RE: READE vs. READPE performance

I should probably also mention why.

If I understand correctly, READE and READPE don't read from the buffer,
they hit the file every time.

So you've got a lot of file I/O going on there.

Of course you'll need to put more code in to make sure you haven't read
back to the beginning of the file or past your key, but that's faster
than file I/O.  Just uglier.  



>-----Original Message-----
>From: rpg400-l-bounces@xxxxxxxxxxxx
[mailto:rpg400-l-bounces@xxxxxxxxxxxx]
>On Behalf Of Fleming, Greg (ED)
>Sent: Friday, December 09, 2005 2:09 PM
>To: RPG programming on the AS400 / iSeries
>Subject: RE: READE vs. READPE performance
>
>If performance is an issue, don't use READE or READPE.
>
>SetGT and ReadP.
>
>I don't know if that is any faster or slower than reading forward, but
I
>can't think of any reason why there would be any difference.
>
>
>
>>-----Original Message-----
>>From: rpg400-l-bounces@xxxxxxxxxxxx
>[mailto:rpg400-l-bounces@xxxxxxxxxxxx]
>>On Behalf Of Ben_Pforsich@xxxxxxxxxxxx
>>Sent: Friday, December 09, 2005 2:03 PM
>>To: rpg400-l@xxxxxxxxxxxx
>>Subject: READE vs. READPE performance
>>
>>
>>Generally speaking, has anyone tried or know for a fact which of the
>>following scenarios result in better performance (faster I/O?)?...
>>1.  READE on logical with a descending key  (ex:  READE (Company :
>Route :
>>Date) LOGICAL1 where Date is keyed descending)
>>2.  READPE on logical with an ascending key  (ex: READPE (Company :
>Route :
>>Date) LOGICAL2 where Date is keyed ascending).
>>
>>I want to read records in a history transaction file keyed with a date
>>field starting with the most recent and going backward.  I'm trying to
>>decide whether I should build a new logical over a fairly large
>physical,
>>or use an existing logical and use READPE instead of READE.  I will be
>>likely reading potentially 10,000 to 50,000 records in one pass and
>>performance is an issue.
>>
>>Let me know if you need more information, but I was hoping for a quick
>and
>>dirty response.
>>
>>Thanks!
>>
>>Ben Pforsich
>>Programmer Analyst
>>Bob Evans Farms, Inc.
>>I/S Department
>>Columbus, Ohio
>>Ben_Pforsich@xxxxxxxxxxxx
>>
>>--
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