[PIG-113] Make Grunt's explain output more understandable

• Type: Improvement
• Status: Closed
• Priority: Minor
• Resolution: Fixed
• Affects Version/s: 0.1.0
• Fix Version/s: 0.1.0
• Component/s: grunt
• Patch Info: Patch Available
• Assignee: Pi Song
• Reporter: Pi Song
• Created: 19/Feb/08 12:33
• Updated: 24/Mar/10 22:01
• Resolved: 01/Mar/08 04:14

Description

I think it would be better if we can display the execution plan in a more understandable way. One intuitive way to do this is to show output as a tree like in SQL Server.

Possibly we can have 'AS <format>' as optional argument for explain command

For example

Grunt> explain bag1 AS tree ;
Grunt> explain bag1 AS xml ;

and

Grunt> explain bag1   

will display the default format

I have included a patch that does generate tree output.

Here is a sample of the existing output format

Logical Plan:
Group root-Sun Feb 17 19:37:07 GMT+10:00 2008-5
Object id: 9814147
Inputs: 26335425 
Schema: (group, (sum, (), (), ()))
EvalSpecs:
        Generate: has 2 children
                Project: (0)
                Star
Split root-Sun Feb 17 19:37:07 GMT+10:00 2008-2
Object id: 25199001
Inputs: 29132923 
Schema: (sum, (), (), ())
EvalSpecs:
Eval root-Sun Feb 17 19:37:07 GMT+10:00 2008-1
Object id: 29132923
Inputs: 10774273 
Schema: (sum, (), (), ())
EvalSpecs:
        Generate: has 4 children
                FuncEval: name: org.apache.pig.impl.builtin.ADD args:
                        Generate: has 2 children
                                Project: (0)
                                Project: (1)
                Project: (0)
                Project: (1)
                Project: (2)
Load root-Sun Feb 17 19:37:07 GMT+10:00 2008-0
Object id: 10774273
Inputs: 
Schema: ()
EvalSpecs:
-----------------------------------------------
Physical Plan:
MAPREDUCE
Object id: 17671659
Inputs: 682933706
Map: 
        Star
Grouping Funcs: 
        Generate: has 2 children
                Project: (0)
                Star
Input Files: /tmp/temp678140026/tmp1867058340
MAPREDUCE
Object id: 17308974
Inputs: 
Map: 
        Composite: has 2 children
                Star
                Generate: has 4 children
                        FuncEval: name: org.apache.pig.impl.builtin.ADD args:
                                Generate: has 2 children
                                        Project: (0)
                                        Project: (1)
                        Project: (0)
                        Project: (1)
                        Project: (2)
Input Files: /tmp/data1.txt
Output File: /tmp/temp678140026/tmp1613817084

Here is a sample of my tree output which is more compact and more understandable :-

grunt> explain c1 as tree ;
Logical Plan:
|---LOCogroup ( GENERATE {[PROJECT $0],[*]} ) 
      |---LOSplitOutput (  ) 
            |---LOSplit ( ([PROJECT $0] < ['5']),([PROJECT $0] >= ['5']) ) 
                  |---LOEval ( GENERATE {[org.apache.pig.impl.builtin.ADD(GENERATE {[PROJECT $0],[PROJECT $1]})],[PROJECT $0],[PROJECT $1],[PROJECT $2]} ) 
                        |---LOLoad ( file = /tmp/data1.txt )
-----------------------------------------------
Physical Plan:
|---POMapreduce
    Map : *
    Grouping : Generate(Project(0),*)
    Input File(s) : /tmp/temp678140026/tmp1867058340
      |---POMapreduce
          Map : Composite(*,Generate(FuncEval(org.apache.pig.impl.builtin.ADD(Generate(Project(0),Project(1)))),Project(0),Project(1),Project(2)))
          Input File(s) : /tmp/data1.txt

I'm also thinking about doing output as xml as it might benefit people who are working on displaying execution plan on GUI.