Question & Answer
Question
Why are large volumes of transactions suspended in ZCIOWAIT DFHZARQ1 waits in my CICS Transaction Server for z/OS (CICS TS) region from time to time? The system dump of my CICS region shows one of the tasks was suspended for about 4 hours. The user who was using the terminal associated with the suspended task said that she had terminated the 3270 emulator.
Answer
The problem with CICS transactions being suspended with ZCIOWAIT DFHZARQ1 waits is usually due to older 3270 emulators. The user of the 3270 emulator can close the window and it sends nothing to the server to indicate the connection is no longer in use. So the telnet server thinks everything is just fine until the emulator check with a timemark (default interval is 3 or 4 hours). The SNA side is tied up even though the client no longer is alive.
You can lower the TIMEMARK value, but it costs cycles to constantly run the chain of connections over and over, and sending timemarks on idle connections looking for one that is gone. Or you can leave TIMEMARK at 3 hours and then you use up a bunch of other resources as users keep connecting back in with new sessions. The best solution is to migrate end user to new emulator that will send a Reset or FIN when the window is closed or disconnected.
Product Synonym
CICS/TS CICSTS CICS TS CICS Transaction Server
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Document Information
Modified date:
11 January 2016
UID
dwa1247192