php5-fpm摇篮

Question

I have a webserver (nginx) running debian and php5-fpm randomly seems to crach, it replys with 504 bad gateway if i call php files.

when it is in a crashed state and i do sudo /etc/init.d/php5-fpm it says that it is running, but it will still it gives 504 bad gateway until i do sudo /etc/init.d/php5-fpm

I'm thinking that it has maybe to do with one of my php files which is in a infinity loop until a certain event occurs (change in mysql database) or until it will be time-outed. I don't know if generally that is a good thing or if i should make the loop quit itself before a timeout occurs.

Thanks in advice!

Answer 1

First look at the nginx error.log for the actual error. I don't think PHP crashed, just your loop is using all available php-fpm processes, so there is none free to serve your next request from nginx. That should produce Timeout error in the logs (nginx will wait for some time for available php-fpm process).

Regarding your second question. You should not use infinite loops for this. And if you do, insert sleep() command inside the loop - otherwise you will overload your CPU with that loop and also database with queries.

Also I guess it is enough to have one PHP process in that loop waiting for a event. In that case use some type of semaphore (file or info in db) to let other processes know that one is already waiting for that event. Otherwise you will always eat up all available PHP processes.