0
我想了解猪的explain
功能(link)。阿帕奇猪的解释功能
假设下面的例子:
A = load 'numbers' using PigStorage(',') as (name, age);
explain A;
这给了我:
#-----------------------------------------------
# New Logical Plan:
#-----------------------------------------------
A: (Name: LOStore Schema: name#5:bytearray,age#6:bytearray)
|
|---A: (Name: LOLoad Schema: name#5:bytearray,age#6:bytearray)RequiredFields:[0, 1]
#-----------------------------------------------
# Physical Plan:
#-----------------------------------------------
A: Store(fakefile:org.apache.pig.builtin.PigStorage) - scope-1
|
|---A: Load(file:///...pig-0.14.0/numbers:PigStorage(',')) - scope-0
2014-12-07 15:07:10,596 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MRCompiler - File concatenation threshold: 100 optimistic? false
2014-12-07 15:07:10,609 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer - MR plan size before optimization: 1
2014-12-07 15:07:10,610 [main] INFO org.apache.pig.backend.hadoop.executionengine.mapReduceLayer.MultiQueryOptimizer - MR plan size after optimization: 1
#--------------------------------------------------
# Map Reduce Plan
#--------------------------------------------------
MapReduce node scope-2
Map Plan
A: Store(fakefile:org.apache.pig.builtin.PigStorage) - scope-1
|
|---A: Load(file:///.../pig-0.14.0/numbers:PigStorage(',')) - scope-0--------
Global sort: false
----------------
我可以在这里看到?我觉得输出很混乱。
http://chimera.labs.oreilly.com/books/1234000001811/ch07.html#describe – 2014-12-08 04:55:33