Re: WordPress with Zend PHP

[Nathan Andelin <nandelin@xxxxxxxxx>]

> From: Alfredo Delgado
> An early strength of PHP over other web scripting platforms was that
> it runs as an Apache module instead of a separate CGI process ...

Could you elaborate on that?  My understanding was that each PHP instance ran as a separate process - not as an HTTP server thread.  Otherwise, why would the MaxClients directive apply to PHP?  But I admit that I don't know whether that process is launched from mod_cgi, or mod_php.  Does it matter?

> By running PHP as a module, the extra steps of sending the request
> off to an outside binary are removed and every Apache job basically
> speaks PHP instead of just simply serving traffic.

Again, it would be helpful if you could elaborate.

Running as a separate process "may have" the advantage of separating an application server from a communication server, so that itinerant applications don't affect client-server communications - static content and so forth.  That's not always the case.  There have been cases where a bug in a CGI program has seized every thread in the HTTP server.  I'm not sure what happens to PHP or the Apache server when they run buggy scripts.

> Now why wouldn't everybody skip the proxy step?

Some folks use a proxy server anyway so that you have one server for static content, but another for dynamic content.  The front-end server might be configured to run 1000 threads, while the back-end is configured to run 100. 

But it's true that you're adding some latency due to inter-process communication.