php-general Digest 26 Sep 2012 06:15:07 -0000 Issue 7980
php-general Digest 26 Sep 2012 06:15:07 - Issue 7980 Topics (messages 319245 through 319256): Re: install PHP 5.4 by RPM 319245 by: Jonathan Sundquist 319247 by: Matijn Woudt Re: memory allocation 319246 by: Matijn Woudt 319248 by: Marcelo Bianchi 319249 by: Marcelo Bianchi 319250 by: shiplu 319251 by: shiplu 319252 by: Marcelo Bianchi 319254 by: Maciek Sokolewicz SOAP problem 319253 by: George Pitcher Vulnerability Announced in phpMyAdmin 319255 by: Daniel Brown 319256 by: tamouse mailing lists Administrivia: To subscribe to the digest, e-mail: php-general-digest-subscr...@lists.php.net To unsubscribe from the digest, e-mail: php-general-digest-unsubscr...@lists.php.net To post to the list, e-mail: php-gene...@lists.php.net -- ---BeginMessage--- What version of centso are you running? - The cold winds are rising On Sep 24, 2012 10:28 PM, lx lxlenovos...@gmail.com wrote: Hello: I have installed the PHP and Apache by RPM, and the version of rpm packets is: httpd-2.2.3-63.el5.centos.1.x86_64.rpm apr-1.2.7-11.el5_3.1.x86_64.rpm apr-util-1.2.7-11.el5.x86_64.rpm postgresql-libs-8.1.18-2.el5_4.1.x86_64.rpm gmp-4.1.4-10.el5.x86_64.rpm php-common-5.1.6-27.el5.x86_64.rpm php-cli-5.1.6-27.el5.x86_64.rpm php-5.1.6-27.el5.x86_64.rpm As you see, this version of PHP is 5.1.6, so I want to installed PHP 5.4. I want to know the list of PHP 5.4 RPM packets, these can replace the php-common-5.1.6-27.el5.x86_64.rpm, php-cli-5.1.6-27.el5.x86_64.rpm and php-5.1.6-27.el5.x86_64.rpm. Thank you. ---End Message--- ---BeginMessage--- On Tue, Sep 25, 2012 at 1:48 PM, Jonathan Sundquist jsundqu...@gmail.com wrote: What version of centso are you running? - The cold winds are rising On Sep 24, 2012 10:28 PM, lx lxlenovos...@gmail.com wrote: Hello: I have installed the PHP and Apache by RPM, and the version of rpm packets is: httpd-2.2.3-63.el5.centos.1.x86_64.rpm apr-1.2.7-11.el5_3.1.x86_64.rpm apr-util-1.2.7-11.el5.x86_64.rpm postgresql-libs-8.1.18-2.el5_4.1.x86_64.rpm gmp-4.1.4-10.el5.x86_64.rpm php-common-5.1.6-27.el5.x86_64.rpm php-cli-5.1.6-27.el5.x86_64.rpm php-5.1.6-27.el5.x86_64.rpm As you see, this version of PHP is 5.1.6, so I want to installed PHP 5.4. I want to know the list of PHP 5.4 RPM packets, these can replace the php-common-5.1.6-27.el5.x86_64.rpm, php-cli-5.1.6-27.el5.x86_64.rpm and php-5.1.6-27.el5.x86_64.rpm. Thank you. You should try the packages from the ius community, for x86_64 CentOS/RHEL 5 they are here: http://mirrors.ircam.fr/pub/ius/stable/Redhat/5/x86_64/ (look for the packages starting with php54-) - Matijn ---End Message--- ---BeginMessage--- On Tue, Sep 25, 2012 at 12:49 PM, Marcelo Bianchi mbian...@gfz-potsdam.de wrote: Dear list, I developed a script that have to create considerable array of integer numbers in memory. Currently my script has to accommodate in memory two arrays of around 120.000 numbers (for one year of data, I would like to reach a 2 years per query) that are loaded from a mysql server. I developed the script on a ubuntu 32bit machine and when I bring this script to our server, a 64bit opensuse the normal 128M of memory limit from php was exhausted. On my ubuntu system the script was consuming around 30Mb of memory / year, on the opensuse to run the same script it consumes more than 90Mb / year of memory. Is there a way to reduce this memory consumption on a 64bits machine ? Also, I made a test with four different virtual box machines (two opensuse and two ubuntu machines with the same PHP version, opensuse 11.4 and ubuntu 11.04 all running php-5.3.5) and it was quite choking the result for me. I am still wandering what is the difference between those and how to explain the results. A print screen of my machine running the four virtual boxes can be seen at: https://sites.google.com/site/foo4funreborn/phpcomp I would greatly thanks any help, with my best regards, Marcelo Bianchi Hi, If you suspect it's because of 64bits, you can always install 32bit PHP next to the 64bit version. At some point Ubuntu should support this out of the box with apt-get, but it seems that it's broken, atleast for now. Other than that, there's probably little you can do, as PHP will use 64bit integers and 64bit pointers internally, and there's pretty much nothing you can do about that. What I would suggest is just change the memory limit of PHP, you can do that with ini_set inside the PHP script. I assume you have plenty of ram in the system? If not, you should probably just go back to 32bit OS. - Matijn ---End Message--- ---BeginMessage--- Hi Matijn, That is good test, to install php 32bit side to side with the 64bit to test. Will see how hard is to accomplish that. regards, Marcelo On
