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Mysql truncate table1/12/2024 ![]() ![]() Setting innodb_adaptive_hash_index=OFF can also improve TRUNCATE TABLE performance in general. In MariaDB 10.2 only, from MariaDB 10.2.19, this performance can also be improved by setting innodb_safe_truncate=OFF. Setting innodb_adaptive_hash_index=OFF (it defaults to ON before MariaDB 10.5) can also help. In that case, using DROP TABLE followed by CREATE TABLE instead of TRUNCATE TABLE may perform better. The performance issues with innodb_file_per_table=ON can be exacerbated in cases where the InnoDB buffer pool is very large and innodb_adaptive_hash_index=ON is set. This is because TRUNCATE TABLE unlinks the underlying tablespace file, which can be an expensive operation. With InnoDB, TRUNCATE TABLE is slower if innodb_file_per_table=ON is set (the default). TRUNCATE TABLE is faster than DELETE, because it drops and re-creates a table. The syntax for TRUNCATE TABLE is very simple, as follows. Oracle-mode from MariaDB 10.3 permits the optional keywords REUSE STORAGE or DROP STORAGE to be used. The TRUNCATE TABLE statement is more efficient than the DELETE statement. Currently, TRUNCATE TABLE drops all historical records from a system-versioned table. TRUNCATE TABLE will only reset the values in the Performance Schema summary tables to zero or null, and will not remove the rows.įor the purposes of binary logging and replication, TRUNCATE TABLE is treated as DROP TABLE followed by CREATE TABLE (DDL rather than DML).The TRUNCATE statement does not invoke ON DELETE triggers. Since truncation of a table does not make any use of DELETE,.Re-created, while the partition definitions (.par) file is The partitioning that is, the data and index files are dropped and When used with partitioned tables, TRUNCATE TABLE preserves.This is true even for MyISAM and InnoDB, which normally Used AUTO_INCREMENT value, but starts countingįrom the beginning. The table handler does not remember the last.With TRUNCATE TABLE, even if the data or index files have become Table can be re-created as an empty table As long as the table format file tbl_m is valid, the.The usual result is "0 rows affected," which should Truncation operations do not return a meaningful value for the number.Truncation operations cannot be performed if the session holds an.Truncate operations cause an implicit commit.Truncate operations drop and re-create the table, which is muchįaster than deleting rows one by one, particularly for large tables.The count of rows affected by TRUNCATE TABLE is accurate onlyįor other storage engines, TRUNCATE TABLE differs from ![]() The AUTO_INCREMENT counter is reset by TRUNCATE TABLE, regardless of whether there is a FOREIGN KEY constraint. TRUNCATE TABLE will fail for an InnoDB table if any FOREIGN KEY constraints from other tables reference the table, returning the error: ERROR 1701 (42000): Cannot truncate a table referenced in a foreign key constraintįoreign Key constraints between columns in the same table are permitted.įor an InnoDB table, if there are no FOREIGN KEY constraints, InnoDB performs fast truncation by dropping the original table and creating an empty one with the same definition, which is much faster than deleting rows one by one. Logically, TRUNCATE TABLE is equivalent to a DELETE statement that deletes all rows, but there are practical differences under some circumstances. Tbl_name can also be specified in the form db_name. TRUNCATE TABLE adb_demo.TRUNCATE TABLE empties a table completely.
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