Reorder and reorganize a file

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  1. Among reorder(ADAORD) and reorg(UNLOAD, DELETE, LOAD), which utility will be better for a file maintenance.

  2. For ADAULD, how a field is chosen for the parameter SORTSEQ.
    In other words, what kind of field to be chosen, is it based on criticality of the field or any particular aspect need to be considered.

  3. Why below warning occurs in ADAULD if we choose a field with NU option in SORTSEQ.

*** Warning ***
The Descriptor ZB in File 39 has the NU-Option.
ADAULD will process this file because the NU-Parameter
is supplied. Records may be lost.

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Are you able to request DBA training? it probably would help give you the basic grounding you need and lots more confidence in maintaining your environment.

  1. Both are useful depending on what “file maintenance” you need to do
  2. If a file has a SP or DE that is most frequently used in READ LOGICAL for that file, it is a candidate for the SORTSEQ as SORTSEQ will organize the data blocks in the sequence of the SORTSEQ descriptor, improving I/O performance for reads on the descriptor.
  3. if SORTSEQ is specified, the utility reads the index exactly like an application program would. If the de/sp is null-suppressed, then only records with an entry for that de/sp will be unloaded by ADAULD. This is often used to provide a “logical delete” - setting the de/sp to a null value, then later running the ADAULD with SORTSEQ and reloading with only the not-null de/sp records. The warning is reminding you that unloading on SORTSEQ may omit records from the unload.