Name
CHECK TABLE
Synopsis
CHECK TABLE table
[, ...] [CHANGED|QUICK|FAST|MEDIUM|EXTENDED|FOR UPGRADE]
Use this statement to check tables for errors; as of version 5.1.9 of MySQL, it works with the
MyISAM, InnoDB, ARCHIVE, and CSV storage engines. If errors are
discovered, you should run the REPAIR TABLE
statement to repair the table. Multiple tables may be given in a
comma-separated list. This statement requires
SELECT
privileges.
There are several ways to control checking, specified after the list of tables:
CHANGED
Checks only tables that have been changed since the last check.
QUICK
Checks tables for errors, but won’t scan individual rows for linking problems.
FAST
Checks only tables that have not been closed properly.
MEDIUM
Determines the key checksum for the rows and compares the results against the checksum for the keys. This option also checks rows to ensure that links were deleted properly.
EXTENDED
Thoroughly checks each row for errors. It takes a long time to complete.
FOR UPGRADE
Checks a table against the version of MySQL in use. If the table was created from an earlier version and there have been changes to the new version that make the table incompatible, the statement will then begin the
EXTENDED
method to thoroughly check the table. If it’s successful, it will note that the table has already been checked so that future checks can avoid the time-consuming check. This option is available starting with version 5.1.7 of MySQL.
Here is an example of how you can use this statement:
CHECK ...
Get MySQL in a Nutshell, 2nd Edition now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.