13.1.27. TRUNCATE TABLE Syntax


TRUNCATE TABLE empties a table completely. It requires the DROP privilege.

Logically, TRUNCATE TABLE is similar to a DELETE statement that deletes all rows, or a sequence of DROP TABLE and CREATE TABLE statements. To achieve high performance, it bypasses the DML method of deleting data. Thus, it cannot be rolled back, it does not cause ON DELETE triggers to fire, and it cannot be performed for InnoDB tables with parent-child foreign key relationships.

Although TRUNCATE TABLE is similar to DELETE, it is classified as a DDL statement rather than a DML statement. It differs from DELETE in the following ways in MySQL 5.7:

TRUNCATE TABLE for a table closes all handlers for the table that were opened with HANDLER OPEN.

TRUNCATE TABLE is treated for purposes of binary logging and replication as DROP TABLE followed by CREATE TABLE—that is, as DDL rather than DML. This is due to the fact that, when using InnoDB and other transactional storage engines where the transaction isolation level does not permit statement-based logging (READ COMMITTED or READ UNCOMMITTED), the statement was not logged and replicated when using STATEMENT or MIXED logging mode. (Bug #36763) However, it is still applied on replication slaves using InnoDB in the manner described previously.

TRUNCATE TABLE can be used with Performance Schema summary tables, but the effect is to reset the summary columns to 0 or NULL, not to remove rows. See Section 20.9.8, "Performance Schema Summary Tables".

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