大数据开发之Hive篇19-Hive分区表详解
备注:
Hive 版本 2.1.1
文章目录
- 一.Hive分区表概述
- 二.静态分区
-
- 2.1 单分区测试
- 2.2 多分区测试
- 三.动态分区
-
- 3.1 动态分区测试
- 3.2 动态分区和静态分区混合使用
- 四.分区的其它操作
-
- 4.1 恢复分区
- 4.2 归档分区
- 4.3 交换分区
- 参考
一.Hive分区表概述
数据分区的概念以及存在很久了，通常使用分区来水平分散压力，将数据从物理上移到和使用最频繁的用户更近的地方，以及实现其目的。 hive中有分区表的概念，我们可以看到分区具重要性能优势，而且分区表还可以将数据以一种符合逻辑的方式进行组织，比如分层存储
Hive官方网站对Hive partition的介绍:
可以使用Partitioned BY子句创建分区表。一个表可以有一个或多个分区列，并且为分区列中的每个不同的值组合创建一个单独的数据目录。此外，可以使用按列聚集的方式对表或分区进行存储，并且可以通过按列排序的方式在存储区内对数据进行排序。这可以提高某些查询的性能。
如果在创建分区表时，出现这样的错误:“FAILED: error in semantic analysis: Column repeated in partitioning columns”，这意味着您试图将分区的列包含在表本身的数据中。您可能确实定义了列。但是，您创建的分区会生成一个可以查询的伪列，因此必须将表列重命名为其他东西(用户不应该查询的东西!)。
分区表分别有静态分区和动态分区
创建分区表语法:
CREATE [TEMPORARY] [EXTERNAL] TABLE [IF NOT EXISTS] [db_name.]table_name -- (Note: TEMPORARY available in Hive 0.14.0 and later)
[(col_name data_type [column_constraint_specification] [COMMENT col_comment], ... [constraint_specification])]
[COMMENT table_comment]
[PARTITIONED BY (col_name data_type [COMMENT col_comment], ...)]
[CLUSTERED BY (col_name, col_name, ...) [SORTED BY (col_name [ASC|DESC], ...)] INTO num_buckets BUCKETS]
[SKEWED BY (col_name, col_name, ...) -- (Note: Available in Hive 0.10.0 and later)]
ON ((col_value, col_value, ...), (col_value, col_value, ...), ...)
[STORED AS DIRECTORIES]
[
[ROW FORMAT row_format]
[STORED AS file_format]
| STORED BY 'storage.handler.class.name' [WITH SERDEPROPERTIES (...)] -- (Note: Available in Hive 0.6.0 and later)
]
[LOCATION hdfs_path]
[TBLPROPERTIES (property_name=property_value, ...)] -- (Note: Available in Hive 0.6.0 and later)
[AS select_statement]; -- (Note: Available in Hive 0.5.0 and later; not supported for external tables)
修改分区表语法:
通过在ALTER TABLE语句中使用PARTITION子句，可以添加、重命名、交换(移动)、删除或归档分区
-- 新增分区
ALTER TABLE table_name ADD [IF NOT EXISTS] PARTITION partition_spec [LOCATION 'location'][, PARTITION partition_spec [LOCATION 'location'], ...];
partition_spec:
: (partition_column = partition_col_value, partition_column = partition_col_value, ...)
