executor: reset default database after drop current database (pingcap…

…#2089)
yanghang8612 · Nov 24, 2016 · 856d723 · 856d723
1 parent 7188225
commit 856d723
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Showing 2 changed files with 36 additions and 1 deletion.
diff --git a/executor/executor_ddl.go b/executor/executor_ddl.go
@@ -25,7 +25,9 @@ import (
 	"github.com/pingcap/tidb/mysql"
 	"github.com/pingcap/tidb/privilege"
 	"github.com/pingcap/tidb/sessionctx"
+	"github.com/pingcap/tidb/sessionctx/variable"
 	"github.com/pingcap/tidb/terror"
+	"github.com/pingcap/tidb/util/types"
 )
 
 // DDLExec represents a DDL executor.
@@ -125,14 +127,27 @@ func (e *DDLExec) executeCreateIndex(s *ast.CreateIndexStmt) error {
 }
 
 func (e *DDLExec) executeDropDatabase(s *ast.DropDatabaseStmt) error {
-	err := sessionctx.GetDomain(e.ctx).DDL().DropSchema(e.ctx, model.NewCIStr(s.Name))
+	dbName := model.NewCIStr(s.Name)
+	err := sessionctx.GetDomain(e.ctx).DDL().DropSchema(e.ctx, dbName)
 	if terror.ErrorEqual(err, infoschema.ErrDatabaseNotExists) {
 		if s.IfExists {
 			err = nil
 		} else {
 			err = infoschema.ErrDatabaseDropExists.Gen("Can't drop database '%s'; database doesn't exist", s.Name)
 		}
 	}
+	sessionVars := e.ctx.GetSessionVars()
+	if err == nil && strings.ToLower(sessionVars.CurrentDB) == dbName.L {
+		sessionVars.CurrentDB = ""
+		err = sessionVars.SetSystemVar(variable.CharsetDatabase, types.NewStringDatum("utf8"))
+		if err != nil {
+			return errors.Trace(err)
+		}
+		err = sessionVars.SetSystemVar(variable.CollationDatabase, types.NewStringDatum("utf8_unicode_ci"))
+		if err != nil {
+			return errors.Trace(err)
+		}
+	}
 	return errors.Trace(err)
 }
 

diff --git a/executor/executor_ddl_test.go b/executor/executor_ddl_test.go
@@ -185,3 +185,23 @@ func (s *testSuite) TestAlterTableModifyColumn(c *C) {
 	expected := "CREATE TABLE `mc` (\n  `c1` bigint(21) DEFAULT NULL,\n  `c2` text DEFAULT NULL\n) ENGINE=InnoDB"
 	c.Assert(createSQL, Equals, expected)
 }
+
+func (s *testSuite) TestDefaultDBAfterDropCurDB(c *C) {
+	defer testleak.AfterTest(c)()
+	tk := testkit.NewTestKit(c, s.store)
+
+	testSQL := `create database if not exists test_db CHARACTER SET latin1 COLLATE latin1_swedish_ci;`
+	tk.MustExec(testSQL)
+
+	testSQL = `use test_db;`
+	tk.MustExec(testSQL)
+	tk.MustQuery(`select database();`).Check(testkit.Rows("test_db"))
+	tk.MustQuery(`select @@character_set_database;`).Check(testkit.Rows("latin1"))
+	tk.MustQuery(`select @@collation_database;`).Check(testkit.Rows("latin1_swedish_ci"))
+
+	testSQL = `drop database test_db;`
+	tk.MustExec(testSQL)
+	tk.MustQuery(`select database();`).Check(testkit.Rows("<nil>"))
+	tk.MustQuery(`select @@character_set_database;`).Check(testkit.Rows("utf8"))
+	tk.MustQuery(`select @@collation_database;`).Check(testkit.Rows("utf8_unicode_ci"))
+}