MySQL is a relational database management system which stores its data dictionary information in .frm file. that is stored in the database dictionaries. At the same time InnoDB storage engine keeps the information of individual data files in table space file.

If circumstances may arise in which the server gets crashed during any data dictionary procedure, then the position in which the FRM file is stored may loose their synchrony with the location of record present in InnoDB inner data dictionary.

So, if such thing happens then the MySQL database will become un-mountable, inconsistent and inaccessible. To make the MySQL database functional users have to use the recent backup and if it is un-available then they have to use effective and efficient MySQL Repair software which will repair FRM file and will avoid the data loss.

Synchronization loss or out-of sync data dictionary indicates many symptoms due to which it can happen like problem while creating tables due to improper working of ‘create statement’ etc. If this situation occurs then user need to check the error log file of the server and if it indicates that the table already exists in the internal data dictionary of InnoDB, but the table is orphan in InnoDB table space file which has no corresponding FRM file then it is clear that corruption has caused.

In that note user need to drop that orphan table by using the ‘Drop Table’ command because the name completion can happen in MySQL client. To perform this action, start MySQL client with skip-auto-rehash option and drop the table using ‘Drop’ command.

The following error message also indicates that out-of-sync issue with the data-dictionary issue is caused –

"ERROR 1016: Can't open file: 'child2.InnoDB'. (errno: 1." In error log of MySQL, you may find the below message: "InnoDB: Cannot find table test/child2 from the internal data dictionary InnoDB: of InnoDB though the .frm file for the table exists. May be your InnoDB: have deleted and recreated InnoDB data files but have forgotten InnoDB: to delete the corresponding .frm files of InnoDB tables?"

This type of behavior of MySQL database needs restoration of data from the latest backup and if it is unavailable or corrupted then repairing of the MySQL database need to be done. MySQL Repair software can be used in this regard which has very effective and powerful algorithm that scans for the fault and repairs it efficiently and makes the data accessible to the user.