Hello Everyone

I am a newbie to pig. I was going through https://cwiki.apache.org/PIG/guide-for-new-contributors.html, specifically the grammar files to start off with.  

I could not understand how LogicalPlanGenerator.g works by looking into the grammar file. Also there isn't much documentation available which explains how logical plans are generated for different pig operators. Is there any reference from which I can learn more about the internals (especially the logical plan generation part)?

Thanks
Prasanth

Hello Everyone

I am a newbie to pig. I was going through
https://cwiki.apache.org/PIG/guide-for-new-contributors.html, specifically
the grammar files to start off with.

I could not understand how LogicalPlanGenerator.g works by looking into the
grammar file. Also there isn't much documentation available which explains
how logical plans are generated for different pig operators. Is there any
reference from which I can learn more about the internals (especially the
logical plan generation part)?

Thanks
Prasanth

Hi, Prasanth,
Check http://wiki.apache.org/pig/PigLogicalPlanOptimizerRewrite. It is
not up-to-date but capture the basic design of logical plan.

Daniel

On Sun, Jan 29, 2012 at 8:41 PM, Prasanth J <[EMAIL PROTECTED]> wrote:
> Hello Everyone
>
> I am a newbie to pig. I was going through
> https://cwiki.apache.org/PIG/guide-for-new-contributors.html, specifically
> the grammar files to start off with.
>
> I could not understand how LogicalPlanGenerator.g works by looking into the
> grammar file. Also there isn't much documentation available which explains
> how logical plans are generated for different pig operators. Is there any
> reference from which I can learn more about the internals (especially the
> logical plan generation part)?
>
> Thanks
> Prasanth

Thanks Daniel. I will look into it.
The images in the link(also some more links in wiki) seems to be broken. Is there any hack to fix it?

Thanks
Prasanth

On Jan 30, 2012, at 2:09 PM, Daniel Dai wrote:

> Hi, Prasanth,
> Check http://wiki.apache.org/pig/PigLogicalPlanOptimizerRewrite. It is
> not up-to-date but capture the basic design of logical plan.
>
> Daniel
>
> On Sun, Jan 29, 2012 at 8:41 PM, Prasanth J <[EMAIL PROTECTED]> wrote:
>> Hello Everyone
>>
>> I am a newbie to pig. I was going through
>> https://cwiki.apache.org/PIG/guide-for-new-contributors.html, specifically
>> the grammar files to start off with.
>>
>> I could not understand how LogicalPlanGenerator.g works by looking into the
>> grammar file. Also there isn't much documentation available which explains
>> how logical plans are generated for different pig operators. Is there any
>> reference from which I can learn more about the internals (especially the
>> logical plan generation part)?
>>
>> Thanks
>> Prasanth

See initial sections in
http://infolab.stanford.edu/~olston/publications/vldb09.pdf for overview
of logical plan.

LogicalPlanGenerator.g is a the place where logical plan is created from
parse tree. You would need to look at antlr basics to understand that.

(almost?) all pig relational operations correspond to a subclass of
LogicalRelationalOperator in org.apache.pig.newplan.logical.relational
package. Expressions within a relation are subclasses of
LogicalExpressionOperator.
This document talks about motivations behind the logical plan redesign
and about some special operations like LOInnerLoad, and special handling
for foreach operator.

http://wiki.apache.org/pig/PigLogicalPlanOptimizerRewrite

-Thejas
On 1/29/12 8:41 PM, Prasanth J wrote:
> Hello Everyone
>
> I am a newbie to pig. I was going through
> https://cwiki.apache.org/PIG/guide-for-new-contributors.html, specifically
> the grammar files to start off with.
>
> I could not understand how LogicalPlanGenerator.g works by looking into the
> grammar file. Also there isn't much documentation available which explains
> how logical plans are generated for different pig operators. Is there any
> reference from which I can learn more about the internals (especially the
> logical plan generation part)?
>
> Thanks
> Prasanth
>