MVSFORUMS.com

[ajaysb]

Hi all,

Just wanted to clarify a small doubt.

DISP=SHR indicates that its open to read and update from multiple jobs at the same time. (correct me if I am wrong).

So whats gonna happen if two or more pgms(say A and B) open the file in i-o for updation and again two or pgms(say C and D) open the file in input just for reading; all at the same time.



Would there be any contention in this case or is it that one or more pgms will wait for the updating pgms to complete ? Which pgms will abend or which pgms will wait ?



Thanks for your answers. Need a little bit of clarity for solving some production issues.


Cheers

[kolusu]

ajaysb,

Please search before posting. check this link

http://www.mvsforums.com/helpboards/viewtopic.php?t=1202&highlight=disp=shr

Hope this helps...

Cheers

Kolusu
_________________
Kolusu
www.linkedin.com/in/kolusu

[ajaysb]

Hi Kolusu,
I should have mentioned this before. I was looking for this information with regards to VSAM datasets and not sequential ones.

Have rephrased my questions a bit. Let me know if somebdy can answer this...

Ques 1) In case of Defining an alternate index, does the system take exclusive access of the cluster and in case it does, will another program using the same vsam cluster in disp=shr abend ?.
One such scenario happened in production at my shop and the other program abended.

Ques 2) In another hypothetical situation, if a vsam file is defined with a SHAREOPTION of 2, and two pgms open the file in i-o mode for updations with disp=shr, will one of the pgms fail ?

Cheers