Matei,
Thanks for the insight, we have to carefully consider our design. We
are in the processing moving our system to Akka, it would be nice to use Akka
all the way. But I understand the limitations.
Thanks
Chester
On Monday, June 9, 2014 5:06 PM, Matei Zaharia <matei.zaha...@gmail.com> wrote:
In general you probably shouldn’t use actors for processing requests because
Spark operations are blocking, and Akka only has a limited thread pool for each
ActorSystem. You risk blocking all the threads with ongoing requests and not
being able to service new ones. That said though, you can configure Akka to
spawn more threads and in that case it would probably be okay. See
http://doc.akka.io/docs/akka/snapshot/java/dispatchers.html for some details on
Akka thread usage and how to configure it.
Matei
On Jun 9, 2014, at 4:54 PM, Chester Chen <chesterxgc...@yahoo.com> wrote:
Matei,
>If we use different Akka actors to process different user's requests, (not
>different threads), is the SparkContext still safe to use for different users
>?
>
>
>Yes, it would be nice to disable UI via configuration,especially when we
>develop locally. We use sbt-web plugin to debug tomcat code. If we can disable
>the UI http Server; it would be much simpler to handle than having two http
>containers to deal with.
>
>
>Chester
>
>
>
>
>
>On Monday, June 9, 2014 4:35 PM, Matei Zaharia <matei.zaha...@gmail.com> wrote:
>
>
>
>You currently can’t have multiple SparkContext objects in the same JVM, but
>within a SparkContext, all of the APIs are thread-safe so you can share that
>context between multiple threads. The other issue you’ll run into is that in
>each thread where you want to use Spark, you need to use SparkEnv.set(env)
>where “env” was obtained by SparkEnv.get in the thread that created the
>context. This requirement will hopefully go away soon.
>
>Unfortunately there’s no way yet to disable the UI — feel free to open a JIRA
>for it, it shouldn’t be hard to do.
>
>Matei
>
>
>On Jun 9, 2014, at 3:50 PM, DB Tsai <dbt...@stanford.edu> wrote:
>
>> Hi guys,
>>
>> We would like to use spark hadoop api to get the first couple hundred
>> lines in design time to quickly show users the file-structure/meta
>> data, and the values in those lines without launching the full spark
>> job in cluster.
>>
>> Since we're web-based application, there will be multiple users using
>> the spark hadoop api, for
exmaple, sc.textFile(filePath). I wonder if
>> those APIs are thread-safe in local mode (each user will have its own
>> SparkContext object).
>>
>> Secondly, it seems that even in local mode, the jetty UI tracker will
>> be lunched. For this kind of cheap operation, having jetty UI tracker
>> for each operation will be very expensive. Is there a way to disable
>> this behavior?
>>
>> Thanks.
>>
>> Sincerely,
>>
>> DB Tsai
>> -------------------------------------------------------
>> My Blog: https://www.dbtsai.com
>> LinkedIn: https://www.linkedin.com/in/dbtsai
>
>
>
