ActiveMQ in Action(3) - Persistence

关键字: activemq

2．3 Persistence
2．3．1 AMQ Message Store
    AMQ Message Store是ActiveMQ5.0缺省的持久化存储。Message commands被保存到transactional journal（由rolling data logs组成）。Messages被保存到data logs中，同时被reference store进行索引以提高存取速度。Date logs由一些单独的data log文件组成，缺省的文件大小是32M，如果某个消息的大小超过了data log文件的大小，那么可以修改配置以增加data log文件的大小。如果某个data log文件中所有的消息都被成功消费了，那么这个data log文件将会被标记，以便在下一轮的清理中被删除或者归档。以下是其配置的一个例子：

<broker brokerName="broker" persistent="true" useShutdownHook="false">
  <persistenceAdapter>
     <amqPersistenceAdapter directory="${activemq.base}/data" maxFileLength="32mb"/>
  </persistenceAdapter>
</broker>

Property name	Default value	Comments
directory	activemq-data	the path to the directory to use to store the message store data and log files
useNIO	true	use NIO to write messages to the data logs
syncOnWrite	false	sync every write to disk
maxFileLength	32mb	a hint to set the maximum size of the message data logs
persistentIndex	true	use a persistent index for the message logs. If this is false, an in-memory structure is maintained
maxCheckpointMessageAddSize	4kb	the maximum number of messages to keep in a transaction before automatically committing
cleanupInterval	30000	time (ms) before checking for a discarding/moving message data logs that are no longer used
indexBinSize	1024	default number of bins used by the index. The bigger the bin size - the better the relative performance of the index
indexKeySize	96	the size of the index key - the key is the message id
indexPageSize	16kb	the size of the index page - the bigger the page - the better the write performance of the index
directoryArchive	archive	the path to the directory to use to store discarded data logs
archiveDataLogs	false	if true data logs are moved to the archive directory instead of being deleted

 

2．3．2 Kaha Persistence
    Kaha Persistence 是一个专门针对消息持久化的解决方案。它对典型的消息使用模式进行了优化。在Kaha中，数据被追加到data logs中。当不再需要log文件中的数据的时候，log文件会被丢弃。以下是其配置的一个例子：

<broker brokerName="broker" persistent="true" useShutdownHook="false">
      <persistenceAdapter>
        <kahaPersistenceAdapter directory="activemq-data" maxDataFileLength="33554432"/>
      </persistenceAdapter>
</broker>

 

2．3．3 JDBC Persistence
    目前支持的数据库有Apache Derby, Axion, DB2, HSQL, Informix, MaxDB, MySQL, Oracle, Postgresql, SQLServer, Sybase。
    如果你使用的数据库不被支持，那么可以调整StatementProvider 来保证使用正确的SQL方言（flavour of SQL）。通常绝大多数数据库支持以下adaptor：

• org.activemq.store.jdbc.adapter.BlobJDBCAdapter
• org.activemq.store.jdbc.adapter.BytesJDBCAdapter
• org.activemq.store.jdbc.adapter.DefaultJDBCAdapter
• org.activemq.store.jdbc.adapter.ImageJDBCAdapter

   也可以在配置文件中直接指定JDBC adaptor，例如：

<jdbcPersistenceAdapter  adapterClass="org.apache.activemq.store.jdbc.adapter.ImageBasedJDBCAdaptor"/>

    以下是其配置的一个例子：

 

<persistence>
      <jdbcPersistence dataSourceRef=" mysql-ds"/>
</persistence>

<bean id="mysql-ds" class="org.apache.commons.dbcp.BasicDataSource" destroy-method="close">
      <property name="driverClassName" value="com.mysql.jdbc.Driver"/>
      <property name="url" value="jdbc:mysql://localhost/activemq?relaxAutoCommit=true"/>
      <property name="username" value="activemq"/>
      <property name="password" value="activemq"/>
      <property name="poolPreparedStatements" value="true"/>
</bean>

    需要注意的是，如果使用MySQL，那么需要设置relaxAutoCommit 标志为true。

 

2．3．4 Disable Persistence
    以下是其配置的一个例子：

<broker persistent="false">
</broker>