[ "Aha!", you say, "now I know why this guy's been doing so much tshark stuff!"
(-: ]
Hi. I'm running into a strange situation, in which more or less all of the
topics on our Kafka server behave exactly as expected... but the data produced
by one family of applications is producing fairly frequent topic corruption.
When this happens, on the client side, the results are all over the place:
sometimes you get a ConsumerFetchSizeTooSmall exception, or an exception for an
unknown error type, or an invalid-offset error, it's all over the map.
On the server side, I think something like this is the first sign of badness:
[2014-08-11 21:03:28,121] ERROR [KafkaApi-1] Error processing ProducerRequest
with correlation id 6750 from client test-producer on partition [mytopic,9]
(kafka.server.KafkaApis)
java.lang.ArrayIndexOutOfBoundsException
[2014-08-11 21:03:28,121] INFO [KafkaApi-1] Send the close connection response
due to error handling produce request [clientId = test-producer, correlationId
= 6750, topicAndPartition = [mytopic,9]] with Ack=0 (kafka.server.KafkaApis)
shortly thereafter, you begin to see oddness facing the clients:
[2014-08-11 21:17:58,132] ERROR [KafkaApi-1] Error when processing fetch
request for partition [mytopic,9] offset 1327 from consumer with correlation id
87204 (kafka.server.KafkaApis)
java.lang.IllegalStateException: Invalid message size: 0
at kafka.log.FileMessageSet.searchFor(FileMessageSet.scala:127)
at kafka.log.LogSegment.translateOffset(LogSegment.scala:100)
at kafka.log.LogSegment.read(LogSegment.scala:137)
at kafka.log.Log.read(Log.scala:386)
at
kafka.server.KafkaApis.kafka$server$KafkaApis$$readMessageSet(KafkaApis.scala:530)
at
kafka.server.KafkaApis$$anonfun$kafka$server$KafkaApis$$readMessageSets$1.apply(KafkaApis.scala:476)
at
kafka.server.KafkaApis$$anonfun$kafka$server$KafkaApis$$readMessageSets$1.apply(KafkaApis.scala:471)
at
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
at
scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:244)
at
scala.collection.immutable.HashMap$HashMap1.foreach(HashMap.scala:224)
at
scala.collection.immutable.HashMap$HashTrieMap.foreach(HashMap.scala:403)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:244)
at scala.collection.AbstractTraversable.map(Traversable.scala:105)
at
kafka.server.KafkaApis.kafka$server$KafkaApis$$readMessageSets(KafkaApis.scala:471)
at kafka.server.KafkaApis.handleFetchRequest(KafkaApis.scala:437)
at kafka.server.KafkaApis.handle(KafkaApis.scala:186)
at kafka.server.KafkaRequestHandler.run(KafkaRequestHandler.scala:42)
at java.lang.Thread.run(Unknown Source)
If I go run the DumpLogSegments tool on the particular topic and partition
that's generating the errors, I can see there's corruption in the log:
Non-secutive offsets in :/data/d3/kafka/log/mytopic-9/00000000000000000000.log
1327 is followed by 1327
The only thing producing data to corrupted topics was also the only thing where
snappy compression was turned on in the Java API being used by the producer
(it's a Storm topology; we've had the same issue with one in Scala and with one
that produces very similar data, but that was written in Java). We turned that
off, published to a different topic name (so it was created fresh), and had a
couple of happy days where all was well. Then we decided that all was well so
we tried to go back to the original topic -- after we'd verified that all data
had aged out of the logs for that topic. And we started seeing errors again.
So we switched to a different topic again, let it be created, and also started
seeing errors on that topic.
We have other producers, written in C and Java and python, which are working
flawlessly, even though the size of the data they produce and the rate at which
they produce it is much larger than what we're seeing with this one problematic
producer. We also have producers written in other languages that produce at
very low rates, so it's (probably) not the sort of thing where the issue is
masked by more frequent data production.
But in any case it looks like there's something the client can send that will
corrupt the topic, which seems like something that shouldn't be able to happen.
I know there's at least some error checking for bad protocol requests, as I
hacked a python client to produce some corrupt messages and saw an error
response from the server.
I'm happy to supply more data but I'm not sure what would be useful. I'm also
fine with continuing to dig into this on my own but I'd reached a point where
it'd be useful to know if anyone had seen something like this before. I have a
ton o' tcpdumps running and some tail -F greps running on the logs so that if
we see that producer error again we can go find the corresponding tcpdump file
and hopefully find the smoking gun. (It turns out that the real-time tshark
processing invocations I sent out earlier can get quite far behind; I had that
running when the corruption occurred today, but the output processing was a
full hour behind the current time, the packet-writing part of tshark was far
ahead of the packet-analyzing part!)
Are there any particular log4j options I should turn on? Is there a way to
just enable trace logging for a specific topic? Does trace logging print the
contents of the message somewhere, not as something all nice and interpreted
but as, say, a bag of hex digits? I might end up rebuilding kafka and adding
some very specialized logging just for this.
Kafka 0.8.1.1, JRE 1.6.0-71, Storm 0.9.1, RHEL6, in likely order of importance.
(-: Also, here's the topic description:
Topic:mytopic PartitionCount:10 ReplicationFactor:1 Configs:
Topic: mytopic Partition: 0 Leader: 0 Replicas: 0 Isr: 0
Topic: mytopic Partition: 1 Leader: 1 Replicas: 1 Isr: 1
Topic: mytopic Partition: 2 Leader: 0 Replicas: 0 Isr: 0
Topic: mytopic Partition: 3 Leader: 1 Replicas: 1 Isr: 1
Topic: mytopic Partition: 4 Leader: 0 Replicas: 0 Isr: 0
Topic: mytopic Partition: 5 Leader: 1 Replicas: 1 Isr: 1
Topic: mytopic Partition: 6 Leader: 0 Replicas: 0 Isr: 0
Topic: mytopic Partition: 7 Leader: 1 Replicas: 1 Isr: 1
Topic: mytopic Partition: 8 Leader: 0 Replicas: 0 Isr: 0
Topic: mytopic Partition: 9 Leader: 1 Replicas: 1 Isr: 1
(2 brokers, 1 ZK server, no obvious issues with delays or process restarts or
disk errors or any of the other usual suspects. One partition per filesystem.
But my gut says none of that's pertinent, it's a matter of which partition the
producer happens to be publishing to when it sends garbage.)
-Steve
