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From Rick Curtis <curti...@gmail.com>
Subject Re: relationship EntityManager and JDBC Connection?
Date Mon, 28 Sep 2009 14:18:24 GMT

http://commons.apache.org/dbcp/configuration.html


Jean-Baptiste BRIAUD -- Novlog wrote:
> 
> 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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