I recently changed to using a MySQL db for authentication and I have noticed from my graphs that there are now lots of inneficient queries coming to the MySQL server from openfire. From packet trace, they seem to be opening a connection and doing this:
SET NAMES utf8
SET character_set_results = NULL
SELECT username,email FROM user WHERE user_id=?
Then closing the connection, and doing that very often. I’m guessing that the SHOW VARIABLES is the real slowdown, though I’m not sure. Is there a way to limit how often, or what type of scan openfire does? I could not see a setting in the config files.