XQPCTL2 is a system parameter that controls improved concurrency. The default value of XQPCTL2 is 1, which turns on improved concurrency. Setting XQPCTL2 to 0 turns off improved concurrency. This parameter affects local access to the extent and file ID caches. This special parameter is use by VSI and is subject to change. Do not change this parameter unless VSI recommends that you do so.