START TRANSACTION

This statement starts a new transaction inside of TiDB. It is similar to the statement BEGIN.

In the absence of a START TRANSACTION statement, every statement will by default autocommit in its own transaction. This behavior ensures MySQL compatibility.

Synopsis

BeginTransactionStmt:

BeginTransactionStmt
BEGINPESSIMISTICOPTIMISTICSTARTTRANSACTIONREADWRITEONLYWITHTIMESTAMPBOUNDTimestampBoundAsOfClauseWITHCONSISTENTSNAPSHOTWITHCAUSALCONSISTENCYONLY
AsOfClause
ASOFTIMESTAMPExpression

Examples

mysql> CREATE TABLE t1 (a int NOT NULL PRIMARY KEY); Query OK, 0 rows affected (0.12 sec) mysql> START TRANSACTION; 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

  • START TRANSACTION immediately starts a transaction inside TiDB. This differs from MySQL, where START TRANSACTION lazily creates a transaction. But START TRANSACTION in TiDB is equivalent to MySQL's START TRANSACTION WITH CONSISTENT SNAPSHOT.

  • The statement START TRANSACTION READ ONLY is parsed for compatibility with MySQL, but still allows write operations.

See also

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