Thread:Project:Support desk/database is suffering from InnoDB corruption, specifically in the mw objectcache table./reply (3)

Hi!

You can truncate the objectcache table. This will keep the table structure, but remove all its content thus making this table smaller (close to 0kb). However, MediaWiki should automatically do some kind of garbage collection in that table anyway; if you have a big wiki, this table will (automatically) become big again. And this will not solve the following problem:

Try to create a full backup of all the databases in your MySQL server (using the mysqldump tool), but with the error message you get, I don't know, if using mysqldump is still possible.

As far as I know the InnoDB ibdata1 file will never shrink and there also is no easy way to make it smaller again. A force recovery can give you a chance to get to your data. Be patient and use the lowest value possible to get the server started so you can make a backup of as much data as possible.

Another question: Do you have a current backup of the database? If so, that would make things way easier! Is it only your stuff in this MySQL server or is it a shared MySQL server? If it's only your stuff on the server, you could try the following:

If you have a backup, then stop MySQL and remove all the databases, ib_logfile* and ibdata* files. When you start MySQL again it will create a new fresh shared tablespace. This table space will then not be corrupted, hopefully solving your initial issue. Then, import your database dump again.

If there are any underlying hardware issues, those need to be addressed first.