MultiIterator Class

[Yamini Joshi <ya...@gmail.com>]

Hello All

I just came across this iterator:
https://github.com/apache/accumulo/blob/e900e67425d950bd4c0c5288a6270d7b362ac458/core/src/main/java/org/apache/accumulo/core/iterators/system/MultiIterator.java

Can someone tell me what exactly can it be used for?
Can it be used to sort data acquired from batch_scan before passing the
data to other iterators?

Best regards,
Yamini Joshi

Re: MultiIterator Class

[Dylan Hutchison <dh...@cs.washington.edu>]

The MultiIterator is used internally in Accumulo to merge sorted streams of
data together.  For example, merging sorted data from several RFiles and an
in-memory map.  It does not sort, nor could it without materializing part
or all of the data stream.

Poking inside Accumulo is fun, isn't it?  Do write down your experiences
and thoughts as you explore Accumulo's architecture.  We're always open for
suggestions and contributions.  I was in exactly your place when I worked
on the Graphulo library.

Cheers, Dylan

On Fri, Oct 21, 2016 at 11:56 AM, Yamini Joshi <ya...@gmail.com>
wrote:

> Hello All
>
> I just came across this iterator:
> https://github.com/apache/accumulo/blob/e900e67425d950bd4c0c5288a6270d
> 7b362ac458/core/src/main/java/org/apache/accumulo/core/iterators/system/
> MultiIterator.java
>
> Can someone tell me what exactly can it be used for?
> Can it be used to sort data acquired from batch_scan before passing the
> data to other iterators?
>
> Best regards,
> Yamini Joshi
>