Name
CHECKSUM TABLE
Synopsis
CHECKSUM TABLE table
[, ...] [QUICK|EXTENDED]
This statement returns a MyISAM table’s live checksum value,
a value that can be optionally maintained to improve a table’s
repairability. To enable live checksum for a table, use the
CREATE TABLE
or ALTER TABLE
statements with a table option of
CHECKSUM=1
.
Multiple tables may be given in a comma-separated list. If the
QUICK
option is employed, the live table checksum
will be returned, if available. If not, NULL will be returned.
Normally one would use the QUICK
option when the
table is probably fine. The EXTENDED
option instructs the server to check each row. You should use
this option only as a last resort. If no option is specified, the
QUICK
option is the default, if available. If not,
the EXTENDED
option is the default. The checksum
value can be different if the row format changes, which can happen
between versions of MySQL. Here is an example of this statement’s use
and its results:
CHECKSUM TABLE workreq; +----------------------+-----------+ | Table | Checksum | +----------------------+-----------+ | workrequests.workreq | 195953487 | +----------------------+-----------+
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