Re: beginning plannings for PEAR for PHP6

Gregory Beaver wrote:
> Lukas Kahwe Smith wrote:
> > Rasmus Lerdorf wrote:
> > > Gregory Beaver wrote:
> > > > Rasmus Lerdorf wrote:
> > > > > Justin Patrin wrote:
> > > > > > On 10/14/06, Gregory Beaver <greg@xxxxxxxxxxxxxxxxx> wrote:
> > > > > > > #2 libraries need to be opcode cache-friendly (require instead of
> > > > > > > require_once, or a class loader)
> > > > > > Could you explain more about this (or point us to some resources on
> > > > > > it)? This is the first I've heard of require_once not being ok to
> > > > > > use.
> > > > > > Why in the world would using _once break an opcode cache?
> > > > > >
> > > > > > Ok, looking myself I found:
> > > > > > http://www.phpinsider.com/smarty-forum/viewtopic.php?t=7674&sid=a4a5feb6971f5dd4201d34aa6327d4d3
> > > > > >
> > > > > >
> > > > > > which links to a post by Rasmus explaining this somewhat:
> > > > > > http://marc.theaimsgroup.com/?l=php-dev&m=113883455711935&w=2
> > > > > > and a post to the lighttpd forum:
> > > > > > http://forum.lighttpd.net/topic/864
> > > > > >
> > > > > > Rasmus' message says he's looking into ways to fix this and tihs was
> > > > > > back in Feb. Perhaps he's fixed it by now? (I'm not subscribed to
> > > > > > php-internals, so...)
> > > > > We don't have a decent fix.  And it isn't that it breaks an opcode
> > > > > cache, just that it isn't very efficient because we end up with a
> > > > > useless open() syscall.  In general you are way better off declaring
> > > > > your dependencies up front and avoiding include spaghetti.  No matter
> > > > > what we do, if a script makes 5 calls to require_once on the same file
> > > > > that is always going to be way slower than a better organized
> > > > > application that makes a single call to require.  We should be
> > > > > encouraging the latter, not the former. 
> > > > Hi Rasmus,
> > > >
> > > > Since PEAR can't reliably load dependencies in libraries without some
> > > > kind of class loading, are you saying that you like the
> > > > autoload/class_exists('classname', true) solution I proposed, or that
> > > > something else would be better?
> > > I personally prefer completely clean libraries that don't do any
> > > runtime checks at all.  Any tricks you add will cause nasty
> > > performance penalties.  autoload is especially nasty because you are
> > > forcing things out of the compiler down into the executor which again
> > > kills performance under an opcode cache.
> > The problem is that right now we need to think about users with and
> > without an opcode cache. If APC is bundled with PHP6, which seems
> > likely at this point, this situation will slant towards opcode cache
> > enabled. However, people running on hosters may till find that their
> > available memory is too limited (or that APC is even disabled because
> > of this). 
> Hi,
>
> I think I have the solution.  My original proposal will only call
> __autoload() if the classes do not already exist.
>
> Users like Rasmus, who wish to load everything up-front can do so:
>
> <?php
> require 'MDB2.php';
> require 'MDB2/Driver/mysqli.php';
> require 'MDB2/Module/Extended.php';
> ...
> ?>

just to note .. this solution means that changes in the internal file 
structure become a BC break and therefore require a bit of dancing around.

regards,
Lukas