> On Dec. 1, 2013, 5:06 p.m., Rohini Palaniswamy wrote:
> > The code is fine if we have union after some processing. But for simple
> > load and union case as below, this will create 3 vertices - 2 load vertices
> > and one union vertex.
> >
> > a = load 'a'
> > b = load 'b'
> > c = union a, b
> >
> > In MR, this is handled in a simple map
> >
> > C: Store(/tmp/tezout:PigStorage) - scope-23
> > |
> > |---C: Union[bag] - scope-22
> > |
> > |---A: New For Each(false,false,false)[bag] - scope-10
> > | | |
> > | ..........
> > |
> > |---B: New For Each(false,false,false)[bag] - scope-21
> > | |
> > | .........
> > |
> > |---B: Load(/tmp/data:org.apache.pig.builtin.PigStorage) -
> > scope-11--------
> >
> > We should also try do that in a single vertex to be more optimal. We can
> > handle that in a separate jira though.
> >
Thank you Rohini for the review!
You're right that we can optimized it once Tez allows multiple inputs on root
vertices. But when I tried to implement union in a single vertex, I ran into
this error-
Caused by: java.lang.IllegalStateException: For now, only a single Root Input
can be added to a Vertex
at org.apache.tez.dag.api.Vertex.addInput(Vertex.java:156)
So it seems not allowed for now.
- Cheolsoo
-----------------------------------------------------------
This is an automatically generated e-mail. To reply, visit:
https://reviews.apache.org/r/15931/#review29567
-----------------------------------------------------------
On Dec. 1, 2013, 7 a.m., Cheolsoo Park wrote:
>
> -----------------------------------------------------------
> This is an automatically generated e-mail. To reply, visit:
> https://reviews.apache.org/r/15931/
> -----------------------------------------------------------
>
> (Updated Dec. 1, 2013, 7 a.m.)
>
>
> Review request for pig, Alex Bain, Daniel Dai, Mark Wagner, and Rohini
> Palaniswamy.
>
>
> Bugs: PIG-3585
> https://issues.apache.org/jira/browse/PIG-3585
>
>
> Repository: pig-git
>
>
> Description
> -------
>
> This patch implements union as follows: load vertices -> broadcast edges ->
> union vertex.
>
> Th changes include:
> * In the front-end, TezCompiler converts POUnion into a new vertex and
> connects it to its predecessors with broadcast edges.
> * In the back-end, a new POPackage class called POBroadcastTezLoad is added.
> This classes implements TezLoad interface, and it pulls every record from
> ShuffledUnorderedKVInputs in order and unions them.
>
>
> Diffs
> -----
>
>
> src/org/apache/pig/backend/hadoop/executionengine/physicalLayer/relationalOperators/Packager.java
> e49de40
>
> src/org/apache/pig/backend/hadoop/executionengine/tez/POBroadcastTezLoad.java
> e69de29
> src/org/apache/pig/backend/hadoop/executionengine/tez/PigProcessor.java
> 9a2b499
> src/org/apache/pig/backend/hadoop/executionengine/tez/TezCompiler.java
> 529bf30
> src/org/apache/pig/backend/hadoop/executionengine/tez/TezDagBuilder.java
> e3f5a5d
> src/org/apache/pig/backend/hadoop/executionengine/tez/TezOperator.java
> dcd6a5a
> test/e2e/pig/tests/tez.conf 7fd5fb1
>
> Diff: https://reviews.apache.org/r/15931/diff/
>
>
> Testing
> -------
>
> * New e2e test case is added.
> * ant test-tez passes.
> * All e2e tests pass.
>
>
> Thanks,
>
> Cheolsoo Park
>
>
