pig相关

1. 重命名pig job name：

在Pig脚本中的一开始处，写上这一句：

set job.name 'This is my job';

2. 设置pig参数：

允许pig时，输入如下：

pig -p JOBNAME="MyJob" test.pig

************test.pig**********

set job.name '$JOBNAME';

......

3. pig分隔符定义：

pig默认分隔符是/t，可以通过如下命令 using PigStorage(',')自定义分隔符：

prices = load 'NYSE_daily' using PigStorage(',') as (exchange, symbol, date, open，high, low, close, volume, adj_close);

4. pig定义reduce个数：

Parallel

设置pig的reduce进程个数

--parallel.pig

daily   = load 'NYSE_daily' as (exchange, symbol, date, open, high, low, close,

            volume, adj_close);

bysymbl = group daily by symbol parallel 10;

parallel只针对一条语句，如果希望脚本中的所有语句都有10个reduce进程，可以使用 set default_parallel 10命令

--defaultparallel.pig

set default_parallel 10;

daily   = load 'NYSE_daily' as (exchange, symbol, date, open, high, low, close,

            volume, adj_close);

bysymbl = group daily by symbol;

average = foreach bysymbl generate group, AVG(daily.close) as avg;

sorted  = order average by avg desc;

其他可以参考：

http://www.cnblogs.com/siwei1988/archive/2012/08/06/2624912.html