为什么php-fpm（nginx）进程不关闭并继续累积？

Question

I have the following Nginx php-fpm5.6 settings

pm = dynamic pm.max_children = 150 min_spare_servers) / 2 pm.start_servers = 10 pm.min_spare_servers = 1 pm.max_spare_servers = 25

Each child process is around 91MB and I have 16GB of of ram.

When the max number of children is reached I start to get errors in the log along the lines of:

- connect() to unix:/run/php/php5.6-fpm.sock failed (11: Resource temporarily unavailable) while connecting to upstream

- failed (104: Connection reset by peer) while reading response header from upstream

Ultimately I end up having to restart php5.6-fpm to get everything working again.

I don't understand why there are so many open child processes that don't appear to be used. I've attached a screenshot of htop which looks like there are a lot of php-fpm not consuming any ram or cpu time. (https://drive.google.com/file/d/11kEjgcMDyc4EDbJU7DE_y87V6RRJ4ekN/view?usp=sharing)

Any ideas on how to solve / diagnose the issue?

Answer 1

I presume you're using socket_connect() for this task? Whatever the case, you should be able to close the resource of the connection you've created by using code similar to:

$connection = socket_connect(...);
// ... code ...
socket_close($connection);

Perhaps you're using a for loop or something to create many connections, but are not closing them until after?

If you could post some of your code, that would be awesome :)

Hope this helps, thanks