http://www.cloudera.com/content/cloudera-content/cloudera-docs/CDH4/latest/CDH4-Quick-Start/cdh4qs_topic_3_3.html
http://www.cloudera.com/content/cloudera-content/cloudera-docs/Impala/latest/Installing-and-Using-Impala/Installing-and-Using-Impala.html
什么是Impala？
Cloudera发布了实时查询开源项目Impala，根据多款产品实测表明，它比原来基于MapReduce的Hive SQL查询速度提升3～90倍。Impala是Google Dremel的模仿，但在SQL功能上青出于蓝胜于蓝。
1. 安装JDK
$ sudo yum install jdk-6u41-linux-amd64.rpm