Journal Files

Journal Record Types

Database activity is recorded on a journal file (tape or disk). CA IDMS/DB writes the following information to the journal:

Journal record entries that contain the image of database records
Checkpoints that describe the status of transactions accessing the database

Writing Journal Blocks

CA IDMS/DB accumulates journal records in the journal buffer. It writes the journal buffer to a journal file when one of the following conditions occurs:

The buffer is full.
A page containing an updated record occurrence whose before image is in the journal buffer, is to be written back to the database.
A database transaction is committed or backed out. A transaction commits or backs out as the result of an explicit request, such as a FINISH or ROLLBACK or because the application aborts.

Note: All journal file blocks are the same length, whether or not the buffer is full when written to a journal file.