Same rdd means same sparkcontext means same workers Cache/persist the rdd to avoid repeated jobs On Jan 17, 2016 5:21 AM, "Mennour Rostom" <mennou...@gmail.com> wrote:
> Hi, > > Thank you all for your answers, > > If I correctly understand, actions (in my case foreach) can be run > concurrently and simultaneously on the SAME rdd, (which is logical because > they are read only object). however, I want to know if the same workers are > used for the concurrent analysis ? > > Thank you > > 2016-01-15 21:11 GMT+01:00 Jakob Odersky <joder...@gmail.com>: > >> I stand corrected. How considerable are the benefits though? Will the >> scheduler be able to dispatch jobs from both actions simultaneously (or on >> a when-workers-become-available basis)? >> >> On 15 January 2016 at 11:44, Koert Kuipers <ko...@tresata.com> wrote: >> >>> we run multiple actions on the same (cached) rdd all the time, i guess >>> in different threads indeed (its in akka) >>> >>> On Fri, Jan 15, 2016 at 2:40 PM, Matei Zaharia <matei.zaha...@gmail.com> >>> wrote: >>> >>>> RDDs actually are thread-safe, and quite a few applications use them >>>> this way, e.g. the JDBC server. >>>> >>>> Matei >>>> >>>> On Jan 15, 2016, at 2:10 PM, Jakob Odersky <joder...@gmail.com> wrote: >>>> >>>> I don't think RDDs are threadsafe. >>>> More fundamentally however, why would you want to run RDD actions in >>>> parallel? The idea behind RDDs is to provide you with an abstraction for >>>> computing parallel operations on distributed data. Even if you were to call >>>> actions from several threads at once, the individual executors of your >>>> spark environment would still have to perform operations sequentially. >>>> >>>> As an alternative, I would suggest to restructure your RDD >>>> transformations to compute the required results in one single operation. >>>> >>>> On 15 January 2016 at 06:18, Jonathan Coveney <jcove...@gmail.com> >>>> wrote: >>>> >>>>> Threads >>>>> >>>>> >>>>> El viernes, 15 de enero de 2016, Kira <mennou...@gmail.com> escribió: >>>>> >>>>>> Hi, >>>>>> >>>>>> Can we run *simultaneous* actions on the *same RDD* ?; if yes how can >>>>>> this >>>>>> be done ? >>>>>> >>>>>> Thank you, >>>>>> Regards >>>>>> >>>>>> >>>>>> >>>>>> -- >>>>>> View this message in context: >>>>>> http://apache-spark-user-list.1001560.n3.nabble.com/simultaneous-actions-tp25977.html >>>>>> Sent from the Apache Spark User List mailing list archive at >>>>>> Nabble.com <http://nabble.com>. >>>>>> >>>>>> --------------------------------------------------------------------- >>>>>> To unsubscribe, e-mail: user-unsubscr...@spark.apache.org >>>>>> For additional commands, e-mail: user-h...@spark.apache.org >>>>>> >>>>>> >>>> >>>> >>> >> >