-- 重命名分区
ALTER TABLE table_name PARTITION partition_spec RENAME TO PARTITION partition_spec;
-- 删除分区
ALTER TABLE table_name DROP [IF EXISTS] PARTITION partition_spec;
-- 删除分区(回收站不保留，直接删除)
ALTER TABLE table_name DROP [IF EXISTS] PARTITION partition_spec PURGE;
-- 归档和还原归档分区表
ALTER TABLE table_name ARCHIVE PARTITION partition_spec;
ALTER TABLE table_name UNARCHIVE PARTITION partition_spec;
二.静态分区
可以根据PARTITIONED BY创建分区表，一个表可以拥有一个或者多个分区，每个分区以文件夹的形式单独存在表文件夹的目录下。
分区是以字段的形式在表结构中存在，通过describe table命令可以查看到字段存在，但是该字段不存放实际的数据内容，仅仅是分区的表示。
分区建表分为2种，一种是单分区，也就是说在表文件夹目录下只有一级文件夹目录。另外一种是多分区，表文件夹下出现多文件夹嵌套模式。
2.1 单分区测试
代码:
-- 创建分区表
create table test_part(key int,value string) partitioned by (dt string);
-- 查看分区表
describe formatted test_part;
-- 往分区表录入数据
insert into test_part partition(dt = '2020-12-29') values (1,'abc');
insert into test_part partition(dt = '2020-12-30') values (2,'def');
insert into test_part partition(dt = '2020-12-31') values (3,'ghi');
-- 新增分区
alter table test_part add partition(dt = '2021-01-01');
-- 重命名分区
alter table test_part partition(dt = '2021-01-01') rename to partition(dt = '2021-01-02');
-- 删除分区
alter table test_part drop partition(dt='2020-12-31');
-- 删除分区(回收站不保留，直接删除)
alter table test_part drop partition(dt='2020-12-30') purge;
测试记录:
hive>
> create table test_part(key int,value string) partitioned by (dt string);
OK
Time taken: 0.087 seconds
hive> describe formatted test_part;
OK
# col_name data_type comment
key int
value string
# Partition Information
# col_name data_type comment
dt string
# Detailed Table Information
Database: test
OwnerType: USER
Owner: root
CreateTime: Tue Dec 29 15:59:02 CST 2020
LastAccessTime: UNKNOWN
Retention: 0
Location: hdfs://nameservice1/user/hive/warehouse/test.db/test_part
Table Type: MANAGED_TABLE
Table Parameters:
COLUMN_STATS_ACCURATE {\"BASIC_STATS\":\"true\"}
numFiles 0
numPartitions 0
numRows 0
rawDataSize 0
totalSize 0
transient_lastDdlTime 1609228742
# Storage Information
SerDe Library: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
InputFormat: org.apache.hadoop.mapred.TextInputFormat
OutputFormat: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
Compressed: No
Num Buckets: -1
Bucket Columns: []
Sort Columns: []
Storage Desc Params:
serialization.format 1
Time taken: 0.193 seconds, Fetched: 38 row(s)
hive>
hive> insert into test_part partition(dt = '2020-12-29') values (1,'abc');
Query ID = root_20201229160327_aef35dcf-1aaa-4b30-b47b-cbe9ea3aec3e
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 16:03:28 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0003, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0003/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0003
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2020-12-29 16:03:35,297 Stage-1 map = 0%, reduce = 0%
2020-12-29 16:03:42,522 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 2.85 sec
MapReduce Total cumulative CPU time: 2 seconds 850 msec
Ended Job = job_1609141291605_0003
Stage-4 is selected by condition resolver.
Stage-3 is filtered out by condition resolver.
Stage-5 is filtered out by condition resolver.
Moving data to directory hdfs://nameservice1/user/hive/warehouse/test.db/test_part/dt=2020-12-29/.hive-staging_hive_2020-12-29_16-03-27_864_460539835119685808-1/-ext-10000
Loading data to table test.test_part partition (dt=2020-12-29)
MapReduce Jobs Launched:
Stage-Stage-1: Map: 1 Cumulative CPU: 2.85 sec HDFS Read: 4229 HDFS Write: 90 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 2 seconds 850 msec
OK
Time taken: 16.389 seconds
hive>
> insert into test_part partition(dt = '2020-12-30') values (2,'def');
Query ID = root_20201229160421_9da78dee-ff03-4d5a-9fef-b3808a69a3c6
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 16:04:22 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0004, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0004/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0004
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2020-12-29 16:04:29,214 Stage-1 map = 0%, reduce = 0%
2020-12-29 16:04:36,442 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 2.99 sec
MapReduce Total cumulative CPU time: 2 seconds 990 msec
Ended Job = job_1609141291605_0004
Stage-4 is selected by condition resolver.
