Hi Erwin my examples all use Connection pools and are even XA enabled.
The trick is to use pax- jdbc for this.
See
https://ops4j1.jira.com/wiki/display/PAXJDBC/Pooling+and+XA+support+for+DataSourceFactory
https://ops4j1.jira.com/wiki/display/PAXJDBC/Create+DataSource+from+config
You just have to install pax-jdbc-mysql, pax-jdbc-config,
pax-jdbc-pool-dbcp2, transaction
Then you create a config like described in the docs and you will get a
DataSource with pooling and XA support.
Christian
On 24.07.2016 22:50, Erwin Hogeweg wrote:
Hi,
Not sure if this is a question for these lists or for the EL list but
I figure I start here. Feel free to redirect when you feel it doesn’t
belong here.
I am trying to get a non-jta connection pool (internal connection
pool) working with EL 2.6.2, Aries 2.4.0 (incl. EL adapter), dbcp2-2.1
and mySQL, but I must be missing something because I just can’t get it
to work properly. Everything works just fine w/o a connection pool, so
this is definitely the source of the misery.
Been struggling with this for a while now, and I am running out of
ideas. I think I could use some sample code to point me in the right
direction that doesn't use Blueprint? I found some of Christian’s
examples, but I don’t think they are using connection pools.
Below a short summary of what I run into.
When I am using the ‘original’ MysqlDataSource...
private DataSource createMySQLDataSource( Dictionary<String,
String> dbConnProps ) {
MysqlDataSource ds = new MysqlDataSource();
ds.setUrl( dbConnProps.get( "jdbc_url" ) );
ds.setUser( dbConnProps.get( "jdbc_user" ) );
ds.setPassword( dbConnProps.get( "jdbc_password" ) );
return ds;
}
… everything kinda works normally. The DataSource, PersistenceProvider
and EntityManagerFactory are all created and registered correctly;
g! services javax.sql.DataSource
{javax.sql.DataSource}={eclipselink.target-database=MySQL,
osgi.jndi.service.name=jdbc/mynonjta, service.id=139,
service.bundleid=104, service.scope=singleton}
"Registered by bundle:"
com.my.project.persistence.mysqldatasource_4.0.0.SNAPSHOT [104]
g! services javax.persistence.EntityManagerFactory
{javax.persistence.EntityManagerFactory}={osgi.unit.version=4.0.0.SNAPSHOT,
osgi.unit.name=my.pu,
osgi.unit.provider=org.eclipse.persistence.jpa.PersistenceProvider,
service.id=142, service.bundleid=98, service.scope=singleton}
"Registered by bundle:" com.my.project.model_4.0.0.SNAPSHOT [98]
The performance is horrible though as I don’t really seem to get a
connection pool. The connection is closed after every query. On top of
that I loose all network connections every few seconds with a:
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException:
Communications link failure
Which has me puzzled for a while now.
So my next attempt was to use the
org.apache.commons.dbcp2.BasicDataSource:
private DataSource createMySQLDataSource( Dictionary<String,
String> dbConnProps ) {
BasicDataSource basicDataSource = new BasicDataSource();
basicDataSource.setDriverClassName("com.mysql.jdbc.Driver");
...
return basicDataSource;
}
This fails because the following exception:
[EL Severe]: 2016-07-24
14:41:55.872--java.lang.UnsupportedOperationException: Not supported
by BasicDataSource
at
org.apache.commons.dbcp2.BasicDataSource.getConnection(BasicDataSource.java:1552)
Which is this method:
@Override
public Connection getConnection(String user, String pass) throws
SQLException {
// This method isn't supported by the PoolingDataSource
returned by
// the createDataSource
throw new UnsupportedOperationException("Not supported by
BasicDataSource");
}
So I figured I create a version with a PoolingDataSource (following
the PoolingDataSourceExample in svn):
ConnectionFactory connectionFactory = new
DriverManagerConnectionFactory(dbConnProps.get( "jdbc_url" ), "user",
"password");
PoolableConnectionFactory poolableConnectionFactory = new
PoolableConnectionFactory(connectionFactory, null);
ObjectPool<PoolableConnection> connectionPool = new
GenericObjectPool<>(poolableConnectionFactory);
poolableConnectionFactory.setPool(connectionPool);
PoolingDataSource<PoolableConnection> dataSource = new
PoolingDataSource<>(connectionPool);
return dataSource;
But that still gives me an exception:
[EL Severe]: 2016-07-24
16:40:30.392--java.lang.UnsupportedOperationException
at
org.apache.commons.dbcp2.PoolingDataSource.getConnection(PoolingDataSource.java:156)
So I am kinda lost now.
This is the relevant stuff from the persistence.xml file:
<non-jta-data-source>osgi:service/javax.sql.DataSource/(osgi.jndi.service.name=jdbc/mynonjta)</non-jta-data-source>
<property name="javax.persistence.jdbc.driver"
value="com.mysql.jdbc.Driver" />
<property name="javax.persistence.jdbc.url"
value="jdbc:mysql://my_db_server:3306/myschema" />
<property name="javax.persistence.jdbc.user" value="user" />
<property name="javax.persistence.jdbc.password" value="password" />
<!-- Configure connection pool. -->
<property name="eclipselink.connection-pool.default.initial"
value="10" />
<property name="eclipselink.connection-pool.default.min" value="16" />
<property name="eclipselink.connection-pool.default.max" value="50" />
Although I only see one DataSource registered it somehow feels like
there is some more stuff going on behind the (EL?) scenes that I don’t
have a handle on yet.
BTW... I have also created an org.apache.aries.jpa.my.pu.cfg
configuration file, but when I leave the DB properties out of the
persistence.xml I get bunch of ClassNotFound exceptions, so that is
suspicious.
BTW2… the examples link at the bottom of this page is broken:
https://commons.apache.org/proper/commons-dbcp/
Regards,
Erwin
--
Christian Schneider
http://www.liquid-reality.de
Open Source Architect
http://www.talend.com
