public static void clearWorkMapForConf(Configuration conf) {
    // Remove cached query plans for the current query only
    Path mapPath = getPlanPath(conf, MAP_PLAN_NAME);
    Path reducePath = getPlanPath(conf, REDUCE_PLAN_NAME);
    if (mapPath != null) {
      gWorkMap.get(conf).remove(mapPath);
    }
    if (reducePath != null) {
      gWorkMap.get(conf).remove(reducePath);
    }
    // TODO: should this also clean merge work?
  }
@param conf
@return the configured VectorizedRowBatchCtx for a MapWork task.
ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java