1）SecureCRT 7.3出现乱码或者删除不掉数据，免安装版的SecureCRT 卸载或者用虚拟机直接操作或者换安装版的SecureCRT

2）连接不上mysql数据库

（1）导错驱动包，应该把mysql-connector-java-5.1.27-bin.jar导入/opt/module/hive/lib的不是这个包。错把mysql-connector-java-5.1.27.tar.gz导入hive/lib包下。

（2）修改user表中的主机名称没有都修改为%，而是修改为localhost

3）hive默认的输入格式处理是CombineHiveInputFormat，会对小文件进行合并。

hive (default)> set hive.input.format;

hive.input.format=org.apache.hadoop.hive.ql.io.CombineHiveInputFormat

可以采用HiveInputFormat就会根据分区数输出相应的文件。

hive (default)> set hive.input.format=org.apache.hadoop.hive.ql.io.HiveInputFormat;

4）不能执行mapreduce程序

可能是hadoop的yarn没开启。

5）启动mysql服务时，报MySQL server PID file could not be found! 异常。

在/var/lock/subsys/mysql路径下创建hadoop102.pid，并在文件中添加内容：4396

6）报service mysql status MySQL is not running, but lock file (/var/lock/subsys/mysql[失败])异常。

解决方案：在/var/lib/mysql 目录下创建： -rw-rw----. 1 mysql mysql 5 12月 22 16:41 hadoop102.pid 文件，并修改权限为 777。

7）JVM堆内存溢出

描述：java.lang.OutOfMemoryError: Java heap space

解决：在yarn-site.xml中加入如下代码

yarn.scheduler.maximum-allocation-mb 2048 yarn.scheduler.minimum-allocation-mb 2048 yarn.nodemanager.vmem-pmem-ratio 2.1 mapred.child.java.opts -Xmx1024m

8、执行/usr/bin/hive命令进入hive时遇到如下错误：

Logging initialized using configuration in jar:file:/opt/cloudera/parcels/CDH-5.7.3-1.cdh5.7.3.p0.5/jars/hive-common-1.1.0-cdh5.7.3.jar!/hive-log4j.properties

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:540)

at org.apache.hadoop.hive.cli.CliDriver.run(CliDriver.java:689)

at org.apache.hadoop.hive.cli.CliDriver.main(CliDriver.java:628)

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:1493)

at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.(RetryingMetaStoreClient.java:67)

at org.apache.hadoop.hive.metastore.RetryingMetaStoreClient.getProxy(RetryingMetaStoreClient.java:82)

at org.apache.hadoop.hive.ql.metadata.Hive.createMetaStoreClient(Hive.java:2935)

at org.apache.hadoop.hive.ql.metadata.Hive.getMSC(Hive.java:2954)

at org.apache.hadoop.hive.ql.session.SessionState.start(SessionState.java:513)

… 8 more

Caused by: java.lang.reflect.InvocationTargetException

at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)

at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:57)

at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)

at java.lang.reflect.Constructor.newInstance(Constructor.java:526)

at org.apache.hadoop.hive.metastore.MetaStoreUtils.newInstance(MetaStoreUtils.java:1491)

… 13 more

Caused by: MetaException(message:Could not connect to meta store using any of the URIs provided. Most recent failure: org.apache.thrift.transport.TTransportException: java.net.ConnectException: Connection refused

at org.apache.thrift.transport.TSocket.open(TSocket.java:187)

at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.open(HiveMetaStoreClient.java:427)

at org.apache.hadoop.hive.metastore.HiveMetaStoreClient.(HiveMetaStoreClient.java:237)

at org.apache.hadoop.hive.ql.metadata.SessionHiveMetaStoreClient.(SessionHiveMetaStoreClient.java:74)