Home | About | Sematext search-lucene.com search-hadoop.com
 Search Hadoop and all its subprojects:

Switch to Threaded View
Pig, mail # dev - POStatus.STATUS_NULL Semantics


Copy link to this message
-
Re: POStatus.STATUS_NULL Semantics
Cheolsoo Park 2013-11-12, 16:35
>> I'll post a patch that makes the second option official and changes all
the examples of the first to return null with STATUS_OK (this is what
happens with the constant null currently).

I am +1 for this.
On Fri, Nov 8, 2013 at 10:16 PM, Mark Wagner <[EMAIL PROTECTED]>wrote:

> Hi Devs,
>
> While discussing the Pig on Tez project today, we were unable to reach
> a conclusion on what the semantics of what POStatus.STATUS_NULL are
> and would like to ask those who remember the history of Pig to chime
> in. The two interpretations are:
>
> 1. POStatus.STATUS_NULL indicates that the pulled output IS null. This
> is used in some places like EqualToExpr.
>
> 2. POStatus.STATUS_NULL indicates that the pull did not produce any
> output. This is backed up by it's usage in POPackage for flattening an
> empty bag, and PigGenericMapBase where pulls on the operator pipeline
> that result in STATUS_NULL are discarded.
>
> If nobody has any concrete documentation or explanation for the
> discrepancy, I'll post a patch that makes the second option official
> and changes all the examples of the first to return null with
> STATUS_OK (this is what happens with the constant null currently).
>
> Thanks,
> Mark
>