php-general Digest 26 Sep 2012 19:43:53 -0000 Issue 7981
php-general Digest 26 Sep 2012 19:43:53 - Issue 7981 Topics (messages 319257 through 319267): Re: Vulnerability Announced in phpMyAdmin 319257 by: Daniel Fenn Re: output compression when host has disabled mod_deflate, mod_gzip and php_value auto_prepend_file 319258 by: tamouse mailing lists PHP as Application Server 319259 by: Maciej Li¿ewski 319260 by: shiplu 319261 by: Daniel Brown 319262 by: Jim Giner 319263 by: Maciej Li¿ewski 319264 by: Alessandro Pellizzari 319265 by: Jim Giner 319266 by: Matijn Woudt 319267 by: Robert Williams Administrivia: To subscribe to the digest, e-mail: php-general-digest-subscr...@lists.php.net To unsubscribe from the digest, e-mail: php-general-digest-unsubscr...@lists.php.net To post to the list, e-mail: php-gene...@lists.php.net -- ---BeginMessage--- Thank you for the heads up. On 9/26/12, tamouse mailing lists tamouse.li...@gmail.com wrote: On Tue, Sep 25, 2012 at 3:20 PM, Daniel Brown danbr...@php.net wrote: Just a three-list cross-post to bring it to everyone's attention at once, in case you weren't already aware. It was announced today that a compromised SourceForge mirror was distributing a malicious file with the phpMyAdmin package that allows an attacker to arbitrarily execute code on a server hosting the exploitable package. Obligatory (not intentionally self-serving) social media link here: https://twitter.com/oidk/status/250688002005811200 Signal boosting... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- Regards, Daniel Fenn ---End Message--- ---BeginMessage--- Crikey, forgot to include the list. -- Forwarded message -- From: tamouse mailing lists tamouse.li...@gmail.com Date: Wed, Sep 26, 2012 at 1:57 AM Subject: Re: [PHP] output compression when host has disabled mod_deflate, mod_gzip and php_value auto_prepend_file To: edward eric pedersson cpsmadn...@googlemail.com On Fri, Sep 21, 2012 at 9:50 AM, edward eric pedersson cpsmadn...@googlemail.com wrote: I want to compress the css and javascript external files as well but without the apache options available I am wondering what other options I have. The files are not massive, all but one less than 20k. Not sure how much of a performance gain I will get but I thought it is worth while asking the question. One solution I have on my mind is to call a php script that pulls in the css and js files and compresses the output e.g You need to ensure that the browser you are sending to has the capability to accept compressed input streams as well. Some don't still, including some screen readers. This may not be as huge a consideration with CSS or JS, but should still be considered, I think. link rel=stylesheet type=text/css href=http://my.domain.com/stylesheet.php?file=/path/to/stylesheet.css; / stylesheet.php -- ?php // initialize ob_gzhandler function to send and compress data ob_start (ob_gzhandler); // send the requisite header information and character set header (content-type: text/css; charset: UTF-8); // check cached credentials and reprocess accordingly header (cache-control: must-revalidate); // set variable for duration of cached content $offset = 60 * 60; // set variable specifying format of expiration header $expire = expires: . gmdate (D, d M Y H:i:s, time() + $offset) . GMT; I am pretty sure the header needs to be capitalized: Expires:. Also, you can simplify the format string a bit: $expire = Expires: . gmdate (DATE_RFC1123, time() + $offset); as that is the standard form the Expires header takes. // send cache expiration header to the client broswer header ($expire); //read and echo the file $file = readfile($_GET[file]); You want to be careful here and validate that you are sending a real file that contains what *you* want to send. *Always* untaint input. echo $file; ? -- Similar code for javascript with different content-type. A few questions: 1) Will apache cache the full url or the url minus the query parameter? Generally, it will cache the full url. 2) Are there any performance benefits as there is an overhead in calling the PHP file? This entirely depends on the size of the file. If your css or js is small (1000 bytes, maybe?) it's not going to be worthwhile. You say yours are mostly 2, so it might very well be worthwhile. Also, it sort of depends on how heavily your server is loaded. Live performance tests would probably be worthwhile to guage your particular implementation. 3) If the PHP call is cached is it cached with the file query parameter? Is this a different question than #1? Something similar was discussed previously, only in the
