Hive索引Demo

一、创建表

CREATE TABLE employees (  
  name         STRING,  
  salary       FLOAT,  
  subordinates ARRAY<STRING>,  
  deductions   MAP<STRING, FLOAT>,  
  address      STRUCT<street:STRING, city:STRING, state:STRING, zip:INT>  
)  
PARTITIONED BY (country STRING, state STRING); 

二、创建PATITION：country索引

CREATE INDEX employees_index  
ON TABLE employees (country)  
AS 'org.apache.hadoop.hive.ql.index.compact.CompactIndexHandler'  
WITH DEFERRED REBUILD  
IDXPROPERTIES ('creator = 'me', 'created_at' = 'some_time')  
IN TABLE employees_index_table  
PARTITIONED BY (country, name)  
COMMENT 'Employees indexed by country and name.'; 

三、Bitmap Indexes

Hive从0.8.0版本开始，增加了built-in bitmap作为索引处理器。

bitmap一般用在列值含有比较少的distinct value，也就是说列值的相同数据比较多的情景。

CREATE INDEX employees_index  
ON TABLE employees (country)  
AS 'BITMAP'  
WITH DEFERRED REBUILD  
IDXPROPERTIES ('creator = 'me', 'created_at' = 'some_time')  
IN TABLE employees_index_table  
PARTITIONED BY (country, name)  
COMMENT 'Employees indexed by country and name.';

rebulid 索引

ALTER INDEX employees_index  
ON TABLE employees  
PARTITION (country = 'US')  
REBUILD;  

查看索引信息

SHOW FORMATTED INDEX ON employees;  

删除索引

DROP INDEX IF EXISTS employees_index ON TABLE employees;