[
https://issues.apache.org/jira/browse/SPARK-2044?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14019531#comment-14019531
]
Raymond Liu commented on SPARK-2044:
------------------------------------
Hi Matei
regarding the changes to block mnager:
That will allow ShuffleManagers to reuse a common block manager.
However the interface also allows ShuffleManagers to try new approaches.
Have you figure out what the interface should looks like? I see the shuffle
writter/read interface is generalize to be a Product2, while eventually, the
specific shuffle module will interaction with the disk, and go through
blockmanager. will you expect it to be Product2 when talk with
DiskBlockmanager, or keep the current implementation by using Files where a lot
of shortcut involved in various components say shuffle, spill etc? or anything
else like a buf , iterator etc?
Since we have also have pluggable storage support in mind spark-1733. the
actually IO for a store, even diskstroe might not always go though FILE
interface. so I have this question.
> Pluggable interface for shuffles
> --------------------------------
>
> Key: SPARK-2044
> URL: https://issues.apache.org/jira/browse/SPARK-2044
> Project: Spark
> Issue Type: Improvement
> Components: Shuffle, Spark Core
> Reporter: Matei Zaharia
> Assignee: Matei Zaharia
> Attachments: Pluggableshuffleproposal.pdf
>
>
> Given that a lot of the current activity in Spark Core is in shuffles, I
> wanted to propose factoring out shuffle implementations in a way that will
> make experimentation easier. Ideally we will converge on one implementation,
> but for a while, this could also be used to have several implementations
> coexist. I'm suggesting this because I aware of at least three efforts to
> look at shuffle (from Yahoo!, Intel and Databricks). Some of the things
> people are investigating are:
> * Push-based shuffle where data moves directly from mappers to reducers
> * Sorting-based instead of hash-based shuffle, to create fewer files (helps a
> lot with file handles and memory usage on large shuffles)
> * External spilling within a key
> * Changing the level of parallelism or even algorithm for downstream stages
> at runtime based on statistics of the map output (this is a thing we had
> prototyped in the Shark research project but never merged in core)
> I've attached a design doc with a proposed interface. It's not too crazy
> because the interface between shuffles and the rest of the code is already
> pretty narrow (just some iterators for reading data and a writer interface
> for writing it). Bigger changes will be needed in the interaction with
> DAGScheduler and BlockManager for some of the ideas above, but we can handle
> those separately, and this interface will allow us to experiment with some
> short-term stuff sooner.
> If things go well I'd also like to send a sort-based shuffle implementation
> for 1.1, but we'll see how the timing on that works out.
--
This message was sent by Atlassian JIRA
(v6.2#6252)
