php-cgi 5.3.x and APC 3.1.3

[Michael Powell]

Joe Auty wrote:

> Hello,
> 
> I'm trying to get the APC user cache to work for me... It works with PHP
> installed as an Apache module, but not as a CGI.

I run Apache with the event mpm. This may, or may not be wise, but I've been 
doing it for a while now and had no problems with it. I also use Xcache so 
my comments are not APC specific.

Since not all of PHP is considered thread safe it is not advisable to run 
PHP on the event mpm as it is a threaded version. The way around this is to 
not use mod_php but instead run mod_fcgid.so so PHP can be run as a FastCGI.
 
> I understand that in order to get this to work one has to add a:
> 
>> FastCgiConfig -maxClassProcesses 1
> 
> to their Apache config (for those that use Apache). I've done this, but
> I'm still not seeing any evidence that the user cache is working.

This I do not know about and have never seen, but I do recall floundering 
around in the beginning and being very confused by the difference between 
exec'ing PHP code as a CGI as opposed to running it in a FastCGI process. 
There is a huge difference, with the FastCGI being many times faster. 
 
> The reason why I'm writing to this list rather than a PHP list is
> because I'm a little confused by some of the PHP install options. It
> looks like in 5.2 there was a FastCGI compile option. I'm assuming this
> is enabled by default in 5.3?

Not sure about what is in the default config, I'd have to look. But to use 
what I've described above you do not need to build/install mod_php, or have 
it in the LoadModule section of httpd.conf. But you do need to build PHP 
with CGI and CLI support. I have mod_fcgid.so in the LoadModule directives 
section of my httpd.conf. See the part below about "connecting" Apache to a 
"long running" PHP process.
 
>> # php-cgi -v
>> PHP 5.3.2 with Suhosin-Patch (cgi-fcgi) (built: May  7 2010 12:53:07)
>> Copyright (c) 1997-2009 The PHP Group
>> Zend Engine v2.3.0, Copyright (c) 1998-2010 Zend Technologies
> 
> What's confusing is the existence of both mod_fastcgi and mod_fcgi. Is
> PHP compiled against fastcgi or fcgi? It looks like the former is
> required for my setup. Since the key ingredient to this is the
> FastCgiConfig directive above, I'm not sure if there is a way to test
> that this directive has been recognized? I'm not seeing it in my
> phpinfo() screens... Could I have mod_fcgi built into php-cgi and this
> FastCGI Apache directive is being ignored?

IIRC correctly, the mod_fastcgi became deprecated when the Apache Foundation 
took over and imported the mod_fcgi codebase into the Apache project. Not 
totally sure, but this is what I seem to think I remember.

But neither mod_fastcgi nor mod_fcgi get built into php-cgi, to reuse your 
terminology. These are Apache server modules designed to connect the Apache 
server to a different process running outside and separate from Apache. The 
module is just a gateway for connecting to the PHP FastCGI process. 

When you execute php -v as a CLI, it runs, returns the info, and exits. The 
difference between this and a FastCGI process is the FastCGI is what is 
known as a "long running process". It starts the PHP interpreter as well as 
loading any PHP modules specified in extensions.ini, but it does not exit or 
"end", but continues to run. The advantage of this is it does not waste 
resource overhead creating and destroying interpreters to run each piece of 
PHP code that comes along. 
 
> In case this is relevant, I'm not doing any suexec stuff just yet.
> 
Me, I would try and avoid suexec whenever/wherever possible. It is very 
slow. 

At any rate, this stuff is *very* confusing. So this example from a working 
Apache running the event mpm and PHP as a FastCGI. In addition to the 
LoadModule line mentioned above there is also the following:

<Directory "/usr/local/www/apache22/data">

[...other stuff here...]

    # added for mod_fcgid
    #SetHandler fcgid-script
    FCGIWrapper /usr/local/bin/php-cgi .php
    Options ExecCGI
    # end of mod_fcgid change

</Directory>

# added to enable mod_fcgid

<IfModule mod_fcgid.c>
  AddHandler fcgid-script .fcgi .php
  SocketPath /var/run/fcgidsock/
  IPCConnectTimeout 10
  IPCCommTimeout 20
  OutputBufferSize 0
  MaxRequestsPerProcess 500
</IfModule>

In phpinfo(); you can see this:

Server API 	CGI/FastCGI 

My options for PHP build:

WITH_CLI=true
WITH_CGI=true
WITH_APACHE=true
WITHOUT_DEBUG=true
WITH_SUHOSIN=true
WITH_MULTIBYTE=true
WITHOUT_IPV6=true
WITHOUT_MAILHEAD=true
WITH_REDIRECT=true
WITH_DISCARD=true
WITH_FASTCGI=true
WITH_PATHINFO=true

Also keep in mind that any time PHP is rebuilt APC will need to be rebuilt 
too.

-Mike