Re: [PHP] Vulnerability Announced in phpMyAdmin
On Tue, Sep 25, 2012 at 3:20 PM, Daniel Brown danbr...@php.net wrote: Just a three-list cross-post to bring it to everyone's attention at once, in case you weren't already aware. It was announced today that a compromised SourceForge mirror was distributing a malicious file with the phpMyAdmin package that allows an attacker to arbitrarily execute code on a server hosting the exploitable package. Obligatory (not intentionally self-serving) social media link here: https://twitter.com/oidk/status/250688002005811200 Signal boosting... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Vulnerability Announced in phpMyAdmin
Thank you for the heads up. On 9/26/12, tamouse mailing lists tamouse.li...@gmail.com wrote: On Tue, Sep 25, 2012 at 3:20 PM, Daniel Brown danbr...@php.net wrote: Just a three-list cross-post to bring it to everyone's attention at once, in case you weren't already aware. It was announced today that a compromised SourceForge mirror was distributing a malicious file with the phpMyAdmin package that allows an attacker to arbitrarily execute code on a server hosting the exploitable package. Obligatory (not intentionally self-serving) social media link here: https://twitter.com/oidk/status/250688002005811200 Signal boosting... -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php -- Regards, Daniel Fenn -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Fwd: [PHP] output compression when host has disabled mod_deflate, mod_gzip and php_value auto_prepend_file
Crikey, forgot to include the list. -- Forwarded message -- From: tamouse mailing lists tamouse.li...@gmail.com Date: Wed, Sep 26, 2012 at 1:57 AM Subject: Re: [PHP] output compression when host has disabled mod_deflate, mod_gzip and php_value auto_prepend_file To: edward eric pedersson cpsmadn...@googlemail.com On Fri, Sep 21, 2012 at 9:50 AM, edward eric pedersson cpsmadn...@googlemail.com wrote: I want to compress the css and javascript external files as well but without the apache options available I am wondering what other options I have. The files are not massive, all but one less than 20k. Not sure how much of a performance gain I will get but I thought it is worth while asking the question. One solution I have on my mind is to call a php script that pulls in the css and js files and compresses the output e.g You need to ensure that the browser you are sending to has the capability to accept compressed input streams as well. Some don't still, including some screen readers. This may not be as huge a consideration with CSS or JS, but should still be considered, I think. link rel=stylesheet type=text/css href=http://my.domain.com/stylesheet.php?file=/path/to/stylesheet.css; / stylesheet.php -- ?php // initialize ob_gzhandler function to send and compress data ob_start (ob_gzhandler); // send the requisite header information and character set header (content-type: text/css; charset: UTF-8); // check cached credentials and reprocess accordingly header (cache-control: must-revalidate); // set variable for duration of cached content $offset = 60 * 60; // set variable specifying format of expiration header $expire = expires: . gmdate (D, d M Y H:i:s, time() + $offset) . GMT; I am pretty sure the header needs to be capitalized: Expires:. Also, you can simplify the format string a bit: $expire = Expires: . gmdate (DATE_RFC1123, time() + $offset); as that is the standard form the Expires header takes. // send cache expiration header to the client broswer header ($expire); //read and echo the file $file = readfile($_GET[file]); You want to be careful here and validate that you are sending a real file that contains what *you* want to send. *Always* untaint input. echo $file; ? -- Similar code for javascript with different content-type. A few questions: 1) Will apache cache the full url or the url minus the query parameter? Generally, it will cache the full url. 2) Are there any performance benefits as there is an overhead in calling the PHP file? This entirely depends on the size of the file. If your css or js is small (1000 bytes, maybe?) it's not going to be worthwhile. You say yours are mostly 2, so it might very well be worthwhile. Also, it sort of depends on how heavily your server is loaded. Live performance tests would probably be worthwhile to guage your particular implementation. 