2014/08/23 OJ and related website open very slowly, training program login Direct error!

Problem:

This problem has been around for nearly one weeks, at the beginning of the discovery of OJ and related sites sometimes open a little slow, then also did not care, and then quickly slowly more and more frequent; this morning has been open very slowly (no matter what time, this situation); Training plan and do the statistics also occasionally appeared error situation, training program login directly from yesterday has been error to today! The problem is serious, I have to ask for help!

Solve:

Enter the database server, into MySQL, with show processlist command to see, found that there are a lot of unauthenticated user;

Google a bit L:

Found that this is a MySQL bug, regardless of whether the connection is through the hosts or IP, MySQL will do DNS counter-check, IP to DNS, due to the inverse of the slow speed

(Whether it is a DNS server provided by the ISP or other reasons), a large number of queries are difficult to cope with, the thread is not enough to increase the thread, but not released, so MySQL will "suspended animation."

The solution is simple, to end this counter-check process, prohibit any parsing.

Open the MySQL configuration file (my.cnf) and add a line under [mysqld]:

Skip-name-resolve

Reload the configuration file or restart the MySQL service.

Lesson:

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2014/08/23 OJ and related website open very slowly, training program login Direct error!