hive笔记-export/import
井宪
该EXPORT命令将表或分区的数据连同元数据一起导出到指定的输出位置。然后可以将此输出位置移至不同的Hadoop或Hive实例，并使用该IMPORT命令从那里导入。
导出分区表时，原始数据可能位于不同的HDFS位置。还支持导出/导入分区子集的功能。
导出的元数据存储在目标目录中，数据文件存储在子目录中。
EXPORT和IMPORT命令中使用的源和目标metastore DBMS的独立工作; 例如，它们可以在Derby和MySQL数据库之间使用。
export:Hive表元数据和文件数据到导出到平台HDFS文件
EXPORT TABLE tablename [PARTITION (part_column="value"[, ...])]
TO 'export_target_path' [ FOR replication('eventid') ]
导出数据：export table emp_dept_partition to '/hive/export/emp_dept_partition';
hive> export table emp_dept_partition
> to '/hive/export/emp_dept_partition';
Copying data from file:/tmp/root/f9237738-62cb-4e43-bf96-7d1c93cb19f5/hive_2018-01-08_20-51-32_269_8661970463753812503-1/-local-10000/_metadata
Copying file: file:/tmp/root/f9237738-62cb-4e43-bf96-7d1c93cb19f5/hive_2018-01-08_20-51-32_269_8661970463753812503-1/-local-10000/_metadata
Copying data from hdfs://hadoop001:9000/user/hive/warehouse/soctt.db/emp_dept_partition/deptno=10
Copying file: hdfs://hadoop001:9000/user/hive/warehouse/soctt.db/emp_dept_partition/deptno=10/000000_0
Copying data from hdfs://hadoop001:9000/user/hive/warehouse/soctt.db/emp_dept_partition/deptno=10
Copying file: hdfs://hadoop001:9000/user/hive/warehouse/soctt.db/emp_dept_partition/deptno=10/000000_0
Copying data from hdfs://hadoop001:9000/user/hive/warehouse/soctt.db/emp_dept_partition/deptno=30
Copying file: hdfs://hadoop001:9000/user/hive/warehouse/soctt.db/emp_dept_partition/deptno=30/000000_0
OK
Time taken: 0.331 seconds检查hdfs上的文件
[root@hadoop001 hiveData]# hadoop fs -ls /hive/export/emp_dept_partition
Found 4 items
-rwxr-xr-x 3 root supergroup 5924 2018-01-08 20:51 /hive/export/emp_dept_partition/_metadata
drwxr-xr-x - root supergroup 0 2018-01-08 20:51 /hive/export/emp_dept_partition/deptno=10
drwxr-xr-x - root supergroup 0 2018-01-08 20:51 /hive/export/emp_dept_partition/deptno=20
drwxr-xr-x - root supergroup 0 2018-01-08 20:51 /hive/export/emp_dept_partition/deptno=30import：将导出的元数据和文件数据导入至hive。
IMPORT [[EXTERNAL] TABLE new_or_original_tablename [PARTITION (part_column="value"[, ...])]]
FROM 'source_path'
[LOCATION 'import_target_path']
删除试验用的表 emp_dept_partition
hive> drop table emp_dept_partition;
OK
Time taken: 0.485 seconds
hive> select * from emp_dept_partition;
FAILED: SemanticException [Error 10001]: Line 1:14 Table not found 'emp_dept_partition'import TABLE emp_dept_partition FROM '/hive/export/emp_dept_partition';
hive> import TABLE emp_dept_partition FROM '/hive/export/emp_dept_partition';
Copying data from hdfs://hadoop001:9000/hive/export/emp_dept_partition/deptno=10
Copying file: hdfs://hadoop001:9000/hive/export/emp_dept_partition/deptno=10/000000_0
Copying data from hdfs://hadoop001:9000/hive/export/emp_dept_partition/deptno=20
Copying file: hdfs://hadoop001:9000/hive/export/emp_dept_partition/deptno=20/000000_0
Copying data from hdfs://hadoop001:9000/hive/export/emp_dept_partition/deptno=30
Copying file: hdfs://hadoop001:9000/hive/export/emp_dept_partition/deptno=30/000000_0
Loading data to table default.emp_dept_partition partition (deptno=10)
Loading data to table default.emp_dept_partition partition (deptno=20)
Loading data to table default.emp_dept_partition partition (deptno=30)
OK
Time taken: 3.931 seconds
hive> select * from emp_dept_partition;
OK
7369 SMITH CLERK 7902 1980/12/17 800.0 NULL 10
7566 JONES MANAGER 7839 1981/4/2 2975.0 NULL 10
7788 SCOTT ANALYST 7566 1987/4/19 3000.0 NULL 10
7876 ADAMS CLERK 7788 1987/5/23 1100.0 NULL 10
7902 FORD ANALYST 7566 1981/12/3 3000.0 NULL 10
7369 SMITH CLERK 7902 1980/12/17 800.0 NULL 20
7566 JONES MANAGER 7839 1981/4/2 2975.0 NULL 20
7788 SCOTT ANALYST 7566 1987/4/19 3000.0 NULL 20
7876 ADAMS CLERK 7788 1987/5/23 1100.0 NULL 20
7902 FORD ANALYST 7566 1981/12/3 3000.0 NULL 20
7499 ALLEN SALESMAN 7698 1981/2/20 1600.0 300.0 30
7521 WARD SALESMAN 7698 1981/2/22 1250.0 500.0 30
7654 MARTIN SALESMAN 7698 1981/9/28 1250.0 1400.0 30
7698 BLAKE MANAGER 7839 1981/5/1 2850.0 NULL 30
7844 TURNER SALESMAN 7698 1981/9/8 1500.0 0.0 30
7900 JAMES CLERK 7698 1981/12/3 950.0 NULL 30
Time taken: 0.419 seconds, Fetched: 16 row(s)检查表信息：
hive> desc formatted emp_dept_partition;
OK
# col_name data_type comment
empno int
ename string
job string
mgr int
hiredate string
sal double
comm double
# Partition Information
# col_name data_type comment
deptno int
# Detailed Table Information
Database: default
Owner: root
CreateTime: Mon Jan 08 20:59:03 CST 2018
LastAccessTime: UNKNOWN
Protect Mode: None
Retention: 0
Location: hdfs://hadoop001:9000/user/hive/warehouse/emp_dept_partition
Table Type: MANAGED_TABLE
Table Parameters:
last_modified_by root
last_modified_time 1515333904
transient_lastDdlTime 1515416343
# 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:
field.delim \t
serialization.format \t
Time taken: 0.091 seconds, Fetched: 40 row(s)【来自@若泽大数据】
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