BEGIN
This statement starts a new transaction inside of TiDB. It is similar to the statements START TRANSACTION and SET autocommit=0.
In the absence of a BEGIN statement, every statement will by default autocommit in its own transaction. This behavior ensures MySQL compatibility.
Synopsis
- BeginTransactionStmt
BeginTransactionStmt ::=
'BEGIN' ( 'PESSIMISTIC' | 'OPTIMISTIC' )?
| 'START' 'TRANSACTION' ( 'READ' ( 'WRITE' | 'ONLY' ( 'WITH' 'TIMESTAMP' 'BOUND' TimestampBound )? ) | 'WITH' 'CONSISTENT' 'SNAPSHOT' )?
Examples
mysql> CREATE TABLE t1 (a int NOT NULL PRIMARY KEY);
Query OK, 0 rows affected (0.12 sec)
mysql> BEGIN;
Query OK, 0 rows affected (0.00 sec)
mysql> INSERT INTO t1 VALUES (1);
Query OK, 1 row affected (0.00 sec)
mysql> COMMIT;
Query OK, 0 rows affected (0.01 sec)
MySQL compatibility
TiDB supports the syntax extension of BEGIN PESSIMISTIC or BEGIN OPTIMISTIC. This enables you to override the default transactional model for your transaction.