Meaning of PHP_FCGI_CHILDREN and max-procs in Lighttpd and Fastcgi configuration

There are 4 fields in fastcgi configuration, max-procs, max-load-per-proc, PHP_FCGI_CHILDREN,PHP_FCGI_MAX_REQUESTS :

fastcgi.server = ( ".php" =>
  (( "socket" => "/tmp/php-fastcgi.socket",
     "bin-path" => "/usr/local/bin/php",
     "max-procs" => "2",
     "bin-environment" => ( 
                           "PHP_FCGI_CHILDREN" => "3",
                           "PHP_FCGI_MAX_REQUESTS" => "10000" )
   ))
)

• Since there is only 1 entry in fastcgi.server, there will be 1 Fastcgi backend.
• Since PHP_FCGI_CHILDREN =3 and max-procs=2, the number of "/usr/local/bin/php" processes will be 2*(3+1)=7.
• Since max-procs=2, in the server status, there would be status of fastcgi.backend.0.0 and fastcgi.backend.0.1

So, there would be 1 fastcgi backend with 2 processes. These processes accept load.

I don't understand the following:

1. What is the significance of PHP_FCGI_CHILDREN?
2. Is a request handled by a PHP_FCGI_CHILDREN or by a proc?
3. Which parameter decides the max-load of 1 proc? And what is its default value?
4. Does the max-load of a proc have any relation with PHP_FCGI_MAX_REQUESTS?
5. What would happen if PHP_FCGI_CHILDREN=0? It was mentioned that max-proc = number of watchers and max-proc*PHP_FCGI_CHILDREN= number of workers. What does that mean?
6. When is a proc said to be overloaded?

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