PIT change accumulation

PIT CA without a timestamp

A PIT CA that is produced without a specified timestamp is identical to a standard CA, except that the utility writes in-flight transaction log records in a special format. This type of PIT CA can be used as input to the following utilities and functions:

• The standard or PIT Recovery function of the BMC Recovery utility

  If you use a PIT CA as input to the PIT Recovery function, you do not need to provide the minimum of two input log data sets.

• The Change Accumulation function of the BMC Change Accumulation utility

• The Incremental Image Copy (IIC) function of the BMC Image Copy utility and Change Accumulation utility

  If you use a PIT CA as input to the IIC function, the function produces a logically correct image copy that can be verified with a pointer checker utility.

Timestamp PIT CA

To produce a timestamp PIT CA, the Change Accumulation utility accumulates changes to the specified timestamp and processes no log input beyond that timestamp.

A timestamp PIT CA contains no in-flight transactions. It is useful when you want to build a CA to a specific timestamp that does not correspond to the end of a log. You can use a PIT CA with the BMC Recovery utility to perform a PIT recovery without any additional logs. You can use the TIMESTMP(LASTPITCA) keyword in the Recovery utility control statement data set to specify the timestamp of the latest PIT CA to use for the recovery.

Keywords

Use the PIT keyword to produce a PIT CA without a timestamp.

Use the following keywords to produce a timestamp PIT CA:

• PIT
• TIMESTMP

Considerations

The following considerations apply to PIT CAs:

• Use the PIT(Y) keyword to indicate that you want to produce a PIT CA.
• If you want to produce a timestamp PIT CA, use the TIMESTMP keyword to specify the timestamp. This timestamp must match the timestamp that is specified for the PIT Recovery function; you can specify TIMESTMP(LASTPITCA) in the Recovery utility control statement data set instead of specifying the specific timestamp. Only one timestamp can be used for the job step--that is, all groups must use the same timestamp. Omit this keyword if you want to produce a PIT CA without a specified timestamp.
• A PIT CA without a timestamp can be used as input to a standard recovery task or PIT recovery task that is performed by the BMC Recovery utility. It can be used as input to a subsequent change accumulation task that is performed by the BMC Change Accumulation utility. It can be used as input to a subsequent incremental image copy task that is performed by the BMC Image Copy utility. It cannot be used as input to the IBM IMS Database Recovery utility or the IBM IMS Database Change Accumulation utility.
• A timestamp PIT CA can be used as input to the PIT Recovery function of the BMC Recovery utility only; it cannot be used as input to the IMS Database Recovery utility, to any subsequent change accumulation functions, or to any subsequent incremental image copy functions. Not all log data is processed and, therefore, the PIT CA stop time is not valid for selecting the next set of input logs. A timestamp PIT CA is marked IN ERROR in the DBRC RECONs.

• A timestamp PIT recovery that uses a PIT CA does not use any log input. The recovery may be faster because logs do not need to be processed.

  When you use a timestamp PIT CA as input to the PIT Recovery function (using the same PIT time and combining it with the appropriate image copy), the PIT Recovery function produces a logically correct data set as of the PIT time. You no longer need two or more logs from each IMS system to use a CA in a PIT recovery. (The two-log requirement becomes unnecessary because using the timestamp PIT CA ensures that no transactions are partially applied.)

• DBRC must be active.

• The NOTIFY.CA message for registering a timestamp PIT CA includes the words TIMESTAMP PIT. To prevent inadvertent use by other utilities or as input to another CA run, the utility flags the timestamp PIT CA as 'in error' to DBRC.

  When you use a timestamp PIT CA as input to the PIT Recovery function, the Recovery utility issues a message to tell you that the input change accumulation is a timestamp PIT CA.

• All input data sets must be dynamically allocated.
• If the Change Accumulation utility is producing a PIT CA, it cannot produce new output log or extract log data sets.
• If the Change Accumulation utility is producing a timestamp PIT CA, it cannot invoke the Incremental Image Copy function to produce an output image copy.