In Adaptive Server version 15.5 and later, the maximum value allowed for the configuration parameter number of pre-allocated extent has been increased from 31 to 32.
Using a value of 32 for the number of pre-allocated extent parameter has a special significance for configuration, and impacts the space allocations Adaptive Server performs internally. If you set the number to 32, Adaptive Server attempts to reserve an entire allocation unit of extent for utility operations that use a large-scale allocation scheme of space reservation, such as bcp in and select into.
Using the maximum for number of pre-allocated extent can greatly improve the performance of these utilities, particularly when you run them in parallel. Using a value of 32 greatly increases the likelihood that each engine running the utility can work independently on its own allocation unit without interference from other engines.