where the four Threshold parameters are numeric values indicating the number of work items in a work queue at which an additional block of filtering work will be created. Each subsequent value, if used, must be greater than the preceding value.
By default, the WIS process uses the thread that is processing an RPC request to perform any work queue filtering required by that RPC request. When the number of items in a work queue reaches one of the threshold values defined in this attribute, the queue is split into equal blocks of filtering work. The first block is still handled by the RPC processing thread. Subsequent blocks are handled by threads from the queue filtering thread pool (the number of which is defined by the
WIS_FILTER_THREAD_POOL_SIZE attribute).
Modifying this attribute can therefore reduce the time taken by the WIS process to filter work queues, particularly when queues are large or use complex filter criteria involving expressions or CDQPs.