lightning: disable foreign key checks

br/pkg/lightning/restore/tidb.go

@@ -95,8 +95,10 @@ func DBFromConfig(ctx context.Context, dsn config.DBStore) (*sql.DB, error) {
 		"tidb_opt_write_row_id": "1",
 		// always set auto-commit to ON
 		"autocommit": "1",
-		// alway set transaction mode to optimistic
+		// always set transaction mode to optimistic
 		"tidb_txn_mode": "optimistic",
+		// disable foreign key checks
+		"foreign_key_checks": "0",
 	}
 
 	if dsn.Vars != nil {
@@ -143,47 +145,6 @@ func (timgr *TiDBManager) Close() {
 	timgr.db.Close()
 }
 
-func InitSchema(ctx context.Context, g glue.Glue, database string, tablesSchema map[string]string) error {
-	logger := log.FromContext(ctx).With(zap.String("db", database))
-	sqlExecutor := g.GetSQLExecutor()
-
-	var createDatabase strings.Builder
-	createDatabase.WriteString("CREATE DATABASE IF NOT EXISTS ")
-	common.WriteMySQLIdentifier(&createDatabase, database)
-	err := sqlExecutor.ExecuteWithLog(ctx, createDatabase.String(), "create database", logger)
-	if err != nil {
-		return errors.Trace(err)
-	}
-
-	task := logger.Begin(zap.InfoLevel, "create tables")
-	var sqlCreateStmts []string
-loopCreate:
-	for tbl, sqlCreateTable := range tablesSchema {
-		task.Debug("create table", zap.String("schema", sqlCreateTable))
-
-		sqlCreateStmts, err = createIfNotExistsStmt(g.GetParser(), sqlCreateTable, database, tbl)
-		if err != nil {
-			break
-		}
-
-		// TODO: maybe we should put these createStems into a transaction
-		for _, s := range sqlCreateStmts {
-			err = sqlExecutor.ExecuteWithLog(
-				ctx,
-				s,
-				"create table",
-				logger.With(zap.String("table", common.UniqueTable(database, tbl))),
-			)
-			if err != nil {
-				break loopCreate
-			}
-		}
-	}
-	task.End(zap.ErrorLevel, err)
-
-	return errors.Trace(err)
-}
-
 func createIfNotExistsStmt(p *parser.Parser, createTable, dbName, tblName string) ([]string, error) {
 	stmts, _, err := p.ParseSQL(createTable)
 	if err != nil {
@@ -199,6 +160,9 @@ func createIfNotExistsStmt(p *parser.Parser, createTable, dbName, tblName string
 		case *ast.CreateDatabaseStmt:
 			node.Name = model.NewCIStr(dbName)
 			node.IfNotExists = true
+		case *ast.DropDatabaseStmt:
+			node.Name = model.NewCIStr(dbName)
+			node.IfExists = true
 		case *ast.CreateTableStmt:
 			node.Table.Schema = model.NewCIStr(dbName)
 			node.Table.Name = model.NewCIStr(tblName)

br/pkg/lightning/restore/tidb_test.go

@@ -165,97 +165,6 @@ func TestCreateTableIfNotExistsStmt(t *testing.T) {
 		`, "m"))
 }
 
