bdfd1m1k | Database Administration |
The following scenario addresses reducing the number of overflow blocks.
A fixed file has been defined as containing 1055-byte prime blocks. This has resulted in a large number of chained overflow blocks. Reduce this by changing the prime block size to 4095.
Reorganize the file by copying the 1055-byte prime blocks into 4095-byte prime blocks. (The application must not modify the file during the reorganization process.) You can then change the prime block size by resetting the set symbol &SW00WRS in the file DSECT. If necessary, you can also change the overflow block size by resetting &SW00ARS.
When you have done this, update the DSECT with the new &SW00WRS value, and check that the DBDEF table is ready to be loaded. Load the new DBDEF before any application accesses the data.
&SW00WRS SETC 'L4' &SW00ARS SETC 'L2'
DBDEF FILE=zzzzzz,(WRS=L4,ARS=L2)