WebSphere Application Server data source properties

Use this page to set advanced data source properties in the application server. These properties activate and configure services that the application server applies to data sources to customize connections within an application server. These properties do not affect connections within the database.

To access this administrative console page complete one of the following paths:

Resources > JDBC > Data sources > data_source > WebSphere Application Server data source properties
Resources > JDBC > JDBC providers > JDBC_provider > Data sources > data_source > WebSphere Application Server data source properties
Applications > Application Types > WebSphere enterprise applications > application_name > Application scoped resources > data_source > WebSphere Application Server data source properties.

Statement cache size

Specifies the number of statements that can be cached per connection. The application server caches a statement after you close that statement.

The WebSphere® Application Server data source optimizes the processing of prepared statements and callable statements by caching those statements that are not used in an active connection. Both statement types help maximize the performance of transactions between your application and data store.

A prepared statement is a precompiled SQL statement that is stored in a PreparedStatement object. The application server uses this object to run the SQL statement multiple times, as required by your application run time, with values that are determined by the run time.
A callable statement is an SQL statement that contains a call to a stored procedure, which is a series of precompiled statements that perform a task and return a result. The statement is stored in the CallableStatement object. The application server uses this object to run a stored procedure multiple times, as required by your application run time, with values that are determined by the run time.

If the statement cache is not large enough, useful entries are discarded to make room for new entries. To determine the highest value for your cache size to avoid any cache discards, add the number of uniquely prepared statements and callable statements, as determined by the SQL string, concurrency, and the scroll type, for each application that uses this data source on a particular server. This value is the maximum number of possible statements that can be cached on a given connection over the life of the server. Setting the cache size to this value means that you never have cache discards. In general, configure a larger cache for applications with a greater number of statements.

You can also use the Tivoli® Performance Viewer to minimize cache discards. Use a standard workload that represents a typical number of incoming client requests, use a fixed number of iterations, and use a standard set of configuration settings.

Note: The higher the statement cache, the more system resources are delayed. Therefore, if you set the number too high, you might lack resources because your system cannot open multiple prepared statements.

If there is a particular statement that you do not want the application server to cache, configure the statement poolability hint to false. The application server does not cache a statement if the poolability hint is set to false. The application specifies the statement poolability hints at run time.

In test applications, tuning the statement cache improves throughput from 10% to 20%. However, because of potential resource limitations, this tuning process might not always be possible.

Information	Value
Data type	Integer
Default	Default values depend on the database. Typically, this value is 10. For Informix® versions 7.3, 9.2, 9.3, and 9.4, without the respective latest fixes, the default value must be 0. A default value of 0 means that there is no cache statement.

Enable multithreaded access detection

If checked, one or both of following warning messages is entered in the WebSphere Application Server system out log if multiple threads attempt to concurrently use the same connection handle. You can use this property to debug connection problems if you think the problems might be caused by multiple threads trying to use the same connection handle. Having multiple threads concurrently using the same connection handle is a programming model violation.

Note: Depending on the exact processing circumstances, using managed connections could result in either message, J2CA0167W or DSRA8720W (or both messages) being issued. You should review job logs for these messages when enable multithreaded access detection is enabled.

J2CA0167W: An attempt to concurrently use the same connection handle by multiple threads has been detected. The connection handle is: {0}.

DSRA8720W: Detected multithreaded access on {0}. Last used with thread id: {1}id multithreaded access. Current thread id: {2} Stack trace of current thread:{3}

Enable database reauthentication

Indicates that the exact match on connections retrieved out of the application server connection pool (the connection pool search criteria does not include a user name and password) cannot exist. Instead, the connection reauthentication is done in the doConnectionSetupPerTransaction() of the DataStoreHelper class. The application server does not provide a connection reauthentication implementation at run time. Therefore, when you check this box, you must extend the DataStoreHelper class to provide implementation of the doConnectionSetupPerTransaction() method where the reauthentication occurs. If you do not complete this process, the application server might return unusable connections. For more information, read the API documentation for the com.ibm.websphere.rsadapter.DataStoreHelper#doConnectionSetupPerTransaction method.

Connection reauthentication can help improve performance by reducing opening and closing connections, particularly for applications that frequently request connections with different user names and passwords.

Avoid trouble: You cannot enable database reauthentication if you select TrustedConnectionMapping for the mapping configuration alias.

Enable JMS one-phase optimization support

When you check this option, the application server uses Java™ Message Service (JMS) to get optimized connections from this data source. This property prevents Java database connectivity (JDBC) applications from sharing connections with container-managed persistence (CMP) applications. This option is not available if the JDBC provider of the data source is an XA provider.

