Re: JDBC PostgreSQL Stored Procedure Meta-data

Hello,

I have an issue with retrieving meta-data for Stored Procedures using the JDBC driver.
I have outlined the details of my issue here: http://stackoverflow.com/questions/21541745/postgresql-9-jdbc-driver-returns-incorrect-metadata-for-stored-procedures#

Essentially I have this example stored procedure:

CREATE FUNCTION testproc(itemid int)
RETURNS TABLE(id int, name varchar(200)) AS $$
BEGIN
    RETURN QUERY SELECT ipperson, firstname FROM testtable
                 WHERE id = itemid;
END;
$$ LANGUAGE plpgsql;

And I want to get the meta-data for this query using the JDBC DatabaseMetaData.

I have written a Java test case, it prints out the parameters returned by the meta-data call:

package com.hof.unittest;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;

public class TestPostgres {

    public static void main(String args[]) {

        try {

            Class.forName("org.postgresql.Driver");

            Connection conn = DriverManager.getConnection("jdbc:postgresql://localhost:5432/testdb", "admin", "admin");

            ResultSet rs = conn.getMetaData().getProcedureColumns(null, null, "testproc", null);

            System.out.println("Driver: " + conn.getMetaData().getDriverVersion());

            while (rs.next()) {

                System.out.println("Parameter Name: " + rs.getString(4) + " Paramter Type: " + rs.getShort(5) + " Data Type: " + rs.getInt(6));

            }

        } catch (Exception e) {
            e.printStackTrace();
        }

    }

}


I get different results with different JDBC drivers (against the same 9.1.11 server):

Driver: PostgreSQL 8.0 JDBC3 with SSL (build 313)
Parameter Name: returnValue Paramter Type: 5 Data Type: 1111
Parameter Name: $1 Paramter Type: 1 Data Type: 4

Driver: PostgreSQL 9.0 JDBC4 (build 801)
Parameter Name: itemid Paramter Type: 1 Data Type: 4
Parameter Name: id Paramter Type: 1 Data Type: 4
Parameter Name: name Paramter Type: 1 Data Type: 12

Driver: PostgreSQL 9.3 JDBC4 (build 1100)
Parameter Name: itemid Paramter Type: 1 Data Type: 4
Parameter Name: id Paramter Type: 1 Data Type: 4
Parameter Name: name Paramter Type: 1 Data Type: 12


The 8.0 driver returns meta-data in a form I can use.. it says there is one IN parameter and one OUT parameter (the resultset).

The 9.0/3 drivers don't return an OUT parameter, and along with the single IN parameter, the columns returned by the resultset are also listed, and listed as a IN parameter.

Are the 9 drivers returning the wrong meta-data?
Was there change in how procedures were handled between JDBC3 and JDBC4?

I need to get meta-data about just the IN parameters for a procedure as I need to dynamically prompt for input values and build the execution string.. ie SELECT * FROM procedure(?) OR { ? = procedure(?) }

Is there any other way to get this information... querying system tables etc?

Thanks.