When an operation fails or you suspect a bug, you should look at the MySQL server error log (see Section 5.3.1, “The Error Log”).

Issues relating to the InnoDB data dictionary include failed CREATE TABLE statements (orphaned table files), inability to open .InnoDB files, and system cannot find the path specified errors. For information about these sorts of problems and errors, see Section 13.2.14.4, “Troubleshooting InnoDB Data Dictionary Operations”.

When troubleshooting, it is usually best to run the MySQL server from the command prompt, rather than through mysqld_safe or as a Windows service. You can then see what mysqld prints to the console, and so have a better grasp of what is going on. On Windows, start mysqld with the --console option to direct the output to the console window.

Use the InnoDB Monitors to obtain information about a problem (see Section 13.2.14.2, “SHOW ENGINE INNODB STATUS and the InnoDB Monitors”). If the problem is performance-related, or your server appears to be hung, you should use the standard Monitor to print information about the internal state of InnoDB. If the problem is with locks, use the Lock Monitor. If the problem is in creation of tables or other data dictionary operations, use the Table Monitor to print the contents of the InnoDB internal data dictionary. To see tablespace information use the Tablespace Monitor.

If you suspect that a table is corrupt, run CHECK TABLE on that table.