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How does a TRUNCATE TABLE statement in MySQL work?
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.
Which is more efficient delete or truncate in MySQL?
The MySQL TRUNCATE TABLE statement allows you to delete all data in a table. Therefore, in terms of functionality, The TRUNCATE TABLE statement is like a DELETE statement without a WHERE clause. However, in some cases, the MySQL TRUNCATE TABLE statement is more efficient than the DELETE statement.
Which is better to delete or drop a table in MySQL?
Delete, Truncate or Drop to clean out a table in MySQL. However, it’s better to use truncate over delete because delete removes the data by each row, thus having a performance hit than truncate. However, truncate will not work on InnoDB tables where referential integrity is enforced unless it is turned off before the truncate command is issued.
Can a TRUNCATE TABLE be rolled back to the start value?
Because a truncate operation causes an implicit commit, therefore, it cannot be rolled back. The TRUNCATE TABLE statement resets value in the AUTO_INCREMENT column to its start value if the table has an AUTO_INCREMENT column.
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, TRUNCATE TABLE bypasses the DML method of deleting data.
How to partition a table in MySQL 8.0?
This clause always begins with PARTITION BY, and follows the same syntax and other rules as apply to the partition_options clause for CREATE TABLE (for more detailed information, see Section 13.1.20, “CREATE TABLE Statement” ), and can also be used to partition an existing table that is not already partitioned.
Can a truncate partition be used on an archive table?
TRUNCATE PARTITION is supported only for partitioned tables that use the MyISAM , InnoDB, or MEMORY storage engine. It also works on BLACKHOLE tables (but has no effect). It is not supported for ARCHIVE tables.
What happens when you drop a partition in MySQL?
Any data that was stored in the dropped partitions named in the partition_names list is discarded. For example, given the table t1 defined previously, you can drop the partitions named p0 and p1 as shown here: DROP PARTITION does not work with tables that use the NDB storage engine.
How to truncate an InnoDB table in MySQL?
Truncating an InnoDB table that resides in a file-per-table tablespace drops the existing tablespace and creates a new one.
Which is better to delete or truncate a table?
Truncate is similar to delete; however, it resets the auto_increment counter back to 1 (or the initial starting value). However, it’s better to use truncate over delete because delete removes the data by each row, thus having a performance hit than truncate.