MyISAMchk

MyISAM tables store their index data in .MYI files alongside the data files. When those index files get corrupted, queries start failing or returning wrong results, and the fastest fix is to run myisamchk directly against the index files while MySQL is stopped.

Repairing MyISAM Index Files

The command below repairs all MyISAM index files in the ariella_info database directory:

myisamchk --repair /var/lib/mysql/ariella_info/*.MYI

A few things to keep in mind before you run it:

• Stop MySQL first. Running myisamchk while the server is active can cause further corruption. Use systemctl stop mysqld (or the equivalent for your platform) before proceeding.
• The --repair flag tells myisamchk to rebuild the index. It is equivalent to --recover but uses a faster algorithm. If the standard repair does not resolve the issue, try --recover instead.
• File permissions. Make sure the user running the command has read and write access to the .MYI files. If you are running as root, you may need to chown the files back to mysql:mysql afterward.

Verifying the Repair

After the repair completes, myisamchk will print a status line for each file. Look for OK at the end of each line. If you see Error or Corrupt, the file may need a full rebuild:

myisamchk --check /var/lib/mysql/ariella_info/*.MYI

Once everything checks out, restart MySQL and confirm your queries are working as expected.

• SysAdmin

• Bash
• Sql
• Mysql