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For 2023 (and 2024 ...) - we are now fully retired from IT training.
We have made many, many friends over 25 years of teaching about Python, Tcl, Perl, PHP, Lua, Java, C and C++ - and MySQL, Linux and Solaris/SunOS too. Our training notes are now very much out of date, but due to upward compatability most of our examples remain operational and even relevant ad you are welcome to make us if them "as seen" and at your own risk.

Lisa and I (Graham) now live in what was our training centre in Melksham - happy to meet with former delegates here - but do check ahead before coming round. We are far from inactive - rather, enjoying the times that we are retired but still healthy enough in mind and body to be active!

I am also active in many other area and still look after a lot of web sites - you can find an index ((here))
A story about benchmarking PHP

I've noticed recently that the response speed of this website hasn't been as brisk as I would have liked, and thought that the cause was a steady growth in the amount of code we run behind the scenes on each page - elements I particularly felt were culprits were identifying visitors to a country by their IP addresses, and the background booking system which I hope will be live within the next few months. Plans for these next few days included a couple of hours to look at each of these areas of concern and see if I could save a few cycles here and there, add in some caches, etc.

But then I have noticed that the occasional page that wasn't going through these areas was also running a little slower, and I started to investigate. The host we're using is a shared server and I have shell login ... and a few uses of the uptime command convinced me that all was not as it should be; there seemed always to be more work that the c.p.u. could handle, and a similar test run on an identical machine on which I look after another site did not show similar overloading. So perhaps something to have a word with my ISP about?

This is one of those cautionary Christmas tales!. One last check before I wrote an "oy - what's going on" type email to the ISP ... I added in a series of 30 calls to PHP's microtime function splattered throughout a sample page, saved them in an array and dumped them out at the end of the page (I don't expect anyone but me saw them - I can't imagine that may people will be looking for the printable form of the Tk course description this morning! And what did I find? That the elements I has suspected were only taking a few milliseconds; the real culprit was a MySQL database enquiry that searched 3 million records on a non-indexed field!. Solution - short term - clean up that table that, frankly, has a lot of old crud in it. Then add an index!!

And a 2 reminder lessons - firstly not to make assumptions, and secondly of just how useful a relatively crude tool like microtime can be!

You can click on that tk course link above if you like - it'll reveal out stats at the bottom. But you shouldn't see a jump of 5 seconds between stages 15 and 16 like I did this morning!





(written 2007-12-23, updated 2007-12-24)

 
Associated topics are indexed as below, or enter http://melksh.am/nnnn for individual articles
H117 - Security in PHP
  [345] Spotting a denial of service attack - (2005-06-12)
  [426] Robust checking of data entered by users - (2005-08-27)
  [920] A lion in a cage - PHP - (2006-11-10)
  [947] What is an SQL injection attack? - (2006-11-27)
  [1052] Learning to write secure, maintainable PHP - (2007-01-25)
  [1086] Injection attacks - safeguard your PHP scripts - (2007-02-20)
  [1323] Easy handling of errors in PHP - (2007-08-27)
  [1387] Error logging to file not browser in PHP - (2007-10-11)
  [1396] Using PHP to upload images / Store on MySQL database - security questions - (2007-10-19)
  [1542] Are nasty programs looking for security holes on your server? - (2008-02-17)
  [1679] PHP - Sanitised application principles for security and useability - (2008-06-16)
  [1694] Defensive coding techniques in PHP? - (2008-07-02)
  [1747] Who is watching you? - (2008-08-10)
  [1779] Injection Attacks - avoiding them in your PHP - (2008-08-31)
  [2025] Injection Attack if register_globals in on - PHP - (2009-02-04)
  [2628] An example of an injection attack using Javascript - (2010-02-08)
  [2688] Security considerations in programming - what do we teach? - (2010-03-22)
  [2939] Protecting your images from use out of context - (2010-08-29)
  [3210] Catchable fatal error in PHP ... How to catch, and alternative solutions such as JSON - (2011-03-22)
  [3698] How to stop forms on other sites submitting to your scripts - (2012-04-15)
  [3747] An easy way to comply with the new cookie law if your site is well designed - (2012-06-02)
  [3813] Injection Attacks - PHP, SQL, HTML, Javascript - and how to neutralise them - (2012-07-22)
  [4642] A small teaching program - demonstration of principles only - (2016-02-08)

