再打开一个客户端窗口启动 hive，会产生 java.sql.SQLException 异常。

坑

> Exception in thread "main" java.lang.RuntimeException:
> java.lang.RuntimeException: Unable to instantiate
> org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
>     at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:522)
> at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:677)
>     at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:621)
>     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
>     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
> at java.lang.reflect.Method.invoke(Method.java:606) at
> org.apache.hadoop.util.RunJar.run(RunJar.java:221) at
> org.apache.hadoop.util.RunJar.main(RunJar.java:136) Caused by:
> java.lang.RuntimeException: Unable to instantiate
> org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient at
> org.apache.hadoop.hive.metastore.MetaStoreUtils.newInstance(MetaStoreUtils.java:1523)
> at
> org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.(RetryingMetaStoreClient.ja
> va:86) at
> org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClien
> t.java:132) at
> org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClien
> t.java:104) at
> org.apache.hadoop.hive.ql.metadata.Hive.createMetaStoreClient(Hive.java:3005)
> at org.apache.hadoop.hive.ql.metadata.Hive.getMSC(Hive.java:3024) at
> org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:503)
> ... 8 more

Cause:Metastore默认存储在自带的derby数据库中，而在实际生产中大多数wgetMySQL存储Metastore.

配置Metastore到MySQL

1. 安装MySQL并拷贝驱动

2. 在$HIVE_HOME/conf创建一个hive-site.xml

3. 在$HIVE_HOME/conf创建一个hive-site.xml
   根据官方文档配置参数，拷贝数据到 hive-site.xml 文件中。

   …

    
    javax.jdo.option.ConnectionURL
   jdbc:mysql://hadoop102:3306/metastore?createDatabaseIfNotExist=true JDBC connect string for a JDBC metastore
   
   
   javax.jdo.option.ConnectionDriverName com.mysql.jdbc.Driver
   Driver class name for a JDBC metastore
   
   
   javax.jdo.option.ConnectionUserName root
   username to use against metastore database
   
   
   
   javax.jdo.option.ConnectionPassword 000000
   password to use against metastore database
    
   hive.cli.print.current.db
   true
   Whether to include the current database in the Hive
   prompt. 
   
   hive.cli.print.header
   false
   Whether to print the names of the columns in query output.
    
   

…