Restoring mysql innodb on windows. []

Over the weekend a company had a power outage, causing corruption to the on premise hosted mysql innodb database. This means the company can’t do any work, so I had to fix this fast before they opened again on Monday. It’s not trivial because the system runs on windows, which means the online guides don’t quite work. Therefore I wrote these notes for future me.

We can boot the database with force recovery In my case I had to set it to 3, try as low as possible. It puts everything in read only but that’s good enough. The recovery is a process of exporting these read only databases to sql, creating an entire new instalation with a new datafolder, and reading these back into that. The linux instruction can be found here. This post is specifically about windows. We need to run from cmd not powershell, powershell doesn’t understand <, and I’ve doubts about it understanding >.

To get a working installation I set innod_force_recovery = 3 in mysql\bin\my.ini, which can be found in xampp. First we have to restart mysql so we can get the data out. Now we can dump the tables:

./mysqldump.exe -u root -pwhatever --skip-lock-tables -A > all.sql

And shut down the server.

./mysqladmin -u root -pwhatever shut

I just emptied the datafolder with explorer, by navigating to T:/xampp/mysql/data, and deleting everything in there. Now I ran:

./mysql_istall_db.exe --datadir="T:\xampp\mysql\data"

I set innod_force_recovery to a comment again and restart mysql from xampp, I also checked if it ran in process monitor.

set the root password correctly again:

mysql -u root
SET PASSWORD FOR 'root'@'localhost' = PASSWORD('whatever');


mysql -u root -pwhatever < all.sql

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