*: Implementing RENAME USER

executor/simple.go

@@ -136,6 +136,8 @@ func (e *SimpleExec) Next(ctx context.Context, req *chunk.Chunk) (err error) {
 		err = e.executeAlterUser(x)
 	case *ast.DropUserStmt:
 		err = e.executeDropUser(x)
+	case *ast.RenameUserStmt:
+		err = e.executeRenameUser(x)
 	case *ast.SetPwdStmt:
 		err = e.executeSetPwd(x)
 	case *ast.KillStmt:
@@ -1026,6 +1028,123 @@ func (e *SimpleExec) executeGrantRole(s *ast.GrantRoleStmt) error {
 	return nil
 }
 
+// Should cover same internal mysql.* tables as DROP USER, so this function is very similar
+func (e *SimpleExec) executeRenameUser(s *ast.RenameUserStmt) error {
+
+	var failedUser string
+	sysSession, err := e.getSysSession()
+	defer e.releaseSysSession(sysSession)
+	if err != nil {
+		return err
+	}
+	sqlExecutor := sysSession.(sqlexec.SQLExecutor)
+
+	if _, err := sqlExecutor.ExecuteInternal(context.TODO(), "begin"); err != nil {
+		return err
+	}
+
+	for _, userToUser := range s.UserToUsers {
+		oldUser, newUser := userToUser.OldUser, userToUser.NewUser
+		exists, err := userExistsInternal(sqlExecutor, oldUser.Username, oldUser.Hostname)
+		if err != nil {
+			return err
+		}
+		if !exists {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " old did not exist"
+			break
+		}
+
+		exists, err = userExistsInternal(sqlExecutor, newUser.Username, newUser.Hostname)
+		if err != nil {
+			return err
+		}
+		if exists {
+			// MySQL reports the old user, even when the issue is the new user.
+			failedUser = oldUser.String() + " TO " + newUser.String() + " new did exist"
+			break
+		}
+
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.UserTable, "User", "Host", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.UserTable + " error"
+			break
+		}
+
+		// rename privileges from mysql.global_priv
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.GlobalPrivTable, "User", "Host", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.GlobalPrivTable + " error"
+			break
+		}
+
+		// rename privileges from mysql.db
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.DBTable, "User", "Host", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.DBTable + " error"
+			break
+		}
+
+		// rename privileges from mysql.tables_priv
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.TablePrivTable, "User", "Host", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.TablePrivTable + " error"
+			break
+		}
+
+		// rename relationship from mysql.role_edges
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.RoleEdgeTable, "TO_USER", "TO_HOST", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.RoleEdgeTable + " (to) error"
+			break
+		}
+
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.RoleEdgeTable, "FROM_USER", "FROM_HOST", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.RoleEdgeTable + " (from) error"
+			break
+		}
+
+		// rename relationship from mysql.default_roles
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.DefaultRoleTable, "DEFAULT_ROLE_USER", "DEFAULT_ROLE_HOST", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.DefaultRoleTable + " (default role user) error"
+			break
+		}
+
+		if err = renameUserHostInSystemTable(sqlExecutor, mysql.DefaultRoleTable, "USER", "HOST", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " " + mysql.DefaultRoleTable + " error"
+			break
+		}
+
+		// rename relationship from mysql.global_grants
+		// TODO: add global_grants into the parser
+		if err = renameUserHostInSystemTable(sqlExecutor, "global_grants", "User", "Host", userToUser); err != nil {
+			failedUser = oldUser.String() + " TO " + newUser.String() + " mysql.global_grants error"
+			break
+		}
+
+		//TODO: need update columns_priv once we implement columns_priv functionality.
+		// When that is added, please refactor both executeRenameUser and executeDropUser to use an array of tables
+		// to loop over, so it is easier to maintain.
+	}
+
+	if failedUser == "" {
+		if _, err := sqlExecutor.ExecuteInternal(context.TODO(), "commit"); err != nil {
+			return err
+		}
+	} else {
+		if _, err := sqlExecutor.ExecuteInternal(context.TODO(), "rollback"); err != nil {
+			return err
+		}
+		return ErrCannotUser.GenWithStackByArgs("RENAME USER", failedUser)
+	}
+	domain.GetDomain(e.ctx).NotifyUpdatePrivilege(e.ctx)
+	return nil
+}
+
+func renameUserHostInSystemTable(sqlExecutor sqlexec.SQLExecutor, tableName, usernameColumn, hostColumn string, users *ast.UserToUser) error {
+	sql := new(strings.Builder)
+	sqlexec.MustFormatSQL(sql, `UPDATE %n.%n SET %n = %?, %n = %? WHERE %n = %? and %n = %?;`,
+		mysql.SystemDB, tableName,
+		usernameColumn, users.NewUser.Username, hostColumn, users.NewUser.Hostname,
+		usernameColumn, users.OldUser.Username, hostColumn, users.OldUser.Hostname)
+	_, err := sqlExecutor.ExecuteInternal(context.TODO(), sql.String())
+	return err
+}
+
 func (e *SimpleExec) executeDropUser(s *ast.DropUserStmt) error {
 	// Check privileges.
 	// Check `CREATE USER` privilege.
@@ -1181,6 +1300,27 @@ func userExists(ctx sessionctx.Context, name string, host string) (bool, error)
 	return len(rows) > 0, nil
 }
 
