Hadoop数据传输工具sqoop(三)用Sqoop导入数据到HIVE

本文详细介绍了如何在Hadoop环境下安装并使用Hive和Sqoop进行数据集成,包括数据导入流程、Hive表创建及数据迁移等关键步骤。

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一、安装Hive

1.1下载解压

下载apache-hive-0.13.1-bin.tar.gz

$ tar zxvf apache-hive-0.13.1-bin.tar.gz

1.2配置环境变量

在/etc/profile中添加:

export HIVE_HOME=/usr/local/app/hadoop/hive-0.13.1-bin
export PATH=$HIVE_HOME/bin:$PATH
1.3建立Hive仓库目录

$ hadoop fs -mkdir/tmp
$ hadoop fs -mkdir/user/hive/warehouse
$ hadoop fs -chmodg+w /tmp
$ hadoop fs -chmodg+w /user/hive/warehouse

1.4启动命令行

通过hive命令进入命令行,操作与MySQL的命令行类似:


二、安装Sqoop

请见 《Hadoop数据传输工具sqoop(一)简介 》


三、用Sqoop导入数据到HIVE

3.1导入HDFS

我们从MySQL数据库中导入一张表的数据来测试一下Sqoop是否配置成功。首先上传mysql-connector-java-5.1.23.jar到sqoop的lib文件夹下,然后执行下列命令:

$ sqoop import --connect jdbc:mysql://ip/database --table tb1 --username user -P

Warning: /usr/lib/hbase does not exist!HBase imports will fail.
Please set $HBASE_HOME to the root of yourHBase installation.
Enter password:

13/06/07 16:51:46 INFOmanager.MySQLManager: Preparing to use a MySQL streaming resultset.
13/06/07 16:51:46 INFO tool.CodeGenTool: Beginning codegeneration
13/06/07 16:51:48 INFO manager.SqlManager:Executing SQL statement: SELECT t.* FROM `tb1` AS t LIMIT 1
13/06/07 16:51:48 INFO manager.SqlManager:Executing SQL statement: SELECT t.* FROM `tb1` AS t LIMIT 1
13/06/07 16:51:48 INFOorm.CompilationManager: HADOOP_MAPRED_HOME is /home/admin/hadoop-0.20.2
13/06/07 16:51:48 INFOorm.CompilationManager: Found hadoop core jar at:/home/admin/hadoop-0.20.2/hadoop-0.20.2-core.jar
Note:/tmp/sqoop-root/compile/44c4b6c5ac57de04b487eb90633ac33e/tb1.java uses oroverrides a deprecated API.
Note: Recompile with -Xlint:deprecation fordetails.
13/06/07 16:51:54 INFO orm.CompilationManager:Writing jar file:/tmp/sqoop-root/compile/44c4b6c5ac57de04b487eb90633ac33e/tb1.jar
13/06/07 16:51:54 WARNmanager.MySQLManager: It looks like you are importing from mysql.
13/06/07 16:51:54 WARNmanager.MySQLManager: This transfer can be faster! Use the --direct
13/06/07 16:51:54 WARNmanager.MySQLManager: option to exercise a MySQL-specific fast path.
13/06/07 16:51:54 INFOmanager.MySQLManager: Setting zero DATETIME behavior to convertToNull (mysql)
13/06/07 16:51:54 INFO mapreduce.ImportJobBase:Beginning import of tb1
13/06/07 16:51:57 INFOdb.DataDrivenDBInputFormat: BoundingValsQuery: SELECT MIN(`id`), MAX(`id`) FROM`tb1`
13/06/07 16:51:59 INFO mapred.JobClient:Running job: job_201306071651_0001
13/06/07 16:52:00 INFOmapred.JobClient:  map 0% reduce 0%
13/06/07 16:52:38 INFOmapred.JobClient:  map 50% reduce 0%
13/06/07 16:52:44 INFOmapred.JobClient:  map 100% reduce 0%
13/06/07 16:52:46 INFO mapred.JobClient:Job complete: job_201306071651_0001
13/06/07 16:52:46 INFO mapred.JobClient:Counters: 5
13/06/07 16:52:46 INFOmapred.JobClient:   Job Counters
13/06/07 16:52:46 INFOmapred.JobClient:     Launched map tasks=2
13/06/07 16:52:46 INFOmapred.JobClient:   FileSystemCounters
13/06/07 16:52:46 INFO mapred.JobClient:     HDFS_BYTES_WRITTEN=212
13/06/07 16:52:46 INFOmapred.JobClient:   Map-Reduce Framework
13/06/07 16:52:46 INFOmapred.JobClient:     Map input records=2
13/06/07 16:52:46 INFOmapred.JobClient:     Spilled Records=0
13/06/07 16:52:46 INFO mapred.JobClient:     Map output records=2
13/06/07 16:52:46 INFOmapreduce.ImportJobBase: Transferred 212 bytes in 51.383 seconds (4.1259bytes/sec)
13/06/07 16:52:46 INFOmapreduce.ImportJobBase: Retrieved 2 records.
数据文件默认被导入到当前用户文件夹下表名对应的文件夹了:


Sqoop默认会同时启动四个Map任务来加速数据导入,可以通过-m 1命令来强制只启动一个map任务,这样就只会在HDFS中生成一个数据文件了。因为tb1表目前就两条数据,所以一共产生两个文件,查看下生成的文件内容:

3.2创建Hive表

首先在hive命令行中创建tb1表。注意hive支持的数据类型有限,并且一定要设置表的分隔符为逗号,否则Hive默认分隔符为Ctrl+A。

CREATE TABLE tb1(
  id int,
 ......
) <span style="color:#FF0000;">row format delimited fields terminated by ‘,’</span>;
也可以通过下面的命令让Sqoop根据MySQL表结构自动创建出Hive表:

$ sqoop create-hive-table --connect jdbc:mysql://ip/database --table tb1 --hive-table tb1 --username user -P

3.3导入Hive

现在将HDFS中的文件导入到Hive,注意Hive从HDFS导入数据后,会将HDFS中的文件/user/root/tb1移动到/user/hive/tb1:

LOADDATA INPATH '/user/root/tb1/part-m-*' OVERWRITE INTO TABLE tb1

3.4一条强大的命令

上面的从MySQL导出数据到HDFS、创建Hive表格、导入数据到Hive三步,可以直接用一条Sqoop命令完成:

$ sqoop import --connect jdbc:mysql://ip/database --table tb1 --username user -P  --hive-import


参考资料:

https://cwiki.apache.org/confluence/display/Hive/GettingStarted

http://sqoop.apache.org/docs/1.99.1/Installation.html



转自:http://blog.youkuaiyun.com/dc_726/article/details/9069871


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