public static long sumOfExcept(Map<String, Long> aliasToSize,
      Set<String> aliases, Set<String> excepts) {
    long total = 0;
    for (String alias : aliases) {
      if (excepts != null && excepts.contains(alias)) {
        continue;
      }
      Long size = aliasToSize.get(alias);
      if (size == null) {
        return -1;
      }
      total += size;
    }
    return total;
  }
Performs a ContentSummary lookup over a set of paths using 1 or more
threads. The 'summary' argument is directly modified.

@param ctx
@param pathNeedProcess
@param work
@param summary
@param executor
@throws IOException
ql/src/java/org/apache/hadoop/hive/ql/exec/Utilities.java