hive 显示当前数据库名

当hive CLI启动时，在hive > 提示符出现之前会优先执行文件.hiverc，Hive会自动在${HIVE_HOME}/bin目录下寻找名为.hiverc文件，由此可以在这个文件中设置配置一些常用的参数。由于它是隐藏文件，我们可以用Linux的ls -a命令查看。

编写 .hiverc，参考链接， 有说放在   $HOME/.hiverc  或者 $HIVE_HOME/bin/.hiverc

Putting the global hiverc in $HIVE_HOME/bin/.hiverc is deprecated. Please use $HIVE_CONF_DIR/.hiverc instead

   #在命令行中显示当前数据库名
    set hive.cli.print.current.db=true; 
    #查询出来的结果显示列的名称
    set hive.cli.print.header=true;
    #启用桶表
    set hive.enforce.bucketing=true;
    #压缩hive的中间结果
    set hive.exec.compress.intermediate=true;
    #对map端输出的内容使用BZip2编码/解码器
    set mapred.map.output.compression.codec=org.apache.hadoop.io.compress.BZip2Codec;
    #压缩hive的输出
    set hive.exec.compress.output=true;
    #对hive中的MR输出内容使用BZip2编码/解码器
    set mapred.output.compression.codec=org.apache.hadoop.io.compress.BZip2Codec;
    #让hive尽量尝试local模式查询而不是mapred方式
    set hive.exec.mode.local.auto=true;

Wednesday, August 28, 2013
Apache Hive: The .hiverc file
What is .hiverc file?
It is a file that is executed when you launch the hive shell - making it an ideal place for adding any hive configuration/customization you want set, on start of the hive shell. This could be:
- Setting column headers to be visible in query results
- Making the current database name part of the hive prompt
- Adding any jars or files
- Registering UDFs

.hiverc file location
The file is loaded from the hive conf directory.
I have the CDH4.2 distribution and the location is: /etc/hive/conf.cloudera.hive1
If the file does not exist, you can create it.
It needs to be deployed to every node from where you might launch the Hive shell.
[Note: I had to create the file;  The distribution did not come with it.]

Sample .hiverc
add jar /home/airawat/hadoop-lib/hive-contrib-0.10.0-cdh4.2.0.jar;
set hive.exec.mode.local.auto=true;
set hive.cli.print.header=true;
set hive.cli.print.current.db=true;
set hive.auto.convert.join=true;
set hive.mapjoin.smalltable.filesize=30000000;