Administering JDBC Connection Pools

A JDBC connection pool is a group of reusable connections for a particular database. Because creating each new physical connection is time consuming, Enterprise Server maintains a pool of available connections. When an application requests a connection, it obtains one from the pool. When an application closes a connection, the connection is returned to the pool.

A JDBC resource is created by specifying the connection pool with which the resource is associated. Multiple JDBC resources can specify a single connection pool. The properties of connection pools can vary with different database vendors. Some common properties are the database name (URL), the user name, and the password.

The following tasks and information are used to administer JDBC connection pools:

• To Create a JDBC Connection Pool

• To List JDBC Connection Pools

• To Contact (Ping) a Connection Pool

• To Reset (Flush) a Connection Pool

• To Update a JDBC Connection Pool

• To Delete a JDBC Connection Pool

To Create a JDBC Connection Pool

Use the create-jdbc-connection-pool subcommand in remote mode to register a new JDBC connection pool with the specified JDBC connection pool name. A JDBC connection pool or a connector connection pool can be created with authentication. You can either use a subcommand option to specify user, password, or other connection information using the asadmin utility, or specify the connection information in the XML descriptor file.

One connection pool is needed for each database, possibly more depending on the application. When you are building the connection pool, certain data specific to the JDBC driver and the database vendor is required. You can find some of the following specifics inConfiguration Specifics for JDBC Drivers:

• Database vendor name

• Resource type, such as javax.sql.DataSource (local transactions only) javax.sql.XADataSource (global transactions)

• Data source class name

• Required properties, such as the database name (URL), user name, and password

Creating a JDBC connection pool is a dynamic event and does not require server restart. However, there are some parameters that do require server restart. See Configuration Changes That Require Server Restart.

Before You Begin

Before creating the connection pool, you must first install and integrate the database and its associated JDBC driver. For instructions, see Setting Up the Database.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. Create the JDBC connection pool by using the create-jdbc-connection-pool(1) subcommand.

3. (Optional) If needed, restart the server.

   Some parameters require server restart. See Configuration Changes That Require Server Restart.

Example 14–3 Creating a JDBC Connection Pool

This example creates a JDBC connection pool named sample_derby_pool on localhost.

asadmin> create-jdbc-connection-pool 
--datasourceclassname org.apache.derby.jdbc.ClientDataSource 
--restype javax.sql.XADataSource 
--property portNumber=1527:password=APP:user=APP:serverName=
localhost:databaseName=sun-appserv-samples:connectionAttribut
es=\;create\\=true sample_derby_pool
Command create-jdbc-connection-pool executed successfully.

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help create-jdbc-connection-pool at the command line.

To List JDBC Connection Pools

Use the list-jdbc-connection-pools subcommand in remote mode to list all existing JDBC connection pools.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. List the JDBC connection pools by using the list-jdbc-connection-pools(1) subcommand.

Example 14–4 Listing JDBC Connection Pools

This example lists the JDBC connection pools that are on localhost.

asadmin> list-jdbc-connection-pools
sample_derby_pool2
poolA
__TimerPool
DerbyPool
sample_derby_pool
Command list-jdbc-connection-pools executed successfully.

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help list-jdbc-connection-pools at the command line.

To Contact (Ping) a Connection Pool

Use the ping-connection-pool subcommand in remote mode to test if a connection pool is usable. For example, if you create a new JDBC connection pool for an application that is expected to be deployed later, you can test the JDBC pool with this subcommand before the application is deployed. Running a ping will force the creation of the pool if it hasn't already been created.

Before You Begin

Before you can contact a connection pool, the connection pool must be created with authentication, and the server or database must be running.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. Ping a connection pool by using the ping-connection-pool(1) subcommand.

Example 14–5 Contacting a Connection Pool

This example tests to see if the DerbyPool connection pool is usable.

asadmin> ping-connection-pool DerbyPool
Command ping-connection-pool executed successfully

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help ping-connection-pool at the command line.

To Reset (Flush) a Connection Pool

Use the flush-connection-pool in remote mode to reinitialize all connections established in the specified connection pool. The JDBC connection pool or connector connection pool is reset to its initial state. Any existing live connections are destroyed, which means that the transactions associated with these connections are lost. The subcommand then recreates the initial connections for the pool, and restores the pool to its steady pool size.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. Reset a connection pool by using theflush-connection-pool(1) subcommand.

Example 14–6 Resetting (Flushing) a Connection Pool

This example resets the JDBC connection pool named __TimerPool to its steady pool size.

asadmin> flush-connection-pool __TimerPool 
Command flush-connection-pool executed successfully.

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help flush-connection-pool at the command line.

To Update a JDBC Connection Pool

You can change all of the settings for an existing pool except its name. Use the get and set subcommands to view and change the values of the JDBC connection pool properties.

1. List the JDBC connection pools by using the list-jdbc-connection-pools(1) subcommand.

2. View the attributes of the JDBC connection pool by using the get subcommand.

   For example:

   asadmin get resources.jdbc-connection-pool.DerbyPool.property

3. Set the attribute of the JDBC connection pool by using the set subcommand.

   For example:

   asadmin set resources.jdbc-connection-pool.DerbyPool.steady-pool-size=9

4. (Optional) If needed, restart the server.

   Some parameters require server restart. See Configuration Changes That Require Server Restart.

To Delete a JDBC Connection Pool

Use the delete-jdbc-connection-pool subcommand in remote mode to delete an existing JDBC connection pool. Deleting a JDBC connection pool is a dynamic event and does not require server restart.

Before You Begin

Before deleting a JDBC connection pool, all associations to the resource must be removed.

1. Ensure that the server is running.

   Remote subcommands require a running server.

2. List the JDBC connection pools by using the list-jdbc-connection-pools(1) subcommand.

3. If necessary, notify users that the JDBC connection pool is being deleted.

4. Delete the connection pool by using the delete-jdbc-connection-pool(1) subcommand.

Example 14–7 Deleting a JDBC Connection Pool

This example deletes the JDBC connection pool named DerbyPool.

asadmin> delete-jdbc-connection-pool jdbc/DerbyPool
Command delete-jdbc-connection-pool executed successfully.

See Also

You can also view the full syntax and options of the subcommand by typing asadmin help delete-jdbc-connection-pool at the command line.