Stage-3 is filtered out by condition resolver.
Stage-5 is filtered out by condition resolver.
Moving data to directory hdfs://nameservice1/user/hive/warehouse/test.db/test_part/dt=2020-12-30/.hive-staging_hive_2020-12-29_16-04-21_921_4429247941950558015-1/-ext-10000
Loading data to table test.test_part partition (dt=2020-12-30)
MapReduce Jobs Launched:
Stage-Stage-1: Map: 1 Cumulative CPU: 2.99 sec HDFS Read: 4232 HDFS Write: 90 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 2 seconds 990 msec
OK
Time taken: 17.229 seconds
hive>
> insert into test_part partition(dt = '2020-12-31') values (3,'ghi');
Query ID = root_20201229160458_be37945d-a462-4ab1-b8fe-0180277c2399
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 16:04:58 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0005, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0005/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0005
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2020-12-29 16:05:06,866 Stage-1 map = 0%, reduce = 0%
2020-12-29 16:05:13,062 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 3.03 sec
MapReduce Total cumulative CPU time: 3 seconds 30 msec
Ended Job = job_1609141291605_0005
Stage-4 is selected by condition resolver.
Stage-3 is filtered out by condition resolver.
Stage-5 is filtered out by condition resolver.
Moving data to directory hdfs://nameservice1/user/hive/warehouse/test.db/test_part/dt=2020-12-31/.hive-staging_hive_2020-12-29_16-04-58_612_6006646373659507783-1/-ext-10000
Loading data to table test.test_part partition (dt=2020-12-31)
MapReduce Jobs Launched:
Stage-Stage-1: Map: 1 Cumulative CPU: 3.03 sec HDFS Read: 4232 HDFS Write: 90 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 3 seconds 30 msec
OK
Time taken: 16.151 seconds
hive>
> alter table test_part add partition(dt = '2021-01-01');
OK
Time taken: 0.147 seconds
hive>
> alter table test_part partition(dt = '2021-01-01') rename to partition(dt = '2021-01-02');
OK
Time taken: 0.353 seconds
hive>
> alter table test_part drop partition(dt='2020-12-31');
Dropped the partition dt=2020-12-31
OK
Time taken: 0.151 seconds
hive> alter table test_part drop partition(dt='2020-12-30') purge;
Dropped the partition dt=2020-12-30
OK
Time taken: 0.135 seconds
hive>
我们来查看下分区的存储
可以看到一份分区一个文件夹，一个分区下可能有0个或多个文件
[root@hp1 ~]# hadoop fs -ls /user/hive/warehouse/test.db/test_part
Found 2 items
drwxrwxrwt - root hive 0 2020-12-29 16:03 /user/hive/warehouse/test.db/test_part/dt=2020-12-29
drwxrwxrwt - root hive 0 2020-12-29 16:09 /user/hive/warehouse/test.db/test_part/dt=2021-01-02
2.2 多分区测试
代码:
-- 创建分区表
create table test_part2(key int,value string) partitioned by (prod_name string,dt string);
-- 查看分区表
describe formatted test_part2;
-- 往分区表录入数据
insert into test_part2 partition(prod_name='PROD1',dt = '2020-12-29') values (1,'abc');
insert into test_part2 partition(prod_name='PROD1',dt = '2020-12-30') values (2,'def');
insert into test_part2 partition(prod_name='PROD1',dt = '2020-12-31') values (3,'ghi');
-- 新增分区
alter table test_part2 add partition(prod_name='PROD2',dt = '2020-12-29');
-- 重命名分区
alter table test_part2 partition(prod_name='PROD2',dt = '2020-12-29') rename to partition(prod_name='PROD3',dt = '2020-12-29');
测试记录:
hive>
>
>
> create table test_part2(key int,value string) partitioned by (prod_name string,dt string);
OK
Time taken: 0.09 seconds
hive> describe formatted test_part2;
OK
# col_name data_type comment
key int
value string
# Partition Information
# col_name data_type comment
prod_name string
dt string
# Detailed Table Information
Database: test
OwnerType: USER
Owner: root
CreateTime: Tue Dec 29 16:43:06 CST 2020
LastAccessTime: UNKNOWN
Retention: 0
Location: hdfs://nameservice1/user/hive/warehouse/test.db/test_part2
Table Type: MANAGED_TABLE
Table Parameters:
