IDMS Maintain Index IDMSDBL3 SYS004 and SYS005 record count

Products

• IDMS
• IDMS - Database
• IDMS - ADS

Issue/Introduction

Why do Maintain Index IDMSDBL3 SYS004 and SYS005 record counts differ?

We recently rebuilt two system-owned indexes using MAINTAIN INDEX.  Rebuilds were successful with no errors, but the messages out of IDMSDBL3 show 2 less records written to SYS005 than were read from SYS004

Example:

3,877,442 INTERMEDIATE RECORDS WERE READ FROM SYS004   
3,877,440 INTERMEDIATE RECORDS WERE WRITTEN TO SYS005

Environment

Release: IDADSO00200-19.0-ADS-for CA-IDMS
Component:

Resolution

The input SYS004 to IDMSDBL3 contains one control record per index being rebuilt.
These are not written to SYS005 output file.
Only the member descriptors that will be used in IDMSDBL4 to update the Index pointers in the members are written to SYS005.

If you rebuild a single index, the SYS005 count will be one less than SYS004.
Two index rebuilds in the same run, the count will be two less, etc