I have a friendly argument going on with a co-worker about this, and my personal opinion is that a ASP.NET-MVC compiled web application would run more efficiently/faster than the same project that would be written in PHP. My friend disagrees.
Unfortunately I do not have any solid data that I can use to back up my argument. (neither does he)
To this, I tried to Google for answers to try and find evidence to prove him wrong but most of the time the debate turned into which platform it is better to develop on, cost, security features, etc... For the sake of this argument I really don't care about any of that.
I would like to know what stack overflow community thinks about the raw speed/efficency of websites in general that are developed in ASP.NET with MVC versus exactly the same website developed with PHP?
Does anyone have any practical examples in real-world scenarios comparing the performance of the two technologies?
(I realize for some of you this may very well be an irrelevant and maybe stupid argument, but it is an argument, and I would still like to hear the answers of the fine people here at S.O.)
It's a hard comparison to make because differences in the respective stacks mean you end up doing the same thing differently and if you do them the same for the purpose of comparison it's not a very realistic test.
PHP, which I like, is in its most basic form loaded with every request, interpreted and then discarded. It is very much like CGI in this respect (which is no surprise considering it is roughly 15 years old).
Now over the years various optimisations have been made to improve the performance, most notably opcode caching with APC, for example (so much so that APC will be a standard part of PHP 6 and not an optional module like it is now).
But still PHP scripts are basically transient. Session information is (normally) file based and mutually exclusive (session_start() blocks other scripts accessing the same user session until session_commit() or the script finishes) whereas that's not the case in ASP.NET. Aside from session data, it's fairly easy (and normal) to have objects that live within the application context in ASP.NET (or Java for that matter, which ASP.NET is much more similar to).
This is a key difference. For example, database access in PHP (using mysql, mysqli, PDO, etc) is transient (persistent connections notwithstanding) whereas .Net/Java will nearly always use persistent connection pools and build on top of this to create ORM frameworks and the like, the caches for which are beyond any particular request.
As a bytecode interpreted platform, ASP.NET is theoretically faster but the limits to what PHP can do are so high as to be irrelevant for most people. 4 of the top 20 visited sites on the internet are PHP for example. Speed of development, robustness, cost of running the environment, etc... tend to be far more important when you start to scale than any theoretical speed difference.
Bear in mind that .Net has primitive types, type safety and these sorts of things that will make code faster than PHP can run it. If you want to do a somewhat unfair test, sort an array of one million random 64 bit integers in both platforms. ASP.NET will kill it because they are primitive types and simple arrays will be more efficient than PHP's associative arrays (and all arrays in PHP are associative ultimately). Plus PHP on a 32 bit OS won't have a native 64 bit integer so will suffer hugely for that.
It should also be pointed out that ASP.NET is pre-compiled whereas PHP is interpreted on-the-fly (excluding opcode caching), which can make a difference but the flexibility of PHP in this regard is a good thing. Being able to deploy a script without bouncing your server is great. Just drop it in and it works. Brilliant. But it is less performant ultimately.
Ultimately though I think you're arguing what's really an irrelevant detail.
ASP.NET runs faster. ASP.NET Development is faster.
Buy fast computer, and enjoy it if you do serious business web applications
ASP.NET code executes a lot faster compared to PHP, when it's builded in Release mode, optimized, cached etc etc. But, for websites (except big players, like Facebook), it's less important - the most time of page rendering time is accessing and querying database.
In connecting database ASP.NET is a lot better - in asp.net we typically use LINQ which translates our object queries into stored procedures in SQL server database. Also connection to database is persistent, one for one website, there is no need for reconnecting.
PHP, in comparison, can't hold sql server connection between request, it connect, grab data from db and destroys, when reconnecting the database is often 20-30% of page rendering time.
Also whole web application config is reloaded in php on each request, where in asp.net it persist in memory. It can be easily seen in big, enterprise frameworks like symfony/symfony2, a lot of rendering time is symfony internal processess, where asp.net loads it's once and don't waste your server for useless work.
