Hive的优点
1) 简单易用
2) 弹性
3) 统一的元数据管理
元数据存放在 metadata mysql
Hive体系架构
JobTracker和TaskTracker对应MR2的是ResourceManager和NodeManger。
MetaStore:存储元数据信息
Hive环境搭建
hive下载:wget http://archive.cloudera.com/cdh5/cdh/5/hive-1.1.0-cdh5.7.0.tar.gz
放到hadoop用户的app文件夹内
tar -zxvf hive-1.1.0-cdh5.7.0.tar.gz -C ~/app
1) 添加HIVE_HOME到系统环境变量
export HIVE_HOME=/home/hadoop/app/hive-1.1.0-cdh5.7.0
export PATH=$HIVE_HOME/bin:$PATH
2) Hive配置修改
hive-env.sh
修改hadoop文件路径:
HADOOP_HOME=/home/hadoop/app/hadoop-2.6.0-cdh5.7.0
hive-site.xml 统一元数据管理(没有这个文件需要创建)
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
<name>javax.jdo.option.ConnectionURL</name>
<value>jdbc:mysql://localhost:3306/ruozedata_basic02?createDatabaseIfNotExist=true</value>
</property>
<property>
<name>javax.jdo.option.ConnectionDriverName</name>
<value>com.mysql.jdbc.Driver</value>
</property>
<property>
<name>javax.jdo.option.ConnectionUserName</name>
<value>root</value>
</property>
<property>
<name>javax.jdo.option.ConnectionPassword</name>
<value>root</value>
</property>
</configuration>
3) 拷贝mysql驱动包到$HIVE_HOME/lib
The specified datastore driver (“com.mysql.jdbc.Driver”) was not found in the CLASSPATH.
Please check your CLASSPATH specification,
and the name of the driver.
4) 出现的问题
创建表失败
FAILED: Execution Error,
return code 1 from org.apache.hadoop.hive.ql.exec.DDLTask.
MetaException(message:For direct MetaStore DB
connections, we don’t support retries at the client
level.)
思路:找日志
日志在哪里: $HIVE_HOME/conf/hive-log4j.properties.template
hive.log.dir=${java.io.tmpdir}/${user.name} --》${java.io.tmpdir}指的是/tmp/目录
不建议放在/tmp/目录下,可以修改路径
hive.log.file=hive.log
ERROR [main]: Datastore.Schema (Log4JLogger.java:error(115)) - An exception was thrown while adding/validating class(es) :
Specified key was too long; max key length is 767 bytes
com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Specified key was too long; max key length is 767 bytes
字符集问题:
alter database ruozedata_basic02 character set latin1;