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  • hive 索引

    hive 有限的支持索引,不支持主键外键,可以对表添加索引,也可以为某个分区添加索引.维护索引也要额外的存储空间和计算资源。

    创建索引需要指定索引处理器 如 as 'org.apache.hadoop.hive.ql.index.compact.CompactIndexHandler'

    in table 用于指定索引存放的表

    hive> create index ix_accid on table account(accid)  as 'org.apache.hadoop.hive.ql.index.compact.CompactIndexHandler' with deferred rebuild in table account_ix_accid;
    OK
    Time taken: 0.458 seconds

    hive> show tables like 'acc.*';
    OK
    tab_name
    account
    account_ix_accid
    Time taken: 0.102 seconds, Fetched: 2 row(s)

    如果指定了deferred rebuild,那么新建的索引就是空的

    hive> select * from account_ix_accid;
    OK
    Time taken: 0.478 seconds

    重建索引,加载索引数据

    hive> alter index ix_accid on account rebuild;

    查看索引

    hive> show index on account;
    OK
    ix_accid                account                 accid                   account_ix_accid        compact            
    Time taken: 0.102 seconds, Fetched: 1 row(s)

    删除索引

    hive> drop index if exists ix_accid on account;
    OK
    Time taken: 3.448 seconds

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  • 原文地址:https://www.cnblogs.com/playforever/p/9667440.html
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