private String buildPartColStr(Table table) {
    String partColStr = "";
    for (int i = 0; i < table.getPartitionKeysSize(); ++i) {
      if (i != 0) {
        partColStr += ",";
      }
      partColStr += table.getPartitionKeys().get(i).getName();
    }
    return partColStr;
  }
Whether to only update stats that already exist and are out of date.
ql/src/java/org/apache/hadoop/hive/ql/stats/StatsUpdaterThread.java