RE: Logical file order of records

Neill,

Another remote possibility: If there is another LF over your non-keyed
PF, and this LF is keyed by field1, field2, field3, fieldX, then it's
possible that your F1/F2/F3-keyed LF is sharing the data path of the
4-keyed LF. Make sure that you have SHARE(*NO) on your "share open data
path" attribute on the 3-keyed LF, and duplicate keys should be
presented in arrival sequence (subject to the caveats expressed in the
other responses)...

Randy Dunfee

-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Booth Martin
Sent: Thursday, November 05, 2009 4:35 PM
To: Midrange Systems Technical Discussion
Subject: Re: Logical file order of records

Would a reorganize assure consistent results?

Neill Harper wrote:

Thank you all for the replies.

The reason I ask is that I have a very hard bug / difference to find

during

some parallel regression testing.

The subtle difference was finally tracked down to the order that the

logical

files were returning records.

The records in both physicals are in the same order (i.e. rrn) but the
logicals return the records differently. One library seems to honour

the rrn

theory for records with the same partial key, but the other logical

seems to

be pretty random.

Unfortunately for me this is a details file and there is special extra
processing performed on the last detail record, hence the difference

in the

regression.


Both files were compiled from the same dds using the same commands

params,

they don't reuse deleted records


-----Original Message-----
From: midrange-l-bounces@xxxxxxxxxxxx
[mailto:midrange-l-bounces@xxxxxxxxxxxx] On Behalf Of Crispin Bates
Sent: 05 November 2009 20:37
To: Midrange Systems Technical Discussion
Subject: Re: Logical file order of records

Neil,

It depends. What do you mean by identical data?

There was an interesting discussion on the System i network last week
regarding this.

http://forums.systeminetwork.com/isnetforums/showthread.php?t=77551

It is possible that two versions of the same physical, with the same

data,

can return the data in different sequences. It really depends on what

you

mean by identical data. The data may have been written in a different
sequence, one physical may have been RGZPFM'd. If REUSEDLT(*YES), then

what

sequence does the system decide to write to deleted records in?

Don't write applications that rely on data to be sequenced without

defining

that sequence as keys. SQL will never guarantee the sequence except

for what

is in the ORDER BY. Use the same approach for DDS LF's and you won't

get

bitten. If you want to see records in the order they are created, the

you

need a Date/Time stamp to sequence them by...

Crispin.

----- Original Message -----
From: "Neill Harper" <neill.harper@xxxxxxxx>
To: "'Midrange Systems Technical Discussion'"

<midrange-l@xxxxxxxxxxxx>

Sent: Thursday, November 05, 2009 3:02 PM
Subject: Logical file order of records

If I have a unkeyed PF FILEA as follows:



Field1, Field2, Field3, Field4



I then have an LF LFA, with a non unique key of Field1,Field2,Field3



When there is more and one record with identical Field1,Field2 and

Field3

columns, what controls the order of the remaining records.



Further to this, if I had 2 copies of FILEA in different libraries

with

EXACTLY the same data in would you expect LFA in both libraries to

show

the
records in exactly the same order?









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