Thursday, February 18, 2010

Error 145 Occurs while accessing Merge Table

A 'merge table' in MySQL is primarily a collection of MyISAM tables. These tables are identical and can be used as single table. A database user can create a merge table by specifying a Union operator between the used MyISAM tables. The user can also apply all kinds of operations, such as, select, insert, update, and delete on the merge table. Just like any other table, these tables can also be corrupted due to various internal and external reasons. In most cases the user encounters an error message after merge table corruption. This message does not allows the user to access the records saved in the merge table. To access the records after merge table corruption, the user needs to restore data from updated table backup. But, if the user has not maintained any backup, then the merge table needs to be repaired using advanced third-party MySQL Repair application.

Consider a practical case, where you have a large merge table containing thousands of records. However, due to a server crash, the table gets corrupted. Now, when you attempt to access the records saved in that particular merge table, you receive an error message:

“ERROR 1016 (HY000): Can't open file: 'merge_employee.MRG' (errno: 145)”

On viewing the server error log, you find the following message:

“060601 21:42:20 [ERROR] /usr/sbin/mysqld: Can't open file: 'mailer_mailsent.MRG' (errno: 145)”

After this error message appears, the data saved in the merge table gets inaccessible.

Resolution:

To resolve the above error message and to access the table data, follow the below mentioned measures:

1.Run Check table command to identify the level of corruption.
2.Run Repair table command to repair the table.

If the problem persists and the table remains corrupt even after following the above steps, then you will need to search for a powerful MySQL Database Repair application to repair the corrupt table. A Repair MySQL Database utility uses latest repairing procedures to comprehensively repair the corrupt table. The tool ensures risk-free repair of tables that allow even a layman to perform MySQL table repair.

MySQL fulfills all the requirements of being the finest MySQL Repair application. The read-only repair tool repairs almost all database components created in MyISAM and InnoDB storage engines. The software is designed for Windows 7, Vista, XP, 2003 and 2000 operating systems. It supports MySQL 5.x and 4.x.

Source Taken From :- http://www.articlesengine.com/Article/Error-145-Occurs-while-accessing-Merge-Table/507466/1

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