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[lacoe1]

We have a created a smaller version (less data) of our Production database of 170+ tables for the purpose of training new users. This is our Training environment. In a class of 15+ students, when the instructor and students fill up data on their individual online screens together and all hit enter at the same time to complete a CICS transaction (which inserts record), only 1 or 2 succeed and the rest gets -911 deadlock or timeout. We are assuming since its a small database everyone is trying to access the same page at the same time.

In Production where users are located at different geographical locations may or may not execute the same transaction and hit ENTER at the same time, plus the database is much bigger so they are accessing different pages. So may be we do not have that issue.

To find a solution

DBA tried to change from Page lock to Row lock
DBA tried to increase the Freespace from 50% to 90% to have less rows per page
CICS Admin tried to single thread the CICS transactions one at a time

None of these improved the condition. The instructor does not like to stagger the ENTRY, means does not like to ask students to hit ENTER one at a time.

Current recommendations are to review the code and introduce retry logic, move all production data to Training environment which may or may not spread the data around.

Any other suggestions that can quickly fix this situation?

[CZerfas]

The single threading for the CICS transaction should do the trick.

All other actions are good for "unavailable ressource" conditions resulting in a timeout. To avoid deadlock conditions means, that the read and write logic in the code has to be reworked. Normaly there is no "quick releave" for such conditions but to single file the incoming work.

regards
Christian

[lacoe1]

Thanks for your response. The single thread did work, currently we are setup for Single Thread for particular Transactions only. Worried if it will slow down the Training environment if a blanket command is issued for all transactions.

[papadi]