I've been wondering about this. Is there a difference in performance
between these two?
val rdd1 = sc.textFile(files.mkString(",")) val rdd2 = sc.union(files.map(sc
.textFile(_)))
I don't know about your use-case, Meethu, but it may be worth trying to see
if reading all the files into one RDD (like rdd1) would perform better in
the join. (If this is possible in your situation.)
On Tue, Jun 17, 2014 at 6:45 PM, Andrew Or <and...@databricks.com> wrote:
> How long does it get stuck for? This is a common sign for the OS thrashing
> due to out of memory exceptions. If you keep it running longer, does it
> throw an error?
>
> Depending on how large your other RDD is (and your join operation), memory
> pressure may or may not be the problem at all. It could be that spilling
> your shuffles
> to disk is slowing you down (but probably shouldn't hang your
> application). For the 5 RDDs case, what happens if you set
> spark.shuffle.spill to false?
>
>
> 2014-06-17 5:59 GMT-07:00 MEETHU MATHEW <meethu2...@yahoo.co.in>:
>
>
>> Hi all,
>>
>> I want to do a recursive leftOuterJoin between an RDD (created from
>> file) with 9 million rows(size of the file is 100MB) and 30 other
>> RDDs(created from 30 diff files in each iteration of a loop) varying from 1
>> to 6 million rows.
>> When I run it for 5 RDDs,its running successfully in 5 minutes.But when
>> I increase it to 10 or 30 RDDs its gradually slowing down and finally
>> getting stuck without showing any warning or error.
>>
>> I am running in standalone mode with 2 workers of 4GB each and a total
>> of 16 cores .
>>
>> Any of you facing similar problems with JOIN or is it a problem with my
>> configuration.
>>
>> Thanks & Regards,
>> Meethu M
>>
>
>
