Both archive and restore/copy operations take checkpoints in the data phase. Every time the specified number of data blocks are processed, Teradata ARC saves the tape positioning and other processing information in the restart log. The frequency of checkpoint operations is controlled by the number of data blocks processed.
Checkpoint operations causes I/Os and additional processing overhead, therefore too many checkpoints might adversely impact performance. Each Teradata ARC data block contains up to 32K.
The CHECKPOINT parameter also controls the frequency of VERBOSE display, if active. To see the amount of data processed every minute with an approximate archive rate of 1MB/second, set the CHECKPOINT value between 2500 and 4500.
- Setting a checkpoint frequency too high (a low CHECKPOINT value) might impact performance.
- Setting a checkpoint frequency too low (a high CHECKPOINT value) causes Teradata ARC to reprocess a large number of data blocks in case of a restart.The CHECKPOINT runtime parameter only applies to Mainframe systems (z/OS). Checkpointing to allow for a restart of Teradata ARC is no longer supported on network-attached systems.