java.lang.OutOfMemoryError: Java heap space wih Flume

zaher_mahdhi — Tue, 26 Jul 2016 16:28:22 GMT

Hi,

I'm using Flume to collect data from a Spool Directory. My configuration is as follows:

agent1.sources = source1
agent1.sinks = sink1
agent1.channels = channel2
agent1.sources.source1.channels = channel2
agent1.sinks.sink1.channel = channel2
agent1.sources.source1.type = spooldir
agent1.sources.source1.basenameHeader = true
agent1.sources.source1.spoolDir = /root/flume_example/spooldir

agent1.sinks.sink1.type = hdfs
agent1.sinks.sink1.hdfs.path = /user/root/flume
agent1.sinks.sink1.hdfs.filePrefix = %{basename}
agent1.sinks.sink1.hdfs.fileSuffix = .csv
agent1.sinks.sink1.hdfs.idleTimeout = 5


agent1.sinks.sink1.hdfs.rollSize = 0
agent1.sinks.sink1.hdfs.rollCount = 100000
agent1.sinks.sink1.hdfs.fileType = DataStream
agent1.channels.channel2.type = file

When placing 43MB file in spooldir, flume starts writing files into HDFS Directory /user/root/flume:

-rw-r--r--   3 root hdfs      7.9 M 2016-07-26 11:10 /user/root/flume/filename.csv.1469524239209.csv
-rw-r--r--   3 root hdfs      7.6 M 2016-07-26 11:11 /user/root/flume/filename.csv.1469524239210.csv

But a java.lang.OutOfMemoryError: Java heap space error is raised:

ERROR channel.ChannelProcessor: Error while writing to required channel: FileChannel channel2 { dataDirs: [/root/.flume/file-channel/data] }
java.lang.OutOfMemoryError: Java heap space
    at java.util.HashMap.resize(HashMap.java:703)
    at java.util.HashMap.putVal(HashMap.java:662)
    at java.util.HashMap.put(HashMap.java:611)
    at org.apache.flume.channel.file.EventQueueBackingStoreFile.put(EventQueueBackingStoreFile.java:338)
    at org.apache.flume.channel.file.FlumeEventQueue.set(FlumeEventQueue.java:287)
    at org.apache.flume.channel.file.FlumeEventQueue.add(FlumeEventQueue.java:317)
    at org.apache.flume.channel.file.FlumeEventQueue.addTail(FlumeEventQueue.java:211)
    at org.apache.flume.channel.file.FileChannel$FileBackedTransaction.doCommit(FileChannel.java:553)
    at org.apache.flume.channel.BasicTransactionSemantics.commit(BasicTransactionSemantics.java:151)
    at org.apache.flume.channel.ChannelProcessor.processEventBatch(ChannelProcessor.java:192)
    at org.apache.flume.source.SpoolDirectorySource$SpoolDirectoryRunnable.run(SpoolDirectorySource.java:235)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)
16/07/26 11:10:59 ERROR source.SpoolDirectorySource: FATAL: Spool Directory source source1: { spoolDir: /root/flume_example/spooldir }: Uncaught exception in SpoolDirectorySource thread. Restart or reconfigure Flume to continue processing.
java.lang.OutOfMemoryError: Java heap space
    at java.util.HashMap.resize(HashMap.java:703)
    at java.util.HashMap.putVal(HashMap.java:662)
    at java.util.HashMap.put(HashMap.java:611)
    at org.apache.flume.channel.file.EventQueueBackingStoreFile.put(EventQueueBackingStoreFile.java:338)
    at org.apache.flume.channel.file.FlumeEventQueue.set(FlumeEventQueue.java:287)
    at org.apache.flume.channel.file.FlumeEventQueue.add(FlumeEventQueue.java:317)
    at org.apache.flume.channel.file.FlumeEventQueue.addTail(FlumeEventQueue.java:211)
    at org.apache.flume.channel.file.FileChannel$FileBackedTransaction.doCommit(FileChannel.java:553)
    at org.apache.flume.channel.BasicTransactionSemantics.commit(BasicTransactionSemantics.java:151)
    at org.apache.flume.channel.ChannelProcessor.processEventBatch(ChannelProcessor.java:192)
    at org.apache.flume.source.SpoolDirectorySource$SpoolDirectoryRunnable.run(SpoolDirectorySource.java:235)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:308)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$301(ScheduledThreadPoolExecutor.java:180)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:294)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
    at java.lang.Thread.run(Thread.java:745)

Any idea how can I fix this issue ?

Thanks.

Re: java.lang.OutOfMemoryError: Java heap space wih Flume

zaher_mahdhi — Tue, 26 Jul 2016 17:52:25 GMT

Problem solved, I changed the channel type from file to memory

agent1.channels.channel2.type = memory

Answers about how to make it work with a channel type file are welcome.

Re: java.lang.OutOfMemoryError: Java heap space wih Flume

bluesmix — Tue, 26 Jul 2016 21:58:10 GMT

Default transactionCapacity for file channel is 10 000. For memory channel - 100

Thats why it works for you. Add transactionCapacity property to your file channel or increase memory available for flume process (like -Xmx1024m)

Re: java.lang.OutOfMemoryError: Java heap space wih Flume

MrBee — Wed, 27 Jul 2016 01:00:40 GMT

Hi @Zaher,

Depending on your data you should care about the channel you choose. The memory-channel is simple and easy, but data is lost when the Flume-agent crashes (OutOfMemory) most likely, or power/hardware-issues also likely... There are channels with higher durability for your data. The filechannel is very durable when underlaying storage is redundant as well.

Take a look at the flume-channels and there configuration options.

For your OutOfMem-problem you can decrease the transaction and batch capacity and increase the heap in the flume-env config in Ambari as @Michael Miklavcic suggests.

Re: java.lang.OutOfMemoryError: Java heap space wih Flume

zaher_mahdhi — Wed, 27 Jul 2016 16:17:25 GMT

Thank you @Michael M and @Alexander Bij for your valuable help.

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