unexpected "Unauthenticated User" connections

[Arda Beyazoğlu]

I have mysql 5.6 running on ubuntu server 14.04 with 64gb ram and 16 cores (Also mysql is configured with file_per_table=1).

Let's say i have 2 databases with more than 100 hundred tables for each, and all of them are innodb except one myisam table. Myisam table has fulltext index and i am using as a cache(mostly for fulltext) layer for data from other tables.

When I query innodb tables joint with myisam table, sometimes it doesnt response or takes too much time when there is a lot of write queue on myisam table. But okay, I can expect this because of myisam characteristics.

The problem is, in this situation server spawns too many unauthenticated user connections I dont know why. Whatever the max_connections and max_user_connections directives are configured, it spawns as much as the maximum possible, so the server doesnt allow another connection for a long time. It spawns all in just a few seconds.

I could say, this is because clients still try to connect to database in the meantime, however any other database connection also fails. If there is a table lock in one database, why other databases are affected ? Also, why the connection status stuck on unauthenticated user ?