @@ func (s *testIntegrationSuite) TestMathBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestStringBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -896,10 +880,7 @@ func (s *testIntegrationSuite) TestStringBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestEncryptionBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -1022,7 +1003,6 @@ func (s *testIntegrationSuite) TestTimeBuiltin(c *C) {
 	defer func() {
 		s.ctx.GetSessionVars().StrictSQLMode = originSQLMode
 		s.cleanEnv(c)
-		testleak.AfterTest(c)()
 	}()
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
@@ -1706,10 +1686,7 @@ func (s *testIntegrationSuite) TestTimeBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestOpBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -1749,10 +1726,7 @@ func (s *testIntegrationSuite) TestOpBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -2120,10 +2094,7 @@ func (s *testIntegrationSuite) TestBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestInfoBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -2209,10 +2180,7 @@ func (s *testIntegrationSuite) TestInfoBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestControlBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -2271,10 +2239,7 @@ func (s *testIntegrationSuite) TestControlBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestArithmeticBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -2444,10 +2409,7 @@ func (s *testIntegrationSuite) TestArithmeticBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestCompareBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -2607,10 +2569,7 @@ func (s *testIntegrationSuite) TestCompareBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestAggregationBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 	tk.MustExec("create table t(a decimal(7, 6))")
@@ -2620,10 +2579,7 @@ func (s *testIntegrationSuite) TestAggregationBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestOtherBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("use test")
 
@@ -2707,11 +2663,7 @@ func (s *testIntegrationSuite) TestOtherBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestDateBuiltin(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
-
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("USE test;")
 	tk.MustExec("DROP TABLE IF EXISTS t;")
@@ -2798,11 +2750,7 @@ func (s *testIntegrationSuite) TestDateBuiltin(c *C) {
 }
 
 func (s *testIntegrationSuite) TestTimeLiteral(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
-
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 
 	r := tk.MustQuery("select time '117:01:12';")
@@ -2846,11 +2794,7 @@ func (s *testIntegrationSuite) TestTimeLiteral(c *C) {
 }
 
 func (s *testIntegrationSuite) TestTimestampLiteral(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
-
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 
 	r := tk.MustQuery("select timestamp '2017-01-01 00:00:00';")
@@ -2879,22 +2823,15 @@ func (s *testIntegrationSuite) TestTimestampLiteral(c *C) {
 }
 
 func (s *testIntegrationSuite) TestLiterals(c *C) {
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
-
+	defer s.cleanEnv(c)
 	tk := testkit.NewTestKit(c, s.store)
 	r := tk.MustQuery("SELECT LENGTH(b''), LENGTH(B''), b''+1, b''-1, B''+1;")
 	r.Check(testkit.Rows("0 0 1 -1 1"))
 }
 
 func (s *testIntegrationSuite) TestFuncJSON(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	tk.MustExec("USE test;")
 	tk.MustExec("DROP TABLE IF EXISTS table_json;")
 	tk.MustExec("CREATE TABLE table_json(a json, b VARCHAR(255));")
@@ -2936,10 +2873,7 @@ func (s *testIntegrationSuite) TestFuncJSON(c *C) {
 
 func (s *testIntegrationSuite) TestColumnInfoModified(c *C) {
 	testKit := testkit.NewTestKit(c, s.store)
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	testKit.MustExec("use test")
 	testKit.MustExec("drop table if exists tab0")
 	testKit.MustExec("CREATE TABLE tab0(col0 INTEGER, col1 INTEGER, col2 INTEGER)")
@@ -2953,10 +2887,7 @@ func (s *testIntegrationSuite) TestColumnInfoModified(c *C) {
 
 func (s *testIntegrationSuite) TestSetVariables(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
-	defer func() {
-		s.cleanEnv(c)
-		testleak.AfterTest(c)()
-	}()
+	defer s.cleanEnv(c)
 	_, err := tk.Exec("set sql_mode='adfasdfadsfdasd';")
 	c.Assert(err, NotNil)
 	_, err = tk.Exec("set @@sql_mode='adfasdfadsfdasd';")