过滤的PIG数据加载了两次？

Question

我有以下PIG脚本：

A = LOAD 'text_a.txt' USING PigStorage();
B = LOAD 'text_b.txt' USING PigStorage();
SOMETHING = FILTER A $0 matches 'SOMETHING';
FOOBAR = FILTER A $0 matches 'FOOBAR';

SOMETHING_B = JOIN SOMETHING BY key, B BY $1;
FOOBAR_B = JOIN FOOBAR BY key, B BY $1;
TEMP = JOIN SOMETHING_B BY key, FOOBAR_B by key;
OUT = FOREACH TEMP GENERATE SOMETHING_B::$1 - FOOBAR_B::$1; 
dump OUT;

当此脚本运行时，看起来A和B中的数据是从源中读取两次？有没有办法阻止它第二次被阅读？

Answer 1

首先才有 在脚本结尾处“解析”以确定数据是否被读取两次。

看着你的脚本剂量看起来像A，B被叫两次