Hive编程指南07---索引

Hive索引

创建索引

    CREATE INDEX tableName_index

    ON TABLE <tableName> (col1)

    AS 'org.apache.hadoop.hive.ql.index.compact.CompactIndexHandler'

    WITH DEFERRED REBUILD

    IDXPROPERTIES('creator' = 'me', 'created_at' = 'some_time')

    IN TABLE tableName_index_table //要求索引处理器在一张新表中保留索引数据

    PARTITIONED BY (col1, col2)

    COMMENT '...';

Bitmap索引

    应用于排重后值较少的列

    CREATE INDEX tableName_index

    ON  TABLE <tableName> (col1)

    AS 'BITMAP'

    WITH DEFERRED REBUILD

    IDXPROPERTIES('creator' = 'me', 'created_at' = 'some_time')

    IN TABLE tableName_index_table

    PARTITIONED BY (col1, col2)

    COMMENT '...';

重建索引

    ALTER INDEX tableName_index

    ON  TABLE <tableName> 

    PARTITION (col1 = '')

    REBUILD;

显示索引

    SHOW FORMATTED INDEX ON <table>;

    //FORMATTED，可以使输出中包含有列名称；INDEXS可以列举出多个索引信息

删除索引

    DROP INDEX IF EXISTS tableName_index ON TABLE <table>;

    //如果有索引表，删除一个索引将会删除这个索引表

    //如果被索引的表被删除，其对应的索引和索引表也会被删除；原始表的某个分区被删除，其对应的分区索引也会被删除