Some digging in the code and pulling hairs out lead to the issue: include_once was failing us. Yes, it was doing include of the same file again! One little detail – that only happened when we used both relative and absolute include path, something like:

include_once("../includes/fancyLibrary.php");
and
include_once("/absolute/path/to/document/root/includes/fancyLibrary.php");

Of course that should not be an issue, according to the PHP documentation.
When I started troubleshooting those includes calling
realpath("../includes/fancyLibrary.php");
the truth popped out – realpath was not returning anything. And then we found why – there was missing “read” attribute on the document root directory, it only had executable bit set (711). Changing permissions to 755 (added read attribute’s bit) fixed the issue.

So, problems with realpath or include_once PHP functions? Check folders permissions!

PHP script which was doing ftp_connect was failing on some installations with Segmentation Fault (core dumped) message. After quite a bit of time wasted looking for answers why, I found that problem was with the FTP host name having trailing line break. Well, that host name was coming from config and technically only developers had access to it, so looks like we assumed that variable “safe” and were not doing standard checks on special characters. To make things worse that line break is hard to see with debug output, because that line break is too easy to miss when you check variable value in debugger.

I am still not sure why Segmentation Fault (instead of proper message) – must be some PHP bug (and that server has Solaris OS).

Anyway, hope that helps somebody

Need a guru on entry level employee budget

It may sound attractive to spend same amount of money and get someone full time, but that may be not the most efficient use of the money. If work really requires high level of knowledge and experience and there is a lot of stake, it only makes sense to get call a high level expert. You won’t get them to spend 40 hours in your office, but they don’t really need to. It’s surprising how much time is wasted in the office environment and how much faster the same work will be done by the person with a lot of experience in the subject. And quality will be noticeably better too. Just make sure you picked up right person!

Jack of all trades

Smaller companies often do not have boundaries where responsibilities end, so everyone has to wear a lot of hats. In web design it may one “webmaster” guy or girl who is doing graphics, programming, server administration, marketing, etc, etc. Probably there are people who can do it all, but then they don’t have time for all those tasks and they are sure not experts in all of those areas, just stop kidding yourself. Getting freelancers who specialize in desired fields will be an easy answer. You don’t need to fill all of those positions full time, you get work done on pay-as-you-go budget and you may do not need to worry that someone doesn’t have enough work and create tasks just to keep people busy.

Team work

Freelancers do have connections. You can get a freelancer to lead the project and get more freelancers on board when/if necessary. There are tasks which may be done by mid or entry level specialist as long as they are guided by someone who knows how it should be done. Every specialist will know what kind of work they are best at and when it’s time to call a fellow freelancer to help with the area where another expertise is required. Experienced freelancers always have connections with other professionals, so it is an easy way to build a team instantly and you will know that team can work well together.

Summary

Make it real, get an expertise you need – call a freelancer. You will get better bang for you buck!

This post id dedicated to International Freelancers Day.

Error 400
Your browser sent a request that this server could not understand.
Size of a request header field exceeds server limit.

That means that your browser is trying to send too much at once. Probably, it’s size of the cookies. The easy way to fix it – delete cookies. Of course, you lose all info in the cookies, but at least you can access site again.

If you develop/manage web site and your customers complain of this error message – there are two things to do:

• Review cookies and limit the size of cookies your application stores in the browser.
• Increase allowed request size in web server configuration

To increase request size in Apache, add directive LimitRequestFieldSize to the configuration file. Default value is 8190 bytes. To increase it 2 times add
LimitRequestFieldSize 16380
Apache restart is required.

Looking around for a solutions I found quite easy tip at
http://www.eclipsezone.com/eclipse/forums/t61618.html

In short – I am now running
eclipse.exe -vmargs -Xms256m -Xmx256m -XX:PermSize=64m -XX:MaxPermSize=64m

and my Eclipse is way faster.

Thanks for the tip, Riyad Kalla!

