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From Jean-Baptiste BRIAUD -- Novlog <j-b.bri...@novlog.com>
Subject Re: relationship EntityManager and JDBC Connection?
Date Mon, 28 Sep 2009 14:12:53 GMT
OK, it works but I'd like to set more options in the persistence.xml  
like the pool size. I didn't find how to set that up. Any link ?

Thanks.

On Sep 28, 2009, at 15:32 , Rick Curtis wrote:

> I'd suggest using DBCP for connection pooling when not running in a  
> JEE
> environment. Checkout this blog post [1] that I wrote about this  
> very issue
> a few months back.
>
> -Rick
>
> [1]
> http://webspherepersistence.blogspot.com/2009/01/jpa-connection-pooling.html
>
> On Mon, Sep 28, 2009 at 3:53 AM, Jean-Baptiste BRIAUD -- Novlog <
> j-b.briaud@novlog.com> wrote:
>
>> OK, so is there a way to have add pool behavior with only JDBC  
>> (without
>> J2EE) ?
>>
>>
>>
>> On Sep 28, 2009, at 05:04 , C N Davies wrote:
>>
>> The doc says:
>>>
>>> "EntityManagerFactory instances are heavyweight objects. Each  
>>> factory
>>> might
>>> maintain a metadata cache, object state
>>> cache, EntityManager pool, connection pool, and more."
>>>
>>> "2.6.3. openjpa.jdbc.DriverDataSource
>>> Property name: openjpa.jdbc.DriverDataSource
>>> Configuration API:
>>> org.apache.openjpa.jdbc.conf.JDBCConfiguration.getDriverDataSource
>>> Resource adaptor config-property: DriverDataSource
>>> Default: pooling"
>>>
>>> "In its default configuration, OpenJPA obtains JDBC connections on  
>>> an
>>> as-needed basis. OpenJPA EntityManagers do not retain
>>> a connection to the database unless they are in a datastore  
>>> transaction or
>>> there are open Query results that are using a live
>>> JDBC result set. At all other times, including during optimistic
>>> transactions, EntityManagers request a connection for each
>>> query, then immediately release the connection back to the pool."
>>>
>>>
>>> -----Original Message-----
>>> From: Christopher Giblin [mailto:CGI@zurich.ibm.com]
>>> Sent: Monday, 28 September 2009 1:11 AM
>>> To: users@openjpa.apache.org
>>> Subject: relationship EntityManager and JDBC Connection?
>>>
>>>
>>> Hi,
>>>
>>> Does an EntityManager instance correspond one-to-one to a JDBC  
>>> connection?
>>> When the EM is closed, is the JDBC connection closed? That is, by  
>>> opening
>>> and closing EMs, is one also opening and closing JDBC connections?
>>>
>>> I am using OpenJPA with Derby. There is no connection pooling:
>>>
>>> <property name="openjpa.ConnectionDriverName" value=
>>> "org.apache.derby.jdbc.ClientDriver"/>
>>>
>>> Sorry if I overlooked in the excellent documentation.
>>>
>>> Thanks,chris
>>>
>>>
>>>
>>


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