Buffer handler simulation utility (FABHBSIM)

FABHBSIM is the buffer handler simulation utility that is used as an aid in tuning the BB and CAB buffer handlers.

This utility enables you to observe the effect of the changes to parameters of the buffer handlers, without actually performing database I/O operations and segment processing. FABHBSIM might help realize significant productivity gains by determining the optimum numbers and sizes of buffers.

With FABHBSIM, you can simulate a previous run of an IMS High Performance Unload job and obtain standard reports produced by HSSR Engine. You can use the FABHBSIM utility to do the following tasks:
  • Analyze buffer handler performance
  • Tune buffer handler parameters
  • Assist in improving performance of your IMS application programs
  • Aid in improving productivity of your IMS database
The following features are provided by FABHBSIM:
  • FABHBSIM simulates database I/O and buffer handling. It produces statistical reports that show the results of the simulation.
  • FABHBSIM reads the HSSRBUTR buffer handler trace data set that is created during the previous run of an IMS High Performance Unload job. This trace contains a record of all HSSR calls that were issued to an IMS database during the execution of your application program.
  • FABHBSIM allows you to use an HSSR buffer handler other than the one used in the original run.
  • FABHBSIM reissues all of the database calls. CAB or BB processes the HSSR calls, but no actual database I/O is performed. FABHBSIM produces the statistical reports that are normally generated by HSSR Engine. From these reports, you can analyze the effect of parameter changes on buffer handler performance.

FABHBSIM runs as an HSSR application program. The utility accepts the HSSRBUTR data set as the input and produces output reports. Any of the three cataloged procedures can be used to run FABHBSIM.