The parameter is currently named internalQueryExecMaxBlockingSortBytes. This is a poor name because it implies that it limits the amount of data that can be sorted. In reality, this just controls the maximum memory consumption of a blocking sort. When the allowDiskUse option is set on a find or aggregate command, the data size that can be sorted is only constrained by the available disk space. We should rename the parameter to internalQueryMaxBlockingSortMemoryUsageBytes.