DB2 FOR LUW / DB2FORLUW / B10 - DB2

Lock-waits/deadlocks may be observed between the agent altering
the module to update with new code , and the agents trying to
execute the old module/procedure.

Even though the module names are different, however the data
types defined/used in the new and old code, have the same type
name which causes this lock conflict between the agents.

Here is the example command to alter the new module to publish
the new code:


ALTER MODULE "new-module-name" PUBLISH PROCEDURE "procedure
name"....

The application doing alter module had several locks/deadlock on
sysdatatypes catalog table.The locks were X locks.

If the procedure name used in this new module, is also the same
as the one being used in old module, this may also cause lock
contention on  the catalog cache.

Hence, to avoid the lock contention on procschema lookup in
catalog cache, please use different procedure name.

This APAR fix will make enhancements for the locking on
SYSDATATYPES catalog table and hence avoid the lock/deadlock
contention.

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* PROBLEM DESCRIPTION:                                         *
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* RECOMMENDATION:                                              *
* Upgrade to Db2 11.1 Mod 4 Fixpack 5 or higher                *
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To avoid lock contention on catalog cache, use different
procedure name in the new modules as well to avoid locking on
catalog cache.

not known / see Local fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

29.01.2019
16.01.2020
16.01.2020