ASP.NET can holds object in cache in application memory - in php you have to write it to files, or use hack like memcache. using memcache is a lot of working with concurrency and hazard problems (storing cache in files also have it's own problems with concurrency - every request start new thread of apache server and many request can work on one time - you have to think about concurrency between those threads, it take a lot of development time and not always work because php don't have any mutex mechanisms in language, so you can't make critical section by any way).
now something about development speed:
ASP.NET have two main frameworks designed for it (Webforms and MVC), installed with environment, where in PHP you must get a open-source framework. There is no standard framework in php like in asp.NET.
ASP.NET language is so rich, standard library has solutions for very much common problems, where PHP standard library is ... naked... they can't keep one naming convention.
.NET has types, where PHP is dynamic, so it means no control about source code until you run it or write unit tests.
.NET has great IDE where PHP IDE's are average or average-good (PHPStorm is still a lot worse than VS+resharper or even without it)
PHP scaffolding in symfony is fired from command line when ASP.NET scaffolding is integrated into environment.
If you have slow computer like my (one core 2,2ghz), developing asp.net pages can be painfull because you have to recompile your project on any change of source code, where PHP code refresh immediately.
PHP language syntax is so unfinished, unsolid and naked compared to C# syntax.
Strong types in C# and many flexible language features can speed up your development and make your code less buggy.
In my (non-hardbenchmarked) experience Asp.Net can certainly compete (and in some areas surpass) PHP in terms of raw speed. But similar with a lot of other language-choice related questions the following statement is (in this case) valid (in my opinion):
There are slow, buggy sites in language x (be it PHP or Asp.Net)
There are great, fast sites in language x (be it PHP or Asp.Net)
What i'm trying to say: the (talents of the) developer will influence the overall speed more than a choice between two (roughly equivalent in some abstracted extent) technologies.
Really, an 'overall speed' comparison does not make a lot of sense as both can catch up to each other in some way or another unless you're in a very specific specialist niche (which you have not informed us about).
I have done performance test.
Program : Sum of 10000000 Numbers
Given output proves that php is slower than C#............
I'd say ASP.net
Things to consider:
ASP.net is pre-compiled
ASP.net is usually written in C#, which should execute faster than PHP
Granted, the differences are very minor. There's advantages to both, I think PHP is much easier to deploy and can run on any server not just IIS. I am quite fond of ASP.net MVC though.
I am a developer expert on both technologies (ASP.Net c# and PHP5).
After years and years of working and comparing them in real production environments these are my impressions:
First of all, cant compare them making a loop of adding values 1.000.000, this is not a real case.
Is not the same comparing them in my development environment than a real production env. Eg: In development ASP.Net does not use IIS by default, use a Inner Development server which has different optimizations. In dev, there is no concurrency.
So my opinion is the next:
Looping 1.000.000 times c# is going to be faster.(no-sense)
Serving a real page, that access DB, shows images, has forms etc....
ASP.Net is slower than PHP.
Weight of ASPX pages is x10 heavier than PHP, so this makes the final user to be waiting more time to get the page.
ASPX is slower to develop than PHP, this is important because at the end is money. We develop a 35% faster in PHP than ASP.Net, because of having to compile and restart every time u want to check smthg.
In big projects, ASP.Net in long term is better for avoiding errors and have a complex architechture.
Because of Windows Servers, IIS, .... at the end u need a powerfull server to hold the same amount of users on ASP than PHP. Eg: We serve with ASP.net arround 20.000 concurrent users and in PHP, the same server can get arround 30.000 users.
The only important thing is not if looping which one is faster. The thing is when website is real and is in production, how many users they can hold, how heavy is the page (heavier== more waiting time from users, more net charge of server, more disk charge of server, more memory charge of server).
Try the checking times with concurrency and u will see.
Hope it helps.
Without any optimizations, a .net compiled app would of course run "faster" than php. But you are correct that it's a stupid and irrelevant argument because it has no bearing on the real world beyond bragging rights.
Generally ASP.Net will perform better on a given hardware than PHP. ASP.Net MVC can do better still (can being the operative word here). Most of the platform is designed with enterprise development in mind. Testable code, separation of concerns etc. A lot of the bloat in ASP.Net comes from the object stack within the page (nested controls). Pre-compiling makes this better performant, but it can be a key issue. MVC tends to allow for less nesting, using the webforms based view engine (others are available).
