6.3. Using JDBC with the High Performance Journal
Overview
The journaled JDBC store is supported mainly for historic reasons and is not recommended for new applications. The journaled JDBC store was designed to optimize performance where there is a slow connection to the remote database. With modern high-speed networks, however, the advantage of this optimization is negligible.
Warning
The journaled JDBC store is incompatible with the JDBC master/slave failover pattern—see Fault Tolerant Messaging.
Prerequisites
Before you can use the journaled JDBC persistence store you need to ensure that the
activeio-core-3.1.4.jar bundle is installed in the container.
The bundle is available in the archived ActiveMQ installation included in the
InstallDir/extras folder or can be downloaded from Maven at http://mvnrepository.com/artifact/org.apache.activemq/activeio-core/3.1.4.
Example
Example 6.4, “Configuring Red Hat JBoss A-MQ to use the Journaled JDBC Persistence Adapter” shows a configuration fragment that configures the journaled JDBC adapter to use a MySQL database.
Example 6.4. Configuring Red Hat JBoss A-MQ to use the Journaled JDBC Persistence Adapter
<beans ... >
<broker ...>
...
1 <persistenceFactory>
2 <journalPersistenceAdapterFactory journalLogFiles="5" dataDirectory="${data}/kahadb" dataSource="#mysql-ds" useDatabaseLock="true" useDedicatedTaskRunner="false />
</persistenceFactory>
...
<broker>
...
3<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>
The configuration in Example 6.4, “Configuring Red Hat JBoss A-MQ to use the Journaled JDBC Persistence Adapter” has three noteworthy elements:
- 1
- The
persistenceFactoryelement wraps the configuration for the JDBC persistence adapter. - 2
- The
journaledJDBCelement specifies that the broker will use the JDBC persistence adapter with the high performance journal. The element's attributes configure the following properties:- The journal will span five log files.
- The configuration for the JDBC driver is specified in a
beanelement with the ID,mysql-ds. - The data for the journal will be stored in
${data}/kahadb.
- 3
- The
beanelement specified the configuration for the MySQL JDBC driver.
Configuration
Table 6.2, “Attributes for Configuring the Journaled JDBC Persistence Adapter” describes the attributes used to configure the journaled JDBC persistence adapter.
| Attribute | Default Value | Description |
|---|---|---|
adapter | Specifies the strategy to use when accessing a non-supported database. For more information see the section called “Using generic JDBC providers”. | |
createTablesOnStartup | true | Specifies whether or not new database tables are created when the broker starts. If the database tables already exist, the existing tables are reused. |
dataDirectory | activemq-data | Specifies the directory into which the default Derby database writes its files. |
dataSource | #derby | Specifies the id of the Spring bean storing the JDBC driver's configuration. For more information see the section called “Configuring your JDBC driver”. |
journalArchiveDirectory | Specifies the directory used to store archived journal log files. | |
journalLogFiles | 2 | Specifies the number of log files to use for storing the journal. |
journalLogFileSize | 20MB | Specifies the size for a journal's log file. |
journalThreadPriority | 10 | Specifies the thread priority of the thread used for journaling. |
useJournal | true | Specifies whether or not to use the journal. |
useLock | true | Specifies in the adapter uses file locking. |
lockKeepAlivePeriod | 30000 | Specifies the time period, in milliseconds, at which the current time is saved in the locker table to ensure that the lock does not timeout. 0 specifies unlimited time. |
