hive> show databases;
FAILED: SemanticException org.apache.hadoop.hive.ql.metadata.HiveException: java.lang.RuntimeException: Unable to instantiate org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient
解决方案：
在hive的配置文件hive-site.xml添加如下配置：
<property>
<name>datanucleus.schema.autoCreateAll</name>
<value>true</value>
</property>
然后删除MySQL中原来的表，重新初始化元数据
drop database hive_metastore;
Query OK, 57 rows affected (0.42 sec)
MariaDB [(none)]> create database hive_metastore;
Query OK, 1 row affected (0.18 sec)
初始化元数据：
[xiaoqiu@s150 /soft/hive/conf]$ schematool -dbType mysql -initSchema
如果没有删除原来映射到MySQL中的表的话会报如下错误：org.apache.hadoop.hive.metastore.HiveMetaException
[xiaoqiu@s150 /soft/hive/conf]$ schematool -dbType mysql -initSchema
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/soft/apache-hive-2.3.3-bin/lib/log4j-slf4j-impl-2.6.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/soft/hadoop-2.7.5/share/hadoop/common/lib/slf4j-log4j12-1.7.10.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.apache.logging.slf4j.Log4jLoggerFactory]
Metastore connection URL: jdbc:mysql://192.168.109.150:3306/hive_metastore?createDatabaseIfNotExist=true
Metastore Connection Driver : com.mysql.jdbc.Driver
Metastore connection User: root
Starting metastore schema initialization to 2.3.0
Initialization script hive-schema-2.3.0.mysql.sql
Error: Duplicate key name 'PCS_STATS_IDX' (state=42000,code=1061)
org.apache.hadoop.hive.metastore.HiveMetaException: Schema initialization FAILED! Metastore state would be inconsistent !!
Underlying cause: java.io.IOException : Schema script failed, errorcode 2
Use --verbose for detailed stacktrace.
*** schemaTool failed ***
解决方案来源：
https://www.cnblogs.com/flyingcr/p/10326883.html
[root@cdh03 bin]# ./schematool -dbType mysql -initSchema
SLF4J: Class path contains multiple SLF4J bindings.
SLF4J: Found binding in [jar:file:/opt/apps/apache-hive-2.3.6-bin/lib/log4j-slf4j-impl-2.6.2.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: Found binding in [jar:file:/opt/cloudera/parcels/CDH-5.13.2-1.cdh5.13.2.p0.3/jars/slf4j-log4j12-1.7.5.jar!/org/slf4j/impl/StaticLoggerBinder.class]
SLF4J: See http://www.slf4j.org/codes.html#multiple_bindings for an explanation.
SLF4J: Actual binding is of type [org.apache.logging.slf4j.Log4jLoggerFactory]
Metastore connection URL: jdbc:mysql://cdh01:3306/hive236?createDatabaseIfNotExist=true&characterEncoding=utf-8&useSSL=false
Metastore Connection Driver : com.mysql.jdbc.Driver
Metastore connection User: root
Starting metastore schema initialization to 2.3.0
Initialization script hive-schema-2.3.0.mysql.sql
Initialization script completed
schemaTool completed
