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From "Pinaki Poddar (JIRA)" <j...@apache.org>
Subject [jira] Commented: (OPENJPA-1604) Setting PessimisticLockManager fails to append "for update clause" to the select statement
Date Wed, 31 Mar 2010 16:33:27 GMT

    [ https://issues.apache.org/jira/browse/OPENJPA-1604?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12851933#action_12851933
] 

Pinaki Poddar commented on OPENJPA-1604:
----------------------------------------

The setting of lock modes based on current lock manager seems to be ambiguous at few places
both in usage and in design/code.

>From a usage point of view, 
  a) setting a specific lock manager be it pessimistic or optimistic should impose a specific
default read and write lock level for all queries. 
  b) that default level can be overwritten by 
       i) setting query.setLockMode()
      ii) setting lockMode attribute of @NamedQuery
     iii) setting query hints
      iv) passing lock properties in find() etc.

  c) the semantics of a joint specification such as 
        <property name="openjpa.LockManager" value="pessimistic"/>
        <property name="openjpa.Optimistc" value="true"/>
      also appears confusing/contradictory. We should either detect specification that are
contradictory or clarify what such apparently contradictory specifications imply.

>From a design/code point of view,
   a) setting a FetchPlan.Lock hint during annotation parsing does not look good to me. We
have reasonable data structures to capture meta information on a query and that seems to be
the right place for lock information rather than a fetch plan hint.
   b) the default read/write lock levels should be dictated by the currently active lock manager.
LockManager.beginTransaction() seems to be one correct place to populate the fetch configuration
with these levels. Outside transaction, fetch plan initialization should take current Lock
Manager into consideration to set its read/write lock levels.
   c) OpenJPAConfiguration should impose consistency between LockManager and setOptimistic()

  


> Setting PessimisticLockManager fails to append "for update clause" to the select statement
> ------------------------------------------------------------------------------------------
>
>                 Key: OPENJPA-1604
>                 URL: https://issues.apache.org/jira/browse/OPENJPA-1604
>             Project: OpenJPA
>          Issue Type: Bug
>    Affects Versions: 2.1.0
>            Reporter: Fay Wang
>
>  I ran a testcase against openjpa 1.2, and found that the "for update" clause is appended
to the SQL when
>  		<property name="openjpa.LockManager" value="pessimistic"/>
> 	is added to the persistence.xml without calling: 
> 		 q.setLockMode(LockModeType.PESSIMISTIC_WRITE);
> However, this behavior changes when running against trunk level code

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