When reading or writing files,
consider increasing the size of the buffers available to the file using
the BUFNO= option, or the BUFNI=, and BUFND= options for VSAM files.
The actual amount of buffers
to specify varies with the size of the input data, so some amount of
experimentation (with a small number of records) may be worthwhile. For
the BUFNO option against the Inventory file for example, a value of 15
to 20 seems to work well. For the Master file, the
“recommended” values are 5 for BUFNI (if reading the file
using keyed reads) and 15 for BUFND.
The buffer values are specified against the DD statement.
e.g. //GENBASE DD DSN=FTMP.CSS.GENEXT.BASE.RES.D199904,DISP=SHR,BUFNO=20
If anyone has any more
experience of using these options (or anything similar), please add
comments here. The use of these options can slow down processing as
easily as speed it up, so previous experience is more than helpful.