3) If the PHP call is cached is it cached with the file query parameter? Is this a different question than #1? Something similar was discussed previously, only in the realm of someone wanting to serve static pages. You can cache the compressed version of the file and serve if up if it is newer than the uncompressed version, which might also speed things up, although probably not a great deal in this case since there's basically no PHP processing happening here. p.s. - somehow the OM wound up in my SPAM folder so I didn't see it for a few days. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] PHP as Application Server
Hi, Maybe this topic have been already on board, but I could not find nothing in google, so my question to PHP maintaneers (and other users too) is: Why there is no possibility to run PHP in application server way among other SAPI modules and other possibilities to run PHP? PHP would encounter great performance boost and became more enterprise :) Just look at Ruby which is slow as hell compared even with PHP. By application server I mean scenario when there is statefull application on server side not only by session mechanizms but all classes definitions maintained in memory (no need to load class definition on every request), static class members (and their changes) persistent, background threads, etc. This way any op-code cachers won't be necessary... sounds great, huh? others have it already, so why doesn't PHP? are there any cons? problems too hard to solve (one can be memory leaks, thread safe coding, etc)? I mean it - I am realy curious why there is no such possibility and is there any hope we could get it? TIA for any answers on this topic.
Re: [PHP] PHP as Application Server
My recent experience is PHP eats more memory. But it matters when you are running it under memory constraint device. For a high end server its not a matter. I built an chat server using socket functions which was intended to run on embedded device. I didn't want to load apache. So I wrote it in plain PHP (as I am good at it). The server was working good until I my memory runs out. My memory requirement was really low, about 32M. Thats the total memory for everything. I ran a heavy RIA chat application with. Later I change the language to non-PHP (name of that language might start flame-war). Now its working well so far. One thing I know is, If you want to do it, you can do it. It'll need some effort but still doable. Performance optimization comes after development. So you can have your high performance enterprise application server. -- Shiplu.Mokadd.im ImgSign.com | A dynamic signature machine Innovation distinguishes between follower and leader
Re: [PHP] PHP as Application Server
On Wed, Sep 26, 2012 at 5:58 AM, Maciej Liżewski maciej.lizew...@gmail.com wrote: Why there is no possibility to run PHP in application server way among other SAPI modules and other possibilities to run PHP? PHP would encounter great performance boost and became more enterprise :) Just look at Ruby which is slow as hell compared even with PHP. By application server I mean scenario when there is statefull application on server side not only by session mechanizms but all classes definitions maintained in memory (no need to load class definition on every request), static class members (and their changes) persistent, background threads, etc. This way any op-code cachers won't be necessary... sounds great, huh? others have it already, so why doesn't PHP? are there any cons? problems too hard to solve (one can be memory leaks, thread safe coding, etc)? I mean it - I am realy curious why there is no such possibility and is there any hope we could get it? While there are no real plans to incorporate a full-fledged application server at this time, PHP 5.4 does have an embedded server[1] for development and such. It's certainly not advisable to use it for production, but the fact is, it's there. With regard to an actual production-worthy application server, you might be interested in HipHop[2], which was developed by some of the engineers over at Facebook. ^1: http://php.net/manual/en/features.commandline.webserver.php ^2: https://developers.facebook.com/blog/post/2010/02/02/hiphop-for-php--move-fast/ -- /Daniel P. Brown Network Infrastructure Manager http://www.php.net/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Re: PHP as Application Server
