When a system error happens to a mySql database, or when a table simple receives a large amount of incorrectly formatted data, the table indexes may become corrupt. The mySql system will inform a user that the table needs to be repaired when a CHECK TABLE command is run on the table. The command to verify the table needs repairing looks like this: CHECK TABLE tablename FOR UPGRADE. If the mySql system responds with “Table upgrade required,” then the table needs the indexes rebuilt. Writer Bio
