Thursday, 30 July 2009

How do you repair the corrupted MySQL tables?

Error: Table ‘tbl_ name’ doesn’t exist databasename_tablesname.frm can’t open


If you get either of the following errors, it usually means that no table exists in the current database with the given name:


Table ‘tbl_name’ doesn’t exist


Can’t find file: ‘tbl_name’ (errno: 2)


A ) In some cases, it may be that the table does exist but that you are referring to it incorrectly:


Because MySQL uses directories and files to store databases and tables, database and table names are case sensitive if they are located on a file system that has case-sensitive filenames.Even for file systems that are not case sensitive, such as on Windows, all references to a given table within a query must use the same letter case.


B ) In some cases, it may be that the table exist but same error occurs then


1 ) Check the permission and ownership of database i.e. it should be same below


drwx—— 2 mysql mysql cpanelusername_dbname.


2) If the permission are corrects but same error occurs then it seems that your database table may be corrupts then there are following way to repair the DB


a) Go to whm >>SQL Services >> Repair a Database >> select database name and click Repair Database.


b) Go to cpanel >> mysql section MySQL Account Maintenance >> search database then click on Repair.


C) You can repair it though shell when mysqld server is running


i) login in mysql to that particular user by using following command



mysql>mysql –u databaseusername –p databasename

ii) select particular database



mysql> use databasename;

iii) Check whether database table is corrupted or not if following command output shows null value then it should be corrupts otherwise it is fine



mysql>show table status like ‘table name’G; Or
mysql>check table tablename ;

iv)If it is corrupts then use the following command to repair that particular database table.



mysql>repair table tablename;

D] You can repair it though shell when mysqld server is not running


Repairing MyISAM mySQL Tables/Databases:



# cd /var/lib/mysql/DBNAME

# myisamchk tablename.MYI

Repairing ISAM mySQL Tables/Databases:



# cd /var/lib/mysql/DBNAME
isamchk tablename.MYI

where


-c –> check database is corrupted or not
-r –> recorver
-o –> optimise the database

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