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From Robert Metzger <rmetz...@apache.org>
Subject Re: Flink and Spark
Date Fri, 26 Dec 2014 15:12:45 GMT
For the Python API, there is a pending pull request:
https://github.com/apache/incubator-flink/pull/202 It is still work in
progress, but feedback is, as always, appreciated.



On Fri, Dec 26, 2014 at 3:41 PM, Samarth Mailinglist <
mailinglistsamarth@gmail.com> wrote:

> Thanks a lot Márton and Gyula!
>
> On Fri, Dec 26, 2014 at 2:42 PM, Márton Balassi <balassi.marton@gmail.com>
> wrote:
>
>> Hey,
>>
>> You can find some ml examples like LinerRegression [1, 2] or KMeans [3,
>> 4] in the examples package in both java and scala as a quickstart.
>>
>> [1]
>> https://github.com/apache/incubator-flink/blob/release-0.8/flink-examples/flink-java-examples/src/main/java/org/apache/flink/examples/java/ml/LinearRegression.java
>> [2]
>> https://github.com/apache/incubator-flink/blob/release-0.8/flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/ml/LinearRegression.scala
>> [3]
>> https://github.com/apache/incubator-flink/blob/release-0.8/flink-examples/flink-java-examples/src/main/java/org/apache/flink/examples/java/clustering/KMeans.java
>> [4]
>> https://github.com/apache/incubator-flink/blob/release-0.8/flink-examples/flink-scala-examples/src/main/scala/org/apache/flink/examples/scala/clustering/KMeans.scala
>>
>> On Fri, Dec 26, 2014 at 7:31 AM, Samarth Mailinglist <
>> mailinglistsamarth@gmail.com> wrote:
>>
>>> Thank you the answers, folks.
>>> Can anyone provide me a link for any implementation of an ML algorithm
>>> on Flink?
>>>
>>> On Thu, Dec 25, 2014 at 8:07 PM, Gyula Fóra <gyfora@apache.org> wrote:
>>>
>>>> Hey,
>>>>
>>>> 1-2. As for failure recovery, there is a difference how the Flink batch
>>>> and streaming programs handle failures. The failed parts of the batch jobs
>>>> currently restart upon failures but there is an ongoing effort on fine
>>>> grained fault tolerance which is somewhat similar to sparks lineage
>>>> tracking. (so technically this is exactly once semantic but that is
>>>> somewhat meaningless for batch jobs)
>>>>
>>>> For streaming programs we are currently working on fault tolerance, we
>>>> are hoping to support at least once processing guarantees in the 0.9
>>>> release. After that we will focus our research efforts on an high
>>>> performance implementation of exactly once processing semantics, which is
>>>> still a hard topic in streaming systems. Storm's trident's exaclty once
>>>> semantics can only provide very low throughput while we are trying hard to
>>>> avoid this issue, as our streaming system is capable of much higher
>>>> throughput than storm in general as you can see on some perf measurements.
>>>>
>>>> 3. There are already many ml algorithms implemented for Flink but they
>>>> are scattered all around. We are planning to collect them in a machine
>>>> learning library soon. We are also implementing an adapter for Samoa which
>>>> will provide some streaming machine learning algorithms as well. Samoa
>>>> integration should be ready in January.
>>>>
>>>> 4. Flink carefully manages its memory use to avoid heap errors, and
>>>> utilizing memory space as effectively as it can. The optimizer for batch
>>>> programs also takes care of a lot of optimization steps that the user would
>>>> manually have to do in other system, like optimizing the order of
>>>> transformations etc. There are of course parts of the program that still
>>>> needs to modified for maximal performance, for example parallelism settings
>>>> for some operators in some cases.
>>>>
>>>> 5. As for the status of the Python API I personally cannot say very
>>>> much, maybe someone can jump in and help me with that question :)
>>>>
>>>> Regards,
>>>> Gyula
>>>>
>>>> On Thu, Dec 25, 2014 at 11:58 AM, Samarth Mailinglist <
>>>> mailinglistsamarth@gmail.com> wrote:
>>>>
>>>>> Thank you for your answer. I have a couple of follow up questions:
>>>>> 1. Does it support 'exactly once semantics' that Spark and Storm
>>>>> support?
>>>>> 2. (Related to 1) What happens when an error occurs during processing?
>>>>> 3. Is there a plan for adding Machine Learning support on top of
>>>>> Flink? Say Alternative Least Squares, Basic Naive Bayes?
>>>>> 4. When you say Flink manages itself, does it mean I don't have to
>>>>> fiddle with number of partitions (Spark), number of reduces / happers
>>>>> (Hadoop?) to optimize performance? (In some cases this might be needed)
>>>>> 5. How far along is the Python API? I don't see the specs in the
>>>>> Website.
>>>>>
>>>>> On Thu, Dec 25, 2014 at 4:31 AM, Márton Balassi <mbalassi@apache.org>
>>>>> wrote:
>>>>>
>>>>>> Dear Samarth,
>>>>>>
>>>>>> Besides the discussions you have mentioned [1] I can recommend one
of
>>>>>> our recent presentations [2], especially the distinguishing Flink
section
>>>>>> (from slide 16).
>>>>>>
>>>>>> It is generally a difficult question as both the systems are rapidly
>>>>>> evolving, so the answer can become outdated quite fast. However there
are
>>>>>> fundamental design features that are highly unlikely to change, for
example
>>>>>> Spark uses "true" batch processing, meaning that intermediate results
are
>>>>>> materialized (mostly in memory) as RDDs. Flink's engine is internally
more
>>>>>> like streaming, forwarding the results to the next operator asap.
The
>>>>>> latter can yield performance benefits for more complex jobs. Flink
also
>>>>>> gives you a query optimizer, spills gracefully to disk when the system
runs
>>>>>> out of memory and has some cool features around serialization. For
>>>>>> performance numbers and some more insight please check out the presentation
>>>>>> [2] and do not hesitate to post a follow-up mail here if you come
across
>>>>>> something unclear or extraordinary.
>>>>>>
>>>>>> [1]
>>>>>> http://apache-flink-incubator-mailing-list-archive.1008284.n3.nabble.com/template/NamlServlet.jtp?macro=search_page&node=1&query=spark
>>>>>> [2] http://www.slideshare.net/GyulaFra/flink-apachecon
>>>>>>
>>>>>> Best,
>>>>>>
>>>>>> Marton
>>>>>>
>>>>>> On Tue, Dec 23, 2014 at 6:19 PM, Samarth Mailinglist <
>>>>>> mailinglistsamarth@gmail.com> wrote:
>>>>>>
>>>>>>> Hey folks, I have a noob question.
>>>>>>>
>>>>>>> I already looked up the archives and saw a couple of discussions
>>>>>>> <http://apache-flink-incubator-mailing-list-archive.1008284.n3.nabble.com/template/NamlServlet.jtp?macro=search_page&node=1&query=spark>
>>>>>>> about Spark and Flink.
>>>>>>>
>>>>>>> I am familiar with spark (the python API, esp MLLib), and I see
many
>>>>>>> similarities between Flink and Spark.
>>>>>>>
>>>>>>> How does Flink distinguish itself from Spark?
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>

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