CA Datacom/AD Environment › CA Datacom/DB Components and System Areas › Logging and Recovery System

Logging and Recovery System

The logging and recovery system consists of the Log Area (LXX), Force Area (FXX), and the Recovery File (RXX). The LXX and the RXX are used when recovering from a system failure or program malfunction. The LXX and FXX are used for RESTART processing.

The LXX is short term permanent storage for the maintenance transactions (such as, the OPEN, CLOSE, ADD, UPDATE, and DELETE functions) logged by application programs.

The RXX permanently stores the log records after they have been written (spilled or archived) from the LXX. If the LXX becomes full, all MUF processing stops. Once a log record is spilled, its space is available for re-use. CA recommends that you use a tape data set for the RXX.

If CA Datacom/DB Transaction Backout is specified for an application that abends, the MUF backs out all data changes made by the program to tables with logging specified since the last checkpoint. For programs not using checkpoint, the backout point is the beginning of when the program started. CA Datacom/DB uses the active LXX and sometimes the latest RXX to accomplish the backout. If required, the RXX can also be used to perform forward or backward recovery of lost data and changes.