Where the biggest slowdowns in web applications happen tends to be remote services, especially database persistence. PHP is programmed without the benefit of connection pooling, or in-memory session state. This can be overcome with memcached and other, more performant service layers (also available to .Net).
It really comes down to the specifics of a site/application. this site happens to run MVC on fairly modest hardware quite well. A similar site under PHP would likely fall under its own weight. Other things to consider. IIS vs. Apache vs LightHTTPD etc. Honestly the php vs asp.net is much more than raw performance differences. PHP doesnt lend itself well to large, complex applications nearly so much as asp.net mvc, it's that simple... This itself has more to do with VS+SCC than anything else.
I'd tend to agree with you (that ASP.NET MVC is faster), but why not make a friendly wager with your friend and share the results? Create a really simple DYNAMIC page, derived from a MySQL database, and load the page many times.
For example, create a table with 1,000,000 rows containing a sequential primary key, and then a random # in the second column. Each of your sites can accept the primary key in a GET, retrieve the random # based on the passed in key, and display the random # in some type of dynamically generated html.
I'd love to know the results ... and if you have a blog or similar, the rest of the world would too (this question gets asked ALL the time).
It would be even better if you could build this simple little app in regular ASP too. Heck, I'd even pay you for these results if the test was well designed. Seriously - just express your interest here and I'll send you my e-mail.
Need to note that question is .NET MVC vs PHP, not .NET (Web Forms) vs PHP.
I don't have the facts, but general feeling is PHP websites run faster than .NET Web form sites (and I do .NET only). .NET web forms despite being compiled vs interpreted PHP is generally slow because all the chunk of code that is autogenerated by the .NET engine to render the HTML for each < asp:control > you use on design mode. Getting a .NET web form to compete in speed with PHP is a complete odisea that starts with setting EnableViewState = false, and can end on using every html control with runat=server... crazy uh?
Now, MVC is a different story, I had made two websites using .NET MVC2 and feeling is good, you can feel the speed now! and code is as clean as any PHP website. So, now, MVC allows you write clean code as PHP does, and MVC is compiled against PHP interpreted, it can only lead to one thing, MVC faster than PHP... time will prove, when the general sense is "MVC websites runs faster than PHP" then we will be right about what I say here today.
see/you/!
C++... Right now the fight will be between PHP and ASP.NET. PHP will win on ease of use, ASP.NET will win on performance ( in a windows server ecosystem). A lot of the larger websites that started with php have graduated to C++.
Related
I am planing to build a website using PHP to be hosted on the public internet with decent user load (between 1000 to 5000). I am using FreeBSD as a server and I configured Apache, PHP and MySQL from scratch.
With proper configuration, is it safe to use such a server, or should I go with some web framework? I am asking as I've heard few horrible things about PHP.
If it is safe, does PHP get too complex when the size of the site increases beyond a certain point?
I know Facebook uses PHP; are there any other big websites that use PHP?
Last, is it recommended to use some PHP framework or should I stick to plain old PHP?
PHP works fine for just about any size server. The question isn't really the programming language but the infrastructure you set up. 1000-5000 users is not very many unless they are all banging on the site at the same time. Are they doing a lot of DB queries or consuming a lot of CPU resources? If so, then you may want to look at a dedicated MySQL server for the DB queries.
I have nothing against frameworks. However, you are usually shoehorning your problem into their solution. Careful design on your part with common routines, etc., are usually just as good as a framework in my opinion. However, some people are more comfortable working within a framework because it removes some of the plumbing issues.
A lot of large sites use PHP. It may not be obvious because they hide the extension of the scripts in the URLs.
With proper configuration PHP is fine. However if youre new to php and server administration you might want to read up on configuring php as well as Apache for security. Youll also need to read specifics on configuration for performance as well but you need to have an app to test before its really worth doing that beyond some basics.
As far as using a framework or just basic PHP that depends totally on you. a framework is othing more really than a set of useful code and structure to accomplish alot of tasks. If you dont use a framework youre going to have to write code that meets similar requirements, so you might save time using a framework. Generally you are going to sacrifice performance in trade for having to design/write less code. You need to decide yourself if a framework (and which one) is right for the project.
