User task physical writes: <count>
Modified pages are displaced from the data cache to the data area, since not all of the data used by the applications can be held in the data cache.
If the data cache were large enough, the physical write would be delayed to the next savepoint, and performed asynchronously. Cache displacements, however, use synchronous writes and reads, and should be avoided if possible.
This phenomenon is almost unavoidable if load times (data import) are long, since the volume of imported data is usually much larger than the size of the data cache.
Increase the size of the data cache.