JDBC-Based Persistence Properties

The full set of properties for configuring a broker to use a JDBC database are listed in Table 17–7. You can specify these properties either in the instance configuration file (config.properties) of each broker instance or by using the -D command line option to the Broker utility (imqbrokerd) or the Database Manager utility (imqdbmgr).

In practice, however, JDBC properties are preconfigured by default, depending on the database vendor being used for the data store. The property values are set in the default.properties file, and only need to be explicitly set if you are overriding the default values. In general, you only need to set the following properties:

• imq.persist.store

  This property specifies that a JDBC-based data store (as opposed to the default file-based data store) is used to store persistent data.

• imq.persist.jdbc.dbVendor

  This property identifies the database vendor being used for the data store; all of the remaining properties are qualified by this vendor name.

• imq.persist.jdbc.connection.limit

  This property specifies the maximum number of connections that can be opened to the database.

• imq.persist.jdbcvendorName.user

  This property specifies the user name to be used by the broker in accessing the database.

• imq.persist.jdbcvendorName.password

  This property specifies the password for accessing the database, if required; imq.persist.jdbc.vendorName.needpassword is a boolean flag specifying whether a password is needed. For security reasons, the database access password should be specified only in a password file referenced with the -passfile command line option; if no such password file is specified, the imqbrokerd and imqdbmgr commands will prompt for the password interactively.

• imq.persist.jdbc.vendorName.property.propName

  This set of properties represents any additional, vendor-specific properties that are required.

• imq.persist.jdbc.vendorName.tableoption

  Specifies the vendor-specific options passed to the database when creating the table schema.

Example 8–1 Broker Properties for MySQL Database

imq.persist.store=jdbc
imq.persist.jdbc.dbVendor=mysql
imq.persist.jdbc.mysql.user=userName
imq.persist.jdbc.mysql.password=password
imq.persist.jdbc.mysql.property.url=jdbc:mysql://hostName:port/dataBase

If you expect to have messages that are larger than 1 MB, configure MySQL's max_allowed_packet variable accordingly when starting the database. For more information see Appendix B of the MySQL 5.0 Reference Manual.

Example 8–2 Broker Properties for HADB Database

imq.persist.store=jdbc
imq.persist.jdbc.dbVendor=hadb
imq.persist.jdbc.hadb.user=userName
imq.persist.jdbc.hadb.password=password
imq.persist.jdbc.hadb.property.serverlist=hostName:port,hostName:port,...

You can obtain the server list using the hadbm get jdbcURL command.

In addition, in an enhanced broker cluster, in which a JDBC database is shared by multiple broker instances, each broker must be uniquely identified in the database (unnecessary for an embedded database, which stores data for only one broker instance). The configuration property imq.brokerid specifies a unique instance identifier to be appended to the names of database tables for each broker. See Enhanced Broker Cluster Properties.

After setting all of the broker’s needed JDBC configuration properties, you must also install your JDBC driver’s .jar file in the appropriate directory location, depending on your operating-system platform (as listed in Appendix A, Distribution-Specific Locations of Message Queue Data) and then create the database schema for the JDBC-based data store (see To Set Up a JDBC-Based Data Store).