[jboss-jira] [JBoss JIRA] (WFLY-4333) Transaction must be sticky to ensure consistency for EJB remote invocation with JPA

[Richard Achmatowicz (JIRA)]

    [ https://issues.jboss.org/browse/WFLY-4333?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13089448#comment-13089448 ] 

Richard Achmatowicz commented on WFLY-4333:
-------------------------------------------

When is a EJB bean stateless? 

"A stateless session bean does not maintain a conversational state with the client. When a client invokes the methods of a stateless bean, the bean’s instance variables may contain a state specific to that client but only for the duration of the invocation. When the method is finished, the client-specific state should not be retained. 

Clients may, however, change the state of instance variables in pooled stateless beans, and this state is held over to the next invocation of the pooled stateless bean. Except during method invocation, all instances of a stateless bean are equivalent, allowing the EJB container to assign an instance to any client. That is, the state of a stateless session bean should apply across all clients."

This EJB holds a reference to an Entity bean across invocations. Is it really a SLSB?
 

> Transaction must be sticky to ensure consistency for EJB remote invocation with JPA
> -----------------------------------------------------------------------------------
>
>                 Key: WFLY-4333
>                 URL: https://issues.jboss.org/browse/WFLY-4333
>             Project: WildFly
>          Issue Type: Bug
>          Components: EJB
>            Reporter: Wolf-Dieter Fink
>            Assignee: Tomasz Adamski
>            Priority: Critical
>              Labels: ejb, transaction
>
> If an application inside of a server uses standard JavaEE persistence JPA, the current implementation include a local 1. level cache which might end in inconsistent reads within the same (uncommited) transaction.
> There are two reasons
> - JPA must not flush changes to an entity until commit
> - The 1. level cache might not read from the persistence if the entity is already loaded in a transaction
> Therefore the server to server invocations of EJB's need to be sticky to one node during a transaction. The granularity must be the application.
> It might be worth to use already known nodes for other applications as well.
> The stickyness should be enabled automatically if a transaction is active and distributed, which is the default within the current implementation, and use the loadbalancing policy if no transaction is active.



--
This message was sent by Atlassian JIRA
(v6.3.15#6346)