Re: Tomcat JDBC Connection Pool interfaces to PostgreSQL...

it would appear that tomcat is not returning the PgConnection object.

I just wrote this as a test:

public void testConnectionUnwrapPGDataSource() throws SQLException {
PGSimpleDataSource dataSource = new PGSimpleDataSource();
assertNotNull(dataSource);
dataSource.setDatabaseName("test");
dataSource.setServerName("localhost");
dataSource.setPortNumber(5432);
Connection connection = dataSource.getConnection("test","test");
assertNotNull(connection);
Object v=connection.unwrap(PGConnection.class);
assertNotNull(v);
assertTrue(v instanceof PGConnection);

}

and it works fine.

Dave Cramer

davec(at)postgresintl(dot)com
www.postgresintl.com

On 17 May 2016 at 14:40, Eric Neron <eneron(at)e-djuster(dot)ca> wrote:

> I am currently working using the Tomcat JDBC Connection Pool (
> http://tomcat.apache.org/tomcat-7.0-doc/jdbc-pool.html) which we plan to
> use in our Java Web application in order to streamline server resources
> usage associated to supporting our PostgreSQL connections (i.e., minimize
> the number or connections required).
>
> I am using the following jar files to support my work:
>
> tomcat-jdbc.jar
> postgresql-9.4.1208.jre7.jar
>
> Although most of it seems to be working fine so far, I am hitting issues
> when I try to "cast" the connection the pool is returning to me (a
> ProxyConnection) into either a PGConnection or BaseConnection. I need
> those in order to access either of the following PostgreSQL
> "advanced/internal" methods:
>
> - addDataType () (PGConnection)
> - CopyManager () (BaseConnection).
>
> The Tomcat documentation suggests to extract the native connection by
> using the following method:
>
> Connection pgConnection = ((javax.sql.PooledConnection) conn).
> getConnection ( );
>
> Although this does not fail, using a debugger, I can see that pgConnection
> is really an
> org.postgresql.jdbc.PgConnection (not an org.postgresql.PGConnection),
> and there is not way it seems that I can bridge between the two... even by
> using:
>
> pgConnection.unwrap ( PGConnection.class );
>
> I am just wondering if this issue is caused by the fact that I use the
>
> org.apache.tomcat.jdbc.pool.DataSource to instantiate my Connection Pool.
>
> Browsing through the list of choice given to me to determine where
> the DataSource class is imported in my Java code, I can see:
>
> javax.sql.DataSource (which I have seen can give one access to
> PGConnection from one of my research on the Web - http://stackoverflow
> .com/questions/27898632/how-to-cast-jdbc4connection-to-pgconnection),
> though if I select it, it tells me that this is an abstract Class that I
> cannot instantiate from!
>
> Similarly, another StackOverlflow page (http://stackoverflow
> .com/questions/36986653/cast-java-sql-connection-to-pgconnection)
> suggests using the following code:
>
> PGConnection pgConnection = dataSource.getConnection().unwrap(PGConnection.class);
>
> but again, if I try this, I get the following SQLException: "Not a wrapper of org.postgresql.PGConnection"
>
> (in fact, it turns out that this is exactly the same solution as the "Tomcat solution" I explained above).
>
> I am running out of alternatives... Any ideas?
>
>
>
>
>
>
>