Fixes are available
8.5.5.2: WebSphere Application Server V8.5.5 Fix Pack 2
8.0.0.9: WebSphere Application Server V8.0 Fix Pack 9
8.5.5.3: WebSphere Application Server V8.5.5 Fix Pack 3
8.5.5.4: WebSphere Application Server V8.5.5 Fix Pack 4
8.0.0.10: WebSphere Application Server V8.0 Fix Pack 10
8.5.5.5: WebSphere Application Server V8.5.5 Fix Pack 5
8.5.5.6: WebSphere Application Server V8.5.5 Fix Pack 6
8.0.0.11: WebSphere Application Server V8.0 Fix Pack 11
8.5.5.7: WebSphere Application Server V8.5.5 Fix Pack 7
8.5.5.8: WebSphere Application Server V8.5.5 Fix Pack 8
8.0.0.12: WebSphere Application Server V8.0 Fix Pack 12
8.5.5.9: WebSphere Application Server V8.5.5 Fix Pack 9
8.5.5.10: WebSphere Application Server V8.5.5 Fix Pack 10
8.5.5.11: WebSphere Application Server V8.5.5 Fix Pack 11
8.0.0.13: WebSphere Application Server V8.0 Fix Pack 13
8.5.5.12: WebSphere Application Server V8.5.5 Fix Pack 12
8.0.0.14: WebSphere Application Server V8.0 Fix Pack 14
8.5.5.13: WebSphere Application Server V8.5.5 Fix Pack 13
8.0.0.15: WebSphere Application Server V8.0 Fix Pack 15
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.15: WebSphere Application Server V8.5.5 Fix Pack 15
8.5.5.14: WebSphere Application Server V8.5.5 Fix Pack 14
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
8.5.5.20: WebSphere Application Server V8.5.5.20
8.5.5.18: WebSphere Application Server V8.5.5 Fix Pack 18
8.5.5.19: WebSphere Application Server V8.5.5 Fix Pack 19
8.5.5.16: WebSphere Application Server V8.5.5 Fix Pack 16
8.5.5.21: WebSphere Application Server V8.5.5.21
APAR status
Closed as program error.
Error description
In a multi-threaded environment, when a JPA 2.0 application running in WebSphere Application Server executes EntityManager.refresh() with LockModeType.PESSIMISTIC_LOCK, the JPA implementation first reads the records from the database and then locks the records, rather than locking immediately.
Local fix
N/A
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM WebSphere Application * * Server V8.0.0, V8.5.0, and V8.5.5 * * who make use of JPA * * LockModeType.PESSIMISTIC_WRITE. * **************************************************************** * PROBLEM DESCRIPTION: Calling * * EntityManager.refresh(PESSIMISTIC_WRITE * * ) generates seperate SQL for the lock. * **************************************************************** * RECOMMENDATION: * **************************************************************** Take the following JPA scenario: EntityManager em..... T1 t1 = em.find(T1.class, "c1"); em.refresh(t1, LockModeType.PESSIMISTIC_WRITE); Object T1 is a JPA entity; the details of the entity are not important. When the 'refresh' occurs, the following two SQL statements will be run (these statements are from DB2, statements generated for other databses will be slightly different, but the results are the same): SELECT t0.CMLT_FOLDER_CONTEXT_UPDATE_TMS, t0.CRE_TIME FROM T1 t0 WHERE t0.c1 = ? [params=(String) c1] SELECT t0.c1 FROM T1 t0 WHERE t0.c1 = ? FOR READ ONLY WITH RR USE AND KEEP UPDATE LOCKS [params=(String) c1] As can be seen, the second SQL statement will get a pessimistic lock for the row. However, two SQL selects to get the lock should not be necessary, one would suffice. Furthermore, in a multi-threaded environment the time between the two selects might allow another thread the lock over other competing rows.
Problem conclusion
With this fix, code has been added to OpenJPA to ensure only one SQL is generated when getting a lock for an entity. With the fix, only one select will be generated, as follows: SELECT t0.CMLT_FOLDER_CONTEXT_UPDATE_TMS, t0.CRE_TIME FROM T1 t0 WHERE t0.c1 = ? FOR UPDATE [params=(String) c1] The fix for this APAR is currently targeted for inclusion in Service Levels (Fix Packs) 8.0.0.9 and 8.5.5.2 of WebSphere Application Server versions 8.0.0 and 8.5.5. Please refer to the recommended updates page for delivery information: http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
Temporary fix
Comments
APAR Information
APAR number
PM94033
Reported component name
WEBS APP SERV N
Reported component ID
5724H8800
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2013-07-29
Closed date
2013-11-19
Last modified date
2013-11-19
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
WEBS APP SERV N
Fixed component ID
5724H8800
Applicable component levels
R800 PSY
UP
R850 PSY
UP
Document Information
Modified date:
27 April 2022