1. Tuning Grails apps
Peter Ledbrook
Monday, 30 May 2011 1

2. Everyone wants to be Facebook
• Few apps start with millions
of hits a day
• Scaling throws up many
more issues than just the
framework
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3. Premature optimisation
Profile
... then optimise
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4. Where can things be slow?
Business
DB Network UI
Logic
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5. Server-side tools
• Spring Insight
• Profiler Plugin
• Hibernate logging
• P6Spy
• Hibernate Statistics
– App Info & Hibernate Stats Plugins
5
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6. UI tools
• Google Speed Tracer (Chrome only)
– Spring Insight integration
• ySlow (Firefox only - requires Firebug)
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7. Monday, 30 May 2011 7

8. Database performance
• Reduce the number of queries
– Use appropriate fetch mode
– Don’t fetch data you don’t need
• Tune your queries
– Add appropriate indexes
– Don’t be afraid to change the model
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9. Fetch mode and indexing
class User {
String username
String passwordHash
Profile profile
static hasMany = [ roles: Role ]
static mapping = {
username index: 'username_idx'
profile fetch: 'join'
roles lazy: false
}
}
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10. Database performance
• Caching
– Hibernate 2nd-level cache
– Distributed cache/data grid
• Terracotta
• GemFire
• Alternative data store!
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11. Hibernate 2nd-level cache
•hibernate {
DomainClass.get()
– Works reliably and well
cache.use_second_level_cache = true
• Query cache
cache.use_query_cache = true
– Each query must be declared= cached
cache.provider_class as
– Changes to data clear the cache
'net.sf.ehcache.hibernate.EhCacheProvider'
} – Best for data that changes infrequently
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12. Data grid
GemFire
GemFire Grails
DB GemFire
App
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13. Business logic
• Caching
– Spring Cache Plugin for service methods
• Go asynchronous
– Ideal for long running tasks
– Spring Events, Executor
– Messaging: JMS, AMQP
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14. Business logic
• Fall back to Java
– Limited applicability
– Numerically intensive tasks?
• Groovy++?
– One JAR
– @Typed on class or method
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15. Business logic
class MyService {
@Typed(TypePolicy.MIXED)
void doSomething() {
expensiveMethod()
}
@Typed
void expensiveMethod() {
// Do something
}
}
15
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16. Network and UI
• Reduce view processing
– Spring Cache plugin for views
• Reduce number of requests (latency)
– Expires HTTP header
– Bundle CSS & Javascript files
– Image spriting
• Reduce amount of data transferred to browser (bandwidth)
– Minify Javascript
– Compress data
• Plugins
– Performance UI, JAWR
– Resources et al.
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17. Spring Cache with views
Sitemesh
Spring Cache
Render GSP Cached View
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18. Spring Cache in code
import grails.plugin.springcache.annotations.*
class PostController {
@Cacheable("myCache")
def list = {
...
}
@CacheFlush("myCache")
def addPost = {
...
}
}
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19. Compressing page content
• Container-dependent
– Tomcat has connector setting
– For Jetty, add GzipFilter to your web.xml
• Enable gzip compression in Tomcat plugin:
eventConfigureTomcat = { tomcat ->
tomcat.connector.setAttribute(
"compression", "on")
tomcat.connector.port = serverPort
}
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20. Resources plugin
• Modularise static content
• Bundle files of the same type
• Caching Resources plugin
– Sets HTTP Expires header 1 year ahead
– Gives static files a unique name
• Zipped Resources plugin
– Gzips static content
– Can exclude files by extension
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21. Monday, 30 May 2011 21

22. Rich UIs
• Browser does the work
• Minimal traffic
• GWT, Flex, etc.
• Data transfer
– JSON
– XML
– GWT-RPC
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23. Summary
• Profile before you optimise!
• Several tools available for profiling
• Several plugins available for improving performance
• Many techniques apply to any web application
• Law of diminishing returns
– At some point, further performance improvements aren’t worth the
required effort
• Resources will be in Grails 1.4
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24. Resources
• Spring Insight
– http://www.springsource.com/developer/tcserver
• Grails Plugins
– http://grails.org/plugin/profiler
– http://grails.org/plugin/springcache
– http://grails.org/plugin/resources
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25. Thank you!
Q&A
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