+// use the same internal executor to read within the same transaction, otherwise same as userExists
+func userExistsInternal(sqlExecutor sqlexec.SQLExecutor, name string, host string) (bool, error) {
+	sql := new(strings.Builder)
+	sqlexec.MustFormatSQL(sql, `SELECT * FROM %n.%n WHERE User=%? AND Host=%?;`, mysql.SystemDB, mysql.UserTable, name, host)
+	recordSet, err := sqlExecutor.ExecuteInternal(context.TODO(), sql.String())
+	if err != nil {
+		return false, err
+	}
+	req := recordSet.NewChunk()
+	err = recordSet.Next(context.TODO(), req)
+	var rows int = 0
+	if err == nil {
+		rows = req.NumRows()
+	}
+	errClose := recordSet.Close()
+	if errClose != nil {
+		return false, errClose
+	}
+	return rows > 0, err
+}
+
 func (e *SimpleExec) executeSetPwd(s *ast.SetPwdStmt) error {
 	var u, h string
 	if s.User == nil {
@@ -1389,7 +1529,7 @@ func (e *SimpleExec) executeDropStats(s *ast.DropStatsStmt) (err error) {
 
 func (e *SimpleExec) autoNewTxn() bool {
 	switch e.Statement.(type) {
-	case *ast.CreateUserStmt, *ast.AlterUserStmt, *ast.DropUserStmt:
+	case *ast.CreateUserStmt, *ast.AlterUserStmt, *ast.DropUserStmt, *ast.RenameUserStmt:
 		return true
 	}
 	return false

planner/core/logical_plan_test.go

@@ -1296,6 +1296,12 @@ func (s *testPlanSuite) TestVisitInfo(c *C) {
 				{mysql.ExtendedPriv, "", "", "", ErrSpecificAccessDenied, false, "BACKUP_ADMIN", true},
 			},
 		},
+		{
+			sql: "RENAME USER user1 to user1_tmp",
+			ans: []visitInfo{
+				{mysql.CreateUserPriv, "", "", "", ErrSpecificAccessDenied, false, "", false},
+			},
+		},
 	}
 
 	for _, tt := range tests {

planner/core/planbuilder.go

@@ -641,7 +641,8 @@ func (b *PlanBuilder) Build(ctx context.Context, node ast.Node) (Plan, error) {
 	case *ast.BinlogStmt, *ast.FlushStmt, *ast.UseStmt, *ast.BRIEStmt,
 		*ast.BeginStmt, *ast.CommitStmt, *ast.RollbackStmt, *ast.CreateUserStmt, *ast.SetPwdStmt, *ast.AlterInstanceStmt,
 		*ast.GrantStmt, *ast.DropUserStmt, *ast.AlterUserStmt, *ast.RevokeStmt, *ast.KillStmt, *ast.DropStatsStmt,
-		*ast.GrantRoleStmt, *ast.RevokeRoleStmt, *ast.SetRoleStmt, *ast.SetDefaultRoleStmt, *ast.ShutdownStmt:
+		*ast.GrantRoleStmt, *ast.RevokeRoleStmt, *ast.SetRoleStmt, *ast.SetDefaultRoleStmt, *ast.ShutdownStmt,
+		*ast.RenameUserStmt:
 		return b.buildSimple(node.(ast.StmtNode))
 	case ast.DDLNode:
 		return b.buildDDL(ctx, x)
@@ -2268,7 +2269,7 @@ func (b *PlanBuilder) buildSimple(node ast.StmtNode) (Plan, error) {
 	case *ast.AlterInstanceStmt:
 		err := ErrSpecificAccessDenied.GenWithStack("SUPER")
 		b.visitInfo = appendVisitInfo(b.visitInfo, mysql.SuperPriv, "", "", "", err)
-	case *ast.AlterUserStmt:
+	case *ast.AlterUserStmt, *ast.RenameUserStmt:
 		err := ErrSpecificAccessDenied.GenWithStackByArgs("CREATE USER")
 		b.visitInfo = appendVisitInfo(b.visitInfo, mysql.CreateUserPriv, "", "", "", err)
 	case *ast.GrantStmt:

privilege/privileges/privileges_test.go

@@ -1400,6 +1400,54 @@ func (s *testPrivilegeSuite) TestSecurityEnhancedModeStatusVars(c *C) {
 	}, nil, nil)
 }
 
