Hive严格模式

严格模式

是什么：防止可能出现不好的结果

防止出现三种场景：

1. 分区表查询中没有写where分区过滤条件
2. orderby 中没有写limit
3. 不允许出现笛卡尔积

hive.mapred.mode值为默认是非严格模式nonstrict 。

怎么用：

修改hive.mapred.mode值为strict，

<property>
    <name>hive.mapred.mode</name>
    <value>strict</value>
    <description>
      The mode in which the Hive operations are being performed. 
      In strict mode, some risky queries are not allowed to run. They include:
        Cartesian Product.
        No partition being picked up for a query.
        Comparing bigints and strings.
        Comparing bigints and doubles.
        Orderby without limit.
    </description>
</property>