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vasanthz
Global Moderator
Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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Hi,
Is there anyway to kill/PURGE a CICS transaction that has been running for over a certain elapsed time limit/CPU time limit.
We have Mainview for CICS
Regards,
Vasanth.S |
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Marso
REXX Moderator
Joined: 13 Mar 2006
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Location: Israel
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vasanthz
Global Moderator
Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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| I will check this. I don't know if we have that product licensed. |
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vasanthz
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Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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Thanks for the link, but I am unable to find the Threshold Advisor from the Mainview menu. I suspect we are not licensed for it.
These are the available options, I did look into each option, but no mention of Thresholds 
| Code: |
--------------------------- MAINVIEW Selection Menu -------
OPTION ===>
0 Parameters and Options
E Alerts and Alarms
P PLEX Management (PLEXMGR)
U Utilities, Tools, and Messages
Solutions for:
A Automated Operations
C CICS
D DB2
I IMS
J JAVA Environments
L Linux and z/VM
N Network Management
O Cost Optimization
S Storage Management
T Application Management and Performance Tuning
W MQ and WAS
Z z/OS and USS |
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Rohit Umarjikar
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Joined: 21 Sep 2010
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Location: NYC,USA
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vasanthz
Global Moderator
Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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| Thanks, We have ICVR set to 20000 - 20 seconds, but the transactions just keep running over 20 minutes, if they are looping. I think there is a specific criteria that needs to be met to satisfy the ICVR time and for a transaction to be cancelled. It is very confusing. |
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enrico-sorichetti
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Joined: 14 Mar 2007
Posts: 10873
Location: italy
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define loop please ?
the ICVR definition is
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| CICS might purge a task if it has not given up control after the RUNAWAY interval for the transaction (or ICVR if the transaction definition specified RUNAWAY=SYSTEM). |
and applies to a CPU loop, but if the loop contains cics calls the ICVR does not apply |
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vasanthz
Global Moderator
Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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Thank you for looking into this.
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| but if the loop contains cics calls the ICVR does not apply |
I honestly have no idea how the handover between CICS and DB2 takes place, when there is a CICS transaction accessing DB2.
In my scenario, there is a CICS transaction that accesses DB2 table and looks for a row, if the row is not found then the program keeps looking for the row indefinitely(this is what I perceived as looping).
The transaction was running for like 15 minutes before it was cancelled. Would ICVR value apply in this case?
I understand that this is a program fault & needs to be corrected, but I am trying to address it from CICS perspective to handle such (rare)buggy transactions. |
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enrico-sorichetti
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Joined: 14 Mar 2007
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Location: italy
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unfortunately that' s not cics point of view 
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| The transaction was running for like 15 minutes before it was cancelled. Would ICVR value apply in this case? |
NO, if the program relinquishes control, for cics is not CPU looping
and how in heaven can cics distinguish a legitimate long running task
from a faulty one ? |
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vasanthz
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Joined: 28 Aug 2007
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Location: Tirupur, India
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and how in heaven can cics distinguish a legitimate long running task
from a faulty one ? |
You are right, it makes sense now. Thank you.
I was looking for a parameter like DB2-Resource Limit Facility in CICS. Many sites say that a monitor is needed and there is no inherent way to limit CPU.
I wish there was an in-built one |
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Rohit Umarjikar
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Joined: 21 Sep 2010
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Location: NYC,USA
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| Quote: |
I was looking for a parameter like DB2-Resource Limit Facility in CICS. Many sites say that a monitor is needed and there is no inherent way to limit CPU.
I wish there was an in-built one
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should ASUTIME set in DB2 gives you -904 in your cics db2 program and then you do a proper error handling to end the current running task ? That’s being followed by almost everyone since it’s one of the bad sqlcode and most common one . |
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vasanthz
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Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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| Quote: |
| should ASUTIME set in DB2 gives you -904 in your cics db2 program and then you do a proper error handling to end the current running task ? That’s being followed by almost everyone since it’s one of the bad sqlcode and most common one . |
AFAIK, the program does not receive a -904 for record not found. The row is 'logically' not found by the program. The program looks for a column with a selective value and just reads sequentially, it is a program logic and not a straight up query.
We are unable to set a limit on DB2 side because
1. It is very hard to identify each stuff that runs on DB2 and set a limit for them. There are just too many variety of things.
2. Queries initiated by CICS are the main culprits, because they run with very high service class and causes outages. |
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Rohit Umarjikar
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Joined: 21 Sep 2010
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Location: NYC,USA
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I mean my point is any sql query being issued it must finish it up in Less than or equal to ASUTIME even if row not found situation else it should give you -904.If it’s not a DB2 thread and some other looping issue in the program then that program needs a emergency fix.
Moreover, I am not sure but you can able to lower the priority of the long running task. |
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John Poulakos
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Joined: 13 Jun 2012
Posts: 178
Location: United States
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Are you sure the CICS transaction is actually running and consuming CPU, or is it just waiting? If you kill the transaction, you should see if you can find a TRU exit in the dump. I have seen transactions hang many times when a TRU exit is present, because a TCB gets posted under the wrong storage key. TRU exits are fairly common with DB2 under CICS.
If you aren't familiar with TRU exits, google "CICS TRUE". |
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vasanthz
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Joined: 28 Aug 2007
Posts: 1742
Location: Tirupur, India
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Hi John,
I do not know CICS TRUE, I will look it up. Thanks.
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| Are you sure the CICS transaction is actually running and consuming CPU, or is it just waiting? |
Yes the transaction was actually running because of a program bug. The program was supposed to loop through a DB2 table and find an available number between 1 and 999.
But for that scenario, there happened to be no free numbers.
This scenario was not handled and the program kept looking for available numbers till eternity. |
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