I am able to connect from local shell, so first thought was if something wrong with recent Zend Framework upgrade, but after a while I figured out that answer is very simple – SELinux was blocking remote connections from PHP scripts executed by Apache web server. The error code (13) at the end of error message means “permission denied”, so that’s the indication to see if you have similar issue or not.

Anyway, login as root and do
setsebool -P httpd_can_network_connect=1
to make it work.

Of course, think twice because you make web server a bit less secure, so don’t do that unless you are sure you need it.

Quick check in the MySQL database showed that there is no really big tables which could cause some delays if not indexed properly or getting locked. So, next step would be naturally looking into the PHP code itself trying to identify bottlenecks.

First of all – copy everything to test site – I don’t really want to shut the site down or display some debug info to the visitors. My test site is actually a linux box which is pretty old one, so it probably will run slower comparing to production, but hopefully still allow me to find which areas of code are causing that.

Next step – tools. To profile PHP scripts I’ll use APD (http://pecl.php.net/package/apd). Best case scenario – you type
pecl install apd
in the shell to install package from PECL.
You may also need to add it to PHP configuration, I just created extra config file
/etc/php.d/apd.ini
with content
[apd]
zend_extension="/usr/lib/php/modules/apd.so"
apd.dumpdir = /var/apd
apd.statement_tracing = 0
(make sure directory specified in dumpdir is created and writable for PHP)

Now we need to add
apd_set_pprof_trace();
at the beginning of the index.php script and open the page we want to profile, front page would be a good place to start.

In the dump directory a file created after each page opening, something like
/var/apd/pprof.08711.0

Let’s see what consumes resources now, by running
/usr/bin/pprofp -R /var/apd/pprof.08711.0

Oh, that hurts:

Total Elapsed Time = 23.58
Total System Time = 0.65
Total User Time = 7.18

Log in to Joomla admin, go to Extensions->Module Manager, delete all modules I do not really use, but which came pre-setup with Joomla.

Total Elapsed Time = 19.51
Total System Time = 0.24
Total User Time = 2.48

Ok, I am starting to see results already

Now let’s pay attention to the actual calls and time spent by script in functions.

14 seconds spent in JDocumentRendererModule->getFeed…
Hm… I do have a feed from my blog, now I wonder what the cache settings for that block is. So, in admin Module Manager -> mod_feed, advanced settings, cache : use global, time 60 minutes (I think I am ok with blog posts delayed for 1 hour, but it’s your call, just make sure it won’t come on every page load). That slashed a lot from the page load – over 15 sec of wasted time (note – check why blog feed is so slow, there should be some reasons!!!)

JDocumentHTML->_parseTemplate – I reviewed template and got rid of calls for modules which are not required or not used (like user1, user2, user3 areas which came with template and similar) – that saved 1-2 seconds per call.

At this point I have

Total Elapsed Time = 2.82
Total System Time = 0.21
Total User Time = 2.48

Which is way better, but still makes me wonder if it can run faster.

There are other options to play with
/usr/bin/pprofp -u /var/apd/pprof.09573.15
gives an idea what subroutines consumed most user time.

Last but not least: for the profiling purposes I turned off cache (Site->admin->global configuration). For life site it should be turned on with reasonable time to keep cached copy, that shaves off another 50% of execution time on subsequent calls of the same page.

Total Elapsed Time = 1.78
Total System Time = 0.17
Total User Time = 1.55

For now it’s as good as it gets on my old server, next thing to do would be profiling the script on the production server to see what it looks like there.

Another tip: if you profile a live site, restrict profiler calls to your own IP:
if($_SERVER['REMOTE_ADDR'] == "xxx.xxx.xxx.xxx") {
apd_set_pprof_trace();
}
otherwise you may get buried in a number of trace logs.

These days a lot of applications are actually switching to web services, so you actually do not have to install software, you can just use it from your internet browser. But I can still see quite a few uses of this tool to create client site components for the application.

So, will keep this in mind and may be one day will use it not just to play.

Here is the link

Here is a good list of freelance positions for PHP developers:
http://workfromhomephpjobs.blogspot.com/