Difference between Intra Partitioned queue and Extra Partitioned Que

[NSaravan]

Hi all,

Could you please send across some information which has the difference between an Intra-partition Queue and Extra-partition Queue.

Thank you

 

[slade]

Hi N,

As I recall IPQs are created and managed in the CICS region. EPQs exist external to CICS. For example, an MVS/390 tape (yes, tape) dataset. They used to be used as log files.

I think the internal reader (INTRDR) is considered an EPQ.

The disadvantage of EPQs is that I/O to them generates an Operating System wait until the I/O is complete. This means that every CICS xaction in the region(and CICS itself) stops processing until the I/O completes.

Well, that's the way it used to work. It may have changed;

I haven't checked for a while. I haven't come across any "real life" examples of EPQs, so, aside from taking note of their existance, I don't think you'll have to be concerned about them.

Regards, Jack.

 

[DiamondDave2005]

In the Cobol/CICS environment, Intrapartition queues are usually Temporary Storage Queues (TSQs) used to pass information from program to program, or commonly for paging applications (each item on the queue can be a page on the screen, etc). TSQs can only be accessed within the CICS environment.TSQs can be read multiple times, updated, etc.

Extrapartition queues are Transient Data Queues (TDQs). TDQs are stored as physical files, and must be set up in a CICS table (I forget which one). The table entry will define the TDQ name and a related DD Name which may be accessed outside the CICS environment. TDQs are usually used to create a file which will be used later on in the batch environment to write reports, etc.

 

[gregsimpson]

TDQ's may be set up as either intrapartition or extrapartition. As diamonddave states when they are set up extra partition the file which the extrapartition queue writes to may be made available to programs outside of CICS.

Greg