Siddharth Wagle created AMBARI-2142:
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Summary: 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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