COLUMN_STATS_ACCURATE {\"BASIC_STATS\":\"true\"}
numFiles 0
numPartitions 0
numRows 0
rawDataSize 0
totalSize 0
transient_lastDdlTime 1609231386
# Storage Information
SerDe Library: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
InputFormat: org.apache.hadoop.mapred.TextInputFormat
OutputFormat: org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
Compressed: No
Num Buckets: -1
Bucket Columns: []
Sort Columns: []
Storage Desc Params:
serialization.format 1
Time taken: 0.074 seconds, Fetched: 39 row(s)
hive> insert into test_part2 partition(prod_name='PROD1',dt = '2020-12-29') values (1,'abc');
Query ID = root_20201229164322_9ffab4bf-8e7b-449f-ac07-91f73016da13
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 16:43:22 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0006, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0006/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0006
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2020-12-29 16:43:29,435 Stage-1 map = 0%, reduce = 0%
2020-12-29 16:43:35,624 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 3.86 sec
MapReduce Total cumulative CPU time: 3 seconds 860 msec
Ended Job = job_1609141291605_0006
Stage-4 is selected by condition resolver.
Stage-3 is filtered out by condition resolver.
Stage-5 is filtered out by condition resolver.
Moving data to directory hdfs://nameservice1/user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-29/.hive-staging_hive_2020-12-29_16-43-22_143_1775810973752071302-1/-ext-10000
Loading data to table test.test_part2 partition (prod_name=PROD1, dt=2020-12-29)
MapReduce Jobs Launched:
Stage-Stage-1: Map: 1 Cumulative CPU: 3.86 sec HDFS Read: 4319 HDFS Write: 107 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 3 seconds 860 msec
OK
Time taken: 16.222 seconds
hive> insert into test_part2 partition(prod_name='PROD1',dt = '2020-12-30') values (2,'def');
Query ID = root_20201229164339_1a52188f-5fcb-4275-a26b-8a36db978218
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 16:43:40 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0007, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0007/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0007
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2020-12-29 16:43:47,977 Stage-1 map = 0%, reduce = 0%
2020-12-29 16:43:55,193 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 3.61 sec
MapReduce Total cumulative CPU time: 3 seconds 610 msec
Ended Job = job_1609141291605_0007
Stage-4 is selected by condition resolver.
Stage-3 is filtered out by condition resolver.
Stage-5 is filtered out by condition resolver.
Moving data to directory hdfs://nameservice1/user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-30/.hive-staging_hive_2020-12-29_16-43-39_784_2410125837572976640-1/-ext-10000
Loading data to table test.test_part2 partition (prod_name=PROD1, dt=2020-12-30)
MapReduce Jobs Launched:
Stage-Stage-1: Map: 1 Cumulative CPU: 3.61 sec HDFS Read: 4319 HDFS Write: 107 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 3 seconds 610 msec
OK
Time taken: 17.101 seconds
hive> insert into test_part2 partition(prod_name='PROD1',dt = '2020-12-31') values (3,'ghi');
Query ID = root_20201229164358_696aac78-0a49-46f0-bb8a-e408b22c48cb
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 16:43:58 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0008, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0008/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0008
Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0
2020-12-29 16:44:06,382 Stage-1 map = 0%, reduce = 0%
2020-12-29 16:44:12,570 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 3.46 sec
MapReduce Total cumulative CPU time: 3 seconds 460 msec
Ended Job = job_1609141291605_0008
Stage-4 is selected by condition resolver.
