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Re: [eclipselink-users] JDBC connection, transaction and EntityManager...
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Well its complicated.
If you are using a JTA EntityManager with a JTA
Connection/DataSource/connection pool, then each JTA transaction will use a
single JDBC connection and Oracle session. A JTA JDBC Connection returned
from a JTA DataSource will use a different Oracle session for each JTA
transaction.
If you are not using JTA, then in EclipseLink the EntityManager will have a
read and a write connection pool. The read connection pool will be used for
any read, until the first write is triggered in the EntityManager
transaction context (such as a flush(), or update-all, native-SQL query,
etc.). Then a single JDBC connection (and Oracle session) from the write
connection pool will be used for the duration of the EntityManager
transaction.
You can also force the EntityManager to always use a single write connection
by setting the "eclipselink.jdbc.exclusive-connection.mode"="Always"
persistence or EntityManager property.
You can also use a read connection pool in JTA by setting the
non-jta-datasource property.
markus hahn wrote:
>
>
> Hi,
> Two short questions referring to relation between connection, transaction
> and EntityManager and DB session:
>
> does the JDBC connection stay the same during one transaction started by a
> EntityManager? And does a JDBC connection always operate on one DB session
> (on Oracle Database)?
> Thanks in advance, Markus
>
>
>
>
-----
http://wiki.eclipse.org/User:James.sutherland.oracle.com James Sutherland
http://www.eclipse.org/eclipselink/
EclipseLink , http://www.oracle.com/technology/products/ias/toplink/
TopLink
Wiki: http://wiki.eclipse.org/EclipseLink EclipseLink ,
http://wiki.oracle.com/page/TopLink TopLink
Forums: http://forums.oracle.com/forums/forum.jspa?forumID=48 TopLink ,
http://www.nabble.com/EclipseLink-f26430.html EclipseLink
Book: http://en.wikibooks.org/wiki/Java_Persistence Java Persistence
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