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https://issues.apache.org/jira/browse/FLUME-2403?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14033331#comment-14033331
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Roshan Naik commented on FLUME-2403:
------------------------------------
Flume was designed around providing "at least once" delivery guarantees for
streaming 'smallish objects' (or events). As you have pointed out already, it
is suboptimal for handling large objects and would need a different
architecture.
You could write a custom flume interceptor do drop large objects.
> Spillable Memory Channel causes OOME for large messages.
> --------------------------------------------------------
>
> Key: FLUME-2403
> URL: https://issues.apache.org/jira/browse/FLUME-2403
> Project: Flume
> Issue Type: Bug
> Components: Channel
> Affects Versions: v1.5.0
> Reporter: Adam Gent
> Priority: Critical
>
> The spillable memory channel will fail rather badly on large messages.
> {code}
> Error while writing to required channel: FileChannel es1 { dataDirs:
> [/var/lib/flume/data] }
> java.lang.OutOfMemoryError: Java heap space
> at java.util.Arrays.copyOf(Arrays.java:2271)
> at java.io.ByteArrayOutputStream.grow(ByteArrayOutputStream.java:113)
> at
> java.io.ByteArrayOutputStream.ensureCapacity(ByteArrayOutputStream.java:93)
> at java.io.ByteArrayOutputStream.write(ByteArrayOutputStream.java:140)
> at
> com.google.protobuf.CodedOutputStream.writeRawBytes(CodedOutputStream.java:984)
> at
> com.google.protobuf.CodedOutputStream.writeRawBytes(CodedOutputStream.java:905)
> at
> com.google.protobuf.CodedOutputStream.writeBytesNoTag(CodedOutputStream.java:386)
> at
> com.google.protobuf.CodedOutputStream.writeBytes(CodedOutputStream.java:229)
> at
> org.apache.flume.channel.file.proto.ProtosFactory$FlumeEvent.writeTo(ProtosFactory.java:6259)
> at
> com.google.protobuf.CodedOutputStream.writeMessageNoTag(CodedOutputStream.java:380)
> at
> com.google.protobuf.CodedOutputStream.writeMessage(CodedOutputStream.java:222)
> at
> org.apache.flume.channel.file.proto.ProtosFactory$Put.writeTo(ProtosFactory.java:4112)
> at
> com.google.protobuf.AbstractMessageLite.writeDelimitedTo(AbstractMessageLite.java:90)
> at org.apache.flume.channel.file.Put.writeProtos(Put.java:93)
> at
> org.apache.flume.channel.file.TransactionEventRecord.toByteBuffer(TransactionEventRecord.java:174)
> at org.apache.flume.channel.file.Log.put(Log.java:611)
> at
> org.apache.flume.channel.file.FileChannel$FileBackedTransaction.doPut(FileChannel.java:458)
> at
> org.apache.flume.channel.BasicTransactionSemantics.put(BasicTransactionSemantics.java:93)
> at
> org.apache.flume.channel.SpillableMemoryChannel$SpillableMemoryTransaction.commitPutsToOverflow(SpillableMemoryChannel.java:490)
> at
> org.apache.flume.channel.SpillableMemoryChannel$SpillableMemoryTransaction.putCommit(SpillableMemoryChannel.java:480)
> at
> org.apache.flume.channel.SpillableMemoryChannel$SpillableMemoryTransaction.doCommit(SpillableMemoryChannel.java:401)
> at
> org.apache.flume.channel.BasicTransactionSemantics.commit(BasicTransactionSemantics.java:151)
> at
> org.apache.flume.channel.ChannelProcessor.processEvent(ChannelProcessor.java:267)
> at
> org.apache.flume.source.rabbitmq.RabbitMQSource.process(RabbitMQSource.java:162)
> at
> org.apache.flume.source.PollableSourceRunner$PollingRunner.run(PollableSourceRunner.java:139)
> at java.lang.Thread.run(Thread.java:744)
> {code}
> My config:
> {code}
> agent.channels.es1.type = SPILLABLEMEMORY
> agent.channels.es1.memoryCapacity = 10000
> agent.channels.es1.overflowCapacity = 1000000
> agent.channels.es1.byteCapacity = 800000
> agent.channels.es1.checkpointDir = /var/lib/flume/checkpoint
> agent.channels.es1.dataDirs = /var/lib/flume/data
> {code}
> I haven't looked at the code but I have some concerns like why a
> ByteArrayOutputStream is being used instead of some other buffered stream
> directly to the file system? Perhaps its because of the transactional nature
> but I'm pretty sure you can write to the filesystem and rollback as Kafka and
> modern databases do this with fsync.
> One could argue that I should just raise the max heap but this message is
> coming from a RabbitMQ which had no issue holding on to the message (I
> believe the message is like 500K).
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