MediaWiki Troubleshooting

• A database query error has occurred. This may indicate a bug in the software.

There are a number of reasons for this error. To get more detail add the following line to your LocalSettings.php

$wgShowSQLErrors = 1;

Now reproduce the error.

The last time I came across this issue I got an error saying that the 'searchindex' table needed to be repaired. The steps I took to fix this issue are as follows:

1. Backup the searchindex table with mysqldump. (mysqldump -u user -p --databases mediawiki --tables searchindex > searchindex.sql)
2. Truncate the table (truncate searchindex;)
3. Verify the table is empty (select * from searchindex;)
4. Run php rebuildall.php (this rebuilds all the indexes)
5. You may have to run rebuildImages.php also (in my case this wasn't necessary)

Also see: Searchindex is marked as crashed and should be repaired

Reference

http://www.mediawiki.org/wiki/Thread:Project:Support_desk/Database_error_in_upgrading_from_1.18_to_1.22
http://www.mediawiki.org/wiki/Manual:Rebuildall.php