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APAR IY63975: Business Process Choreographer (BPC) database deadlocks during simultaneous claim or queryWorkItem requests.

Fix readme


This problem occurs only under high system load when a very high
number of claim requests and query work item requests are
started simultaneously. Some requests cannot be completed
successfully and end with a deadlock exception.
Concurrent threads query work items for claimable activities and
then try to claim the same activity. This can lead to deadlocks
in some situations.


This fix includes the following changes:
1. Change to the locking strategy in the appropriate claim
2. The ability to specify a different database transaction
isolation level for the work item query.
The transaction isolation level for the query can be changed
only for DB2 UDB, DB2 zOS V7, and DB2 iSeries. For other
database systems, the transaction isolation level cannot be

To enable the "Uncommitted Read" isolation level for queries,
create a file with the name '' in the
WebSphere\AppServer\properties directory (on every node if it
is a cluster). This file must contain the
following line:


Fixed in WBISF 5.1.1 CF1 (

Document information

More support for: WebSphere Business Integration Server Foundation
Process Choreographer

Software version: 5.1.1

Operating system(s): AIX, HP-UX, Linux, Solaris, Windows

Reference #: 1468929

Modified date: 27 October 2014

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