Re: "This ResultSet is closed" exception on a PreparedStatement getMetaData()

Emmanuel,

The assumption that the spec makes about the prepared statement being
compiled are not valid for PostgreSQL. The metadata comes from the result
set, not from the statement. You could in fact not call getMetaData on a
statement which was not executed.

That being said, do you know if this behaviour is consistent with previous
versions of the JDBC driver ?

Dave Cramer

dave.cramer(at)credativ(dot)ca
http://www.credativ.ca

On Thu, Dec 19, 2013 at 4:33 AM, Emmanuel GUITON <
Emmanuel(dot)GUITON(at)intrinsec(dot)com> wrote:

> Hello,
>
> I ran into troubles fetching metadata on a PreparedStatement. After some
> time, I isolated a simple test case that shows the issue (see the code
> snippet below). On a brand new PreparedStatement, I call the getMetaData()
> method without any problem. However, if I execute the query
> (executeQuery()) on this same statement, close the ResultSet and then calls
> again
> getMetaData() (still on the same PreparedStatement), getMetaData() throws
> a RuntimeException saying "This ResultSet is closed".
> I would expect to be able to get the metadata. Is that a bug in the JDBC
> driver ?
>
> I tested this behavior on several flavours of the 9.3 driver version,
> including 9.3-1100-jdbc4 .
>
> Regards,
> - Emmanuel
>
>
> package test;
>
> import java.sql.Connection;
> import java.sql.DriverManager;
> import java.sql.PreparedStatement;
> import java.sql.ResultSet;
> import java.sql.ResultSetMetaData;
> import java.sql.SQLException;
> import junit.framework.Assert;
> import org.testng.annotations.Test;
>
> /**
> * Test on the PostgreSql JDBC driver.
> */
> public class JdbcTest
> {
> /**
> * This test shows a driver issue on the PreparedStatement management.
> *
> * @throws ClassNotFoundException On driver initialization failure.
> * @throws SQLException On datbase operation failure.
> */
> @Test
> public void test2()
> throws SQLException, ClassNotFoundException
> {
> Class.forName("org.postgresql.Driver");
> final Connection connection =
> DriverManager.getConnection("jdbc:postgresql://server/db_name", "username",
> "password");
>
> final String query = "SELECT 1 AS toto, 2 AS titi";
>
> final PreparedStatement pstmt = connection.prepareStatement(query);
> final ResultSetMetaData rsMetadata = pstmt.getMetaData();
> Assert.assertNotNull(rsMetadata);
>
> final ResultSetMetaData rsMetadata2 = pstmt.getMetaData();
> Assert.assertNotNull(rsMetadata2);
>
> final ResultSet rs = pstmt.executeQuery();
> Assert.assertNotNull(rs);
> rs.close();
>
> Assert.assertFalse(pstmt.isClosed());
> try
> {
> // Guess what ? The next line throws an exception !
> final ResultSetMetaData rsMetadata3 = pstmt.getMetaData();
> Assert.assertNotNull(rsMetadata3);
> }
> catch (final RuntimeException exception)
> {
> Assert.fail(exception.getMessage());
> }
> pstmt.close();
>
> connection.close();
> }
> }
>
>
>
>
> *Emmanuel GUITON*
>
> *Ingénieur Développement *
> Fixe : +33170928416 l Standard : +33141917777
>
> 215, avenue Georges Clemenceau l 92024 Nanterre
>
> <http://http://www.forum-fic.com/2014/fr/inscription-fic/>
> <http://www.intrinsec.com/>
>
>
>
>