Setting ALTERSZE values for HALDB alter

To increase the OSAM block size or VSAM CI size of the database data sets when you are modifying the structure of a database with the HALDB alter function, you must set ALTERSZE values for each data set group that is changing in each partition record in the RECON data set.

To set the ALTERSZE values, you can use either DBRC command CHANGE.PART or the HALDB Partition Definition utility (%DFSHALDB).

If you use the CHANGE.PART command to set the ALTERSZE values, the values must be specified as positional, comma-separated values. The value in the first position applies to the first data set group. The value in the second position applies to the second data set group, and so on.

For example, the following ALTERSZE specification sets a new block or CI size for the third data set group, but leaves the sizes unchanged for the first and second data set groups, as well as for the fourth through tenth data set groups, if they exist: ALTERSZE(,,4096).

You can determine the position in which to enter a size for a data set group by looking at the DSGROUP keyword in the SEGM statement that defines the segment that you are altering. DSGROUP=A indicates the first position, DSGROUP=B, the second position, and so on, up to DSGROUP=J, which indicates the tenth position.

Procedure

To set ALTERSZE values for the output database data sets of an alter operation by using batch DBRC commands, specify the following command.

After the command is successfully processed, the block or CI sizes to be used by the alter process are listed under “ALTER BLOCK SIZE” in the RECON record for a partition, which can be displayed by issuing the DBRC command LIST.DB DBD(partitionname).

After the alter size values are set, you can start the alter process by issuing the IMS type-2 command INIT OLREORG NAME(masterdb) OPTION(ALTER).