Recently, in our MySQL replication setup, the replication slave crashed due to 'too many open files' error. We brought it backup, but trying to figure out what caused the unexpected hike in the number of open files. We habitually see too many connections in 'sleep' status. Would these 'sleeping' connections open files other than the sockets they keep open?
MySQL version is 5.6.20. OS is RHEL 6.4
Edit: Our MySQL is started with a huge number of 'open-files' limit and the OS has already allowed
mysql user to open that many number of files. I am doing an RCA and would like to know whether the sleeping connections would open files other than the network socket they open.