I had a situation where a wordpress site stopped responding, showing a database connection error. I was unable to connect to phpMyAdmin as well, it was showing that there were too many open connections to the database. Working with the host provider tech support, i was told that i should delete the plugins from the site, as they were the culprit.
Now, i know that you can disable the plugins by renaming the plugin folder, but the tech support insisted i delete them, as they claimed that even when i do disable them using that method, the plugins still make connections to the database.
Is this really the case, as it does not make sense to me – you disable the plugin, and it is not active, so it should do no work, let alone connect to the database?