Generate and view Apache Hive statistics

You can use statistics to optimize queries for improved performance. The cost-based optimizer (CBO) also uses statistics to compare query plans and choose the best one. By viewing statistics instead of running a query, you can sometimes get answers to your data questions faster.

1. Launch a hive shell and log in.
2. Gather statistics for the non-partitioned table mytable:
   ANALYZE TABLE mytable COMPUTE STATISTICS;
3. Confirm that the hive.stats.autogather property is enabled.
   1. In Ambari, select Services > Hive > Configs.
   2. In Filter, enter hive.stats.autogather.
4. View table statistics you generated:
   DESCRIBE EXTENDED mytable;
5. Gather column statistics for the table:

   ANALYZE TABLE mytable COMPUTE STATISTICS FOR COLUMNS;

6. View column statistics for the name column in my_table in the my_db database:
   DESCRIBE FORMATTED my_db.my_table name;