OPTIMIZE

OPTIMIZE is a SQL command used to optimize and analyze a table which can enhance the performance of the database. This command updates index statistics of the tables, allowing for better query performance. Additionally, it assists in reclaiming the unused space and defragmenting the data file. Mostly used in MySQL, the process entails three stages: table check, table repair, and data file defragmentation.

Example

OPTIMIZE TABLE Employees

Output

+--------------+----------+----------+--------------------------------+
| Table        | Op       | Msg_type | Msg_text                       |
+--------------+----------+----------+--------------------------------+
| mydb.employees  | optimize | status   | Table is already up to date |
+--------------+----------+----------+--------------------------------+

Explanation

The OPTIMIZE TABLE command in MySQL is used to reclaim the unused space and to defragment the data file. In the example, the OPTIMIZE TABLE command runs on ‘Employees’ table. After executing the operation, it returns a table with columns: ‘Table’, ‘Op’, ‘Msg_type’, ‘Msg_text’ detailing operation’s status and message text. Here, message text “Table is already up to date” implies there was no need for optimization.

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