In terms of sites that use php... There are a ton... Facebook, Yahoo Bookmarks, Daily Motion, parts of MySpace (at one time, not sure if its still the case), anything running Drupal or Wordpress... PHP is more than capable.
PHP is just a tool and choice of framework does not really makes your application secure or fast, unless you understand the principles of web security and how things works.
Facebook is good example of what php is capable of in hands of processionals. And there are plenty of websites that capable to handle 10K visitors a day on a single low end server.
I was surprised to learn today that PHP is used widely in high-traffic websites.
I always thought that PHP is not strong in terms of performance, being a dynamic, scripting language (e.g. compared to statically typed, compiled language like C/Java/C# etc.).
So how come it performs so well?
What you'll usually find is that it's not as slow as you think. The reason a lot of sites are slow is because the hosts are overloaded.
But one primary benefit of PHP over a compiled language is ease of maintenance. Because PHP is designed from the ground up for HTTP traffic, there's less to build than with most other compiled languages. Plus, merging in changes becomes easier as you don't need to recompile and restart the server (as you would with a compiled binary)...
I've done a considerable amount of benchmarks on both, and for anywhere under about 50k requests per second (based upon my numbers) there really isn't a significant gain to using a compiled binary (FastCGI). Sure, it's a little faster using compiled C, but unless you're talking Facebook level traffic, that's not really going to mean significant $$$. And it's definitely not going to offset the relatively rapid rate of development that PHP will afford in comparison to using C (which more than likely will require many times the code since it's not memory managed)...
PHP, if properly written can be quite scalable. The limiting factors are typically in your database engine. And that's going to be a common factor no matter what technology you use...
Java deployments in a big enterprise setting are a mess...fighting with builds and code that might not compile for the slightest little things. Also, PHP runs on a fairly simple setup server-wise, not the bulky code that is Weblogic (or others), so others are right in that it's low cost to develop and cheap to deploy on several different machines. It certainly didn't help that I was soured by working in a large, VERY inefficient corporate setting while doing Java....
I wouldn't say that PHP developers are cheaper per se (I make more now as a PHP developer than I did as a Java UI developer) but I do know that my last employer paid me for a not-insignificant amount of time spent configuring, deploying, compiling, etc that is not required in PHP. We're talking probably one day/week of related configuration fussing due to new branch roll outs or release-related configurations. So, the extra I'm paid now is made up for by a significant amount more code that I'm able to work through each week.
PHP is certainly being helped by the fact that MySQL and Postgres (to a smaller extent) have become so much more powerful. They're not directly linked, but having that as a common pairing just sweetens the deal for those making decisions.
It doesn't really perform "so well", just well enough to be used. Keep in mind, though, that Java and C#.NET are also run as bytecode inside a VM. PHP, with tools such as Zend Optimizer, can also skip the compilation step and run as bytecode.
PHP will not run as fast as native, compiled C code, but websites such as Facebook compile PHP to C++ to make it run faster (see HipHop-PHP).
Most websites have performance bottle necks when querying a database etc. The amount of time the script spends executing is usually small compared to this. Using things like libmemcached can help mitigate this.
Many sites started as low-traffic sites. Once you have your PHP website running and suddenly you have to handle much higher traffic, it's cheaper just to buy more servers than to rewrite your app from PHP to something else. Moreover there are tools that improve PHP performance.
Also note, that there are other factors: database, caching strategy which affect performance more than PHP itself.
It doesn't, which is why there are projects like HipHop, but dynamic languages are often faster to develop in, and hardware is cheaper than developers.
In my opinion the stateless nature of PHP is the most important factor to it's scalability. It's been a while since I've done any web work with Java/ASP.NET, but I recall that both technologies have a central application "engine" that all requests are piped through. That's great, because information and state can be shared between instances, and a lot of bootstrapping (reading configuration files, connecting to databases, etc) can be done once, and then shared among instances. It's bad though because that central "engine" itself becomes a bottleneck for the whole application.
