Dynamic PSBs

Dynamic PSBs are temporary PSBs generated by ZDT/IMS when a function is started and deleted when it finishes. ZDT/IMS generates a PSB that is sensitive to all the segments in the specified DBD. If you don't want your function to be sensitive to all segments in a physical DBD, you can use a logical DBD that only includes the physical segments that you want the function to process. For the Extract and Load functions, the PSB is generated with PCBs for the primary database and all logically related databases.

Advantages in using a dynamic PSB

  • A database administrator is not required to generate PSBs for the ZDT/IMS functions.
  • ZDT/IMS generates a PSB that best suits the ZDT/IMS function.

Disadvantages in using a dynamic PSB

  • The same processing option (PROCOPT) is used for all segments in the DBD. For example, you cannot prevent the Edit from updating one segment type in the DBD.
  • A dynamic PSB can access any database in the subsystem, so unless special measures are taken they can be a security risk. See Securing dynamic PSBs in BMP mode for a description of some special measures that can be taken to remove this security risk.
  • The PSB is not available for use if Batch Backout is required.

IMS system considerations for BMP support

If you plan to use dynamic PSBs to access an IMS™ subsystem in BMP mode, you must:
  • Include in the system definition an APPLCTN macro statement for each dynamic PSB name that ZDT/IMS will use. For information on how you do this, see Declaring the dynamic PSBs.
  • Provide a DOPT ACBLIB data set into which ZDT/IMS can dynamically build PSBs. For more information on how you do this, see Providing a DOPT ACBLIB data set.