Newsgroups: php.internals
Path: news.php.net
Xref: news.php.net php.internals:56893
Mailing-List: contact internals-help@lists.php.net; run by ezmlm
Received-SPF: error (pb1.pair.com: domain mindplay.dk from 209.85.161.170 cause and error)
MIME-Version: 1.0
Date: Mon, 12 Dec 2011 12:47:14 -0500
Message-ID: <CADqTB_iRGN-2w_SRmDB7+ev2TPmqmJXrVxMuxxC-rNNA4nka1w@mail.gmail.com>
To: internals@lists.php.net
Content-Type: multipart/alternative; boundary=f46d0444e96b97584304b3e8b937
Subject: APC caching identical files multiple times
From: rasmus@mindplay.dk (Rasmus Schultz)

--f46d0444e96b97584304b3e8b937
Content-Type: text/plain; charset=ISO-8859-1

Hello Folks,

We're hosting an increasing number of Drupal (ick) sites on our servers,
and while going over the diagnostic screen for APC, we noticed that
identical files are being cached multiple times.

For example, "user.module" is cached 3 times for 3 sites.

I've seen other people asking this question around forums and on SO, but no
clear answer.

According to the change-log, release 3.1.1 includes a "file_md5" option,
which seems to be a dud - or maybe this was intended to be implemented at
some point, but currently does nothing? The documentation isn't clear on
what this option is for.

It seems like it should not be too difficult to use an md5 (or other hash)
of the file contents plus filename (sans path) and use that as the cache
key?

In shared hosting environments, this could reduce in-memory duplication
quite a lot, or not?

I think it's common to host multiple Drupal, Joomla or WordPress sites -
all of which could share a common codebase, but personally I don't want
them to, since this creates problems with deployment and
maintenance/upgrades, and it seems like this would be a work-around more
than a solution.

Most sites use a framework these days, and most companies have one or two
frameworks they prefer, so this feature would make a lot of sense.

Is there some reason this is not as easy to implement as it might seem?

(and just occurred to me, is this the correct list for this post? my
apologies if it's not. looks like a lot of the contributors are on this
list...)

--f46d0444e96b97584304b3e8b937--