RE: A question about record locks

-----Original Message-----
From: midrange-l-bounces+cwilt=meaa.mea.com@xxxxxxxxxxxx 
[mailto:midrange-l-bounces+cwilt=meaa.mea.com@xxxxxxxxxxxx] 
On Behalf Of Pete Helgren
Sent: Monday, October 23, 2006 11:49 PM
To: Midrange Systems Technical Discussion
Subject: A question about record locks

I have a couple of applications that are experiencing conflicts on 
record locking and I am not sure what to look for.

App 1 is a maintenance application on the file.  The CLLE 
program that 
calls the app has the following OVRBDF statement in it:

OVRDBF     FILE(MYFILE1) MBR(&MBR) RCDFMTLCK((FMTFILE1 +
             *SHRUPD)) OVRSCOPE(*JOB)         

When I run the program and use the WRKOBJLCK command I see 
the following:

Job          User         Lock      Status          Scope
QPADEV0005   PETE         *SHRRD     HELD           *JOB

Details show:

                      
Object                                                        Member
Object           Library     Type           Lock           
Status    Locks
MYFILE1     MYLIB  *FILE-PHY  *SHRRD    HELD    YES

The member locks show the following detail:

Member       Lock Type   Lock      Status   Share   Scope
MYMBR       MBR        *SHRRD     HELD            *JOB
                      DATA       *SHRRD     HELD            *JOB
                      DATA       *SHRUPD    HELD            *JOB

Records are retrieved in the RPG program with a CHAIN(N)

If CHAIN(N) is the only thing being used, then
1) You wouldn't be able to update the record.
2) You wouldn't get the lock error you are describing.

I'd imagine that you've missed a normal CHAIN somewhere in the program.

It seems kind of funny to have a program that does a CHAIN(N) followed
by a CHAIN without an immediate UPDATE, thus holding the lock on the
record longer than need be.

In other words, as both Simon and Chris mentioned, the use of CHAIN(N)
is usually part of the solution to this problem.

Normally, in this situation you'd see the following:

CHAIN
 //screen I/O & validation
UPDATE

Which would be corrected by changing it like so
CHAIN(N)
 //save original data
 //screen I/O & validation
CHAIN
 //check that no one else has changed the record (or fields you have)
UPDATE


HTH,

Charles Wilt
--
iSeries Systems Administrator / Developer
Mitsubishi Electric Automotive America
ph: 513-573-4343
fax: 513-398-1121