On 9/26/2012 5:58 AM, Maciej Liżewski wrote: Hi, Maybe this topic have been already on board, but I could not find nothing in google, so my question to PHP maintaneers (and other users too) is: Why there is no possibility to run PHP in application server way among other SAPI modules and other possibilities to run PHP? PHP would encounter great performance boost and became more enterprise :) Just look at Ruby which is slow as hell compared even with PHP. By application server I mean scenario when there is statefull application on server side not only by session mechanizms but all classes definitions maintained in memory (no need to load class definition on every request), static class members (and their changes) persistent, background threads, etc. This way any op-code cachers won't be necessary... sounds great, huh? others have it already, so why doesn't PHP? are there any cons? problems too hard to solve (one can be memory leaks, thread safe coding, etc)? I mean it - I am realy curious why there is no such possibility and is there any hope we could get it? TIA for any answers on this topic. Thirty+ years as a professional application designer, developer and manager and I don't have a clue about what you are proposing. I must have been in a different world. :) -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: PHP as Application Server
Well.. many things changed during last 30 years. Cobol is not
mainstream, we have got OOP, Java, Python, Ruby, Google and other
great things :)
I am talking about stateful application server. There are plenty
examples in other programming languages: Java has Jetty, Tomcat, Ruby
On Rails, Python and Passenger WSGI.
All of them have one common thing: application persist in memory
between requests. Even for interpreted languages (such Ruby) - this
has advantage of loading sources only once, parse it only once and
initialize memory structures for those definitions only once. On the
opposite - PHP loads EVERY single resource on every request. This is
why it needs op-code cachers, accelerators etc.
Another advantage of using stateful application servers is that you
can simply keep gloabal state of your application (global variables,
static object properties) in memory. It simplifies many tasks which in
PHP require sessions, writing files with serialized data and
deserialize them on every request...
Just imagine such scenarios:
now PHP acts like this on every request:
1. locate resources (source files in this case), parse and load them
(possibly with op-code cache)
2. initialize global context ($_SERVER, $GLOBALS, $_POST, $_GET, etc)
3. run code
4. destroy all resource and free memory for next request
persistent application servers load resources only on startup (or when
needed) and keep them in memory until programatically freed or until
end of application (server shutdown). So every request looks like
this:
1. initialize global context
2. run already parsed code
is that makes whole thing clear?
Another nice example - simple counter. In PHP you have to:
1. read file with counter
2. increment value
3. write serialized value to file
...on every request.
in Java (for example) you just write class:
class Counter {
static private counter = 0;
public void increment() {
this.counter++;
}
}
and because class definition persists in application server - static
member is maintained between requests and whole things works as
expected...
2012/9/26 Jim Giner jim.gi...@albanyhandball.com:
On 9/26/2012 5:58 AM, Maciej Liżewski wrote:
Hi,
Maybe this topic have been already on board, but I could not find nothing
in google, so my question to PHP maintaneers (and other users too) is:
Why there is no possibility to run PHP in application server way among
other SAPI modules and other possibilities to run PHP? PHP would encounter
great performance boost and became more enterprise :) Just look at Ruby
which is slow as hell compared even with PHP.
