Talk by Kevin Schroeder of Zend at ZendCon 2009

1. Application Diagnosis with Zend Server Tracing Kevin Schroeder Zend Technologies

2. About me Kevin Schroeder Consultant for Zend Programmer Sys Admin Author Etc. Me!

3. "As soon as we started programming, we found to our surprise that it wasn't as easy to get programs right as we had thought. Debugging had to be discovered. I can remember the exact instant when I realized that a large part of my life from then on was going to spent in finding mistakes in my own programs" - Maurice Wilkes, 1949

4. Why do we need diagnostic tools?

5. Let’s see that again in slow motion

6. The point NOT to highlight an individual company Why not? How many web-based applications look like this when an error occurs? Answer All of them Web requests are intended to be short and quick If an error occurs, recover, quit and go on to the next request

7. Debugging the old way var_dump($var)(I still use this occasionally) Some obvious problems What if you forget to remove it? Are you doing this in a production environment? If you are … Very limited scope

8. Debugging the better way – ZS Debugging You can see what the variable values are at run time and modify them too Good for development Not good for production

9. Monitoring MUCH better for production systems You get a lot of really good information to help replay the issue

10. Monitoring You are able to debug or profile the event on a remote machine

11. Events that can be monitored

12. Instrumentation on the next level Zend Code Tracing

13. Code Tracing: Rapid Problem Resolution Similar in concept to a black box flight recorder - Eliminates the need to reproduce problems in order to find root cause Activated automatically (through rules) or manually Records live application execution Function calls Arguments and return values Errors Duration Useful in all parts of the software development lifecycle

14. Practical Code Tracing Functionality By capturing PHP applications code in real time: Code Tracing enables to capture problems when they occur. Code Tracing recorded data eliminate the need to reproduce the steps led up to a failure. Code Tracing enables to analyze PHP applications execution both in production and in test lab environments, by that, it enables to quickly find the root cause of problems. 14 Insert->Header & Footer

15. Supported Workflows Manual workflow: Used while performing unit tests during development or when running functional tests in QA. Calling URLs as part of the testing process Monitoring events workflow Used when running automated tests and load tests and when running your application in staging or production environments. Code tracing extends the monitoring rules mechanism by enabling to save trace data when a monitoring event is generated. Suitable for production in Standby mode

16. Detailed Runtime Instrumentation Pinpoint root cause by viewing the sequence of events that led up to an error

17. Detailed Runtime Instrumentation Optimize your code by analyzing application performance at the function level

18. Code Tracing – Monitoring Level Modes Always on Collects trace data when monitoring event is kicked off Collects trace data for manual requests. Inactive Collects data only for manual requests. Standby Off (turn code tracing extension off)

19. Code Tracing – Operating Modes Standby mode A monitoring event activates code tracing Trace mode: On Standby Tracing switches back for “Standby” mode Tracing is activated for X minutes Time A monitoring event with an “Activate Trace” action is generated Collect trace data according to the monitoring set of rules

20. The basics Trace a Request

21. Interpreting the results Screenshots are boring. Let’s look at live data

22. Setup Attaching traces to events Tracing can be attached to any PHP-specific events

24. Tracing Log Step 1 – Make sure that you have it set to log Step 2 – Set the verbosity between 1 and 5 Restart

25. Example log file [Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Tracer request startup [Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Setting dump reason to 0 [Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Dump reason is now 0 [Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Remote address is 127.0.0.1 [Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Allow hostmask is 127.0.0.1/32,10.0.0.0/8,192.168.0.0/16,172.16.0.0/12 [Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Deny hostmask is [Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Remote access allowed [Tracing Log 08.10.2009 14:14:56 DBG1] 5387 Request parameter requires dump [Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Setting dump reason to 2 [Tracing Log 08.10.2009 14:14:56 NOTICE] 5387 Installing signal handler [Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Staring trace generation [Tracing Log 08.10.2009 14:14:56 DBG2] 5387 Tracer request startup done [Tracing Log 08.10.2009 14:14:56 DBG3] 5387 Options updated to 7FFF [Tracing Log 08.10.2009 14:14:57 DBG1] 5387 Tracer request shutdown [Tracing Log 08.10.2009 14:14:57 WARNING] 5387 Code tracing buffer full [Tracing Log 08.10.2009 14:14:57 DBG1] Using socket /usr/local/zend/tmp/monitor_events.sock rules /usr/local/zend/etc/events_rules.xml [Tracing Log 08.10.2009 14:14:58 NOTICE] Event type 1 (0) reported [Tracing Log 08.10.2009 14:14:58 NOTICE] 5387 Generating trace dump, format 2 [Tracing Log 08.10.2009 14:14:58 DBG2] 5387 Dump name is /usr/local/zend/var/codetracing/dump.5387.1 Monitoring Event was triggered

26. Functional Examples Uncaught exceptions Destructor being called Prepared Statements

27. Where did all my memory go? Memory usage Large variable going out of scope

28. Impact

29. The all-important question… “Where should I use this?” Development – Possibly, though profiling and debugging may be more pertinent Testing – Absolutely Staging – Absolutely Production - Absolutely In Standby mode Activated on a subset of servers

30. Questions? Want to join in the public beta? Go to http://www.zend.com/en/products/server/zend-server-5-new for more information kevin@zend.com

31. Additional Information

32. What happens when you have too much data Need to up the zend_codetracing.buffer_size setting

33. Increasing the buffer size to 5MB That’s better

34. Settings

35. Settings

36. Settings

37. Settings