For eligible sorts, the FASTSRT compiler option specifies that the SORT product will handle all of the I/O
and that COBOL does not need to do it.
This eliminates all of the overhead of returning control to COBOL after each record is read in or after processing each record that COBOL returns to sort.
The use of FASTSRT is recommended when direct access devices are used for the sort work files since the compiler will then determine which sorts are eligible for this option and generate the proper code.
If the sort is not eligible for this option, the compiler will still generate the same code as if the NOFASTSRT option were in effect.
A list of requirements for using the FASTSRT option is in the COBOL programming guide.
Performance considerations using FASTSRT:
One program that processed 100,000 records was 35% faster when using FASTSRT compared to using NOFASTSRT.
This eliminates all of the overhead of returning control to COBOL after each record is read in or after processing each record that COBOL returns to sort.
The use of FASTSRT is recommended when direct access devices are used for the sort work files since the compiler will then determine which sorts are eligible for this option and generate the proper code.
If the sort is not eligible for this option, the compiler will still generate the same code as if the NOFASTSRT option were in effect.
A list of requirements for using the FASTSRT option is in the COBOL programming guide.
Performance considerations using FASTSRT:
One program that processed 100,000 records was 35% faster when using FASTSRT compared to using NOFASTSRT.
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