bdfd1m1oDatabase Administration

Packing Subfiles after Replacing an LREC

The following scenario addresses packing subfiles after replacing an LREC.

Problem

DBREP macros and dfrep functions can result in LRECs occupying less space in a block than that specified in the packing threshold. (The packing threshold is either the TPFDF default for the block type, a value specified in a &SW00PIN DSECT statement, or a value specified with the DBDEF PIN parameter.)

However, the TPFDF product normally packs subfiles only after deleting LRECs, not after replacing LRECs. As a result, the number of blocks in a subfile can become unnecessarily high.

Solution

Set indicator &SW00OP1, #BIT6 in the DSECT to 1. When the TPFDF product closes a subfile, it packs the subfile if the LRECs in any block are below the packing threshold.

Note:
Subfile packing results in significant I/O processing. This can affect system performance.

DSECT Set Symbols

      &SW00OP1  SETC   '......1.'

DBDEF Statements

No changes are necessary if the changes are made in the DSECT macro.

Application Coding

Not applicable.