A common cause of performance problems is when request handling threads get hung up waiting for a resource from a resource pool that has become unresponsive. To limit this problem, you can set the ResourcePool’s creationTimeLimit and maxPendingCreations properties.
creationTimeLimit
When creationTimeLimit is set, if a resource creation fails and the attempt exceeded the value of creationTimeLimit in milliseconds, then the resource pool is disabled. In addition, before an attempt to create a resource occurs, a check is made to see if a resource creation attempt already in progress has exceeded the creationTimeLimit. If so, then the resource pool is disabled.
maxPendingCreations
If you set the maxPendingCreations property, then the resource pool has a limit on the maximum number of resource creation attempts that can be pending at one time. This can prevent a situation where all available request handling threads are tied up trying to create resources in an unresponsive resource pool.
If the maxPendingCreations property is set to a value other than zero, and:
the resource pool is not in its startup cycle,
the minimum resources (set by the
minproperty of the resource pool) is greater than zero,there are no valid resources being managed by the resource pool, and
the number of pending resource creation attempts exceeds the value of the
maxPendingCreationsproperty,
then the resource pool is disabled.
Disabled ResourcePools
When a resource pool is marked as disabled, it can still attempt to create resources when a thread attempts to check out resources from the pool. However, only one thread at a time can do so. Any other threads are returned a ResourcePoolException. This prevents more than one thread at a time from getting hung on a disabled pool. The resource pool is not shut down; it is simply marked disabled so that threads seeking resources will know that the resource pool is not behaving properly. The pool is marked enabled as soon as there is a successful resource creation.
