KSDS record length (HISAM)
The database administrator needs to perform trade-offs when determining the KSDS record length for a HISAM database.
Selecting a large KSDS LRECL allows reduction of the number of database records that cannot be stored entirely in the KSDS record. This will reduce the average number of I/Os per database record. On the other hand, selection of a KSDS LRECL that is too large may represent a waste of DASD space, if a high percentage of database record do not fill reasonably the KDSD record.
The table containing the distribution of the database record length (see Figure 1) provides assistance in determining a reasonable KSDS LRECL.