HIVE "show partitions" 命令不显示正确的分区

Question

我有一个带动态分区的分区 table，分区字段是国籍和生日，

当我使用select * from emp_new where nationality='China'时，我得到以下三个记录，

+---------------+--------------+--------------+------------------+----------------------+--------------------+--+
| emp_new.name  | emp_new.sex  | emp_new.age  |   emp_new.job    | emp_new.nationality  | emp_new.birthdate  |
+---------------+--------------+--------------+------------------+----------------------+--------------------+--+
| Tony          | M            | 34           | IT specialist    | China                | 198202             |
| Katrina       | F            | 33           | IT specialist    | China                | 198408             |
| Cathy         | F            | 30           | IT specialist    | China                | 198704             |

但是当我运行 show partitions emp_new partition(nationality='China') 时，我得到以下结果：

+-------------------------------------+--+
|              partition              |
+-------------------------------------+--+
| nationality=China/birthdate=198408  |
| nationality=China/birthdate=198202  |
| nationality=China/birthdate=198704  |
| nationality=China/birthdate=197509  |
| nationality=China/birthdate=196704  |
| nationality=China/birthdate=197805  |
| nationality=China/birthdate=198201  |
| nationality=China/birthdate=197701  |
| nationality=China/birthdate=196708  |
+-------------------------------------+--+

实际上，我之前使用静态和动态分区(nationality='China', birthdate) 将数据加载到此 table，然后运行对 table 进行分类并使用动态分区重新加载 (nationality, birthdate) 稍后.

我不明白为什么旧的分区还在。

Answer 1

Truncate 删除 table 的数据文件。
它不会从 Metastore 中删除分区定义。
它不会删除文件系统目录。

演示

hive> create table mytable (i int) partitioned by (p int);
OK

hive> insert into mytable partition (p) values (1,10),(2,10),(3,20),(4,30),(5,30),(6,30);
OK

hive> select * from mytable;
OK
mytable.i   mytable.p
1   10
2   10
3   20
4   30
5   30
6   30


hive> show partitions mytable;
OK
partition
p=10
p=20
p=30

hive> !tree ../local_db/mytable;
../local_db/mytable
├── p=10
│   └── 000000_0
├── p=20
│   └── 000000_0
└── p=30
    └── 000000_0

3 directories, 3 files

hive> truncate table mytable;
OK

hive> select * from mytable;
OK
mytable.i   mytable.p

hive> show partitions mytable;
OK
partition
p=10
p=20
p=30

hive> !tree ../local_db/mytable;
../local_db/mytable
├── p=10
├── p=20
└── p=30

3 directories, 0 files

Answer 2

我知道原因，我需要在截断 table 后删除分区，谢谢

HIVE "show partitions" 命令不显示正确的分区

HIVE "show partitions" command do not show correct partitions

hive

partition