FastSort Manual

Using Supported File Types

FastSort Manual—429834-003

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Tape Files

If you want to use input records from a blocked tape file, use FUP to deblock the

records by loading them into a disk file. Then specify the disk file as an input file for the

sort or merge run.

If you want to store output records in a blocked tape file, use FUP to block the records

by loading them to the tape file from a disk file. Then specify the disk file as the output

file for the sort or merge run.

For information about using the FUP LOAD command, see the FUP Reference

Manual.

The COBOL85 SORT and MERGE statements use FastSort to deblock and block tape

files for you. For a description of the SORT and MERGE statements, see the

COBOL85 Reference Manual.

Partitioned Files

FastSort accepts partitioned input files and can write records to a partitioned output

file. FastSort can also use a partitioned scratch file. A partitioned file, however, must

exist before you use it as an input, output, or scratch file. To create a partitioned file,

use FUP. For more information on how to create a partitioned scratch file, see

Section 9, Optimizing Sort Performance.

Partitioned Output Files

Use a partitioned output file for a distributed database or for a set of output records that

will not fit on one disk volume. To estimate the size of the output file, multiply the total

number of input records by the maximum output record length.

If one or more input files is partitioned, you do not need to use a partitioned output file,

unless the output records will not fit on one disk volume. Output records from

permutation sorts are shorter than output records from record sorts, and output records

from key sorts can be even shorter. Also, if you have FastSort remove records with

duplicate key values, the output records from a record sort usually take up less space

than the input records.

If FastSort determines that an output file is too small, it purges and re-creates the file.

For a partitioned output file, however, you can prevent FastSort from purging and re-

creating the file in order to preserve the original partitioning and extents of the file. To

prevent FastSort from purging the file, specify the NOPURGE parameter of the

TO command or set the SORTMERGESTART procedure flags.<5> bit to 1.