executor: accelerate TestShowVar (#24131)

executor/show_test.go

@@ -1233,27 +1233,37 @@ func (s *testSerialSuite1) TestShowCreateTableWithIntegerDisplayLengthWarnings(c
 func (s *testSuite5) TestShowVar(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	var showSQL string
+	sessionVars := make([]string, 0, len(variable.GetSysVars()))
+	globalVars := make([]string, 0, len(variable.GetSysVars()))
 	for _, v := range variable.GetSysVars() {
 		if variable.FilterImplicitFeatureSwitch(v) {
 			continue
 		}
-		// When ScopeSession only. `show global variables` must return empty.
+
 		if v.Scope == variable.ScopeSession {
-			showSQL = "show variables like '" + v.Name + "'"
-			res := tk.MustQuery(showSQL)
-			c.Check(res.Rows(), HasLen, 1)
-			showSQL = "show global variables like '" + v.Name + "'"
-			res = tk.MustQuery(showSQL)
-			c.Check(res.Rows(), HasLen, 0)
+			sessionVars = append(sessionVars, v.Name)
 		} else {
-			showSQL = "show global variables like '" + v.Name + "'"
-			res := tk.MustQuery(showSQL)
-			c.Check(res.Rows(), HasLen, 1)
-			showSQL = "show variables like '" + v.Name + "'"
-			res = tk.MustQuery(showSQL)
-			c.Check(res.Rows(), HasLen, 1)
+			globalVars = append(globalVars, v.Name)
 		}
 	}
+
+	// When ScopeSession only. `show global variables` must return empty.
+	sessionVarsStr := strings.Join(sessionVars, "','")
+	showSQL = "show variables where variable_name in('" + sessionVarsStr + "')"
+	res := tk.MustQuery(showSQL)
+	c.Check(res.Rows(), HasLen, len(sessionVars))
+	showSQL = "show global variables where variable_name in('" + sessionVarsStr + "')"
+	res = tk.MustQuery(showSQL)
+	c.Check(res.Rows(), HasLen, 0)
+
+	globalVarsStr := strings.Join(globalVars, "','")
+	showSQL = "show variables where variable_name in('" + globalVarsStr + "')"
+	res = tk.MustQuery(showSQL)
+	c.Check(res.Rows(), HasLen, len(globalVars))
+	showSQL = "show global variables where variable_name in('" + globalVarsStr + "')"
+	res = tk.MustQuery(showSQL)
+	c.Check(res.Rows(), HasLen, len(globalVars))
+
 	// Test for switch variable which shouldn't seen by users.
 	for _, one := range variable.FeatureSwitchVariables {
 		res := tk.MustQuery("show variables like '" + one + "'")