Stage-3 is filtered out by condition resolver.
Stage-5 is filtered out by condition resolver.
Moving data to directory hdfs://nameservice1/user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-31/.hive-staging_hive_2020-12-29_16-43-58_167_5034454344356683760-1/-ext-10000
Loading data to table test.test_part2 partition (prod_name=PROD1, dt=2020-12-31)
MapReduce Jobs Launched:
Stage-Stage-1: Map: 1 Cumulative CPU: 3.46 sec HDFS Read: 4319 HDFS Write: 107 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 3 seconds 460 msec
OK
Time taken: 17.146 seconds
hive> alter table test_part2 add partition(prod_name='PROD2',dt = '2020-12-29');
OK
Time taken: 0.114 seconds
hive> alter table test_part2 partition(prod_name='PROD2',dt = '2020-12-29') rename to partition(prod_name='PROD3',dt = '2020-12-29');
OK
Time taken: 0.309 seconds
hive>
我们来查看下分区的存储
可以看到多级分区目录为多级，每一个prod_name一个文件夹，产品文件夹下面，每一个dt是一个目录。
多分区虽然会产生比较多的文件，如果数据量不大的情况下，谨慎使用。
[root@hp1 ~]# hadoop fs -ls /user/hive/warehouse/test.db/test_part2
Found 3 items
drwxrwxrwt - root hive 0 2020-12-29 16:43 /user/hive/warehouse/test.db/test_part2/prod_name=PROD1
drwxrwxrwt - root hive 0 2020-12-29 16:44 /user/hive/warehouse/test.db/test_part2/prod_name=PROD2
drwxrwxrwt - root hive 0 2020-12-29 16:44 /user/hive/warehouse/test.db/test_part2/prod_name=PROD3
[root@hp1 ~]# hadoop fs -ls /user/hive/warehouse/test.db/test_part2/prod_name=PROD1
Found 3 items
drwxrwxrwt - root hive 0 2020-12-29 16:43 /user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-29
drwxrwxrwt - root hive 0 2020-12-29 16:43 /user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-30
drwxrwxrwt - root hive 0 2020-12-29 16:44 /user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-31
[root@hp1 ~]# hadoop fs -ls /user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-29
Found 1 items
-rwxrwxrwt 3 root hive 6 2020-12-29 16:43 /user/hive/warehouse/test.db/test_part2/prod_name=PROD1/dt=2020-12-29/000000_0
[root@hp1 ~]#
三.动态分区
官方文档对静态分区和动态分区的简单解释:
Static Partition (SP) columns: in DML/DDL involving multiple partitioning columns, the columns whose values are known at COMPILE TIME (given by user).
Dynamic Partition (DP) columns: columns whose values are only known at EXECUTION TIME.
