DBBF= parameter for procedures

Use the DBBF= parameter in procedure to specify the maximum number of Fast Path buffers.

Storage is obtained as needed from either:

  • The extended common storage area (ECSA).
  • FDBR private storage, if the default value FPBUFF=LOCAL is specified in the DFSFDRxx IMS.PROCLIB member.
You can adjust the ECSA or region to meet your requirements. If you do not specify a value for DBBF, IMS uses a default of 10 buffers. If you specify a value for DBBF, IMS overrides the default with your value, and you must adjust for any change in DBFX specification.

The maximum number of Fast Path buffers can vary based on the buffer size (BSIZ):

Buffer size (BSIZ) Maximum number of Fast Path buffers
512 4 000 000
1024 2 000 000
2048 1 000 000
4096 500 000
8192 250 000
12 288 175 000
16 384 130 000
20 480 100 000
24 576 87 000
28 672 74 000

If the Fast Path 64-bit buffer manager is enabled, IMS sets the initial total number of buffers for the 64-bit subpools to 25% of this value.