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Top K statistics are gathered along with partition level statistics. The interface IStatsAggregator needs to add a method aggregateStatsTopK() that reads multiple entries from the temporary storage:

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public interface IStatsAggregator {

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  /**
 * This method aggregates top K statistics.
   *
 * */
  public List<String> aggregateStatsTopK(String keyPrefix, String statType);

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}

Usage

Top K statistics are not enabled by default. The user can set the boolean variable hive.stats.topk.collect to be true to enable computing top K and putting top K into skewed information.

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