Checkpoint/Restart File

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The IBM® Connect:Direct® checkpoint/restart file contains positioning information for both files involved in executing a COPY statement. IBM Connect:Direct maintains the checkpoint records throughout data transmission and deletes them when a transmission completes successfully.

Note: Checkpoints take place on the receiving end of a transfer. During restart, this information is exchanged with the sender so that appropriate positioning can take place.

A checkpoint record can be left in the Checkpoint file if an interrupted Process is deleted by the operator. IBM Connect:Direct scans the checkpoint records during initialization and deletes records older than the value specified in the CKPT.DAYS initialization parameter.

The Key attribute of the CKPT file has been updated for IBM Connect:Direct z/OS version 6.4. A new sequence number is added to each CKPT record key with a default value of '00'. In prior versions of IBM Connect:Direct for z/OS, if the z/OS server received more than one Copy Process request with the same Process name from multiple instances of a Connect:Direct Unix server working behind a Load Balancer, and these processes were triggered simultaneously, their Process number would become the same, causing the CKPT record initialization to fail. In version 6.4, the Unix Instance Identifier is used to differentiate between these processes, allowing the CKPT record initialization to succeed. A new CKPT record is created in the CKPT file for such cases, with the sequence number incremented by ‘1’. Like other checkpoint records, this record is deleted upon successful process completion.