Regular File Maintenance Can Improve Unload Utility Performance.

Document ID : KB000053219
Last Modified Date : 06/03/2018
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Introduction:
When running the C1BM5000 utility to UNLOAD (Full or INCRemental) an environment, one can experience performance issues, with long elapsed times, when the inventory files are not properly tuned.
Question:
Why the performance of your daily or weekly Unload jobs start to degrade?
Answer:

When the performance of your daily or weekly Unload jobs start to degrade, the first thing you should check is the state of the inventory files defined to the environment causing the bottleneck.

  1. Perform an IDCAMS LISTCAT against the Endevor VSAM files (MCF, PACKAGE, ELMCATL, EINDEX?):

    Verify low Extents, CI/CA Splits, etc.
     
  2. Perform a BC1PNLIB INQUIRE (with Option Analyze) against any ELIB base and delta files.

    Check the number of library extends and number of directory overflows (which should be 0).
     
  3. View statistics of any PDS or PDS/e Base and Delta libraries.

    Check number of physical extents. Ideally there is only one. A weekly compress of any PDS is highly recommended. For PDS/e libraries, refer to IBM's PDS/e documentation.
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