在哪里设置PHP_FCGI_MAX_REQUESTS值？

I have a

"mod_fcgid ap_pass_brigade failed in handle_request_ipc function"

error in my apache log. Some StackOverflow qnswers suggested I change the PHP_FCGI_MAX_REQUESTS value to fix this issue. However I cannot seem to find where this value is to be set(i.e. what file? path?) I am using LAMP on centos with Plesk panel to maintain.

Just set FcgidOutputBufferSize to 0 in /etc/httpd/conf.d/fcgid.conf for fixing this issue.