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Home » Eclipse Projects » EclipseLink » [SOLVED] For each call a new connection? Need only one when using RCP with Gemini or Swing
[SOLVED] For each call a new connection? Need only one when using RCP with Gemini or Swing [message #1243812] Tue, 11 February 2014 08:27 Go to next message
Jack Kilian is currently offline Jack Kilian
Messages: 36
Registered: March 2012
Member
[EL Fine]: sql: 2014-02-11 14:19:32.238--ServerSession(32763213)--Connection(12471488)--Thread(Thread[main,6,main])-- SELECT ... FROM ... WHERE ...
bind => [138]
[EL Fine]: sql: 2014-02-11 14:19:32.261--ServerSession(32763213)--Connection(21809008)--Thread(Thread[main,6,main])-- SELECT ... FROM ... WHERE ...
[EL Fine]: sql: 2014-02-11 14:19:32.287--ServerSession(32763213)--Connection(14435067)--Thread(Thread[main,6,main])-- SELECT ... FROM ... WHERE ...
[EL Fine]: sql: 2014-02-11 14:19:32.31--ServerSession(32763213)--Connection(11986356)--Thread(Thread[main,6,main]) -- SELECT ... FROM ... WHERE ...
[EL Fine]: sql: 2014-02-11 14:19:32.336--ServerSession(32763213)--Connection(27439281)--Thread(Thread[main,6,main])-- SELECT ... FROM ... WHERE ...
[EL Info]: 2014-02-11 14:19:32.351--ServerSession(32763213)--Thread(Thread[main,6,main])--Communication failure detected when attempting to perform read query outside of a transaction. Attempting to retry query. Error was: Exception [EclipseLink-4002] (Eclipse Persistence Services - 2.5.1.v20130824-981335c): org.eclipse.persistence.exceptions.DatabaseException
Internal Exception: java.sql.SQLException: Listener refused the connection with the following error:
ORA-12519, TNS:no appropriate service handler found
The Connection descriptor used by the client was:
oracle:1234:XE

persistence.xml:
<properties>
<property name="eclipselink.jdbc.native-sql" value="false"/>
<property name="javax.persistence.jdbc.url" value="jdbc:oracle:thin:@server:1234:XE"/>
<property name="javax.persistence.jdbc.user" value="user"/>
<property name="javax.persistence.jdbc.password" value="password"/>
<property name="javax.persistence.jdbc.driver" value="oracle.jdbc.OracleDriver"/>

<property name="eclipselink.weaving" value="true"/>
<property name="eclipselink.weaving.internal" value="true"/>
<property name="eclipselink.logging.level" value="FINE" />
</properties>


For each call a new connection is opened. I think anytime the amount of maximum connections is fully reached, then an error is raised. How can I configure that in the case I use EclipseLink in RCP or Swing only one or two connections a used and not changed for each call.

[Updated on: Wed, 12 February 2014 01:54]

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Re: For each call a new connection? Need only one when using RCP with Gemini or Swing [message #1243982 is a reply to message #1243812] Tue, 11 February 2014 13:42 Go to previous messageGo to next message
Chris Delahunt is currently offline Chris Delahunt
Messages: 1018
Registered: July 2009
Senior Member
As per http://www.eclipse.org/eclipselink/documentation/2.4/concepts/data_access006.htm
EclipseLink will pool connections by default. Judging by the timestamp though, your application might not be done with the query before another connection is needed.

The settings for connection pools are configurable and somewhat described here:
http://eclipse.org/eclipselink/documentation/2.4/jpa/extensions/p_connection_pool.htm
You will want to set the max connection number to match what your server is configured to allow, and remember that there is both a read and write connection pool.
[SOLVED] For each call a new connection? Need only one when using RCP with Gemini JPA [message #1244320 is a reply to message #1243982] Wed, 12 February 2014 01:54 Go to previous message
Jack Kilian is currently offline Jack Kilian
Messages: 36
Registered: March 2012
Member
thx for your answer.

but the problem was deeper. i found a bug-report regarding Gemini JPA I use in my project. since eclipse link 2.5.1 there is a bugfix regarding my problem. when I use that property the connection is not changed for each db call.

see https://bugs.eclipse.org/bugs/show_bug.cgi?id=379397

<properties>
[...]
<property name="eclipselink.connection-pool.force-internal-pool" value="true"/>
[...]
</properties>




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