ResourceRefExtension
An optional extension to a resource ref which allows specifying addtional metadata such as isolation level support and connection management policy at a resource ref level.@since WAS5.0
Attributes Summary
isolationLevel Specifies the isolation level for this resource. connectionManagementPolicy This resource ref extension can be used for specifying the connection management policy on WebSphere platforms which support this option (such as zOS). resourceRef A reference to one of the resource refs that has been defined within the deployment descriptor of the same module.
Attribute Details
isolationLevel
Specifies the isolation level for this resource.One of:TRANSACTION_NONETRANSACTION_READ_UNCOMMITTEDTRANSACTION_READ_COMMITTEDTRANSACTION_REPEATABLE_READTRANSACTION_SERIALIZABLE
Data type: IsolationLevelKind
Default value: unspecified
Allowed Values:
connectionManagementPolicy
This resource ref extension can be used for specifying the connection management policy on WebSphere platforms which support this option (such as zOS).Connection StarvationConnection starvation occurs when the number of connections being held by applications reaches the maxium number of connections set during config. If connections aren't being returned to the pool fast enough, or not at all, then new requests for connections will not be able to be serviced.Connection starvation due to users not closing connections is one of the main issues this design wants to address. Poorly written applications often have one or two places where they forget to close connections (sometimes in error paths). If nothing is done, it does not take long before the connection pool is completely and indefinitely out of connections. This type of starvation, which is permanent, is different from that where connections are closed when the user is done with them, but because of high usage the pool is temporarily exhausted. Reducing Connection StarvationShareable ConnectionsFor shareable connections, the ManagedConnection will always be returned to the pool when the UOW ends. Since all connections will always run in a UOW this means that it won't be possible for users to "leak" connections because they forgot to close them. It also means that the connection handles will be "parked" on a dummy connection and reassociated to a new connection on the next preinvoke. Unshareable ConnectionsFor unshareable connections we'll have two options for the user to choose from to police users who don't close their connection handles in a timely maner. <connection-mgmt-policy> Aggressive | Normal </connection-mgmt-policy>Aggressive - under