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COMMIT

This statement commits a transaction inside of the TIDB server.

In the absence of a BEGIN or START TRANSACTION statement, the default behavior of TiDB is that every statement will be its own transaction and autocommit. This behavior ensures MySQL compatibility.

Synopsis

CommitStmt:

CommitStmt

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

  • TiDB 2.1 uses Optimistic Locking. It is important to consider that a COMMIT statement might fail because rows have been modified by another transaction. This changes in later versions of TiDB, where pessimistic locking is available.
  • By default, UNIQUE and PRIMARY KEY constraint checks are deferred until statement commit. This behavior can be changed by setting tidb_constraint_check_in_place=TRUE.

See also