Retrieval VERB NUMBERS in JREPORT 008

Products

• IDMS

Issue/Introduction

VERB NUMBERs identifying retrieval only DML verbs can appear in BFOR and AFTR images of journal records in JREPORT 008. For example, 11 (FIND NEXT) or 19 (FIND FIRST) can be seen. IDMS never journals retrieval-only DML verbs, even if JOURNAL RETRIEVAL is in use. So how is this possible?

Environment

Release : All supported releases

Cause

There are conditions under which IDMS will fragment records. What this means is that the entire record is stored in several smaller fragments spread across multiple database pages (in a network set like structure). The "root" of the record has the record-id of the original record type, and the fragments have a record-id of 4.

See Storing Variable-Length Records.

In subsequent processing, if IDMS reads a fragmented record and identifies that there is enough space on the page on which the root resides to hold the entire record, and the area has been READYed in an update usage-mode, IDMS will unfragment the record. This process reconstructs the record as one root on the original page and no fragments. This will happen even if the DML which read the record was a retrieval DML (FIND/OBTAIN).

The updates involved in this process are journaled individually, and is how it might be possible to see BFOR and AFTR records in the journal with retrieval VERB NUMBERs.

Resolution

This is not a problem - it's how the software works, so there is no resolution. However, an UNLOAD/RELOAD or REORG will remove all SR4s.

Additional Information

DB Call Formats (COBOL)