Hi,

Seems you have such a large window (24 hours), so the phenomena of memory 
increasing is expectable, because of window operation will cache the RDD within 
this window in memory. So for your requirement, memory should be enough to hold 
the data of 24 hours.

I don't think checkpoint in Spark Streaming can alleviate such problem, because 
checkpoint are mainly for fault tolerance.

Thanks
Jerry

From: balu.naren [mailto:balu.na...@gmail.com]
Sent: Tuesday, January 20, 2015 7:17 PM
To: user@spark.apache.org
Subject: spark streaming with checkpoint


I am a beginner to spark streaming. So have a basic doubt regarding 
checkpoints. My use case is to calculate the no of unique users by day. I am 
using reduce by key and window for this. Where my window duration is 24 hours 
and slide duration is 5 mins. I am updating the processed record to mongodb. 
Currently I am replace the existing record each time. But I see the memory is 
slowly increasing over time and kills the process after 1 and 1/2 hours(in aws 
small instance). The DB write after the restart clears all the old data. So I 
understand checkpoint is the solution for this. But my doubt is

  *   What should my check point duration be..? As per documentation it says 
5-10 times of slide duration. But I need the data of entire day. So it is ok to 
keep 24 hrs.
  *   Where ideally should the checkpoint be..? Initially when I receive the 
stream or just before the window operation or after the data reduction has 
taken place.

Appreciate your help.
Thank you

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