Quote:

But my host does not limited the MySQL connections

Ok...I got enough time to do a roll back to 2.0.5 and I now get this error:

This page cannot be displayed due to an internal error.

If you are the administrator of this site, please visit the XOOPS Troubleshooting Page for assistance.

Warning [PHP]: mysql_pconnect() [function.mysql-pconnect]: Link to server lost, unable to reconnect in file C:\Program Files\Apache Group\Apache2\htdocs\xoops\class\database\mysqldatabase.php line 72
Error [Xoops]: Unable to connect to database in file C:\Program Files\Apache Group\Apache2\htdocs\xoops\class\database\databasefactory.php line 34

I have even tried going back to MySQL 3.21 and the error is still there. So, by rolling back a version it is plain to see that something has changed...

I'm going to try to roll back even further...

Ok, after more tinkering then I care to type out the problem turned out to be the persistent connections option in mainfile.php. I had it set to 1 (the default and the choice if you are 'not sure') but with the failure to connect I turned it off and the problem is gone. I'm not sure why XOOPS looses the connection (does MySQL have a timeout?) but it works fine with XOOPS_DB_PCONNECT=0 so I'm not bothering with it anymore...

In my site the XOOPS_DB_PCONNECT is 0

but still got this problem and 502 Bad Gateway frequently

All errors have mysteriously stopped with no intervention from myself.

Go figure