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Improving copy performance<br />
If the to-file does not exist and CRTFILE(*YES) is specified so that the copy<br />
command creates the to-file, then you must have operational authority to the<br />
CRTPF command.<br />
You can improve the performance of your copy operations by following these<br />
guidelines:<br />
v “Avoiding keyed sequence access paths”<br />
v “Specifying fewer parameters”<br />
In addition, when you copy distributed files, you should be familiar with the<br />
various factors that affect the performance of the copy command. The DB2<br />
Multisystem feature provides support for distributed files, or files that are spread<br />
across multiple AS/400 systems. When you copy distributed files, you should be<br />
familiar with the various factors that affect the performance of the copy command.<br />
You should be aware of restrictions that apply when you copy to and from<br />
distributed files.For information about copying distributed files, see the DB2<br />
Multisystem for AS/400 book.<br />
Avoiding keyed sequence access paths<br />
A copy that requires maintenance of a keyed sequence access path is slower than a<br />
copy from or to an arrival sequence access path. You can improve copy<br />
performance if you reorganize the from-file so that its arrival sequence is the same<br />
as its keyed sequence access path. You can also improve copy performance if you<br />
select records by using the FROMRCD or TORCD parameter so that the keyed<br />
sequence access path is not used.<br />
Create fewer logical access paths over the to-file. This improves copy performance<br />
because the copy process does not need to update as many access paths.<br />
The smaller the length of the records within the file, the faster the copy.<br />
Specifying fewer parameters<br />
In general, you can improve copy performance if you specify fewer optional copy<br />
parameters. The following parameters affect the performance of the copy<br />
operation:<br />
v INCCHAR<br />
v INCREL<br />
v ERRLVL<br />
v FMTOPT<br />
v SRCOPT<br />
v PRINT<br />
Using the COMPRESS function does not significantly affect performance. You<br />
should request COMPRESS(*NO) if you want deleted records in the to-file, for<br />
example, when the relative record numbers need to be identical.<br />
Chapter 4. Copying files 129
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