Hi there Radhakrishna,
On 19/05/2014 08:15, Radhakrishna Kalyan wrote:
Hi,
I have question around entityManager.flush().
Is it ok to call multiple times? Or will there be any performance issue.
Every time you hit the the database you will take a performance hit back
- How much is impossible to say and is very dependant on what your app
is doing. Just always think along the lines of 'how can I do this with
less' and you'll be fine.
My case is, I have a timer service which executes periodically where I
create a database entity using a dao object using entityManager.persist(),
after that I also call entityManager.flush().
The reason to do so is, if database commit fails due to certain reason like
unique constrain exception then I want the timer service to send a JMS
message.
What you are doing is not necessarily wrong, but why not just let the
container do the work for you. The container managed transactions are
your friend.
If I don't call entityManager.flush() then I am not able to catch any
exception in my timer service thus fails to send any JMS message.
In your service look up another local bean that handles the persistence
and if required sends a message on success, this will all run in a
transacted context - The success message will only be sent if the bean
method actually completes.
If the bean method call fails then you can catch the error and do the
extra leg work to send the 'fail' message.
However at the end the database entity is never created which is correct.
But if I can't able to send the JMS message upon exception then I does not
meet the requirement.
Any ideas or recommendations to do it in a better way
So I guess my suggestion is to not try and do all the work in the timer
service method, rather call another bean method do do the work.
Andy.
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