PPT Slide
PSORT_DBTEMP & PSORT_NPROCS
PSORT_NPROCS specifies the number of sort threads the engine will use which is limited to 10 but also the number of sort work areas in memory which seems not to be so limited. I typically set PSORT_NPROCS=40 on a 32 way server w/ 28 CPU VPS.
PSORT_DBTEMP set to a list of at least 3 (4 is better) filesystems on different structures each of which has enough space to hold a copy of the sort-work files.
Setting PSORT_NPROCS >= 2 enables parallel sorting for queries, index builds, and for update statistics significantly reducing sort times. Setting PDQPRIORITY as high as practical will further enhance the effect by increasing the number of scan threads supplying data to the sort threads and the amount of memory available for in-memory sorting.