The AWO compiler option causes the APPLY WRITE-ONLY clause to be in effect for all physical sequential,
variable-length, blocked files, even if the APPLY WRITE-ONLY clause is not specified in the program.
With APPLY WRITE-ONLY in effect, the file buffer is written to the output device when there is not enough space in the buffer for the next record.
Without APPLY WRITE-ONLY, the file buffer is written to the output device when there is not enough space in the buffer for the maximum size record.
If the application has a large variation in the size of the records to be written, using APPLY WRITE-ONLY can result in a performance savings since this will generally result in fewer calls to Data Management Services to handle the I/Os.
Performance considerations using AWO:
One program using variable-length files and AWO was 88% faster than NOAWO. This faster processing was the result of using 98% fewer EXCPs to process the writes.
With APPLY WRITE-ONLY in effect, the file buffer is written to the output device when there is not enough space in the buffer for the next record.
Without APPLY WRITE-ONLY, the file buffer is written to the output device when there is not enough space in the buffer for the maximum size record.
If the application has a large variation in the size of the records to be written, using APPLY WRITE-ONLY can result in a performance savings since this will generally result in fewer calls to Data Management Services to handle the I/Os.
Performance considerations using AWO:
One program using variable-length files and AWO was 88% faster than NOAWO. This faster processing was the result of using 98% fewer EXCPs to process the writes.
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