Amit,
Have you explored chainMapper class?
*Devin Suiter*
Jr. Data Solutions Software Engineer
100 Sandusky Street | 2nd Floor | Pittsburgh, PA 15212
Google Voice: 412-256-8556 | www.rdx.com
On Sun, Jan 12, 2014 at 7:28 PM, John Lilley john.lil...@redpoint.netwrote:
Isn’t this is what you’d
More than a solution, I'd like to know if a combiner is allowed to change
the key ? will it interfere with the mappers sort/merge ?
On Mon, Jan 13, 2014 at 3:06 PM, Devin Suiter RDX dsui...@rdx.com wrote:
Amit,
Have you explored chainMapper class?
*Devin Suiter*
Jr. Data Solutions
I believe combine process is after that step, so, no.
What comes out of a mapper is a set of records {k1, v1} {k1, v2} {k1, v(n)}
{k2, v1} {k2, v2} {k2, v(n)} and then reducers aggregate that into arrays
like {k1, {v1, v2, v(n)}}, {k2, {v1, v2, v(n)}} and performs logic on the
value set for each
Isn't this is what you'd normally do in the Mapper?
My understanding of the combiner is that it is like a mapper-side pre-reducer
and operates on blocks of data that have already been sorted by key, so mucking
with the keys doesn't *seem* like a good idea.
john
From: Amit Sela
