XF 1.2 Re-installing database to correct errors - how much will I lose?


Active member
The Xenforo installation which I've been working on but is not open to the public appears to be repeatedly breaking down and when it does it takes my wordpress site and server down. This has happened repeatedly...Bluehost says I have numerous corrupted tables and they suggest that I re-install the database.

My question is how much I will lose by doing that. I've added plugins, have several themes, have created numerous categories in research manager, modified the styling, created subforums, etc. it's been a ton of work. What am I going to lose if I reinstall the database?


XenForo moderator
Staff member
You can export the style but any other changes will be lost.

An alternative would be to do an XF to XF import but RM content isn't imported.

What proof does your host have that the tables are corrupt?
How did they become corrupt?


Active member
This is how it started

An exception occurred: Mysqli prepare error: Unknown storage engine 'InnoDB' in /home/cortjohn/public_html/forums/library/Zend/Db/Statement/Mysqli.php on line 77

Zend_Db_Statement_Mysqli->_prepare() in Zend/Db/Statement.php at line 115
Zend_Db_Statement->__construct() in Zend/Db/Adapter/Mysqli.php at line 381
Zend_Db_Adapter_Mysqli->prepare() in Zend/Db/Adapter/Abstract.php at line 478
Zend_Db_Adapter_Abstract->query() in Zend/Db/Adapter/Abstract.php at line 825
Zend_Db_Adapter_Abstract->fetchOne() in XenForo/Error.php at line 55
XenForo_Error::unexpectedException() in XenForo/Application.php at line 363

Then there was this - from Bluehost

It looks like the tables in that database are corrupt. I tried to repair one of them with PHPMyAdmin, but it failed. The next course of action that will need to be done is restoring that database from a backup of when it was working. You can try to repair the current database, but because it has become corrupt, it may be impossible.

The database restore worked temporarily -

It's gone up and down several times. Finally they recommend

In looking at the issue you were having I found that the database was showing some corruption:


I was able to find the error from the mysql logs that was showing the following:

InnoDB: Waiting for the background threads to start

With the error showing this in the logs I have tried to repair the database but it seems to be more than one table. This is not preventing the database from loading but there is a slowness when trying to start mysql. At this point I would consider dumping the database to to import a clean version the database.


Active member
They have no idea why the tables are corrupted. They suggested a plugin - I removed a bunch of plugins and still suspect one -but I can't get at it now.


XenForo moderator
Staff member
Corruption is typically due to server related issues, MySQL not shutting down correctly, servers suffering outages, etc.

If your current build and all backups are corrupt then the choices I explained above are possible.

You should also consider looking for a new host to avoid it repeating in the future.


Active member
Getting the same error as @nassella :

An exception occurred: Mysqli prepare error: Unknown storage engine 'InnoDB' in /home/cortjohn/public_html/forums/library/Zend/Db/Statement/Mysqli.php on line 77

The error goes away when I have restarted the server. And I have done this 3 times in the past week.

I just saw the mysql config file.. it has

default-storage-engine= MyISAM

Is the error because of this? Is it safe to change the default storage engine to InnoDB (considering a site has multiple WordPress installations and one XenForo installation)

A Google search revealed that moving/deleting the logs would also do. What do you suggest?


XenForo moderator
Staff member
The table engines have been defined as they have for a reason.

You can change them but you may see performance issues.