Manage cached handles

Specifies whether the container tracks cached handles, which are connection handles that an application component holds active across transaction and method boundaries. You can use this property to debug connection problems, but tracking handles can cause large performance issues during run time.

If the Manage cached handles property is selected in the administrative console, and you clear it, the field is no longer visible for resources that are at Version 7.0 or greater of the application server. This field is only displayed if the manageCachedHandles property is set to true in the resources.xml file. To make the field available, change the value for the manageCachedHandles entry from false to true in the resources.xml file, or enter the following Jython command from the wsadmin tool:

AdminConfig.modify(myDataSourceVariable, '[[manageCachedHandles "true"]]')

Note: For any resources that are running at Version 6.x of the application server, the Manage cached handles property is always visible. For example, if you have a node that is at Version 6.1, the entry in the resources.xml file does not affect how the field is displayed in the administrative console.

For a different method to debug problems, use the multi-thread and cross-component diagnostic alerts to detect violations in the Java Connector Architecture (JCA) programming model. To enable these alerts, select those options from Servers > Application servers > application_server > Performance > Performance and Diagnostic Advisor Configuration > Performance and Diagnostic Advice configuration panel. These alerts force the connection manager to manage cached handles, detect the connection conditions, and send alerts.

Note: For these alerts to be active, you must also select Enable Performance and Diagnostic Advisor Framework (Runtime Performance Advisor) from the Servers > Application servers > application_server > Performance > Performance and Diagnostic Advisor Configuration panel.

Log missing transaction context

Specifies whether the container issues an entry to the activity log when an application obtains a connection without a transaction context. These are exceptions to the Java Platform, Enterprise Edition (Java EE) programming model connection requirements.

Non-transactional data source

Specifies that the application server does not enlist the connections from this data source in global or local transactions. Applications must explicitly call setAutoCommit(false) on the connection if they want to start a local transaction on the connection, and they must commit or roll back the transaction that they started.

Avoid trouble: Set this property to true in rare circumstances, except when a Java Persistence API (JPA) application requires both JTA and non-JTA data sources. The non-JTA data source requires this property to be set to true.

Use WebSphere Application Server exception checking model

Specifies that the application server uses the error mapping facility that is defined in the data store helper to identify errors. The application server does not replace exceptions that are thrown by the JDBC driver with exceptions that are defined in the error map of the data store helper.

Use WebSphere Application Server exception mapping model

Specifies that the application server uses the error mapping facility that is defined in the data store helper to identify errors, and the application server replaces the exceptions that are thrown by the JDBC driver with exceptions that are defined in the error map of the data store helper.

Supported configurations: This error detection model functions with JDBC Version 3.0 and earlier.

Validate new connections

Specifies whether the connection manager tests newly created connections to the database.

Number of retries

Specifies the number of times you want to retry making the initial connection to a database after the first pretest operation fails.

Retry interval: Validate new connections

If you select Validate new connections, this option specifies the length of time, in seconds, that the application server waits before retrying to make a connection if the initial attempt fails.

Validate existing pooled connections

Specifies whether the connection manager tests the validity of pooled connections before returning them to applications.

Retry interval: Pretest existing pooled connections

If you select Pretest existing pooled connections, this option specifies the length of time, in seconds, to allot to the JDBC driver for validating a connection. Validation is done only once.

Validation by JDBC driver

Specifies that the application server uses the JDBC driver to validate the connections. The JDBC provider must support JDBC 4.0 or greater to use this option. This option is available only if either Validate new connections or Validate existing pooled connections is selected.

Timeout

Specifies the timeout in seconds for testing connections, either new or pooled by the application server, to the database. If the timeout expires before validating then the connection is considered unusable. If retries are configured, the full value of the timeout applies to each retry. A value of 0 indicates the JDBC driver does not impose a timeout on validation attempts.

Supported configurations: This option is only available for JDBC drivers that are JDBC 4.0 compliant.

Validation by SQL string (deprecated)

Specifies an SQL statement that the application server sends to the database to test the connection. Use a query that is likely to have low impact on performance. This option is available only if either Validate new connections or Validate existing pooled connections is selected.

Optimize for get/use/close connection pattern with heterogenous pooling

Optimizes the data source for applications that use the get/use/close connection pattern. This optimization enables the connection pool for the data source to share connections that are in the same transaction. With this optimization pattern, you can share one connection during a transaction even if connections use different connection properties.

If you use the heterogeneous pooling feature, you must first extend the data source definition so that you can specify different custom properties or applications to override non-core properties for the data source. For more information about extending data sources, see the information on extending DB2® data source definitions at the application level.