Understanding the CICS VR scavengers
Descriptions of the three scavengers that the CICS VR server address space runs: the history, server and inventory scavengers.
Throughout various CICS® VR processing, resources can be allocated to CICS VR.
However, over time, some resources might no longer be required by CICS VR. Therefore,
to free up storage, the CICS VR server address space periodically runs various
scavengers to clean up and remove resources related to various CICS VR entities
that are no longer necessary.
- HISTORY SCAVENGER
- Function: Cleans up resources related to past CICS VR events. The history scavenger flushes all messages written by the CICS VR server address space to the data set allocated to the DWWMSG ddname. Therefore, after the history scavenger is run, you can view the data set allocated to the DWWMSG ddname to see all messages recently written by CICS VR. The default is for the history scavenger to run once an hour and you can set the history scavenger to run at the time of your choice. See The CICS VR User's guideSetting CICS VR server address space scavenger parameters for more information.
- SERVER SCAVENGER
- Function: Cleans up resources related to the CICS VR server address space. The server scavenger releases all unused resources in both the CICS VR server address space and the client address space to prevent out-of-storage conditions. The server scavenger runs every 60 seconds.
- INVENTORY SCAVENGER
- Function: Cleans up outdated resources that are registered in the CICS VR recovery control data sets (RCDSs). The inventory scavenger deregisters information from the RCDS, and optionally delete items, that are older than specified CICS VR automatic deregistration criteria to prevent your RCDSs from becoming full. The default is for the inventory scavenger to run once a day, however, you can set the inventory scavenger to run at the time of your choice, and more often than once a day if required. See The CICS VR User's guideSetting CICS VR server address space scavenger parameters for more information. Also, see Understanding CICS VR automatic deregistration for more information about setting automatic deregistration criteria.