@Override
  public String getName() {
    return "COLUMNSTATS UPDATE TASK";
  }
ColumnStatsUpdateTask implementation. For example, ALTER TABLE src_stat
UPDATE STATISTICS for column key SET ('numDVs'='1111','avgColLen'='1.111');
For another example, ALTER TABLE src_stat_part PARTITION(partitionId=100)
UPDATE STATISTICS for column value SET
('maxColLen'='4444','avgColLen'='44.4');
ql/src/java/org/apache/hadoop/hive/ql/exec/ColumnStatsUpdateTask.java