code: @Override
      protected VoltTable.ColumnInfo getColumnInfo(String columnTypeName, String colName) {
          return super.getColumnInfo(getVoltColumnTypeName(columnTypeName), colName);
      }
docs: Returns a VoltTable.ColumnInfo of appropriate type, based on a
  <i>columnTypeName</i> and <i>colName</i> (both Strings).
  This version checks for column types used only by PostgreSQL,
  and then passes the remaining work to the base class version.