H115 - Designing PHP-Based Solutions: Best Practice
  [123] Short underground journeys and a PHP book - (2004-11-19)
  [237] Crossfertilisation, PHP to Python - (2005-03-06)
  [261] Putting a form online - (2005-03-29)
  [340] Code and code maintainance efficiency - (2005-06-08)
  [394] A year on - should we offer certified PHP courses - (2005-07-28)
  [563] Merging pictures using PHP and GD - (2006-01-13)
  [572] Giving the researcher power over database analysis - (2006-01-22)
  [839] Reporting on the 10 largest files or 10 top scores - (2006-08-20)
  [896] PHP - good coding practise and sticky radio buttons - (2006-10-17)
  [936] Global, Superglobal, Session variables - scope and persistance in PHP - (2006-11-21)
  [945] Code quality counts - (2006-11-26)
  [1047] Maintainable code - some positive advice - (2007-01-21)
  [1166] Back button - ensuring order are not submitted twice (PHP) - (2007-04-28)
  [1181] Good Programming practise - where to initialise variables - (2007-05-09)
  [1182] Painting a masterpiece in PHP - (2007-05-10)
  [1194] Drawing hands on a clock face - PHP - (2007-05-19)
  [1321] Resetting session based tests in PHP - (2007-08-26)
  [1381] Using a MySQL database to control mod_rewrite via PHP - (2007-10-06)
  [1389] Controlling and labelling Google maps via PHP - (2007-10-13)
  [1390] Converting from postal address to latitude / longitude - (2007-10-13)
  [1391] Ordnance Survey Grid Reference to Latitude / Longitude - (2007-10-14)
  [1487] Efficient PHP applications - framework and example - (2007-12-28)
  [1490] Software to record day to day events and keep an action list - (2007-12-31)
  [1533] Short and sweet and sticky - PHP form input - (2008-02-06)
  [1623] PHP Techniques - a workshop - (2008-04-26)
  [1794] Refactoring - a PHP demo becomes a production page - (2008-09-12)
  [2199] Improving the structure of your early PHP programs - (2009-05-25)
  [2221] Adding a newsfeed for your users to a multipage PHP application - (2009-06-06)
  [2430] Not just a PHP program - a good web application - (2009-09-29)
  [2679] How to build a test harness into your PHP - (2010-03-16)
  [3539] Separating program and artwork in PHP - easier maintainance, and better for the user - (2011-12-05)
  [3820] PHP sessions - a best practice teaching example - (2012-07-27)
  [3926] Filtering PHP form inputs - three ways, but which should you use? - (2012-11-18)
  [4069] Even early on, separate out your program from your HTML! - (2013-04-25)
  [4118] We not only teach PHP and Python - we teach good PHP and Python Practice! - (2013-06-18)
  [4326] Learning to program - comments, documentation and test code - (2014-11-22)
  [4641] Using an MVC structure - even without a formal framework - (2016-02-07)
  [4691] Real life PHP application using our course training MVC example - (2016-06-05)


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Next course - 7th January 2008, Regular Expressions
FSB leaves its members feeling like mushrooms
Some new C programming examples - files, structs, unions etc
Decisions - small ones, or big ones?
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This is a page archived from The Horse's Mouth at http://www.wellho.net/horse/ - the diary and writings of Graham Ellis. Every attempt was made to provide current information at the time the page was written, but things do move forward in our business - new software releases, price changes, new techniques. Please check back via our main site for current courses, prices, versions, etc - any mention of a price in "The Horse's Mouth" cannot be taken as an offer to supply at that price.

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