#1262 PostgreSQL metadata read fix (Generic driver)

plugins/org.jkiss.dbeaver.ext.postgresql/src/org/jkiss/dbeaver/ext/postgresql/model/jdbc/PostgreResultSetMetaDataImpl.java

@@ -17,6 +17,7 @@
 package org.jkiss.dbeaver.ext.postgresql.model.jdbc;
 
 import org.jkiss.dbeaver.ext.postgresql.model.PostgreDataSource;
+import org.jkiss.dbeaver.model.DBPDataSource;
 import org.jkiss.dbeaver.model.exec.jdbc.JDBCResultSet;
 import org.jkiss.dbeaver.model.impl.jdbc.JDBCUtils;
 import org.jkiss.dbeaver.model.impl.jdbc.exec.JDBCResultSetMetaDataImpl;
@@ -39,7 +40,11 @@ public class PostgreResultSetMetaDataImpl extends JDBCResultSetMetaDataImpl
      */
     @Override
     public String getCatalogName(int column) throws SQLException {
-        return ((PostgreDataSource)resultSet.getSession().getDataSource()).getDefaultInstance().getName();
+        DBPDataSource dataSource = resultSet.getSession().getDataSource();
+        if (dataSource instanceof PostgreDataSource) {
+            return ((PostgreDataSource)dataSource).getDefaultInstance().getName();
+        }
+        return null;
     }
 
     @Override