public List<String> getSkewedColumnNames(String alias) {
    List<String> skewedColNames = null;
    if (null != qbm &&
        null != qbm.getAliasToTable() &&
            qbm.getAliasToTable().size() > 0) {
      Table tbl = getMetaData().getTableForAlias(alias);
      skewedColNames = tbl.getSkewedColNames();
    }
    return skewedColNames;

  }
Retrieve skewed column name for a table.
@param alias table alias
@return
ql/src/java/org/apache/hadoop/hive/ql/parse/QB.java