ILE COBOL Programmer's Guide
The following considerations apply for opening distributed files when
distributed data processing is not overridden:
- The system will process a distributed file that is open for input-only
using buffered retrieval (*BUFFERED). Buffered retrieval will achieve
the best performance along with maximum record concurrency, however, you might
not see all of the changes made to the file as they occur. Refer to Input/Output Considerations for Distributed Files for more information.
- The system will process a distributed file that is opened for output-only
one record at a time. If your distributed file is opened for
output-only, the DSTDTA parameter will have no effect. Also, if
SEQONLY(*YES) processing has been requested, it will be changed to
SEQONLY(*NO). The SEQONLY(*NO) processing will provide feedback on a
record-by-record basis when the records are inserted into the file.
- The system will process a distributed file that has been opened with an
option that includes update or delete using non-buffered retrieval
(*CURRENT). Non-buffered retrieval ensures that you are updating or
deleting the same record that would have been updated or deleted if all of the
distributed file data had been contained in a non-distributed database
file. Since non-buffered retrieval will be used, the best performance
for the distributed file will not be achieved, but the best data integrity and
the maximum record concurrency will be guaranteed.
- Note:
- For arrival sequence distributed files, records will be retrieved in arrival
sequence starting with the first node, then the second node, and so on.
For duplicate key considerations, refer to Input/Output Considerations for Distributed Files.
- The system will process a distributed file that is opened with all
operations (*INP, *OUT, *UPD, *DLT) using non-buffered retrieval (*CURRENT),
since it includes both update and delete options.
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