如何在不删除数据的情况下撤消ALTER TABLE ... ADD PARTITION [英] How to undo ALTER TABLE ... ADD PARTITION without deleting data

问题描述

假设我有两个配置单元表， table_1 和 table_2 .我使用:

Let's suppose I have two hive tables, table_1 and table_2. I use:

ALTER TABLE table_2 ADD PARTITION (col=val) LOCATION [table_1_location]

现在， table_2 将在 col = val 的分区中将数据存储在 table_1 中.

Now, table_2 will have the data in table_1 at the partition where col = val.

我想做的就是逆转此过程.我希望 table_2 不在 col = val 上具有分区，并且我希望table_1保留其原始数据.

What I want to do is reverse this process. I want table_2 not to have the partition at col=val, and I want table_1 to keep its original data.

我该怎么做?

推荐答案

首先将表设为EXTERNAL:

Make your table EXTERNAL first:

ALTER TABLE table_2 SET TBLPROPERTIES('EXTERNAL'='TRUE');

然后放置分区，数据将保留，仅table_2分区元数据将被删除:

Then drop partition, the data will remain, only table_2 partition metadata will be deleted:

ALTER TABLE table_2 DROP PARTITION (col=val)

table_1分区数据将保持不变.

table_1 partition data will remain as is.

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