The lack of a central engine in PHP also means scaling your application is usually a simple matter of adding another web server to your rig (although scaling the database along with it is more complicated). I imagine scaling a Java/ASP.NET application is a good deal more complicated, and they reach a saturation point where adding more hardware gives less of a boost each time.
I build database-driven web sites. Previously I have used Perl or PHP with MySQL.
Now I am starting a big new project, and I want to do it in the way that will result in the most responsive possible site.
I have seen several pages here where questions about how to optimize PHP are criticized with various versions of "it's not worth going to great lengths to optimize PHP since it's an interpreted language and it won't make that much difference".
I have also heard various discussions (especiallon on the SO podcast) about the benefits of compiled vs. interpreted languages, and it seems as though it would be in my interests to use a compiled language to serve up the site instead of an interpreted language.
Is this even possible in a web context? If so, what would be a reasonable language choice?
In addition to speed one benefit I forsee is the possiblity of finding bugs at compile time instead of having to debug the web site. Is this reasonable to expect?
What you can do is what multiple heavy-traffic websites do (like Facebook or Twitter), aka write your "CPU consuming" algorythm in a C-plugin.
For example, you could write a PHP extension if you plan to use PHP, or a Ruby extension if you plan to use Ruby / Ruby on Rails, etc.
That way, you can keep your streamline code simple and easy to maintain (it might be way harder to handle request from C rather than from PHP), while having a strong and solid background core (because it's compiled, and the compiler tells you what the issues are at compile time)
If you were going to build a new language... and you came up with all the semantics and it was complete, and you had some magic box that had a switch between making the language compiled vs. interpreted, the compiled version would be faster than the interpreted version.
Why? Because compiling brings your semantics down to a lower level on the machine which means it can executed much faster, whereas interpreting means the semantics of your language will translated by some thing (i.e. the interpreter) when the user actually uses your site.
Having said that... that doesn't necessarily mean that your site is going to 100% run faster on a compiled language vs an interpreted language. There are interpreters out there that are very fast nowadays for various languages (i.e. PHP), and there are even optimizers for interpreted languages that make them faster even still.
There are many other things that go into the performance of your site that are agnostic of the language you choose. Hardware setup, Database setup, Network topology, etc. These things can have a bigger impact on you. I would suggest measuring to be sure.
For me, finding bugs at compile time is a huge time saver, so I tend to prefer compiled languages which are strongly typed. It lets me get my work done faster, but that doesn't make it objectively the best option. Some people have no issue writing weakly typed code, and running test suites on them to verify their functionality, which I would think would work just as well.
IMHO it is quite a non-sense to write a complex web app using a compiled language, as it gives not benefits against a number of manageability problems.
There a lot of ways to rise up performances and scalability in a scripted language, both at language level and at system level, being the minor performances gain eventually available with a compiled language totally influential.
On the other side I find very useful to be possible to follow an agile development and bug hunting schema, simply changing your code and seeing the results.
Perl isn't an interpreted language: it is compiled to bytecode, so you pay the price of interpretation only when the perl executable is started. So when using it with Apache, don't use CGI but mod_perl.
Whatever you do, development time is probably going to widely exceed response time if you pick a language that isn't suitable to web programming or doesn't have good libraries to support what you need to do. E.g. I'd never pick C or C++. You don't want a web app that is blisteringly fast but buggy and 6 months late.
Tomcat is a common way to use compiled languages to deploy webpages, but before you go too far, seriously consider what your speed bottlenecks will be. There are a few main sources of slowdown in web applications:
Network latencies
Static media, especially images
Database queries
Server-side processing code
Client-side processing code
1 and 5 don't really have much to do with this question.
2 will be relevant if you have many images that vary from page to page. If that's the case, client browsers won't do such a good job caching, and each page-load will take some time. In this case, it is very likely that your server-side language won't be noticed, because the overhead from static media will dominate.
3 is likely to be a bigger factor than 4 for a lot of applications. If you have very little data, but you do a whole lot of processing, then 4 may dominate, but otherwise, 3 will dominate even if you're using an interpreted language.
People can ask "Why optimize php?" because the 2 and 3 are often more important anyway. Often, a good database caching framework is going to be a better (and easier) optimization.