By application server I mean scenario when there is statefull
application
on server side not only by session mechanizms but all classes definitions
maintained in memory (no need to load class definition on every request),
static class members (and their changes) persistent, background threads,
etc. This way any op-code cachers won't be necessary...
sounds great, huh? others have it already, so why doesn't PHP? are there
any cons? problems too hard to solve (one can be memory leaks, thread safe
coding, etc)? I mean it - I am realy curious why there is no such
possibility and is there any hope we could get it?
TIA for any answers on this topic.
Thirty+ years as a professional application designer, developer and manager
and I don't have a clue about what you are proposing. I must have been in a
different world. :)
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To unsubscribe, visit: http://www.php.net/unsub.php
--
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[PHP] Re: PHP as Application Server
Il Wed, 26 Sep 2012 17:23:35 +0200, Maciej Liżewski ha scritto: persistent application servers load resources only on startup (or when needed) and keep them in memory until programatically freed or until end of application (server shutdown). You don't mention the downsides: - every application must be structured to not overwrite session data (you risk saving one user's data in another user's space) - when changing even a single line in your code, you must restart (shutdown and start up) the whole app, closing all user connections and possibly losing all session data, forcing users to relogin. - memory leaks are much more problematic - you must manage threads, somehow, sometime. Application servers have (IMHO) very little advantages (counters, and?) and a lot of disadvantages. All (or nearly all) the advantages of application server have been superseded in PHP (precompiled caches, memcache, gearman, ... nodephp :) without losing its advantages (you can change a single file in the app and the precompiled cache auto-updates. You risk less with memory leaks, etc.) Yes, some things are easier in Java (threading, syncronizing, etc.) but you can always write abstraction classes to do that for you. I don't think I would use a PHP application server, even if it existed. Bye. -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Re: PHP as Application Server
On 9/26/2012 11:23 AM, Maciej Liżewski wrote:
Well.. many things changed during last 30 years. Cobol is not
mainstream, we have got OOP, Java, Python, Ruby, Google and other
great things :)
I am talking about stateful application server. There are plenty
examples in other programming languages: Java has Jetty, Tomcat, Ruby
On Rails, Python and Passenger WSGI.
All of them have one common thing: application persist in memory
between requests. Even for interpreted languages (such Ruby) - this
has advantage of loading sources only once, parse it only once and
initialize memory structures for those definitions only once. On the
opposite - PHP loads EVERY single resource on every request. This is
why it needs op-code cachers, accelerators etc.
Another advantage of using stateful application servers is that you
can simply keep gloabal state of your application (global variables,
static object properties) in memory. It simplifies many tasks which in
PHP require sessions, writing files with serialized data and
deserialize them on every request...
Just imagine such scenarios:
now PHP acts like this on every request:
1. locate resources (source files in this case), parse and load them
(possibly with op-code cache)
2. initialize global context ($_SERVER, $GLOBALS, $_POST, $_GET, etc)
3. run code
4. destroy all resource and free memory for next request
persistent application servers load resources only on startup (or when
needed) and keep them in memory until programatically freed or until
end of application (server shutdown). So every request looks like
this:
1. initialize global context
2. run already parsed code
is that makes whole thing clear?
Another nice example - simple counter. In PHP you have to:
1. read file with counter
2. increment value
3. write serialized value to file
...on every request.
in Java (for example) you just write class:
class Counter {
static private counter = 0;
public void increment() {
this.counter++;
}
}
and because class definition persists in application server - static
member is maintained between requests and whole things works as
expected...
2012/9/26 Jim Giner jim.gi...@albanyhandball.com:
On 9/26/2012 5:58 AM, Maciej Liżewski wrote:
Hi,
Maybe this topic have been already on board, but I could not find nothing
in google, so my question to PHP maintaneers (and other users too) is:
Why there is no possibility to run PHP in application server way among
other SAPI modules and other possibilities to run PHP? PHP would encounter
great performance boost and became more enterprise :) Just look at Ruby
which is slow as hell compared even with PHP.
