Re: Strange problem with an _Rreadk()

James,

It talks a little about this in the ILE C/C++ Programmers Guide but all of the implications are not explained there.

With SHARE(*NO), the system builds a new ODP for each job/process opening the file. As a result, the locking rules change and areas, such as the i/o feedback area are shared. This also has implications for multi-threaded jobs. You will need to look at the specific exception in the job log to determine the exact nature of the problem.

To better understand the differences, look at
http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/books/sc415606.pdf
Pages 3-4, 41-43, 87 and 117 or search on ODP

Although it is Display Programming specific, I also take the information in section "Sharing Display Files in the Same Job" in the Application Display Programming manual (http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/rzakc/sc415715.pdf) to heart any time I'm potentially using a shared path. To prevent problems, you may have to do file locking; although, this may not be an option if the file is generally in use by other processes. If this is a busy file, changing to SHARE(*NO) may not be an option because it may have an extremely detrimental affect on access times.

See also
http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/dbp/rbafonoid20.htm?
and
http://publib.boulder.ibm.com/infocenter/iseries/v6r1m0/topic/dbp/rbafosfile.htm

Mike

James H. H. Lampert wrote:

Mike Amos wrote:

What level of OS is the customer running? Does this happen with only one file or multiple files? Is journaling or some other service running against the affected files? Have you checked the see if there are any APARs against this or a similar problem?

I just got the joblog this morning.

They're on V5R4M0.

And I'm onto something: I saw two "open options ignored" messages regarding the file, both of them involving shared open data paths.

The application opens the file twice, and doesn't use shared ODPs.

I changed a copy of the file on our V4 box to SHARE(*YES), and suddenly I could duplicate the problem freely.

Now that I know what the problem is, and given that this is an application that opens user-specified files, what do I do about it?

--
JHHL