Journaling Procedures › Offloading Disk Journal Files › How to Offload the Disk Journal

How to Offload the Disk Journal

ARCHIVE JOURNAL Utility Statement

To offload the journal, you execute the ARCHIVE JOURNAL utility statement using the batch command facility. You should use the default option of AUTO so that the oldest non-archived journal file is selected for processing.

If change tracking is in effect for the CV whose journals are being offloaded, you should reference the CV's SYSTRK file in your ARCHIVE JOURNAL execution jcl so that the archive job is sharing the description of the journal files that are currently in use by CV.

Note: For more information about change tracking and how to reference a SYSTRK file, see "Change Tracking" in the CA IDMS System Operations Guide.

System Failure During Offload

If the operating system fails while an ARCHIVE JOURNAL statement is executing, resubmit the ARCHIVE JOURNAL job using the RESTART parameter and identifying the journal file that was being processed at the time of failure.

Potential Problems While Offloading

You may encounter two types of problems when you offload journal files in an active system:

1. The offloaded journal file is still full following the offload because it contains before images for uncommitted transactions active at the time of the offload. The ARCHIVE JOURNAL utility statement issues messages indicating how full the disk journal file is after being offloaded. If it is full, it is usually because a long-running batch job is updating the database without issuing intermediate COMMIT statements. If all journal files fill, the system will halt database processing until corrective action is taken. See 19.4.3, “Handling Full Journal Files" for how to recover from this situation.
2. The remaining disk journal files fill before ARCHIVE JOURNAL completes offloading a single file. When this occurs, CA IDMS/DB temporarily halts further database activity until the offload job is complete.

Prevention For Problem 1

To prevent a full disk journal following an offload, take one or more of the following steps:

• Ensure that batch update programs issue frequent COMMITs to reduce the number of before images that must be retained on the journal file
• Allocate larger disk journal files
• Execute long-running update programs in local mode

Prevention For Problem 2

To prevent future disk journal file overloading, take one or more of the following steps:

• Allocate larger disk journal files
• Increase the number of disk journal files
• Execute long-running update programs in local mode.