jboss性能相关（二）
This Performance tuning tutorial is updated to the release 4.x of the application server. If you want to learn all about JBoss 4.x-5.x-6.x Performance tuning, Optimal data Persistence, Clustering tuning, Web application tuning and much more you should not miss the JBoss Performance Tuning book.
Read more about the book here
JBoss Performance Tuning Part 2
Tip 15: Lots of EJB requests ? switch to the PoolInvoker
JBoss uses RMI for EJB communication and by default creates a single thread for every incoming request.
When the number of requests is very large this could be a bottleneck. However you can switch from the standard jrmp service invoker to the pool invoker.
How to do it ? open standardjboss.xml and find the following fragment:
On JBoss 4.x you should find 4 occurrences of it: stateless-rmi-invoker, clustered-stateless-rmi-invoker, stateful-rmi-invoker,entity-rmi-invoker. Now replace this fragment with :
Notice you can even have a mixed environment: that is stateless invocation managed by the pool and all others by jrmp.
If you want to change the default attributes of your pool then open jboss-service.xml
There are two key attributes for the PooledInvoker in regards to how many threads are used in processing requests. The first is the NumAcceptThreads attribute. The value for this attribute will determine how many threads are created to listen for incoming requests. These threads will be the ones that call the accept() method of the server socket (which is a blocking call and will wait there till data is received on the network interface for the server socket).
The MaxPoolSize is the other key factor: it's the size of the pool containing the ServerThreads .
How can MaxPoolSize become a bottleneck ? if the accept thread can not get a worker thread from the pool and the pool size has reached the MaxPoolSize value, it will wait for one to become available (instead of creating a new one).
Tip 16: Have you got readonly Entity Beans ? tell it to JBoss
JBoss offers a way to handle this situation by defining either an entire EJB as being "read-only" or simply as a subset of its methods. When accessing a read-only method (or EJB), while JBoss still prevents concurrent access to the same bean instance, the bean will not be enrolled in the transaction and will not be locked during the whole transaction lifetime. Consequently, other transactions can directly use it for their own work.
Tip 17: Disable the hot deployer in production
For performance reason you might want to disable JBoss hot deployment's feature.
Simply open the conf/jboss-service.xml file and find the line:
Simply change to false and hot deployment will be disabled.
If on the other hand you simply want to reduce scan polling time, look for a few lines before:
This will set the scan time (in milliseconds)
Tip 18: Configure the EJB container to use cache, when possible.
If the EJB container has exclusive access to the persistent store, it doesn’t need to synchronize the in-memory bean state from the persistent store at the beginning of each transaction.
So you could activate the so-called Commit-A option that caches entity bean state between transactions. In order to activate this option :
Tip 19: Use Cache invalidation in a Cluster for Commit Option A
Commit option A can boost your Entity Bean but what happens when running in a cluster ? in a cluster configuration more than one JBoss node will access the same database. Furthermore, they will not only read data, but may also update the db store.Consequently, we now have as many points of write access to the database as we have JBoss instances in the cluster.
For these scenarios, JBoss incorporates a handy tool: the cache invalidation framework. It provides automatic invalidation of cache entries in a single node or across a cluster of JBoss instances. As soon as an entity bean is modified on a node, an invalidation message is automatically sent to all related containers in the cluster and the related entry is removed from the cache. The next time the data is required by a node, it will not be found in cache, and will be reloaded from the database.
In order to activate it, add to your Entity Bean the cache-invalidation tag.
Tip 20: Synchronize at commit time when possible.
The sync-on-commit-only element configures a performance optimization that will cause entity bean state to be synchronized with the database only at commit time. Normally the state of all the beans in a transaction would need to be synchronized when an finder method is called or when an remove method is called :
Tip 21: Use Prepared Statement Cache:
In JBoss, by default,prepared statements are not cached. To improve performance one can configure a prepared statement cache of an arbitrary size. You can use in your -ds.xml file the
Tip 22: Remove services you don't need
JBoss ships with lots of services, however you'll seldom need to use them all. The service is usually deployed as *-service.xml under the deploy directory. Sometimes it's also deployed as .sar/.rar archive.
In order to remove the service, remove the file in the "Server/deploy" column. If needed remove also the relative libs stated under "Server/lib"
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Servizio
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Server/deploy
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Server/lib
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Mail service
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mail-service.xml
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mail-plugin.jar, mail.jar,activation.jar
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Cache invalidation service
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cache-invalidation-service.xml
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J2EE client deployer service
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client-deployer-service.xml
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Hibernate HAR support
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hibernate-deployer-service.xml
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jboss-hibernate.jar, hibernate2.jar, cglib-full-2.0.1.jar, odmg-3.0.jar
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HSQL DB
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hsqldb-ds.xml
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hsqldb-plugin.jar, hsqldb.jar
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Default JMS Service
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jms folder
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jbossmq.jar
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HTTP Invoker (tunnels RMI through HTTP)
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http-invoker.sar
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XA Datasources
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jboss-xa-jdbc.rar
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JMX Console
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jmx-console.war
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Web Console
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management/web-console.war
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JSR-77
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management/console-mgr.sar
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Monitoring mail alerts
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monitoring-service.xml
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jboss-monitoring.jar
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Schedule Manager
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schedule-manager-service.xml
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scheduler-plugin.jar, scheduler-plugin-example.jar
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Sample Schedule service
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scheduler-service.xml
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If you are removing a core JBoss service like JMS or EAR Deployer then you need to remove it also from the jboss-service.xml :
Simply comment the attribute relative to the unwanted service
Tip 22: Tell log4j to shut up !
Wel not really anyway Log4j uses a valuable amount of time/CPU so you had better remove unnecessary logs, for example :
Comment the following line in log4j.xml in order to remove logs on the Console:
remove also the relative appender:
....
Consider raising the log level to the highest level possible in production. Here only error logs are written:
Read more about Performance tuning book here