Requesting SB with SB control statements

You can put SBPARM control statements in the optional //DFSCTL file. This file is defined by a //DFSCTL DD statement in the JCL of your batch, dependent, or online region.

You can use the SBPARM control statement to:

  • Specify which database PCBs (and which data sets referenced by the database PCB) should use SB
  • Override the default number of buffer sets

This control statement allows you to override PSB specifications without requiring you to regenerate the PSB.

You can specify keywords that request use of SB for all or specific DBD names, DD names, PSB names, and PCB labels. You can also combine these keywords to further restrict when SB is used.

By using the BUFSETS keyword of the SBPARM control statement, you can change the number of buffer sets allocated to SB buffer pools. The default number of buffer sets is four. Badly organized databases can require six or more buffer sets for efficient sequential processing. Well-organized databases require as few as two buffer sets. An indicator of how well-organized your database is can be found in the optional //DFSSTAT reports.

The example below shows the SBPARM control statement necessary to request conditional activation of SB for all DBD names, DD names, PSB names, and PCBs. 
SBPARM ACTIV=COND

The next example shows the parameters necessary to:

  • Request conditional activation of SB for all PCBs that were coded with 'DBDNAME=SKILLDB' during PSB generation
  • Set the number of buffer sets to 6
SBPARM ACTIV=COND,DB=SKILLDB,BUFSETS=6