Hello All, Link to question and discussion:
http://stackoverflow.com/questions/36920695/hibernate-and-transaction-using-method-annotation Below i have pasted whats in the link: Help/suggestion/advise/data points is really appreciated. Thanks in Advance: ------------------------------------------ Firstly, I have given few data points. Next will be the problem described. ------------------------------ *DATA POINTS:* *[D1]* In Hibernate and Annotation and managed objects world, what i have seen a common pattern like @Transactionalpublic void createStuff(..){// get entity manager and call persist and other operatation}@Transactionalpublic SomeDtoObject getStuff(..){// get entity manager and call find and getter to polulate a object to return} In managed beans the Hibernate transaction is started and commited when we call this methods. Hibernate doc says (link <https://docs.jboss.org/hibernate/orm/3.5/reference/en/html/transactions.html> ): The most common pattern in a multi-user client/server application is session-per-request. *[D2]* Also it is advised that connection to database should be pooled using connection pool library C3P0 as stated on postgres documentation (link <https://jdbc.postgresql.org/documentation/91/thread.html>): Pg will usually complete the same 10,000 transactions faster by doing them 5, 10 or 20 at a time than by doing them 500 at a time. *[D3]* Also with JDBC *Given a single connection we can run one transaction at a time and as many statement as we like within that transaction.Its upto the application(C3P0) to make sure that two different thread executing two different transactional method should not use same connection and one should wait before calling the other method .* ------------------------------ *Problem:* Now if we use the managed bean transaction pattern using annotation along with a connection pool(*Let say only with 1 connection*) with hibernate and session-per-request Also let say the code is something like @Transactionalpublic SomeDtoObject getStuff(..){// get entity manager and call find and getter to polulate a object to returnSomeEntity se = entityManager.find(someentity, primaryKey);//create Dtos// access someEntity to all over this method to create SomeDtoObject that we have to return.// also may access some file on system to fetch some data is order to populate someDtoObject.// overall let say the method take 150 milli second to do all its work} Now imagine there are two different thread(T1, T2) called for getStuff(...) T1 will enter the method and will acquire jdbc connection from connection pool. And when T2 will reach entityManager.find the C3P0 will check that there is no connection left it will put T2 on hold till T1 complete the execution which will take around 150 milli second. Ideally, Given that getStuff(...) is going to do read only querys, both thread can use same connection and dont hold thread from executing queries. In above case we are keep that connection idle and also keeping the thread to wait. *MAIN QUESTION* *Is there a way i can say to hibernate that a particular hibernate transaction is readonly and hibernate can then reuse an already acquired connection instead of asking for a new connection from the connection pool ?* ------------------------------ *Few solution found/suggested:(not convincing)* 1 <https://docs.jboss.org/hibernate/orm/3.5/reference/en/html/transactions.html> If you are so much worried, dont use transaction using annotation, use hibernate session yourself..... no i like that pattern :) 2 <https://jdbc.postgresql.org/documentation/91/thread.html> Hibernate provide a ConnectionReleaselink <https://docs.jboss.org/hibernate/orm/3.5/reference/en/html/transactions.html#transactions-connection-release> option which can be set to after_statement. *First* Hibernate C3P0 connection pool provider does not support after_statement. *Second* it will be a overhead just release and reacquire a connection. _______________________________________________ hibernate-dev mailing list hibernate-dev@lists.jboss.org https://lists.jboss.org/mailman/listinfo/hibernate-dev
