Hi Apoorv,

Sorry for the late reply, have been quite busy with backlog items the past
days.

On Fri, Mar 20, 2020 at 4:37 PM Apoorv Upadhyay <
apoorv.upadh...@razorpay.com> wrote:

> Thanks Gordon for the suggestion,
>
> I am going by this repo :
> https://github.com/mrooding/flink-avro-state-serialization
>
> So far I am able to alter the scala case classes and able to restore from
> savepoint using memory state backend, but when I am using rocksdb as
> statebackend and try to restore from savepoint it break with following
> error :
>

When you say restoring it with the RocksDB backend, was the savepoint you
are attempting to restore from taken with the RocksDB backend as well?
I'm asking that, because currently you cannot change the state backend
across restores, as they have different savepoint binary formats.
This is also the case when you use the State Processor API - when you load
an existing savepoint, you first have to load it with the same state
backend that was used to create the savepoint. You can change the state
backend using the State Processor API, by creating a new savepoint with
your desired target backend, and dumping all state data extracted from the
loaded savepoint into the new fresh savepoint.
There has been previous proposals (FLIP-41) [1] to unify the savepoint
formats which would make a lot of this easier, but AFAIK this isn't on the
roadmap in the near future.

Best Regards,
Gordon

[1]
https://cwiki.apache.org/confluence/display/FLINK/FLIP-41%3A+Unify+Binary+format+for+Keyed+State


