Peter Ledbrook

Tuning Grails apps

1Monday, 30 May 2011

Everyone wants to be Facebook

• Few apps start with millions of hits a day

• Scaling throws up many more issues than just the framework

2Monday, 30 May 2011

Premature optimisation

Profile... then optimise

3Monday, 30 May 2011

Where can things be slow?

DB BusinessLogic Network UI

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Server-side tools

• Spring Insight• Profiler Plugin• Hibernate logging• P6Spy• Hibernate Statistics

– App Info & Hibernate Stats Plugins

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UI tools

• Google Speed Tracer (Chrome only)– Spring Insight integration

• ySlow (Firefox only - requires Firebug)

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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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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 }}

9Monday, 30 May 2011

Database performance

• Caching– Hibernate 2nd-level cache– Distributed cache/data grid

• Terracotta• GemFire

• Alternative data store!

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• DomainClass.get()– Works reliably and well

• Query cache– Each query must be declared as cached– Changes to data clear the cache– Best for data that changes infrequently

Hibernate 2nd-level cache

hibernate { cache.use_second_level_cache = true cache.use_query_cache = true cache.provider_class = 'net.sf.ehcache.hibernate.EhCacheProvider'}

11Monday, 30 May 2011

Data grid

DB GrailsApp

GemFireGemFireGemFire

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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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13Monday, 30 May 2011

Business logic

• Fall back to Java– Limited applicability– Numerically intensive tasks?

• Groovy++?– One JAR– @Typed on class or method

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Business logic

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class MyService { @Typed(TypePolicy.MIXED) void doSomething() { expensiveMethod() }

@Typed void expensiveMethod() { // Do something }}

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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.

16Monday, 30 May 2011

Spring Cache with views

Sitemesh

Spring Cache

Render GSP Cached View

17Monday, 30 May 2011

Spring Cache in code

import grails.plugin.springcache.annotations.*

class PostController { @Cacheable("myCache") def list = { ... } @CacheFlush("myCache") def addPost = { ... }}

18Monday, 30 May 2011

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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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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Rich UIs

• Browser does the work• Minimal traffic• GWT, Flex, etc.• Data transfer

– JSON– XML– GWT-RPC

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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

23Monday, 30 May 2011

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

24Monday, 30 May 2011

Q&A

Thank you!

25Monday, 30 May 2011