RocksDB State Backend Exception

[Ning Shi <ni...@gmail.com>]

Hi,

We are doing some performance testing on a 12 node cluster with 8 task
slots per TM. Every 15 minutes or so, the job would run into the
following exception.

java.lang.IllegalArgumentException: Illegal value provided for SubCode.
	at org.rocksdb.Status$SubCode.getSubCode(Status.java:109)
	at org.rocksdb.Status.<init>(Status.java:30)
	at org.rocksdb.RocksDB.put(Native Method)
	at org.rocksdb.RocksDB.put(RocksDB.java:511)
	at org.apache.flink.contrib.streaming.state.AbstractRocksDBAppendingState.updateInternal(AbstractRocksDBAppendingState.java:80)
	at org.apache.flink.contrib.streaming.state.RocksDBReducingState.add(RocksDBReducingState.java:99)
	at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.processElement(WindowOperator.java:358)
	at org.apache.flink.streaming.runtime.io.StreamInputProcessor.processInput(StreamInputProcessor.java:202)
	at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:105)
	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:300)
	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
	at java.lang.Thread.run(Thread.java:745)

I saw an outstanding issue with similar exception in [1]. The ticket
description suggests that it was due to out of disk error, but in our
case, we have plenty of disk left on all TMs.

Has anyone run into this before? If so, is there a fix or workaround?

Thanks,

[1] https://issues.apache.org/jira/browse/FLINK-9233

--
Ning

Re: RocksDB State Backend Exception

[Ning Shi <ni...@gmail.com>]

Hi Andrey,

Thank you for the explanation. I think you are right. It is either
kStaleFile or kNoSpace. We found the cause of the issue, even though we
still don't know how to explain it.

We set the java.io.tmpdir to an EBS-backed drive instead of the
default and the exception started happening. The issue was gone after we
changed it back to use the default.

Thanks,

On Thu, Oct 25, 2018 at 02:23:31PM +0200, Andrey Zagrebin wrote:
> Hi Ning,
>
> The problem here first of all is that RocksDB java JNI client diverged from RocksDB cpp code in status.h,
> as mentioned in the Flink issue you refer to.
>
> Flink 1.6 uses RocksDB 5.7.5 java client.
> The JNI code there misses these status subcodes:
> kNoSpace = 4,
> kDeadlock = 5,
> kStaleFile = 6,
> kMemoryLimit = 7
> which could be potential problems in the job.
>
> kNoSpace is only one of them.
> Another probable cause could be kStaleFile, some file system IO problem.
> kDeadlock seems to be used only with transactions, so not relevant.
> kMemoryLimit means that write batch exceeded max size, but we do not have limit for it as I understand.
>
> It would be easier to debug if RocksDB JNI client would at least log the unknown subcode but i do not see any easy way to log it in the current version, without rebuilding RocksDB and subsequently Flink.
>
> In master branch, java Status and status.h are also unsynced. You could report this issue in RocksDB repo, along with extending exception logging message with the number of unknown error code. Flink community plans to upgrade to the latest RocksDB version again in one of the next Flink releases.
>
> Best,
> Andrey

--
Ning

Re: RocksDB State Backend Exception

[Andrey Zagrebin <an...@data-artisans.com>]

Hi Ning,

The problem here first of all is that RocksDB java JNI client diverged from RocksDB cpp code in status.h,
as mentioned in the Flink issue you refer to.

Flink 1.6 uses RocksDB 5.7.5 java client. 
The JNI code there misses these status subcodes:
kNoSpace = 4,
kDeadlock = 5,
kStaleFile = 6,
kMemoryLimit = 7
which could be potential problems in the job.

kNoSpace is only one of them.
Another probable cause could be kStaleFile, some file system IO problem.
kDeadlock seems to be used only with transactions, so not relevant.
kMemoryLimit means that write batch exceeded max size, but we do not have limit for it as I understand.

It would be easier to debug if RocksDB JNI client would at least log the unknown subcode but i do not see any easy way to log it in the current version, without rebuilding RocksDB and subsequently Flink.

In master branch, java Status and status.h are also unsynced. You could report this issue in RocksDB repo, along with extending exception logging message with the number of unknown error code. Flink community plans to upgrade to the latest RocksDB version again in one of the next Flink releases.

Best,
Andrey

> On 25 Oct 2018, at 04:31, Ning Shi <ni...@gmail.com> wrote:
> 
> Hi,
> 
> We are doing some performance testing on a 12 node cluster with 8 task
> slots per TM. Every 15 minutes or so, the job would run into the
> following exception.
> 
> java.lang.IllegalArgumentException: Illegal value provided for SubCode.
> 	at org.rocksdb.Status$SubCode.getSubCode(Status.java:109)
> 	at org.rocksdb.Status.<init>(Status.java:30)
> 	at org.rocksdb.RocksDB.put(Native Method)
> 	at org.rocksdb.RocksDB.put(RocksDB.java:511)
> 	at org.apache.flink.contrib.streaming.state.AbstractRocksDBAppendingState.updateInternal(AbstractRocksDBAppendingState.java:80)
> 	at org.apache.flink.contrib.streaming.state.RocksDBReducingState.add(RocksDBReducingState.java:99)
> 	at org.apache.flink.streaming.runtime.operators.windowing.WindowOperator.processElement(WindowOperator.java:358)
> 	at org.apache.flink.streaming.runtime.io.StreamInputProcessor.processInput(StreamInputProcessor.java:202)
> 	at org.apache.flink.streaming.runtime.tasks.OneInputStreamTask.run(OneInputStreamTask.java:105)
> 	at org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:300)
> 	at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
> 	at java.lang.Thread.run(Thread.java:745)
> 
> I saw an outstanding issue with similar exception in [1]. The ticket
> description suggests that it was due to out of disk error, but in our
> case, we have plenty of disk left on all TMs.
> 
> Has anyone run into this before? If so, is there a fix or workaround?
> 
> Thanks,
> 
> [1] https://issues.apache.org/jira/browse/FLINK-9233
> 
> --
> Ning