1. Everyone likes fast things

2. Alex Hennecke
Senior Java Dev
GreenHopper JIRA Plugin

3. JIRA Plugin Performance Tuning
Why tune a plugin?
Server Side Profiling
Client Side Profiling
Performance Pitfalls

4. Why tune a plugin?
JIRA is optimised for own use cases
Plugins may do crazy, unexpected things with
JIRA's data
Slow applications suck

5. Server Side Profiling
allows you to...
find long-running code
find code waiting for locks
but...
profiling can have deceptive overhead
depends on external factors like GC, I/O, ...

6. JIRA and JProfiler
add profile option to catalina.sh
watch the console for when to connect the profiler

7. JProfiler CPU View
identify long-running call
see the chain of calls that leads to slow methods

8. Profiling under Load
Keep an eye on memory usage and GC times
jconsole

9. Profiling under Load
Watch for pool size limits
server.xml

10. Wrap-Up
Setting up JIRA for Profiling is not hard
Profiling saves time pinning down performance
problems

11. Client Side Profiling
why?
rich UIs are heavy on JavaScript
JS frameworks can hide performance traps
allows to...
identify reasons for slow page load
find performance hotspots in JavaScript

12. JIRA and dynaTrace
install a VM with Windows and target IE Version
install dynaTrace AJAX Edition
login and remember-me to JIRA from IE
add the URL you're testing to dynaTrace

13. Profiling Result - Overview

14. JavaScript Details
identify hotspots
script call
stack
script source

15. Wrap-Up
Use client side profiling as a starting point
Tune JavaScript and page load time

16. Performance Pitfalls
JQLs vs HitCollector: Example from GreenHopper
for a 50% gain
Dangerous convenience: CSS selectors in IE

17. JQL vs HitCollector
For statistics, both use Lucene
LuceneSearchProvider.searchCount is faster for
few queries
Single search with a HitCollector is faster than
many JQL queries

18. Why is that?
Creating a JQL query does permission checking

19. HitCollector
JIRA offers DocumentHitCollector

20. HitCollector
DocumentHitCollector has to load the document
from Lucene, not just count the index
Custom logic is required to do the actual counting
But it still beats many JQL queries

21. GreenHopper 5.0
Statistics performance on the server increased by 50%

22. CSS Selector in IE
IE has no native way to find nodes by class
Attribute selectors or selectors with wildcards
have to walk the DOM tree
Prototype's extension mechanism is slow on IE

23. Bad examples
$('.myCssClass')
$('div[class*=myCssClass]')
$('div#myId')

24. Good examples
$('#myId div.myCssClass')
$('#myId div[class*=myCssClass]')
$('#myId')

25. Prototype CSS Selector in IE
Timeline view in the profiler
slow method

26. Prototype CSS Selector calls
prototype element
extension
prototype CSS
selector

27. CSS Selector after tuning
Modified Prototype with switch for element extension
hotspot is gone

28. There's a lot more
Cache data that's expensive to fetch
Use Web Resources, they give you
no cache expiry (no more 304's)
batched mode (less requests)

29. Further Reading
http://confluence.atlassian.com/display/ATL/Alex+Hennecke
JIRA Web Resource
http://confluence.atlassian.com/display/JIRA/Web+Resource+Plugin+Module
jQuery Performance Rules
http://www.artzstudio.com/2009/04/jquery-performance-rules/
dynaTrace Application Performance Almanac
http://blog.dynatrace.com/2010/01/12/dynatrace-application-performance-almanach-2010/
Kirk Pepperdine
http://www.javaperformancetuning.com/

30. Performance is King
alex@atlassian.com