Re: Yahoo is moving to PHP ??

Mithun Bhattacharya wrote:

> No it is not being removed but this could have been a very big thing
> for mod_perl. Can someone find out more details as to why PHP was
> preferred over mod_perl it cant be just on a whim.
Think about what they are using it for.  Yahoo is the most extreme 
example of a performance-driven situation.  They have so much volume 
that they are willing to write things in C++ just to get the speed that 
is required.  They pre-process and cache things as much as they possibly 
can.  The server-side scripting language they use is basically a 
glorified include processor.  They pull in pre-built include files and 
read things out of dbms with it.  That's all.  The real application 
stuff is built in other languages.  (At least this is the impression I 
get from the paper and from talking to people there.)
Given that, PHP is a reasonable fit.  It's fast, has a less flexible 
syntax, and uses less memory than mod_perl.  They also have more of a 
need than most people to integrate with C/C++, and I've been told that 
it's easier to hack those into PHP.
Think about the implications of the memory graph.  If they can run 5 
more apache children at once on PHP because of its lower memory 
consumption, 5 * 4500 = 22500 more users they can handle at any given 
moment!
> Also how does one go about justifying the fact that Ioncube cache is
> doing a better cacheing than any mod_perl based solution ??
Sorry, I read that wrong.  It was actually mod_perl that had the best 
performance.  The cache they use works just the same as Perl's normal 
operation, i.e. once some code is compiled it stays in memory and 
doesn't need to be compiled again.  You don't have to do anything to get 
that in Perl.
- Perrin