private Set<String> getBigTables(ParseContext joinCtx) {
    Set<String> bigTables = new HashSet<String>();

    for (JoinOperator joinOp : joinCtx.getJoinOps()) {
      if (joinOp.getConf().getStreamAliases() != null) {
        bigTables.addAll(joinOp.getConf().getStreamAliases());
      }
    }

    return bigTables;
  }
Find all big tables from STREAMTABLE hints.

@param joinCtx
         The join context
@return Set of all big tables
ql/src/java/org/apache/hadoop/hive/ql/optimizer/JoinReorder.java