There are lots of parts that goes into a web application. The time taken by the application layer doesn't need to be big. For a typical application, the biggest hogs would be in the webserver and in the database. Replacing PHP with a binary cgi isn't going to change this.
Furthermore, while the interpreted parts of PHP may be somewhat slow, that is only a small part of what goes on in the execution of a PHP script. All the functions that are provided as part of the language are implemented in native code. For example, when you call a function like preg_match, it will call out a native code library and let it do its work. This means that there is less actual interpretation going on than you might think.
There may be some cases where using a different language than PHP might be worthwhile, but those are special cases. In general, there is nothing to gain here.
The latency of the network is by far the greatest determining factor in this argument. In fact, network latency is so much of a factor that it renders language considerations rather unimportant from a performance issue. So...go with what you know. Use the language that you are most comfortable and most productive with and other considerations can be worked out as you go along. Now, that said, it's always fun to try new stuff and learning new things can become an obsession, so if the project is a personal one that allows you the opportunity to experiment, well, by all means.....
If I write a hello world app using a PHP web framework such as CodeIgniter and then I compile it and run it using HipHop. Will it run faster than if I write the same hello world app in django or rails?
HIPHOP converts php code into C++ code, which needs to be compiled to run. Since pre-compiled code runs faster and uses less memory then scriping languages like python/php it will probably run faster in the example you have given.
However, HIPHOP does not convert all code. A lot of code in php is dynamic and can not be changed to c++, this means you will have to write your code with this in mind. If codeigniter can even be compiled using HIPHOP is another question.
Terry Chay wrote a big article about HIPHOP, covering when to use it, it's limitations and future. I would recomment reading this, as it will most likely answer most of your questions and give you some insight into how it works :)
http://terrychay.com/article/hiphop-for-faster-php.shtml
At that point the run time is inconsequential. HipHop was designed for scaling... meaning billions of requests. There's absolutely no need to use something like HipHop for even a medium size website.
But more to the point of your question... I don't think there have been comparison charts available for us to see, but I doubt the run time would be faster at that level.
i don't know about django or rails, so this is a bit off-topic.
with plain php, the request goes to apache, then to mod_php. mod_php loads the helloworld.php script from disk, parses & tokenizes it, compiles it to bytecode, then interprets the bytecode, passes the output back to apache, apache serves it to the user.
with php and an optimizer the first run is about the same as with plain php, but the compiled source code is stored in ram. then, for the second request: goes to apache, apache to mod_php, apc loads bytecode from ram, interprets it, passes it back to apache, back to the user.
with hiphop there is no apache, but hiphop itself and there's no interpreter, so request goes directly to hiphop and back to the user. so yes, it's faster, because of several reasons:
faster startup because there's no bytecode compilation needed - the program is already in machine-readable code. so no per-request compilation and no source file reading.
no interpreter. machine code is not necessarily faster - that depends on the quality of source translation (hiphop) and the quality of the static compiler (g++). hiphop translated code is not fast compared to hand-written c code, because there's a bit of overhead because of type handling and such.
with node.js, there's also no apache. the script is started and directly compiled to machine code (because the V8 compiler does that), so it's kind of AOT (ahead of time) compiling (or is it still called JIT? i don't really know). every request is then directly handled by the already compiled machine code; so node.js is actually very comparable to hiphop. i assume hiphop to be multithreaded or something like this, while node does evented IO.
facebook claims a 50% speed gain, which is not really that much; if you compare the results of the language shootout, you'll see for the execution speed of assorted algorithms, php is 5 to 250 times slower.
so why only 50%? because ...
web apps depend on much more than just execution speed, e.g. IO
php's type system prevents hiphop to make the best use of c++'s static types
in practice, a lot of php is already C, because most of the functionality is either built in or comes from extensions. extensions are programmed in C and statically compiled.
i'm not sure if there was a huge performance gain for hello world, because hello world, even with a good framework, is still so small execution speed could be negligible in comparison to all the other overhead (network latency and stuff).
imo: if you want speed and ease of use, go for node.js :)
Running a simple application is always faster in any language. When it's become as complex as facebook, then you will face numerous of problems. PHP slowness will be show it's face. In same times, converting existing code to another language is not an options, since all logic and code is not so easy to translated to other language's syntax. That's why facebook developer decide to keep the old code, and make PHP faster. That's the reason they create their own PHP compiler, called HipHop.