静态分区(SP)列:在涉及多个分区列的DML/DDL中，这些列的值在编译时已知(由用户给出)。
Dynamic Partition (DP)列:在执行时才知道其值的列。
上面我们测试静态分区的时候，可以看到操作分区表的时候一定要指定分区，动态分区就解决了这个问题。
3.1 动态分区测试
开启动态分区，需要调整如下配置:
set hive.exec.dynamic.partition=true; --开启动态分区 默认为true，开启
set hive.exec.dynamic.partition.mode=nonstrict; --指定动态分区模式，默认为strict，即必须指定至少一个分区为静态分区，nonstrict模式表示允许所有的分区字段都可以使用动态分区
代码:
CREATE TABLE emp_dynamic_partition (
empno int,
ename string,
job string,
mgr int,
hiredate string,
salary double,
comm double
)
PARTITIONED BY (deptno int);
insert into emp_dynamic_partition partition(deptno) select * from emp;
测试记录:
hive>
>
> CREATE TABLE emp_dynamic_partition (
> empno int,
> ename string,
> job string,
> mgr int,
> hiredate string,
> salary double,
> comm double
> )
> PARTITIONED BY (deptno int);
OK
Time taken: 0.106 seconds
hive>
> insert into emp_dynamic_partition select * from emp;
FAILED: SemanticException 1:12 Need to specify partition columns because the destination table is partitioned. Error encountered near token 'emp_dynamic_partition'
hive>
> set hive.exec.dynamic.partition.mode=nonstrict;
hive>
>
> insert into emp_dynamic_partition select * from emp;
FAILED: SemanticException 1:12 Need to specify partition columns because the destination table is partitioned. Error encountered near token 'emp_dynamic_partition'
hive>
>
> insert into emp_dynamic_partition partition(deptno) select * from emp;
Query ID = root_20201229170212_e550dbfe-6d2e-49b0-83c8-9bc7d88c3144
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 17:02:13 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0009, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0009/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0009
Hadoop job information for Stage-1: number of mappers: 2; number of reducers: 0
2020-12-29 17:02:20,034 Stage-1 map = 0%, reduce = 0%
2020-12-29 17:02:26,274 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 6.77 sec
MapReduce Total cumulative CPU time: 6 seconds 770 msec
Ended Job = job_1609141291605_0009
Stage-4 is filtered out by condition resolver.
Stage-3 is selected by condition resolver.
Stage-5 is filtered out by condition resolver.
Launching Job 3 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 17:02:28 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0010, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0010/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0010
Hadoop job information for Stage-3: number of mappers: 3; number of reducers: 0
2020-12-29 17:02:39,398 Stage-3 map = 0%, reduce = 0%
2020-12-29 17:02:44,560 Stage-3 map = 67%, reduce = 0%, Cumulative CPU 3.5 sec
2020-12-29 17:02:48,675 Stage-3 map = 100%, reduce = 0%, Cumulative CPU 5.11 sec
MapReduce Total cumulative CPU time: 5 seconds 110 msec
Ended Job = job_1609141291605_0010
Loading data to table test.emp_dynamic_partition partition (deptno=null)
Time taken to load dynamic partitions: 0.18 seconds
Time taken for adding to write entity : 0.001 seconds
MapReduce Jobs Launched:
Stage-Stage-1: Map: 2 Cumulative CPU: 6.77 sec HDFS Read: 13606 HDFS Write: 1041 HDFS EC Read: 0 SUCCESS
