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I haven't done any benchmarking and am not sure if IBM has either.
I have switched to using identity column attribute due to ease of use and
design concept that pushing function into low level database code is a good
thing from maintenance, portability and performance standpoint (usually :)).
Elvis
Celebrating 10-Years of SQL Performance Excellence
http://centerfieldtechnology.com/training.asp
-----Original Message-----
Subject: Performance question about "next number" methods
Can anyone comment on the performance of the following alternative "next
number" techniques:
1) increment a value stored in a data area (e.g. in RPG, something
like this):
*LOCK IN DATAAREA
ADD 1 NEXTNBR
OUT DATAAREA
2) store a record in a keyed "next numbers" file that stores the
current value for each file
(where the "key" is the name of the file that this next number
pertains to)
pseudo-code below:
read record with key, with a record lock
increment next number value
update record, releasing the record lock
return new value to caller
3) using newer features in DB2 UDB, e.g. a sequence or identity field
These techniques could be implemented in any ILE language, RPG IV,
COBOL, C, etc.
I am interested in the relative performance of one technique versus another.
Thanks.
Mark S. Waterbury
midrange.com
