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From Robert Metzger <rmetz...@apache.org>
Subject Re: How to use static data with streams?
Date Thu, 05 Nov 2015 14:22:20 GMT

you should be able to implement it as you described initially. I would do
the transformation in a map() operator of Flink. The RichMapFunction
provides you with an open() method which is called before the first record
In the open() method, I would read the csv file(s) from HDFS or another
file system accessible by all nodes.

Then, you can access the data from the files in the map operator.

In order to utilize the memory best, I would recommend to start Flink in
the "streaming" mode. (-st argument on YARN). With that enabled, we provide
more memory to streaming operators.
Also, I would only expose one processing slot per TaskManager, this way we
ensure that the files are only read once per TaskManager. (make sure you
have only one TaskManager per machine).

Why did your previous approach fail? Do you still have the error message?


On Thu, Nov 5, 2015 at 3:02 PM, Kashmar, Ali <Ali.Kashmar@emc.com> wrote:

> Hi Robert,
> The CSV file (or files as there will definitely be more than one) can be
> large (let¹s say 1 GB). Memory is not an issue though. Each node has at
> least 64 GB RAM mounted. The CSV files should easily fit in the memory of
> each node.
> Regards,
> Ali
> On 2015-11-05, 6:30 AM, "Robert Metzger" <rmetzger@apache.org> wrote:
> >Hi Ali,
> >
> >I'm excited to hear that EMC is looking into Apache Flink. I think the
> >solution to this problem depends on one question: What is the size of the
> >data in the CSV file compared to the memory you have available in the
> >cluster?
> >Would the mapping table from the file fit into the memory of all nodes
> >running Flink?
> >
> >Regards,
> >Robert
> >
> >PS: Did you subscribe to the mailing list? I've CCed you in case you're
> >not
> >subscribed yet
> >
> >On Wed, Nov 4, 2015 at 4:54 PM, Kashmar, Ali <Ali.Kashmar@emc.com> wrote:
> >
> >> Hi there,
> >>
> >> I¹m trying to design and implement a use case in Flink where I¹m
> >>receiving
> >> protocol packets over a socket. Each packet has the subscriber IMSI in
> >>it
> >> and a bunch of more data. At the same time, I have a csv file with a
> >> mapping from IMSI -> subscriber group. I need to inject the group into
> >> packet and then send it to the sink.
> >>
> >> I¹ve tried loading the CSV into a memory map and then accessing the map
> >> from within the Flink operators but that only works when the CSV is very
> >> small (a few hundred subscribers). I¹ve tried creating another stream
> >>for
> >> the CSV and connecting the streams but that doesn¹t yield anything as I
> >> can¹t have access to objects from both streams at the same time.
> >>
> >> How would you guys approach this?
> >>
> >> Thanks,
> >> Ali
> >>

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