Stage-Stage-3: Map: 3 Cumulative CPU: 5.11 sec HDFS Read: 11072 HDFS Write: 635 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 11 seconds 880 msec
OK
Time taken: 37.464 seconds
hive>
可以看到根据deptno自动创建了3个分区
[root@hp1 ~]# hadoop fs -ls /user/hive/warehouse/test.db/emp_dynamic_partition
Found 3 items
drwxrwxrwt - root hive 0 2020-12-29 17:02 /user/hive/warehouse/test.db/emp_dynamic_partition/deptno=10
drwxrwxrwt - root hive 0 2020-12-29 17:02 /user/hive/warehouse/test.db/emp_dynamic_partition/deptno=20
drwxrwxrwt -
3.2 动态分区和静态分区混合使用
动态分区和静态分区可以混合使用
假设此时我有一个订单表，订单有一个状态。
我需要做一个快照表，每天凌晨把所有订单的状态做一个快照，但是数据量比较大，除了按天分区外，我还想根据状态进行分区，此时我们可以将两种分区混合使用
代码:
create table test1(user_id int,prod_name string,apply_status string);
insert into test1 values (1,'Prod1','申请中');
insert into test1 values (2,'Prod1','审批中');
insert into test1 values (3,'Prod1','完成');
insert into test1 values (4,'Prod1','拒绝中');
create table test_mix_partition
(user_id int,
prod_name string
)
partitioned by (dt string,apply_status string);
insert into test_mix_partition partition(dt='2020-12-29',apply_status) select user_id,prod_name,apply_status from test1;
测试记录
hive>
>
> create table test_mix_partition
> (user_id int,
> prod_name string
> )
> partitioned by (dt string,apply_status string);
OK
Time taken: 0.069 seconds
hive> insert into test_mix_partition partition(dt='2020-12-29',apply_status) select user_id,prod_name,apply_status from test1;
Query ID = root_20201229172136_c5b5e88f-f2ad-4863-944e-c1dc89be7030
Total jobs = 3
Launching Job 1 out of 3
Number of reduce tasks is set to 0 since there's no reduce operator
20/12/29 17:21:36 INFO client.ConfiguredRMFailoverProxyProvider: Failing over to rm69
Starting Job = job_1609141291605_0015, Tracking URL = http://hp3:8088/proxy/application_1609141291605_0015/
Kill Command = /opt/cloudera/parcels/CDH-6.3.1-1.cdh6.3.1.p0.1470567/lib/hadoop/bin/hadoop job -kill job_1609141291605_0015
Hadoop job information for Stage-1: number of mappers: 2; number of reducers: 0
2020-12-29 17:21:43,261 Stage-1 map = 0%, reduce = 0%
2020-12-29 17:21:49,445 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 3.77 sec
MapReduce Total cumulative CPU time: 3 seconds 770 msec
Ended Job = job_1609141291605_0015
Stage-4 is selected by condition resolver.
Stage-3 is filtered out by condition resolver.
Stage-5 is filtered out by condition resolver.
Moving data to directory hdfs://nameservice1/user/hive/warehouse/test.db/test_mix_partition/dt=2020-12-29/.hive-staging_hive_2020-12-29_17-21-36_213_8707202021987000828-1/-ext-10000
Loading data to table test.test_mix_partition partition (dt=2020-12-29, apply_status=null)
Time taken to load dynamic partitions: 0.175 seconds
Time taken for adding to write entity : 0.001 seconds
MapReduce Jobs Launched:
Stage-Stage-1: Map: 2 Cumulative CPU: 3.77 sec HDFS Read: 9390 HDFS Write: 423 HDFS EC Read: 0 SUCCESS
Total MapReduce CPU Time Spent: 3 seconds 770 msec
OK
Time taken: 14.95 seconds
hive>
[root@hp1 ~]# hadoop fs -ls /user/hive/warehouse/test.db/test_mix_partition
Found 1 items
drwxrwxrwt - root hive 0 2020-12-29 17:21 /user/hive/warehouse/test.db/test_mix_partition/dt=2020-12-29
[root@hp1 ~]#
