To avail the improved features of mysql database application, mysql upgrade is required after which you can get the advanced and latest features. To accomplish the task of upgradation of mysql tables, you can make use of mysql_upgrade utility. But at times, when using this upgrade utility you can face certain problems that lead to data inaccessibility or even complete data loss.

To demonstrate the above example, consider a practical situation where you are using mysql mysql_upgrade command but once the upgradation process gets completed, you find that some of the database tables are inaccessible and when you attempt to access those tables, the following error message appears on the screen:

“e-systemusr/local/mysql/bin#./myisamchk -a
/usr/local/mysql/var/centralf/postscobe1.MYI
myisamchk: error: 138 when opening MyISAM-table
‘/usr/local/mysql/var/centralf/postscobe1.MYI'
e-systemusr/local/mysql/bin#…….”

Cause:

The main reason behind this mysql upgrade error is the mysql database corruption and the probable cause behind this is improper or incomplete upgradation

Solution:

Below are some commands stated that will help you to check the consistency of the database tables as well as also repairs them in case of corruption:

• First of all, run CHECK TABLE command in order to know the corruption level of the damaged mysql tables in this way:
  ‘CHECK TABLE table_name'
• Then after, run ‘REPAIR TABLE table_name' to perform the task of corrupt database table repair

But the above mysql commands do not prove to be useful in all the cases especially in severe situations. So, in such situations the best would be opt for mysql repair tool that works to fix up all the corruption issues existing within database tables due to improper mysql upgrade. So, use this software and get rid of mysql database corruption problems occurred at the time of mysql upgrade.