-func TestInitSchema(t *testing.T) {
-	s := newTiDBSuite(t)
-	ctx := context.Background()
-
-	s.mockDB.
-		ExpectExec("CREATE DATABASE IF NOT EXISTS `db`").
-		WillReturnResult(sqlmock.NewResult(1, 1))
-	s.mockDB.
-		ExpectExec("\\QCREATE TABLE IF NOT EXISTS `db`.`t1` (`a` INT PRIMARY KEY,`b` VARCHAR(200));\\E").
-		WillReturnResult(sqlmock.NewResult(2, 1))
-	s.mockDB.
-		ExpectExec("\\QSET @@SESSION.`FOREIGN_KEY_CHECKS`=0;\\E").
-		WillReturnResult(sqlmock.NewResult(0, 0))
-	s.mockDB.
-		ExpectExec("\\QCREATE TABLE IF NOT EXISTS `db`.`t2` (`xx` TEXT) AUTO_INCREMENT = 11203;\\E").
-		WillReturnResult(sqlmock.NewResult(2, 1))
-	s.mockDB.
-		ExpectClose()
-
-	s.mockDB.MatchExpectationsInOrder(false) // maps are unordered.
-	err := InitSchema(ctx, s.tiGlue, "db", map[string]string{
-		"t1": "create table t1 (a int primary key, b varchar(200));",
-		"t2": "/*!40014 SET FOREIGN_KEY_CHECKS=0*/;CREATE TABLE `db`.`t2` (xx TEXT) AUTO_INCREMENT=11203;",
-	})
-	s.mockDB.MatchExpectationsInOrder(true)
-	require.NoError(t, err)
-}
-
-func TestInitSchemaSyntaxError(t *testing.T) {
-	s := newTiDBSuite(t)
-	ctx := context.Background()
-
-	s.mockDB.
-		ExpectExec("CREATE DATABASE IF NOT EXISTS `db`").
-		WillReturnResult(sqlmock.NewResult(1, 1))
-	s.mockDB.
-		ExpectClose()
-
-	err := InitSchema(ctx, s.tiGlue, "db", map[string]string{
-		"t1": "create table `t1` with invalid syntax;",
-	})
-	require.Error(t, err)
-}
-
-func TestInitSchemaErrorLost(t *testing.T) {
-	s := newTiDBSuite(t)
-	ctx := context.Background()
-
-	s.mockDB.
-		ExpectExec("CREATE DATABASE IF NOT EXISTS `db`").
-		WillReturnResult(sqlmock.NewResult(1, 1))
-
-	s.mockDB.
-		ExpectExec("CREATE TABLE IF NOT EXISTS.*").
-		WillReturnError(&mysql.MySQLError{
-			Number:  tmysql.ErrTooBigFieldlength,
-			Message: "Column length too big",
-		})
-
-	s.mockDB.
-		ExpectClose()
-
-	err := InitSchema(ctx, s.tiGlue, "db", map[string]string{
-		"t1": "create table `t1` (a int);",
-		"t2": "create table t2 (a int primary key, b varchar(200));",
-	})
-	require.Regexp(t, ".*Column length too big.*", err.Error())
-}
-
-func TestInitSchemaUnsupportedSchemaError(t *testing.T) {
-	s := newTiDBSuite(t)
-	ctx := context.Background()
-
-	s.mockDB.
-		ExpectExec("CREATE DATABASE IF NOT EXISTS `db`").
-		WillReturnResult(sqlmock.NewResult(1, 1))
-	s.mockDB.
-		ExpectExec("CREATE TABLE IF NOT EXISTS `db`.`t1`.*").
-		WillReturnError(&mysql.MySQLError{
-			Number:  tmysql.ErrTooBigFieldlength,
-			Message: "Column length too big",
-		})
-	s.mockDB.
-		ExpectClose()
-
-	err := InitSchema(ctx, s.tiGlue, "db", map[string]string{
-		"t1": "create table `t1` (a VARCHAR(999999999));",
-	})
-	require.Regexp(t, ".*Column length too big.*", err.Error())
-}
-
 func TestDropTable(t *testing.T) {
 	s := newTiDBSuite(t)
 	ctx := context.Background()

br/tests/lightning_foreign_key/config.toml

@@ -0,0 +1,4 @@
+[tikv-importer]
+# Set on-duplicate=error to force using insert statement to write data.
+# It seems that foreign key check is not supported in replace statement.
+on-duplicate = "error"

br/tests/lightning_foreign_key/data/fk.t-schema.sql

@@ -0,0 +1,8 @@
+CREATE TABLE `t`
+(
+    `a` bigint(20) NOT NULL,
+    `b` bigint(20) DEFAULT NULL,
+    PRIMARY KEY (`a`) /*T![clustered_index] CLUSTERED */,
+    KEY `fk_1` (`b`),
+    CONSTRAINT `fk_1` FOREIGN KEY (`b`) REFERENCES `test`.`t2` (`a`)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_bin;

br/tests/lightning_foreign_key/data/fk.t.csv

@@ -0,0 +1,6 @@
+a,b
+1,1
+2,2
+3,3
+4,4
+5,5

br/tests/lightning_foreign_key/run.sh

@@ -0,0 +1,28 @@
+#!/bin/bash
+#
+# Copyright 2022 PingCAP, Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+set -eu
+
+# Create existing tables that import data will reference.
+run_sql 'CREATE DATABASE IF NOT EXISTS fk;'
+run_sql 'CREATE TABLE fk.t2 (a BIGINT PRIMARY KEY);'
+
+for BACKEND in tidb local; do
+  run_sql 'DROP TABLE IF EXISTS fk.t;'
+  run_lightning --backend $BACKEND
+  run_sql 'SELECT GROUP_CONCAT(a) FROM fk.t ORDER BY a;'
+  check_contains '1,2,3,4,5'
+done