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Pig, mail # user - debug feature??


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Re: debug feature??
Ruslan Al-Fakikh 2012-10-22, 12:55
As for:
>the
>best scenario is to put a "marker" so that certain variables are stored or
>skipped computation but instead LOADed
I remember there was some discussion on this in the past. Actually
this is not trivial. What would it do if you changed a UDF internal
code, for example? How would it know that it should reprocess instead
of load? As far as I remember some other problems were mentioned.

Ruslan

On Fri, Oct 19, 2012 at 11:01 PM, Yang <[EMAIL PROTECTED]> wrote:
> I am using PigUnit, but it's somewhat limited: it can run only localmode,
> so I can't find issues that come with fairly large test data; you have to
> create small snippets of code that you cut out manually from your original
> code, so after you tested a snippet to be fine, you have to copy-paste that
> back into the production code, which introduces possible copy-paste errors.
>  if you compare this to java junit, this is really very crude: in java, you
> have a class, and you can do junit testing on individual methods of the
> class, instead of having to copy paste and create a special "test version"
> of that class.
>
>
> overall, I feel that testability is an area where PIG could spend a lot
> more efforts and it will greatly benefit its wider adoption.  ----- some
> other tools (Cascading, Cascalog etc) advertise testability as one of their
> important features.
>
> let me check out penny... thanks
>
> On Fri, Oct 19, 2012 at 2:18 AM, Jagat Singh <[EMAIL PROTECTED]> wrote:
>
>> Hello ,
>>
>> I understand the pain :)
>>
>> Have you seen PigUnit and Penny
>>
>> http://pig.apache.org/docs/r0.10.0/test.html
>>
>>
>>
>> On Fri, Oct 19, 2012 at 8:09 PM, Yang <[EMAIL PROTECTED]> wrote:
>>
>> > one of the greatest pains I face with debugging a pig code is that the
>> > iteration cycles are really long:
>> > the applications for which we use pig typically deal with large dataset,
>> > and if a pig script involves many
>> > JOIN/generate/filter steps, every step takes a lot of time, but every
>> time
>> > I fix one step, I have to run from the start,
>> > which is meaningless.
>> >
>> > what I am doing so far to reduce the meaningless wasted time to re-run
>> > already-debugged steps, is to
>> > manually divide my script into many small scripts, and save the last
>> > variable out into hdfs, and once the
>> > small script is debugged fine, I load the previous variable in the next
>> > small script
>> >
>> > after all small scripts are done, I connect them back manually to the
>> > original big script.
>> >
>> >
>> > is there a way to automate this? for example add a mark around a
>> particular
>> > step, and tells pig
>> > that the result is to be saved up, and all following steps are not to be
>> > executed. and when we move
>> > onto the next step, it knows where to pick up the last-saved data.
>> >
>> > writing a preprocessor to do the above is not trivial so that I can't
>> whip
>> > up something immediately , cuz it needs to figure out the
>> > schemas of variables that propagate through the steps.
>> >
>> >
>> > Thanks
>> > Yang
>> >
>>