Sun GlassFish Message Queue 4.4 Administration Guide

JDBC-Based Persistence

Instead of using a file-based data store, you can set up a broker to access any data store accessible through a JDBC-compliant driver. This involves setting the appropriate JDBC-related broker configuration properties and using the Database Manager utility (imqdbmgr) to create the proper database schema. See Configuring a JDBC-Based Data Store for specifics.

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:


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).

Configuring a JDBC-Based Data Store

To configure a broker to use a JDBC database, you set JDBC-related properties in the broker’s instance configuration file and create the appropriate database schema. The Message Queue Database Manager utility (imqdbmgr) uses your JDBC driver and the broker configuration properties to create the schema and manage the database. You can also use the Database Manager to delete corrupted tables from the database or if you want to use a different database as a data store. See Database Manager Utility for more information.


Note –

If you use an embedded database, it is best to create it under the following directory:

   
.../instances/instanceName/dbstore/databaseName

If an embedded database is not protected by a user name and password, it is probably protected by file system permissions. To ensure that the database is readable and writable by the broker, the user who runs the broker should be the same user who created the embedded database using the imqdbmgr command.


ProcedureTo Set Up a JDBC-Based Data Store

  1. Set JDBC-related properties in the broker’s instance configuration file.

    The relevant properties are discussed, with examples, in JDBC-Based Persistence Properties and listed in full in Table 17–7. In particular, you must specify a JDBC-based data store by setting the broker’s imq.persist.store property to jdbc.

  2. Place a copy of, or a symbolic link to, your JDBC driver’s .jar file in the Message Queue external resource files directory, depending on how Message Queue was installed (see Appendix A, Distribution-Specific Locations of Message Queue Data):

      IPS packages: IMQ_HOME/lib/ext


      Solaris SVR4 packages: /usr/share/lib/imq/ext


      Linux RPM packages: /opt/sun/mq/share/lib/ext


    For example, if you are using HADB on an IPS package-based installation, the following command copies the driver’s .jar file to the appropriate location:

    cp  /opt/SUNWhadb/4/lib/hadbjdbc4.jar  IMQ_HOME/lib/ext
    

    The following command creates a symbolic link instead:

    ln  -s  /opt/SUNWhadb/4/lib/hadbjdbc4.jar  IMQ_HOME/lib/ext
    
  3. Create the database schema needed for Message Queue persistence.

    Use the imqdbmgr create all command (for an embedded database) or the imqdbmgr create tbl command (for an external database); see Database Manager Utility.

    1. Change to the directory where the Database Manager utility resides, depending on how Message Queue was installed:

        IPS packages: cd IMQ_HOME/bin


        Solaris SVR4 packages: cd /usr/bin


        Linux RPM packages: cd /opt/sun/mq/bin


    2. Enter the imqdbmgr command:

         
      imqdbmgr create all
      

ProcedureTo Display Information About a JDBC-Based Data Store

You can display information about a JDBC-based data store using the Database Manager utility (imqdbmgr) as follows:

  1. Change to the directory where the Database Manager utility resides, depending on how Message Queue was installed:

      IPS packages: cd IMQ_HOME/bin


      Solaris SVR4 packages: cd /usr/bin


      Linux RPM packages: cd /opt/sun/mq/bin


  2. Enter the imqdbmgr command:

       
    imqdbmgr query
    

    The output should resemble the following

    dbmgr query
    
    [04/Oct/2005:15:30:20 PDT] Using plugged-in persistent store:
            version=400
            brokerid=Mozart1756
            database connection url=jdbc:oracle:thin:@Xhome:1521:mqdb
            database user=scott
    Running in standalone mode.
    Database tables have already been created.

Securing a JDBC-Based Data Store

The persistent data store can contain, among other information, message files that are being temporarily stored. Since these messages may contain proprietary information, it is important to secure the data store against unauthorized access. This section describes how to secure data in a JDBC-based data store.

A broker using JDBC-based persistence writes persistent data to a JDBC-compliant database. For a database managed by a database server (such as Oracle), it is recommended that you create a user name and password to access the Message Queue database tables (tables whose names start with MQ). If the database does not allow individual tables to be protected, create a dedicated database to be used only by Message Queue brokers. See the documentation provided by your database vendor for information on how to create user name/password access.

The user name and password required to open a database connection by a broker can be provided as broker configuration properties. However it is more secure to provide them as command line options when starting up the broker, using the imqbrokerd command’s -dbuserand -dbpassword options (see Broker Utility).

For an embedded database that is accessed directly by the broker by means of the database’s JDBC driver, security is usually provided by setting file permissions on the directory where the persistent data will be stored, as described above under Securing a File-Based Data Store To ensure that the database is readable and writable by both the broker and the Database Manager utility, however, both should be run by the same user.