[jira] [Updated] (AMBARI-2142) Unecessary use of @Transactional on all DAO methods

["Siddharth Wagle (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/AMBARI-2142?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Siddharth Wagle updated AMBARI-2142:
------------------------------------

    Attachment: AMBARI-2142.patch
    
> Unecessary use of @Transactional on all DAO methods
> ---------------------------------------------------
>
>                 Key: AMBARI-2142
>                 URL: https://issues.apache.org/jira/browse/AMBARI-2142
>             Project: Ambari
>          Issue Type: Bug
>          Components: controller
>    Affects Versions: 1.3.0
>            Reporter: Siddharth Wagle
>            Assignee: Siddharth Wagle
>             Fix For: 1.3.0
>
>         Attachments: AMBARI-2142.patch
>
>
> Most of the DAO objects in Ambari are annotated with @Transactional.  (see org.apache.ambari.server.orm.dao.HostRoleCommandDAO).
> {quote}
>  Any method or class marked with this annotation will be considered for transactionality. Consult the documentation on http://code.google.com/p/google-guice for detailed semantics. Marking a method @Transactional will start a new transaction before the method executes and commit it after the method returns.
> If the method throws an exception, the transaction will be rolled back unless you have specifically requested not to in the #ignore() clause.
> Similarly, the set of exceptions that will trigger a rollback can be defined in the #rollbackOn() clause. By default, only unchecked exceptions trigger a rollback.
> {quote}
> I think that marking simple getter methods as transactional may be introducing unnecessary overhead.  I don't think that a non-mutating method that does not require read consistency needs to be marked transactional.
> Profiling a service start on a 200 node cluster shows that about 1/3 of the time is spent in almost 3000 JDBC commit() and over 1400 setAutoCommit() calls. 

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