@Override
  @Explain(displayName = "filter mappings", explainLevels = { Level.EXTENDED })
  @Signature
  public Map<Integer, String> getFilterMapString() {
    return toCompactString(filterMap);
  }
@param dumpFilePrefix
         the dumpFilePrefix to set
ql/src/java/org/apache/hadoop/hive/ql/plan/HashTableSinkDesc.java