Read this story from the perspective one of Facebook developer, so you know the history of HipHop.
That is not really an apple to apples comparison. In the most level playing field you might have something like:
Django running behind apache
Django rendering an HTML template to say hello world (no caching)
AND
HPHP running behind apache
HPHP rendring an HTML template to say hello world (again, no caching)
There is no database, almost no file I/O, and no caching. If you hit the page 10,000 times with a load generator at varying concurrency levels you will probably find that HPHP will outperform Django or rails - that is to say it can serve render more pages per second and keep up with your traffic a bit better.
The question is, will you ever have this many concurrent users? If you will, will they likely be hitting a database or a cached page?
HPHP sounds cool, but IMHO there is no reason to jump ship just yet (unless you are getting lots of traffic, in which case it might make sense to check it out).
Will it run faster than if I write the
same hello world app in django or
rails?
It probably will, but don't fret. If we're talking prospective speed improvements from yet unreleased projects, Pythonistas have pypy-jit and unladen-swallow to look forward to ;)
Aside from scalability issues, has anyone here actually stumbled upon a web-development problem where PHP just didn't cut it and had to go for another language / platform?
I am interested in particular scenarios and the ways they have been handled.
Thanks.
I've been working as a PHP developper (sometimes on projects not too small) for more than 3 years, and I have never really met anything that PHP wouldn't allow me to do.
Of course, you sometimes/always have to use several servers, some other piece of software (database, reverse proxy, cache, ...) ; but that's part of the game ;-)
Actually, the best thing about PHP is its "glue" nature : what PHP does is allow you to glue stuff together, to build your application using different components.
And PHP does that really well.
Sometimes, you'd have to programm in C to code a PHP extension, to glue to something no-one else has ever used (there are a lot of PHP extension which do that already like mysql or curl, to say only two names) ; but there are so many extensions that already exist that I've never had to do that -- even if I'll probabaly do so one day or another, just for fun ;-)
An important thing to note is that there is probably always a solution to your problems :
You're speaking about scalability ; what about caching ? using several servers ? using a reverse proxy ? PHP has no problem with that.
And, as you can see on SO (and in so many places) : PHP has a great community !
If I had to think about one thing that PHP is not well suited for, I'd say "comet" : PHP model of one process per request is not good for long polling and the like...
PHP is not quite good for long running batches, too ; and you often have some of those alongside your web application ; and using the same language allows you to reuse code -- still, I've always found a (not too difficult) solution.
Oh, and I'd also say : PHP is great for web applications... But not that great when is comes to desktop applications -- even if it's possible (see PHP-GTK for example).
The only limit I've ever reached as a programmer was that of my own abilities. I've worked on sites that did a few hundred hits a day and maintained software for a network of sites doing over 1M uniques/day total and both ran on the same piece of the software. The pressure wasn't on PHP, the pressure was on me to make PHP, the servers and the databases all work together to make use of them properly and to do things in a scalable way.
Query optimization
Database optimization
HTTP Caching
Memcache/APC
Server optimization
Master/Slave database setup
Profiling
Choosing just the right amount of DB normalization
Proper logging (only logging what's useful and not so much logging that it becomes useless)
Attention to detail
Proper testing
Code organization
Version control with good branching/tagging
File servers vs web servers vs database servers
Reverse proxies
General security (preventing SQL Injection, preventing XSS attacks, Session hijacking, etc)
All things learned along the way to making myself a better programmer. There's very few languages that can't run any site on the internet without the proper hardware behind it. Much of your job as a programmer is finding out the best way to take advantage of that hardware.
There are things however that PHP isn't all that good at by it's nature. Such things would include:
Desktop software (although possible)
Daemons (again, possible)
Large scale string manipulation (such as scraping sites) in a timely manner
PHP is Turing-complete, so it technically doesn't have any limits than any other language doesn't have. However, there are things that I find easier to do in other languages.