XF 2.2 An unexpected database error occurred. Please try again later.

[sam2019]

I have done nothing on the server side or even in the admin panel of the forum.
the first symptom was that the forum came up without formatting on my mobile (impossible to access).
then it did the same on my laptop, then when trying again while re-loading the browser it declined access altogether.
This has happened about a week ago also, so this is the second occurrence.
after about 5 minutes wait it works again.

what is going on?

 

[sam2019]

here we go again: (after a reload it works again)

XF\Db\Exception: MySQL query error [1615]: Prepared statement needs to be re-prepared in src/XF/Db/AbstractStatement.php at line 230

2. XF\Db\AbstractStatement->getException() in src/XF/Db/Mysqli/Statement.php at line 198
4. XF\Db\Mysqli\Statement->getException() in src/XF/Db/Mysqli/Statement.php at line 79
6. XF\Db\Mysqli\Statement->execute() in src/XF/Db/AbstractAdapter.php at line 96
8. XF\Db\AbstractAdapter->query() in src/XF/Mvc/Entity/Finder.php at line 1397
10. XF\Mvc\Entity\Finder->fetchOne() in src/XF/Mvc/Entity/Manager.php at line 151
12. XF\Mvc\Entity\Manager->find() in src/XF/Pub/Controller/Thread.php at line 1635
14. XF\Pub\Controller\Thread->assertViewableThread() in src/XF/Pub/Controller/Thread.php at line 17
16. XF\Pub\Controller\Thread->actionIndex() in src/XF/Mvc/Dispatcher.php at line 352
18. XF\Mvc\Dispatcher->dispatchClass() in src/XF/Mvc/Dispatcher.php at line 259
20. XF\Mvc\Dispatcher->dispatchFromMatch() in src/XF/Mvc/Dispatcher.php at line 115
22. XF\Mvc\Dispatcher->dispatchLoop() in src/XF/Mvc/Dispatcher.php at line 57
24. XF\Mvc\Dispatcher->run() in src/XF/App.php at line 2487
26. XF\App->run() in src/XF.php at line 524
28. XF::runApp() in index.php at line 20

 

[Paul B]

This is an old mysql bug which I haven't seen for a long time.

Try increasing the table_definition_cache value in my.cnf and/or upgrading the version of mysql, or switching to MariaDB.