5 Tricky Questions on VSAM alternate Index

  1. VSAM -Alternate index only allowed on KSDS and ESDS, but not on RRDS
  2. Alternate index should be declared for alternate key,and a path. So alternate key is different from alternate index. The path behaves like we are accessing a record from KSDS or ESDS cluster.
  3. Path is for Alternate Index. Base is main cluster.
  4. When you update a record by path, the alternate index is automatically updated
  5. For CICS application program to access a file that has been directly defined as an alternate index rather than a path. This results in index data being returned to the application program rather than file data. This operation is not supported for files opened in record-level sharing (RLS) mode.
Related: More tips on VSAM alternate index