JDBCConnectionPoolParamsBean

Overview

Contains the connection pool parameters of a data source.

Configuration parameters for a data source's connection pool are specified using the connection pool parameters bean.

Attributes

This section describes the following attributes:

CapacityIncrement

The number of connections created when new connections are added to the connection pool.

When there are no more available physical connections to satisfy connection requests, WebLogic Server creates this number of additional physical connections and adds them to the connection pool.

ConnectionCreationRetryFrequencySeconds

The number of seconds between attempts to establish connections to the database.

If you do not set this value, data source creation fails if the database is unavailable. If set and if the database is unavailable when the data source is created, WebLogic Server will attempt to create connections in the pool again after the number of seconds you specify, and will continue to attempt to create the connections until it succeeds.

When set to 0, connection retry is disabled.

ConnectionReserveTimeoutSeconds

The number of seconds after which a call to reserve a connection from the connection pool will timeout.

When set to 0, a call will never timeout.

When set to -1, a call will timeout immediately.

CredentialMappingEnabled

Enables credential mapping for the data source. When an application requests a database connection, WebLogic Server sets a light-weight client ID on the database connection based on a map of database IDs.

You must also specify the map of WebLogic Server user IDs to database user IDs (credential mapping).

This feature relies on features in the JDBC driver and DBMS. It is not supported with all drivers and DBMSs.

DriverInterceptor

Specifies the absolute name of the application class used to intercept method calls to the JDBC driver. The application specified must implement the weblogic.jdbc.extensions.DriverInterceptor interface.

Weblogic Server will invoke the preInvokeCallback(), postInvokeExceptionCallback(), and postInvokeCallback() methods of the registered application before and after invoking any method inside the JDBC driver. You can use this feature to profile JDBC driver usage and monitor:

• Methods being executed

• Any exceptions thrown

• Time spent inside the driver executing methods

HighestNumWaiters

The maximum number of connection requests that can concurrently block threads while waiting to reserve a connection from the data soiurce's connection pool.

IdentityBasedConnectionPoolingEnabled

Enables identity-based-connection-pooling for the data source. When an application requests a database connection, WebLogic Server picks or creates a physical connection with requested DBMS identity based on a map of WebLogic user IDs and database IDs.

You must also specify the map of WebLogic Server user IDs to database user IDs (credential mapping).

IgnoreInUseConnectionsEnabled

Enables the data source to be shutdown even if connections obtained from the pool are still in use.

InactiveConnectionTimeoutSeconds

The number of inactive seconds on a reserved connection before WebLogic Server reclaims the connection and releases it back into the connection pool.

You can use the Inactive Connection Timeout feature to reclaim leaked connections - connections that were not explicitly closed by the application. Note that this feature is not intended to be used in place of properly closing connections.

When set to 0, the feature is disabled.

InitialCapacity

The number of physical connections to create when creating the connection pool in the data source. If unable to create this number of connections, creation of the data source will fail.

This is also the minimum number of physical connections the connection pool will keep available.

InitSql

SQL statement to execute that will initialize newly created physical database connections. Start the statement with SQL followed by a space.

If the Init SQL value begins with "SQL ", then the rest of the string following that leading token will be taken as a literal SQL statement that will be used to initialize database connections. If the Init SQL value does not begin with "SQL ", the value will be treated as the name of a table and the following SQL statement will be used to initialize connections:
"select count(*) from InitSQL"

The table InitSQL must exist and be accessible to the database user for the connection. Most database servers optimize this SQL to avoid a table scan, but it is still a good idea to set InitSQL to the name of a table that is known to have few rows, or even no rows.

JDBCXADebugLevel

Specifies level of JDBC debugging for XA drivers.

LoginDelaySeconds

The number of seconds to delay before creating each physical database connection. This delay supports database servers that cannot handle multiple connection requests in rapid succession.

The delay takes place both during initial data source creation and during the lifetime of the data source whenever a physical database connection is created.

MaxCapacity

The maximum number of physical connections that this connection pool can contain.

PinnedToThread

PinnedToThread is an option that can improve performance by enabling execute threads to keep a pooled database connection even after the application closes the logical connection.

When PinnedToThread is enabled, WebLogic Server pins a database connection from the connection pool to an execution thread the first time an application uses the thread to reserve a connection. When the application finishes using the connection and calls connection.close(), which otherwise returns the connection to the connection pool, WebLogic Server keeps the connection with the execute thread and does not return it to the connection pool. When an application subsequently requests a connection using the same execute thread, WebLogic Server provides the connection already reserved by the thread.

With PinnedToThread, there is no locking contention on the connection pool that occurs when multiple threads attempt to reserve a connection at the same time and there is no contention for threads that attempt to reserve the same connection from a limited number of database connections.

If an application concurrently reserves more than one connection from the connection pool using the same execute thread, WebLogic Server creates additional database connections and pins them to the thread, as well.

