Prerequisites

R+/CHANGE ACCUM accesses the bootstrap data set (BSDS) to obtain information about the logs being used. R+/CHANGE ACCUM also accesses the Db2 catalog and directory to obtain information about the objects in the change accumulation group, the image copies taken for each object, and the log ranges in which updates to the target objects are found. In a single pass of the log, R+/CHANGE ACCUM can extract log record data for any number of change accumulation groups in one run as long as you have specified a sufficient amount of REGION on the EXEC statement.

The following figure shows an example of how to log record data is accumulated for two change accumulation groups:

• The change accumulation group named GROUP_AB_AND_CD consists of two simple table spaces, A.B and C.D. Two copies of the change accumulation file are defined for the group: the local site primary copy is stored on DASD, and the local site backup copy is stored on tape.
• The change accumulation group named GROUP_EF consists of one simple table space E.F, with INDEXES YES specified to accumulate associated indexes. Only one change accumulation file is defined and stored on tape.

You can run R+/CHANGE ACCUM alone if you specify only ACCUM statements, or with BMC AMI Recover (if you specify ACCUM, RECOVER, and REBUILD statements). R+/CHANGE ACCUM executes all ACCUM, RECOVER, and REBUILD commands input with one pass of the necessary change accumulation records or Db2 log records.

R+/CHANGE ACCUM creates one file set per change accumulation group per run. This consists of from one to four change accumulation files, each containing identical information. The file templates in the group control the allocation of these files (unit specification, data set name, space, and so on). R+/CHANGE ACCUM records a log range in the repository for each target object that is defined as part of the group.

ACCUM TABLESPACE works like ACCUM GROUP except that R+/CHANGE ACCUM creates the group dynamically, with definitions corresponding to the table space specifications in the input. The file templates come from the default group, DEFG0000, which was created during the installation of R+/CHANGE ACCUM. You may customize the default definitions through the R+/CHANGE ACCUM interface. We recommend the use of ACCUM TABLESPACE for conducting trials or testing, but not for production.

R+/CHANGE ACCUM sorts the extracted log information about each change accumulation file by object, partition or DSNUM, page number, and the log record sequence number (LRSN) of the source log record. For more information, see Ordering-change-accumulation-file-data.