RE: CHAIN Versus SETLL and READ When Data Needed

AFAIK, chain will not clear any data in the program when not found.
With that say, I think chain is faster.  Since setll and read require
two trips.  If chain is not found, it would be like setll. 

-----Original Message-----
From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx] On Behalf Of Steve Landess
Sent: Wednesday, February 28, 2007 2:50 PM
To: RPG programming on the AS400 / iSeries
Subject: Re: CHAIN Versus SETLL and READ When Data Needed

Shannon -

SETLL does NOT move any data or clear any buffers - it simply positions
the file cursor to be ahead of the record containing the key value
specified in the KLIST.

So, as far as efficiency goes, I'd say that the first example which uses
SETLL (except using %EQUAL instead of %FOUND) will be much more
efficient than using the CHAIN operation code, since CHAIN does perform
I/O and if a record is not found it clears the buffer area.

- sjl