IBM Mainframe Forum

[purushothaman]

I'm a Beginner in IMSDB. Can anyone tell me. How to perform a Pure ROLLBACK function without using a (CHKP) Checkpoint/Commit using IMS Call.

Actually my Program have the process on both IMSDB & DB2 Tablebases. Could anyone please suggest me how to use a IMS ROLLBACK using IMS CALL. And more thing is i have already tried the same using DB2 ROLLBACK, But it doesn't work.!


Regards,
Purushoth.

[Ed Goodman]

ROLB uses the log to do the roll back. The log needs to have the first call be a XRST call for good processing.

You can actually never take a checkpoint, and still use the ROLB call. It will just go back to the XRST call at the beginning.

If if do take a checkpoint, the ROLB call will roll back to it.

You MAY be looking for the ROLS/STOP combination, which is a way to place a marker in the log without taking a checkpoint, then being able to return to it. I've never used it, so I can't warn you about any common problems with it. I think the main difference is that you can't do a restart from a STOP point, but you can from a check point.

[purushothaman]

Actually, i forgot to mention one thing that. i don't want a partial update. i need to issue a Pure ROLLBACK. Yes, i've previously tried to issuing the ROLLBACK using 'ROLB' log only.

I have already referred this below link.

http://ibmmainframes.com/about33768.html
CALL 'CBLTDLI' USING NUM-OPS,
'CHKP',
IO-PCB,
CHKP-LENGTH,
CHKP-AREA.

You can also code the IMS rollback command as follows:

CALL 'CBLTDLI' USING NUM-OPS,
'ROLB',
IO-PCB,
CHKP-LENGTH,
CHKP-AREA.



Please tell me how to issue the 'ROLB' without issuing any ROLS/STOP combination

[purushothaman]

ROLB uses the log to do the roll back. The log needs to have the first call be a XRST call for good processing.

You can actually never take a checkpoint, and still use the ROLB call. It will just go back to the XRST call at the beginning.

If if do take a checkpoint, the ROLB call will roll back to it.

You MAY be looking for the ROLS/STOP combination, which is a way to place a marker in the log without taking a checkpoint, then being able to return to it. I've never used it, so I can't warn you about any common problems with it. I think the main difference is that you can't do a restart from a STOP point, but you can from a check point.

Hi Ed,

Thanks for your reply. . But,this is not exactly i want. i don't want to issue a partial update.. . Please guide me, if any other possible way to issue a Pure 'ROLB' only:?:

[NicC]

Are you trying to do this in the DEBUG tool or in your program?

[purushothaman]

Hi Nic,
I'm trying to do this in Program Only.!

[NicC]

Then why post in the IBM Debug Tool section of the forum?

Moved.

Our way of doing this was to simply restore the database from the latest backup. If this is online and not batch then this option is not available.

[Ed Goodman]

I can't tell the difference between what you asked for originally and what you said to clarify it.

A pure ROLB will rollback all updates to the last commit point. I'm nit sure what you meant when you wrote 'I don't want a partial update.'

Try a longer example and maybe it will get through to me!

[dick scherrer]

Hello,

If one or more checkpoint(s) is issued by the run and it later abends, there Will be a partial update.

[Ed Goodman]

Ah, then two options that I can think of:

1) Don't take any checkpoints during the program, just one at the VERY beginning, right after the XRST call. Then the ROLB will go all the way back.

2) Take an early checkpoint, abend when you find that you need rollback, then do a batch backout specifying the first checkpoint.

I'm the last guy to do this to a honest question, but WHY are you trying to do this?