By application server I mean scenario when there is statefull
application
on server side not only by session mechanizms but all classes definitions
maintained in memory (no need to load class definition on every request),
static class members (and their changes) persistent, background threads,
etc. This way any op-code cachers won't be necessary...
sounds great, huh? others have it already, so why doesn't PHP? are there
any cons? problems too hard to solve (one can be memory leaks, thread safe
coding, etc)? I mean it - I am realy curious why there is no such
possibility and is there any hope we could get it?
TIA for any answers on this topic.
Thirty+ years as a professional application designer, developer and manager
and I don't have a clue about what you are proposing. I must have been in a
different world. :)
--
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To unsubscribe, visit: http://www.php.net/unsub.php
Sounds to me like you'd need more hardware to support such a concept. I
realize that memory can be mapped to disk to avoid the need to have HUGE
amounts of ram in your server(S!) but with ever-increasing processor
speed, is it really necessary to go this route?
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Re: [PHP] Re: PHP as Application Server
On Wed, Sep 26, 2012 at 5:23 PM, Maciej Liżewski
maciej.lizew...@gmail.com wrote:
in Java (for example) you just write class:
class Counter {
static private counter = 0;
public void increment() {
this.counter++;
}
}
And here's where things go wrong.. You assume ++ is an atomic
operation, but in Java that's not true for static variables (it is for
local, but what does it matter?)
So you might end up with a race condition here where the counter will
only be incremented once when there are two or more threads. You need
a mutex or semaphore to make sure there's only one thread
reading/writing the counter at the same time (though volatile would
work here too probably).
Writing scripts for an application server requires a much deeper
understanding of threads and computer internals,so as a result it
probably increases error rate.
I think Alessandro explained the rest of the downsides pretty clearly.
- Matijn
Ps. Please bottom-post on this mailing list
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Re: [PHP] Re: PHP as Application Server
On 9/26/12 10:18, Matijn Woudt tijn...@gmail.com wrote: Writing scripts for an application server requires a much deeper understanding of threads and computer internals,so as a result it probably increases error rate. Well... yes and no. PHP's architecture pretty much keeps you from having to mess with thread management, but it does so by shifting the burden to a higher level, either process management of multiple PHP processes or thread management within the context of the HTTP server. If your application is sufficiently simple, that shift may be enough to keep you from having to worry about the problem. For most applications, however, it's still a concern. In some ways, this can make things worse, simply because PHP programmers tend to be oblivious of the potential problems, whereas the typical C# or Java programmer has at least some awareness of the various traps that await them. As an example, I see PHP code *all the time* that is wide open to concurrency issues with the database. Most code just assumes it's the only code doing updates, but unless the server is set up to serialize requests, that's an invalid assumption. Recently, more folks have started to address this by using database transactions, but this is often done in ignorance of what isolation level is being used and what the impact of that is upon the code - which can just make things worse. Even when there is that awareness, there are database concurrency issues with which transactions can't help. (Of course, people who are aware of isolation levels also tend to be aware of other concurrency issues.) The point is, if you have multiple things running in parallel, whether that be threads within your application or entirely separate physical servers running multiple copies of your application, you have to deal with concurrency issues. It's a necessary evil of parallel programming, and no mere technological solution (language, database, whatever), now or in the future, can fully overcome it. Well, maybe an AI engine somewhere in the chain, but that's about it, and that's not coming anytime soon. Incidentally, another advantage of PHP's share-nothing approach that hasn't been mentioned is relatively easy scalability. In a shared pool architecture, the easiest way to scale is typically vertically, that is, adding RAM, faster drives, etc. This is fine, but you can only scale vertically to a certain point, which you can usually hit pretty quickly. With PHP's share-nothing approach, you can still scale vertically, but you can almost as easily scale horizontally by adding more servers that each run merrily in their own worlds, with the primary added coordination logic being in the areas of communicating with the database and the data cache, something the application should be designed with, anyway. In contrast, the shared approach requires added logic, somewhere, to coordinate the sharing amongst the