>
> org.apache.flink.util.FlinkRuntimeException: Error while retrieving data from 
> RocksDB.
>       at 
> org.apache.flink.contrib.streaming.state.RocksDBValueState.value(RocksDBValueState.java:92)
>       at 
> nl.mrooding.ProductProcessor.processElement1(ProductProcessor.scala:14)
>       at 
> nl.mrooding.ProductProcessor.processElement1(ProductProcessor.scala:8)
>       at 
> org.apache.flink.streaming.api.operators.co.KeyedCoProcessOperator.processElement1(KeyedCoProcessOperator.java:78)
>       at 
> org.apache.flink.streaming.runtime.io.StreamTwoInputProcessor.processInput(StreamTwoInputProcessor.java:238)
>       at 
> org.apache.flink.streaming.runtime.tasks.TwoInputStreamTask.run(TwoInputStreamTask.java:117)
>       at 
> org.apache.flink.streaming.runtime.tasks.StreamTask.invoke(StreamTask.java:302)
>       at org.apache.flink.runtime.taskmanager.Task.run(Task.java:711)
>       at java.lang.Thread.run(Thread.java:748)
> Caused by: java.io.EOFException
>       at org.apache.avro.io.BinaryDecoder.ensureBounds(BinaryDecoder.java:473)
>       at org.apache.avro.io.BinaryDecoder.readInt(BinaryDecoder.java:128)
>       at org.apache.avro.io.BinaryDecoder.readIndex(BinaryDecoder.java:423)
>       at 
> org.apache.avro.io.ResolvingDecoder.doAction(ResolvingDecoder.java:290)
>       at org.apache.avro.io.parsing.Parser.advance(Parser.java:88)
>       at 
> org.apache.avro.io.ResolvingDecoder.readIndex(ResolvingDecoder.java:267)
>       at 
> org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:179)
>       at 
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:153)
>       at 
> org.apache.avro.generic.GenericDatumReader.readField(GenericDatumReader.java:232)
>       at 
> org.apache.avro.generic.GenericDatumReader.readRecord(GenericDatumReader.java:222)
>       at 
> org.apache.avro.generic.GenericDatumReader.readWithoutConversion(GenericDatumReader.java:175)
>       at 
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:153)
>       at 
> org.apache.avro.generic.GenericDatumReader.read(GenericDatumReader.java:145)
>       at 
> nl.mrooding.state.CustomAvroSerializer$class.deserialize(CustomAvroSerializer.scala:42)
>       at 
> nl.mrooding.state.ProductSerializer.deserialize(ProductSerializer.scala:9)
>       at 
> nl.mrooding.state.ProductSerializer.deserialize(ProductSerializer.scala:9)
>       at 
> org.apache.flink.contrib.streaming.state.RocksDBValueState.value(RocksDBValueState.java:90)
>       ... 8 more
>
>
>
>
> On Wed, Mar 18, 2020 at 10:56 AM Tzu-Li (Gordon) Tai <tzuli...@apache.org>
> wrote:
>
>> Hi Apoorv,
>>
>> Flink currently does not natively support schema evolution for state
>> types using Scala case classes [1].
>>
>> So, as Roman has pointed out, there are 2 possible ways for you to do
>> that:
>> - Implementing a custom serializer that support schema evolution for your
>> specific Scala case classes, as Roman suggested.
>> - or, using the State Processor API [2] to migrate your case classes
>> offline as a batch job
>>
>> For your question on how to implement a schema-evolution supporting
>> serializer, can you share with me the problems you have met so far?
>> Otherwise, if you take a look at the PojoSerializerSnapshot class, that
>> would be a starting point to implement something similar for your case
>> classes.
>>
>> As you will quickly realize, it's not simple, so I would strongly suggest
>> trying out the approach of using the State Processor API.
>> Either way, if you bump into any problems, feel free to let me know.
>>
>> Cheers,
>> Gordon
>>
>> [1] https://issues.apache.org/jira/browse/FLINK-10896
>> [2]
>> https://ci.apache.org/projects/flink/flink-docs-stable/dev/libs/state_processor_api.html
>>
>> On Wed, Mar 18, 2020 at 1:04 PM Apoorv Upadhyay <
>> apoorv.upadh...@razorpay.com> wrote:
>>
>>> Thanks a lot , Also can you share one example where these has been
>>> implemented? I have gone through docs does not happen to work still
>>>
>>> On Wed, Feb 26, 2020 at 7:59 PM Khachatryan Roman <
>>> khachatryan.ro...@gmail.com> wrote:
>>>
>>>> Hi Apoorv,
>>>>
>>>> You can achieve this by implementing custom serializers for your state.
>>>> Please refer to
>>>> https://ci.apache.org/projects/flink/flink-docs-release-1.8/dev/stream/state/custom_serialization.html
>>>>
>>>> Regards,
>>>> Roman
>>>>
>>>>
>>>> On Wed, Feb 26, 2020 at 6:53 AM Apoorv Upadhyay <
>>>> apoorv.upadh...@razorpay.com> wrote:
>>>>
>>>>> Hi Roman,
>>>>>
>>>>> I have successfully migrated to flink 1.8.2 with the savepoint created
>>>>> by flink 1.6.2.
>>>>> Now I have to modify few case classes due to new requirement I have
>>>>> created a savepoint and when I run the app with modified class from the
>>>>> savepoint it throws error "state not compatible"
>>>>> Previously there were no serializer used.
>>>>> I now wish to support state schema Hence need suggestion how can i
>>>>> achieve that ?
>>>>>
>>>>> Regards
>>>>>
>>>>> On Tue, Feb 25, 2020 at 9:08 PM Khachatryan Roman <
>>>>> khachatryan.ro...@gmail.com> wrote:
>>>>>
>>>>>> Hi ApoorvK,
>>>>>>
>>>>>> I understand that you have a savepoint created by Flink 1.6.2 and you
>>>>>> want to use it with Flink 1.8.2. The classes themselves weren't modified.
>>>>>> Is that correct?
>>>>>> Which serializer did you use?
>>>>>>
>>>>>> Regards,
>>>>>> Roman
>>>>>>
>>>>>>
>>>>>> On Tue, Feb 25, 2020 at 8:38 AM ApoorvK <apoorv.upadh...@razorpay.com>
>>>>>> wrote:
>>>>>>
>>>>>>> Hi Team,
>>>>>>>
>>>>>>> Earlier we have developed on flink 1.6.2 , So there are lots of case
>>>>>>> classes
>>>>>>> which have Map,Nested case class within them for example below :
>>>>>>>
>>>>>>> case class MyCaseClass(var a: Boolean,
>>>>>>>                                  var b: Boolean,
>>>>>>>                                  var c: Boolean,
>>>>>>>                                  var d: NestedCaseClass,
>>>>>>>                                  var e:Int){
>>>>>>> def this(){this(false,false,new NestedCaseClass,0)}
>>>>>>> }
>>>>>>>
>>>>>>>
>>>>>>> Now we have migrated to flink 1.8.2 , I need help to figure out how
>>>>>>> can I
>>>>>>> achieve state schema evolution for such classes.
>>>>>>>
>>>>>>> 1. Is creating avro for these classes now, and implement avro
>>>>>>> serialisation
>>>>>>> will that work ?
>>>>>>> 2. Or if I register kyroserialiser with protobuf serialiser at env?
>>>>>>>
>>>>>>> Please suggest what can be done here, or redirect for the avros
>>>>>>> serialisation example.
>>>>>>>
>>>>>>> Thanks
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Sent from:
>>>>>>> http://apache-flink-user-mailing-list-archive.2336050.n4.nabble.com/
>>>>>>>
>>>>>>

Reply via email to