ProfileHarvestFrequencySeconds

The number of seconds between when WebLogic Server harvests profile data.

When set to 0, harvesting of data is disabled.

ProfileType

Specifies that type of profile data to be collected for the JDBC subsystem.

You can specify combinations of the following profile types:

• JDBCLegalHelper.PROFILE_TYPE_CONN_USAGE - Profile threads currently using connections from the pool of connections in the data source.

• JDBCLegalHelper.PROFILE_TYPE_CONN_RESV_WAIT - Profile threads currently waiting to reserve a connection from the data source.

• JDBCLegalHelper.PROFILE_TYPE_CONN_LEAK - Profile threads that have reserved a connection from the data source and the connection leaked (was not properly returned to the pool of connections).

• JDBCLegalHelper.PROFILE_TYPE_CONN_RESV_FAIL - Profile threads that attempt to reserve a connection from the data source but fail.

• JDBCLegalHelper.PROFILE_TYPE_STMT_CACHE_ENTRY - Profile prepared and callable statements added to the statement cache, and profile the threads that originated the cached statements.

• JDBCLegalHelper.PROFILE_TYPE_STMT_USAGE - Profile threads currently executing SQL statements from the statement cache.

• JDBCLegalHelper.PROFILE_TYPE_CONN_LAST_USAGE - Profile the previous thread that last used the connection. This information is useful when debugging problems with connections infected with pending transactions that cause subsequent XA operations on the connections to fail.

• JDBCLegalHelper.PROFILE_TYPE_CONN_MT_USAGE - Profile threads that erroneously use a connection previously obtained by a different thread.

• JDBCLegalHelper.PROFILE_TYPE_NONE - Disable profiling for the data source.

• JDBCLegalHelper.PROFILE_TYPE_ALL - Enable all profile types for the data source.

RemoveInfectedConnections

Specifies whether a connection will be removed from the connection pool after the application uses the underlying vendor connection object.

If you disable removing infected connections, you must make sure that the database connection is suitable for reuse by other applications.

When set to true (the default), the physical connection is not returned to the connection pool after the application closes the logical connection. Instead, the physical connection is closed and recreated.

When set to false, when the application closes the logical connection, the physical connection is returned to the connection pool and can be reused by the application or by another application.

SecondsToTrustAnIdlePoolConnection

The number of seconds within a connection use that WebLogic Server trusts that the connection is still viable and will skip the connection test, either before delivering it to an application or during the periodic connection testing process.

This option is an optimization that minimizes the performance impact of connection testing, especially during heavy traffic.

ShrinkFrequencySeconds

The number of seconds to wait before shrinking a connection pool that has incrementally increased to meet demand.

When set to 0, shrinking is disabled.

StatementCacheSize

The number of prepared and callable statements stored in the cache. (This may increase server performance.)

WebLogic Server can reuse statements in the cache without reloading the statements, which can increase server performance. Each connection in the connection pool has its own cache of statements.

Setting the size of the statement cache to 0 turns off statement caching.

StatementCacheType

The algorithm used for maintaining the prepared statements stored in the statement cache.

Options are:

• LRU - when a new prepared or callable statement is used, the least recently used statement is replaced in the cache.

• FIXED - the first fixed number of prepared and callable statements are cached.

StatementTimeout

The time after which a statement currently being executed will time out.

StatementTimeout relies on underlying JDBC driver support. WebLogic Server passes the time specified to the JDBC driver using the java.sql.Statement.setQueryTimeout() method. If your JDBC driver does not support this method, it may throw an exception and the timeout value is ignored.

A value of -1 disables this feature.

A value of 0 means that statements will not time out.

TestConnectionsOnReserve

Enables WebLogic Server to test a connection before giving it to a client. (Requires that you specify a Test Table Name.)

The test adds a small delay in serving the client's request for a connection from the pool, but ensures that the client receives a viable connection.

TestFrequencySeconds

The number of seconds between when WebLogic Server tests unused connections. (Requires that you specify a Test Table Name.) Connections that fail the test are closed and reopened to re-establish a valid physical connection. If the test fails again, the connection is closed.

In the context of multi data sources, this attribute controls the frequency at which WebLogic Server checks the health of data sources it had previously marked as unhealthy.

When set to 0, the feature is disabled.

TestTableName

The name of the database table to use when testing physical database connections. This name is required when you specify a Test Frequency and enable Test Reserved Connections.

The default SQL code used to test a connection is "select count(*) from TestTableName"

Most database servers optimize this SQL to avoid a table scan, but it is still a good idea to set the Test Table Name to the name of a table that is known to have few rows, or even no rows.

If the Test Table Name begins with "SQL ", then the rest of the string following that leading token will be taken as a literal SQL statement that will be used to test connections instead of the standard query.

Operations

This section describes the following operations:

isSet

Return true if the given property has been explicitly set in this bean.

unSet

Restore the given property to its default value.