pools of all that data that the application takes for granted is always available at low cost. Having said all that, there are many advantages and disadvantages to both approaches. And honestly, I would love to have the option of a shared approach with PHP, since that architecture simply works better as a solution to certain problems. Assuming the shared-nothing model continues on, it would make PHP that much more well-rounded. In that respect, the added option isn't that different from the addition of OOP: we now have the great ability to use procedural code where it makes sense, and to use OOP code where it makes sense. Where neither is a perfect fit, you can choose the one that creates the least personal pain. It's a wonderful choice to have. Regards, Bob -- Robert E. Williams, Jr. Associate Vice President of Software Development Newtek Businesss Services, Inc. -- The Small Business Authority https://www.newtekreferrals.com/rewjr http://www.thesba.com/ Notice: This communication, including attachments, may contain information that is confidential. It constitutes non-public information intended to be conveyed only to the designated recipient(s). If the reader or recipient of this communication is not the intended recipient, an employee or agent of the intended recipient who is responsible for delivering it to the intended recipient, or if you believe that you have received this communication in error, please notify the sender immediately by return e-mail and promptly delete this e-mail, including attachments without reading or saving them in any manner. The unauthorized use, dissemination, distribution, or reproduction of this e-mail, including attachments, is prohibited and may be unlawful. If you have received this email in error, please notify us immediately by e-mail or telephone and delete the e-mail and the attachments (if any). -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
[PHP] Static constructor support
Hi, I couldn't find out whether PHP supports static constructors, and how the syntax is. The web and the PHP manual don't mention it. So is it not supported? If it is, is there a PHP version restriction? -- Yves Goergen - nospam.l...@unclassified.de - http://unclassified.de -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Static constructor support
On 26 Sep 2012, at 22:13, Yves Goergen nospam.l...@unclassified.de wrote:
I couldn't find out whether PHP supports static constructors, and how
the syntax is. The web and the PHP manual don't mention it. So is it not
supported? If it is, is there a PHP version restriction?
If you mean what C# calls a static constructor, no that does not exist in PHP,
but you can fake it. Make sure the class is in it's own file, and you can
initialise it like so…
?php
MyStaticClass::init();
class MyStaticClass
{
static public function init()
{
// Do initialisation here
}
}
Then, when the class file is required the initialisation method will
automatically be executed. However, I wouldn't encourage you to use static
classes like this. The singleton pattern would be my recommendation.
-Stuart
--
Stuart Dallas
3ft9 Ltd
http://3ft9.com/
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Re: [PHP] Static constructor support
On 26.09.2012 23:20 CE(S)T, Stuart Dallas wrote: If you mean what C# calls a static constructor, no that does not exist in PHP, but you can fake it. Okay, thank you for the quick info. How do other languages than C# call that? :-) My class is a debug helper class, that can write trace messages and so on. I have added a random per-request tag to distinguish concurrent requests in the trace file and thought that generating such a tag would perfectly fit in a static constructor. Now a helper function does that check and generates one on the first call of the method. -- Yves Goergen - nospam.l...@unclassified.de - http://unclassified.de -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
Re: [PHP] Static constructor support
On 26 Sep 2012, at 22:29, Yves Goergen nospam.l...@unclassified.de wrote: On 26.09.2012 23:20 CE(S)T, Stuart Dallas wrote: If you mean what C# calls a static constructor, no that does not exist in PHP, but you can fake it. Okay, thank you for the quick info. How do other languages than C# call that? :-) They generally don't. C# is the only language I've ever come across that support such a thing, and I only found that by accident because it would never occur to me to look for it. My class is a debug helper class, that can write trace messages and so on. I have added a random per-request tag to distinguish concurrent requests in the trace file and thought that generating such a tag would perfectly fit in a static constructor. Now a helper function does that check and generates one on the first call of the method. I would strongly recommend a singleton, or if you must use a static class you can either use the initialisation mechanism I described or, if the class has a single method as I'm guessing, have that method check the static variable to see if it's been set yet, and if not generate it before doing anything else. -Stuart -- Stuart Dallas 3ft9 Ltd http://3ft9.com/ -- PHP General Mailing List (http://www.php.net/) To unsubscribe, visit: http://www.php.net/unsub.php
