PQ56060: WHEN USING EXCLUSIVE TYPE A LOCKING, CUSTOMER APPLICATION HANGS AS LOAD INCREASES | |||||||||||||||||||||||||||||||||||||
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APAR status Closed as program error. Error description When customer application uses exclusive type A locking, their application hangs under load. In container trace received from the customer, it shows a behavior where a lock is acquired by a thread that was owned by a thread that was releasing the lock, but had not yet released the lock, yet the lock does get released in the next trace entries. However, at this point all users requesting this same lock hang.Local fix Problem summary **************************************************************** * USERS AFFECTED: All WebSphere Application Server Users * **************************************************************** * PROBLEM DESCRIPTION: Cumulative APAR for 4.0 for the * * EJB container. * **************************************************************** * RECOMMENDATION: * **************************************************************** Cumulative Container APAR for 4.0Problem conclusion This Container E-fix is cumulative for 4.0 The following defects were fixed in this E-fix: 1) (APAR PQ44001) Description of problem: WAS 3.5 is throwing different security exceptions then WAS 3.0.2. It seems that specific exceptions that were seen in 3.0.2 arebeing replaced by a more general rollback exception in 3.5. 2) (APAR PQ46998) Description of problem: Strange passivation/timeout behaviour - incorrect cache time out This fix ensures that the the caching of the stateful session beans would not follow the cache count set in the container properties. 3) (APAR PQ48160) Description of problem: Ensures that the proper "stub" type is returned for object references to EJBs Symptoms of problem include some include NotSerializableExceptions during marshalling of return arguments where an EJB reference is returned. Also some types of "Unable to read value from underlying bridge" errors. Changes were made to classes related to EJB container to correct the problem. 4) (APAR PQ50116) Description of problem: RemoveException trying to remove stateless session bean A call to remove() on a stateless session bean within a transaction wil cause the error "Cannot remove session bean within a transaction. This efix removes the transaction restriction, thus allowing the remove() with a transaction to succeed. 5) (APAR PQ52534) Description of problem: IsolationLevel causes Exception during ejbCreate This fix ensures that the home methods for session beans are performed in an "unspecified transaction" mode, which ensures that isolation levels to not conflict. It now includes a fix for the StatefulSessionActivationStrategy, and the FileBeanStore which allows for successful passivation and removal of stateful session beans. 6) (APAR PQ52564) Description of problem: Proper cleanup not taking place during a transaction rollback with Option A caching. The problem here stems from the use of Option A caching (Exclusive database access). With Option A caching in use, the application server assumes that it is the only thing that touches the database (i.e.nothing else can modify the data outside of the EJB Container, not even another clone of the EJB Container). In a scenario where a transaction encounters a problem and attempts to rollback. During this rollback,the locks on the database are removed and the EJB is released. However, the cache does not release the locks on the EJB. Thus, when another (second) client tries to call that EJB, it shows as locked, because the released EJB is still locked in the cache. 7) (APAR PQ53065) Description of problem: Backport 4.0 Option A caching fixes. Several Option A caching issues have been addressed in WebSphere 4.0. This efix backports to 3.5 these fixes. NOTES: This E-Fix must be installed simultaneously on all systems which interoperate at the EJB level (clients as well as servers).Temporary fix PQ53065.jarComments
APAR is sysrouted FROM one or more of the following: PQ53065 APAR is sysrouted TO one or more of the following: Modules/Macros
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Document Information |
Product categories: Software > Application Servers >
Distributed Application & Web Servers > WebSphere Application
Server > General
Operating system(s):
Software version: 400
Software edition:
Reference #: PQ56060
IBM Group: Software Group
Modified date: Apr 29, 2003
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