+func (s *testPrivilegeSuite) TestRenameUser(c *C) {
+	rootSe := newSession(c, s.store, s.dbName)
+	mustExec(c, rootSe, "DROP USER IF EXISTS 'ru1'@'localhost'")
+	mustExec(c, rootSe, "DROP USER IF EXISTS ru3")
+	mustExec(c, rootSe, "DROP USER IF EXISTS ru6@localhost")
+	mustExec(c, rootSe, "CREATE USER 'ru1'@'localhost'")
+	mustExec(c, rootSe, "CREATE USER ru3")
+	mustExec(c, rootSe, "CREATE USER ru6@localhost")
+	se1 := newSession(c, s.store, s.dbName)
+	c.Assert(se1.Auth(&auth.UserIdentity{Username: "ru1", Hostname: "localhost"}, nil, nil), IsTrue)
+
+	// Check privileges (need CREATE USER)
+	_, err := se1.ExecuteInternal(context.Background(), "RENAME USER ru3 TO ru4")
+	c.Assert(err, ErrorMatches, ".*Access denied; you need .at least one of. the CREATE USER privilege.s. for this operation")
+	mustExec(c, rootSe, "GRANT UPDATE ON mysql.user TO 'ru1'@'localhost'")
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER ru3 TO ru4")
+	c.Assert(err, ErrorMatches, ".*Access denied; you need .at least one of. the CREATE USER privilege.s. for this operation")
+	mustExec(c, rootSe, "GRANT CREATE USER ON *.* TO 'ru1'@'localhost'")
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER ru3 TO ru4")
+	c.Assert(err, IsNil)
+
+	// Test a few single rename (both Username and Hostname)
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER 'ru4'@'%' TO 'ru3'@'localhost'")
+	c.Assert(err, IsNil)
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER 'ru3'@'localhost' TO 'ru3'@'%'")
+	c.Assert(err, IsNil)
+	// Including negative tests, i.e. non existing from user and existing to user
+	_, err = rootSe.ExecuteInternal(context.Background(), "RENAME USER ru3 TO ru1@localhost")
+	c.Assert(err, ErrorMatches, ".*Operation RENAME USER failed for ru3@%.*")
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER ru4 TO ru5@localhost")
+	c.Assert(err, ErrorMatches, ".*Operation RENAME USER failed for ru4@%.*")
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER ru3 TO ru3")
+	c.Assert(err, ErrorMatches, ".*Operation RENAME USER failed for ru3@%.*")
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER ru3 TO ru5@localhost, ru4 TO ru7")
+	c.Assert(err, ErrorMatches, ".*Operation RENAME USER failed for ru4@%.*")
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER ru3 TO ru5@localhost, ru6@localhost TO ru1@localhost")
+	c.Assert(err, ErrorMatches, ".*Operation RENAME USER failed for ru6@localhost.*")
+
+	// Test multi rename, this is a full swap of ru3 and ru6, i.e. need to read its previous state in the same transaction.
+	_, err = se1.ExecuteInternal(context.Background(), "RENAME USER 'ru3' TO 'ru3_tmp', ru6@localhost TO ru3, 'ru3_tmp' to ru6@localhost")
+	c.Assert(err, IsNil)
+
+	// Cleanup
+	mustExec(c, rootSe, "DROP USER ru6@localhost")
+	mustExec(c, rootSe, "DROP USER ru3")
+	mustExec(c, rootSe, "DROP USER 'ru1'@'localhost'")
+}
+
 func (s *testPrivilegeSuite) TestSecurityEnhancedModeSysVars(c *C) {
 	tk := testkit.NewTestKit(c, s.store)
 	tk.MustExec("CREATE USER svroot1, svroot2")

session/session.go

@@ -2862,7 +2862,8 @@ func logStmt(execStmt *executor.ExecStmt, vars *variable.SessionVars) {
 	switch stmt := execStmt.StmtNode.(type) {
 	case *ast.CreateUserStmt, *ast.DropUserStmt, *ast.AlterUserStmt, *ast.SetPwdStmt, *ast.GrantStmt,
 		*ast.RevokeStmt, *ast.AlterTableStmt, *ast.CreateDatabaseStmt, *ast.CreateIndexStmt, *ast.CreateTableStmt,
-		*ast.DropDatabaseStmt, *ast.DropIndexStmt, *ast.DropTableStmt, *ast.RenameTableStmt, *ast.TruncateTableStmt:
+		*ast.DropDatabaseStmt, *ast.DropIndexStmt, *ast.DropTableStmt, *ast.RenameTableStmt, *ast.TruncateTableStmt,
+		*ast.RenameUserStmt:
 		user := vars.User
 		schemaVersion := vars.GetInfoSchema().SchemaMetaVersion()
 		if ss, ok := execStmt.StmtNode.(ast.SensitiveStmtNode); ok {

session/tidb.go

@@ -239,7 +239,7 @@ func autoCommitAfterStmt(ctx context.Context, se *session, meetsErr error, sql s
 	sessVars := se.sessionVars
 	if meetsErr != nil {
 		if !sessVars.InTxn() {
-			logutil.BgLogger().Info("rollbackTxn for ddl/autocommit failed")
+			logutil.BgLogger().Info("rollbackTxn called due to ddl/autocommit failure")
 			se.RollbackTxn(ctx)
 			recordAbortTxnDuration(sessVars)
 		} else if se.txn.Valid() && se.txn.IsPessimistic() && executor.ErrDeadlock.Equal(meetsErr) {