当前位置

网站首页> 电脑教程 > 操作系统教程 > 系统常识 > 浏览文章

hive数据怎么导入

作者:小梦 来源: 网络 时间: 2024-01-24 阅读:

   1.通过外部表导入

  用户在hive上建external表,建表的同时指定hdfs路径,在数据拷贝到指定hdfs路径的同时,也同时完成数据插入external表。

  例如:

  编辑文件test.txt

  $ cat test.txt

  1 hello

  2 world

  3 test

  4 case

  字段之间以'\t'分割

  启动hive:

  $ hive

  建external表:

  hive> CREATE EXTERNAL TABLE MYTEST(num INT, name STRING)

  > COMMENT 'this is a test'

  > ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t'

  > STORED AS TEXTFILE

  > LOCATION '/data/test';

  OK

  Time taken: 0.714 seconds

  hive> show tables;

  OK

  mytest

  partition_test

  partition_test_input

  test

  Time taken: 0.07 seconds

  hive> desc mytest ;

  OK

  num int

  name string

  Time taken: 0.121 seconds|

  数据拷贝到hdfs:

  $ hadoop fs -put test.txt /data/test

  查看hive表数据:

  hive> select * from mytest;

  OK

  1 hello

  2 world

  3 test

  4 case

  Time taken: 0.375 seconds

  hive> select num from mytest;

  Total MapReduce jobs = 1

  Launching Job 1 out of 1

  ......

  Total MapReduce CPU Time Spent: 510 msec

  OK

  1

  2

  3

  4

  Time taken: 27.157 seconds

  这种方式常常用于当hdfs上有一些历史数据,而我们需要在这些数据上做一些hive的操作时使用。这种方式避免了数据拷贝开销

  2.从本地导入

  数据不在hdfs上,直接从本地导入hive表

  文件/home/work/test.txt内容同上

  建表:

  hive> CREATE TABLE MYTEST2(num INT, name STRING)

  > COMMENT 'this is a test2'

  > ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t'

  > STORED AS TEXTFILE;

  OK

  Time taken: 0.077 seconds

  导数据入表:

  hive> LOAD DATA LOCAL INPATH '/home/work/test.txt' INTO TABLE MYTEST2;

  Copying data from file:/home/work/test.txt

  Copying file: file:/home/work/test.txt

  Loading data to table default.mytest2

  OK

  Time taken: 0.24 seconds

  查看数据:

  hive> select * from MYTEST2;

  OK

  1 hello

  2 world

  3 test

  4 case

  Time taken: 0.11 seconds

  这种方式导入的本地数据可以是一个文件,一个文件夹或者通配符,需要注意的是,如果是文件夹,文件夹内不能包含子目录,同样,通配符只能通配文件。

  3.从hdfs导入

  上述test.txt文件已经导入/data/test

  则可以使用下述命令直接将数据导入hive表:

  hive> CREATE TABLE MYTEST3(num INT, name STRING)

  > COMMENT "this is a test3"

  > ROW FORMAT DELIMITED FIELDS TERMINATED BY '\t'

  > STORED AS TEXTFILE;

  OK

  Time taken: 4.735 seconds

  hive> LOAD DATA INPATH '/data/test/test.txt' INTO TABLE MYTEST3;

  Loading data to table default.mytest3

  OK

  Time taken: 0.337 seconds

  hive> select * from MYTEST3 ;

  OK

  1 hello

  2 world

  3 test

  4 case

  Time taken: 0.227 seconds

  4. 从其它表导入数据:

  hive> CREATE EXTERNAL TABLE MYTEST4(num INT) ;

  OK

  Time taken: 0.091 seconds

  hive> FROM MYTEST3 test3

  > INSERT OVERWRITE TABLE MYTEST4

  > select test3.num where name='world';

  Total MapReduce jobs = 2

  Launching Job 1 out of 2

  Number of reduce tasks is set to 0 since there's no reduce operator

  Starting Job = job_201207230024_0002, Tracking URL = http://localhost:50030/jobdetails.jsp?jobid=job_201207230024_0002

  Kill Command = /home/work/hadoop/hadoop-1.0.3/libexec/../bin/hadoop job -Dmapred.job.tracker=localhost:9001 -kill job_201207230024_0002

  Hadoop job information for Stage-1: number of mappers: 1; number of reducers: 0

  2012-07-23 18:59:02,365 Stage-1 map = 0%, reduce = 0%

  2012-07-23 18:59:08,417 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 0.62 sec

  2012-07-23 18:59:09,435 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 0.62 sec

  2012-07-23 18:59:10,445 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 0.62 sec

  2012-07-23 18:59:11,455 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 0.62 sec

  2012-07-23 18:59:12,470 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 0.62 sec

  2012-07-23 18:59:13,489 Stage-1 map = 100%, reduce = 0%, Cumulative CPU 0.62 sec

  2012-07-23 18:59:14,508 Stage-1 map = 100%, reduce = 100%, Cumulative CPU 0.62 sec

  MapReduce Total cumulative CPU time: 620 msec

  Ended Job = job_201207230024_0002

  Ended Job = -174856900, job is filtered out (removed at runtime).

  Moving data to: hdfs://localhost:9000/tmp/hive-work/hive_2012-07-23_18-58-44_166_189728317691010041/-ext-10000

  Loading data to table default.mytest4

  Deleted hdfs://localhost:9000/user/hive/warehouse/mytest4

  Table default.mytest4 stats: [num_partitions: 0, num_files: 1, num_rows: 0, total_size: 2, raw_data_size: 0]

  1 Rows loaded to mytest4

  MapReduce Jobs Launched:

  Job 0: Map: 1 Accumulative CPU: 0.62 sec HDFS Read: 242 HDFS Write: 2 SUCESS

  Total MapReduce CPU Time Spent: 620 msec

  OK

  Time taken: 30.663 seconds

  hive> select * from mytest4;

  OK

  2

  Time taken: 0.103 seconds

相关阅读

热点阅读

网友最爱