Requirements to use recoup optimized chain chasing

To use recoup optimized chain chasing, several requirements must be met.

• Ensure that the z/TPF transaction manager is enabled; that is, ensure that the &NOTMC symbol is set to 0 in the DBLCL macro.
• For index files, you must specify ID1=(RCPOPTIDX) on the index file DBDEF and the index file must meet all of the following requirements:
  • The file must be a z/TPFDF file (that is, ACPDB=YES is specified or implied on the DBDEF macro).
  • The file must be an R-type file.
  • The file must be a top-level index file.
  • All forward index paths specify the FAL=8 parameter.
  • The file cannot use extended LRECs.
• For detail files, you must specify IMI bit 4 on each backward path that you want to use recoup optimized chain chasing for and the detail file must meet all of the following requirements:
  • The file must be a z/TPFDF file (that is, ACPDB=YES is specified or implied on the DBDEF macro).
  • The file must be an R-type file.
  • The file cannot be an index file, and the file cannot contain embedded references to other subfiles or z/TPF records.
  • The highest technical LREC ID must be set to 15 (that is, TQK=15 must be specified or implied on the DBDEF macro).
  • The file must be defined to use variable length LRECs.
  • A backward path that uses recoup optimized chain chasing (that is, IMI bit 4 is specified on the DBDEF macro) cannot be a read-only path and must refer back to a top-level index file without any middle level index files.
  • The file cannot be a block index file.
  • The file cannot be a B⁺Tree data or node file.
  • The file cannot be a pushdown chaining or add current file.