Recovery period of change accumulation data sets and GRPMAX

When you register a CA group in the RECON data set, you specify the maximum number of change accumulation generations for DBRC to record with the GRPMAX keyword of the INIT.CAGRP command. When this number is exceeded, DBRC discards the information related to the oldest change accumulation execution record.

For example, if you run change accumulations daily and want to keep 30 days of back level change accumulations, specify a GRPMAX value of 30. In some situations, however, you might run change accumulation more frequently.

To prevent DBRC from discarding information related to the earlier change accumulations, specify the optional recovery period keyword (RECOVPD) to indicate the number of days you want information retained. If the GRPMAX limit is reached, but the RECOVPD for the oldest change accumulation record has not expired, DBRC issues an informational message (DSP1232I), and does not discard the record. If the DSP1232I message appears frequently, you might need to tune the GRPMAX or RECOVPD values with the CHANGE.CAGRP command.

A recovery period is the minimum amount of time that information is maintained in the RECON data set. For example, if the recovery period of a CA group is 30 days, DBRC maintains sufficient change accumulation generation information for at least 30 days. DBRC uses the stop time in the change accumulation execution records to determine if the recovery period has expired.

If both GRPMAX and RECOVPD keyword values are specified for a CA group, DBRC uses both values to determine whether to reuse or delete a change accumulation execution data set.

The following table shows the results of running the Change Accumulation utility when both GRPMAX and RECOVPD values are specified for a CA group that is defined with the REUSE keyword:

The following table shows the results of running the Change Accumulation utility when both GRPMAX and RECOVPD values are specified for a CA group that is defined with the NOREUSE keyword: