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morfius9
Warnings : 1
New User
Joined: 22 Feb 2006
Posts: 27
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Does anyone have any documentation about the different performances of CICS START/LINK & CALL commands?
I have a new program which would be called by a number of existing programs. I am at loggerheads whether to use a CALL or an EXEC CICS START or EXEC CICS LINK command. Can someone help me decide which is the command that would give the best performance? |
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Bill O'Boyle
CICS Moderator
Joined: 14 Jan 2008
Posts: 2501
Location: Atlanta, Georgia, USA
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From a Main-Program -
01) A CALL to a sub-program is recommended providing that the sub-program is Called more than once.
02) A single LINK and a single Call to a sub-program are equivalent in overhead.
03) A START is a task which runs concurrently with the STARTER (IE: The Main-Program).
When you use a START, control will never be returned to the STARTER, as this is an Asynchronous/Concurrent task, unrelated to the Main-Program.
Otherwise, a CALL and a LINK will eventually return control to the Main-Program (IE: The LINKER/CALLER) and this process is Synchronous.
HTH....
Regards,
Bill |
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UmeySan
Active Member
Joined: 22 Aug 2006
Posts: 771
Location: Germany
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Hi !
There is a difference between these two commands, START & LINK:
When a CICS program issues an EXEC CICS LINK command, control passes to a second program. The second program executes and, after completion, returns control back to the first program.
With the EXEC CICS START you're initiating another task.
Also look at EXEC CICS XCTL:
With that, you're terminating the current program and execute the one specified in the Command. |
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UmeySan
Active Member
Joined: 22 Aug 2006
Posts: 771
Location: Germany
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@Bill:
Sorry, the time you where sending your message, i was still typing mine.
You already said it. I'm getting old and turning into grey. |
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morfius9
Warnings : 1
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Joined: 22 Feb 2006
Posts: 27
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| Is there any extra overhead or over utilization of the resources that take place if i start say 10 transactions from the initiating program. i.e. In a loop, i have the CICS START commands that would be started with different data on each iteration of the loop? |
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