Atomikos Forum

Hi, Guy.

1) What is the JTA overhead for JDBC/JMS XA transaction for TransactionEssentials in average percentage terms?

2) Some methods in application use both JDBC/JMS - one database and one ActiveMQ. Others use the same transaction manager, but only use one JDBC data source. In this case does your software detect it needs to fall back on simple JDBC transaction and forgo XA?

Additionally, what do you think about Postgres. From reading some forums it seems that Postgres people think they do support two-phase commit, while others think their support is inadequate (I think it has to do with ability to have different XA transactions using same connection; Postgres seems to always require one connection per one XA transaction?)

Thank you for your comprehensive reply. This is my first time using Atomikos, and so far so good.

Hi,

Re 1): depends largely on the hard disk, but on my machine 25% is usual.

Re 2): 1PC optimisation is there, except if you use Synchronization callbacks (like Hibernate does). In that case, things can be more delicate.

For Postgresql: we are in close contact with their professional support to make sure XA is supported soon enough. More on this later in an official announcement...

HTH

Guy, how can I maintain the atomicity but turn off logging? Do I lose just crash recoverability in this case, or something else?

Hi,

By setting com.atomikos.icatch.enable_logging - see http://www.atomikos.com/Documentation/JtaProperties

You lose recoverability in that case...

HTH

So, and last question:

I am using JPA and Hibernate. So "Synchronization Callbacks", whatever that means. How and in what situations does Atomikos fail to optimize if I am using just ona JDBC data source?

Thanks for your time!

AFAIK Hibernate will use the Synchronization callbacks to flush cache state to the DBMS before commit.

We are improving this for the future but for now this will incur 2PC overhead.

HTH