[root@hp1 ~]# hadoop fs -ls /user/hive/warehouse/test.db/test_mix_partition/dt=2020-12-29
Found 4 items
drwxrwxrwt - root hive 0 2020-12-29 17:21 /user/hive/warehouse/test.db/test_mix_partition/dt=2020-12-29/apply_status=完成
drwxrwxrwt - root hive 0 2020-12-29 17:21 /user/hive/warehouse/test.db/test_mix_partition/dt=2020-12-29/apply_status=审批中
drwxrwxrwt - root hive 0 2020-12-29 17:21 /user/hive/warehouse/test.db/test_mix_partition/dt=2020-12-29/apply_status=拒绝中
drwxrwxrwt - root hive 0 2020-12-29 17:21 /user/hive/warehouse/test.db/test_mix_partition/dt=2020-12-29/apply_status=申请中
[root@hp1 ~]#
四.分区的其它操作
4.1 恢复分区
语法:
MSCK [REPAIR] TABLE table_name [ADD/DROP/SYNC PARTITIONS];
msck repair table命令执行后Hive会检测如果HDFS目录下存在 但表的metastore中不存在的partition元信息，更新到metastore中。如果有一张表已经存放好几年了，用这个命令去执行的话 半天都反应不了，所以这个命令太暴力了，生产中不推荐使用。可以用Add partition来添加分区。
4.2 归档分区
语法:
ALTER TABLE table_name ARCHIVE PARTITION partition_spec;
ALTER TABLE table_name UNARCHIVE PARTITION partition_spec;
归档分区可以减轻 name node的压力，当然，数据量非常大、文件非常多(千万级别)的时候，再考虑做归档。
4.3 交换分区
EXCHANGE PARTITION命令将一个分区从源表移动到目标表，并更改每个表的元数据。
约束:
- 目标表不能包含要交换的分区。
- 如果有索引，操作将失败。
- 交换分区不允许将事务表作为源或目标。或者，使用LOAD DATA或INSERT OVERWRITE命令在事务性表之间移动分区。
- 此命令要求源表名和目标表名具有相同的表模式。
- 如果模式不同，抛出以下异常:
The tables have different schemas. Their partitions cannot be exchanged
语法:
ALTER TABLE EXCHANGE PARTITION (<[partial] partition spec>) WITH TABLE
例1:
-- 创建两个分区表
CREATE TABLE T1(a string, b string) PARTITIONED BY (ds string);
CREATE TABLE T2(a string, b string) PARTITIONED BY (ds string);
ALTER TABLE T1 ADD PARTITION (ds='1');
-- 将t1表的分区 ds=‘1' 移动到t2表
ALTER TABLE T2 EXCHANGE PARTITION (ds='1') WITH TABLE T1;
测试记录:
hive>
> CREATE TABLE T1(a string, b string) PARTITIONED BY (ds string);
OK
Time taken: 0.081 seconds
hive> CREATE TABLE T2(a string, b string) PARTITIONED BY (ds string);
OK
Time taken: 0.085 seconds
hive> ALTER TABLE T1 ADD PARTITION (ds='1');
OK
Time taken: 0.103 seconds
hive> ALTER TABLE T2 EXCHANGE PARTITION (ds='1') WITH TABLE T1;
OK
Time taken: 0.303 seconds
hive>
例2
-- 创建2个多分区列的分区表
CREATE TABLE T1 (a string, b string) PARTITIONED BY (ds string, hr string);
CREATE TABLE T2 (a string, b string) PARTITIONED BY (ds string, hr string);
ALTER TABLE T1 ADD PARTITION (ds = '1', hr = '00');
ALTER TABLE T1 ADD PARTITION (ds = '1', hr = '01');
ALTER TABLE T1 ADD PARTITION (ds = '1', hr = '03');
-- ds='1' 的三个分区同时移动到 t1分区表
ALTER TABLE T2 EXCHANGE PARTITION (ds='1') WITH TABLE T1;
测试记录:
hive>
>
> CREATE TABLE T1 (a string, b string) PARTITIONED BY (ds string, hr string);
OK
Time taken: 0.092 seconds
hive> CREATE TABLE T2 (a string, b string) PARTITIONED BY (ds string, hr string);
OK
Time taken: 0.073 seconds
hive> ALTER TABLE T1 ADD PARTITION (ds = '1', hr = '00');
OK
Time taken: 0.106 seconds
hive> ALTER TABLE T1 ADD PARTITION (ds = '1', hr = '01');
OK
Time taken: 0.122 seconds
hive> ALTER TABLE T1 ADD PARTITION (ds = '1', hr = '03');
OK
Time taken: 0.093 seconds
hive> ALTER TABLE T2 EXCHANGE PARTITION (ds='1') WITH TABLE T1;
OK
Time taken: 0.337 seconds
hive>
参考
1.https://cwiki.apache.org/confluence/display/Hive/LanguageManual+DDL#LanguageManualDDL-PartitionedTables