PSORT_NPROCS environment variable

The PSORT_NPROCS environment variable enables the database server to improve the performance of the parallel-process sorting package by allocating more threads for sorting.

Before the sorting package performs a parallel sort, make sure that the database server has enough memory for the sort.

1  setenv PSORT_NPROCS threads
is an integer, specifying the maximum number of threads to be used to sort a query. This value cannot be greater than 10.
The following command sets PSORT_NPROCS to 4:
To disable parallel sorting, enter the following command:
It is recommended that you initially set PSORT_NPROCS to 2 when your computer has multiple CPUs. If subsequent CPU activity is lower than I/O activity, you can increase the value of PSORT_NPROCS.
Tip: If the PDQPRIORITY environment variable is not set, the database server allocates the minimum amount of memory to sorting. This minimum memory is insufficient to start even two sort threads. If you have not set PDQPRIORITY, check the available memory before you perform a large-scale sort (such as an index build) to make sure that you have enough memory.