MySQL Reference Manual :: 5.8.3.8 How to Check MyISAM Tables for Errors

myisamchk tbl_name

This finds 99.99% of all errors. What it can't find is corruption that involves only the data file (which is very unusual). If you want to check a table, you should normally run myisamchk without options or with either the -s or --silent option.

myisamchk -m tbl_name

This finds 99.999% of all errors. It first checks all index entries for errors and then reads through all rows. It calculates a checksum for all keys in the rows and verifies that the checksum matches the checksum for the keys in the index tree.

myisamchk -e tbl_name

This does a complete and thorough check of all data (-e means ``extended check''). It does a check-read of every key for each row to verify that they indeed point to the correct row. This may take a long time for a large table that has many indexes. Normally, myisamchk stops after the first error it finds. If you want to obtain more information, you can add the --verbose (-v) option. This causes myisamchk to keep going, up through a maximum of 20 errors.

myisamchk -e -i tbl_name

Like the previous command, but the -i option tells myisamchk to print some informational statistics, too.