Several thoughts:
First and most important -- as far as I can tell, there's little community
experience using Kryo for Akka Persistence. I'm currently building that
out for my own project, and when I asked about it, nobody could name a
project that was already doing it. It's been a bit of an adventure getting
it right -- indeed, I wound up contributing an enhancement to the romix
library
<https://github.com/romix/akka-kryo-serialization/commit/ffb2fec2dc9cfbca9c3503d6f32c6500cd1c40cd>
a couple of weeks ago, which will be in 0.4.2. Most of the community
appear to be using protobuf for persistence. So keep in mind that this may
be a bit bleeding-edge. (Eventually, after my code gets to production,
I'll probably do a long blog entry on it. The relevant branch can be found
here <https://github.com/jducoeur/Querki/tree/feature/add-cassandra>.)
As for your error, I'm a bit surprised you got that with "default", which
isn't supposed to be using class IDs but should instead be using FQCNs
across the board. "default" *is* explicitly slow, which might account for
some of the time issues (although I wouldn't expect it to be *that* slow),
but the error you're showing is kinda weird. The implications seems to be
that, for some reason, it's synthesizing some class IDs even in "default"
mode.
Mind, that error is *exactly* what I'd expect to see if you use
"incremental". Really, I don't think "incremental" is ever a great idea,
but it is absolutely a terrible one for persistence. It's a recipe for
accidentally persisting random class IDs that can't later be deserialized.
"Automatic" mode should, in principle, work, but "incremental" is very
likely to cause random accidental failures.
Personally, I think that "explicit" is the most sensible way to go. It's a
bit of a pain in the ass, and will give you errors if you fail to
pre-register any classes (and you will discover that you need to register
many, many standard-library classes to get it to work), but when you're
using this in the context of persistence I think it's the sanest approach,
ensuring that *all* of your persisted classes are using the more-efficient
IDs and *all* of them are pre-registered...
On Thu, Aug 4, 2016 at 1:25 PM, Muthukumaran Kothandaraman <
muthu.kmk2...@gmail.com> wrote:
> Hi,
>
> I am using following combination for a basic persistence actor
>
> Version combination : Cassandra 3.7 + akka-persistence-cassandra-0.7 +
> akka 2.4.8 + akka-kryo-serialization_2.11 version-0.4.1
>
> I am using following conf to serialize using kryo-serialization
>
> kryo {
>
> type = "graph"
> idstrategy = "default"
> buffer-size = 4096
> max-buffer-size = -1
> use-manifests = false
> post-serialization-transformations = "lz4,aes"
> implicit-registration-logging = false
> kryo-trace = false
> kryo-custom-serializer-init = "CustomKryoSerializerInitFQCN"
> resolve-subclasses = false
> mappings {
> "com.myexperiments.akkaexps.persistence.events.Evt" = 20
> }
> classes = [
> "com.myexperiments.akkaexps.persistence.events.Evt"
> ]
> }
>
>
> Observations :
>
> ==============
>
>
> 1. I am able to see that the events do get persisted without any issues -
> checked via cqlsh of Cassandra to verify the message count in akka.messages
> table
>
> Performance observation : there is an abnormal reduction in
> persistence-rate of events
>
> in fact,with Kryo serialization + persistAsync I got around ~580
> events persisted/sec with Cassandra plugin when compared to plain java
> serialization which for same test run on same machine yielded upto 800
> events/sec
>
> which looks weird. Cassandra runs in local node - no clustering
> (trying to thrash-out all variances before I can go to cluster with larger
> configuration so that I can isolate issues)
>
>
>
> 2. During recovery phase, however, I got following exception and recovery
> failed. Also tried changing idstrategy from 'default' to 'incremental' and
> still facing the same Exception
>
>
> [ERROR] [08/02/2016 10:46:16.119] [example-akka.actor.default-dispatcher-8]
> [akka://example/system/cassandra-journal/$b/flow-1-0-asyncReplayMessages]
> Encountered unregistered class ID:
> 1406735620*com.esotericsoftware.kryo.KryoException: Encountered unregistered
> class ID: 1406735620*
> at
> com.esotericsoftware.kryo.util.DefaultClassResolver.readClass(DefaultClassResolver.java:137)
> at com.esotericsoftware.kryo.Kryo.readClass(Kryo.java:670)
> at com.esotericsoftware.kryo.Kryo.readClassAndObject(Kryo.java:781)
> at
> com.romix.akka.serialization.kryo.KryoBasedSerializer.fromBinary(KryoSerializer.scala:483)
> at
> com.romix.akka.serialization.kryo.KryoSerializer.fromBinary(KryoSerializer.scala:339)
> at
> akka.serialization.Serialization$$anonfun$deserialize$2.apply(Serialization.scala:124)
> at scala.util.Try$.apply(Try.scala:192)
> at akka.serialization.Serialization.deserialize(Serialization.scala:114)
> at
> akka.persistence.serialization.MessageSerializer.akka$persistence$serialization$MessageSerializer$$payload(MessageSerializer.scala:216)
> at
> akka.persistence.serialization.MessageSerializer.akka$persistence$serialization$MessageSerializer$$persistent(MessageSerializer.scala:198)
> at
> akka.persistence.serialization.MessageSerializer.fromBinary(MessageSerializer.scala:69)
> at
> akka.persistence.serialization.MessageSerializer.fromBinary(MessageSerializer.scala:28)
> at
> akka.serialization.Serialization$$anonfun$deserialize$3.apply(Serialization.scala:142)
> at scala.util.Try$.apply(Try.scala:192)
> at akka.serialization.Serialization.deserialize(Serialization.scala:142)
> at
> akka.persistence.cassandra.query.EventsByPersistenceIdPublisher.persistentFromByteBuffer(EventsByPersistenceIdPublisher.scala:90)
> at
> akka.persistence.cassandra.query.EventsByPersistenceIdPublisher.extractEvent(EventsByPersistenceIdPublisher.scala:84)
> at
> akka.persistence.cassandra.query.EventsByPersistenceIdPublisher.updateState(EventsByPersistenceIdPublisher.scala:77)
> at
> akka.persistence.cassandra.query.EventsByPersistenceIdPublisher.updateState(EventsByPersistenceIdPublisher.scala:48)
> at
> akka.persistence.cassandra.query.QueryActorPublisher.exhaustFetch(QueryActorPublisher.scala:213)
> at
> akka.persistence.cassandra.query.QueryActorPublisher.akka$persistence$cassandra$query$QueryActorPublisher$$exhaustFetchAndBecome(QueryActorPublisher.scala:117)
> at
> akka.persistence.cassandra.query.QueryActorPublisher$$anonfun$idle$1.applyOrElse(QueryActorPublisher.scala:101)
> at akka.actor.Actor$class.aroundReceive(Actor.scala:484)
> at
> akka.persistence.cassandra.query.QueryActorPublisher.akka$stream$actor$ActorPublisher$$super$aroundReceive(QueryActorPublisher.scala:45)
> at
> akka.stream.actor.ActorPublisher$class.aroundReceive(ActorPublisher.scala:270)
> at
> akka.persistence.cassandra.query.QueryActorPublisher.aroundReceive(QueryActorPublisher.scala:45)
> at akka.actor.ActorCell.receiveMessage(ActorCell.scala:526)
> at akka.actor.ActorCell.invoke(ActorCell.scala:495)
> at akka.dispatch.Mailbox.processMailbox(Mailbox.scala:257)
> at akka.dispatch.Mailbox.run(Mailbox.scala:224)
> at akka.dispatch.Mailbox.exec(Mailbox.scala:234)
> at scala.concurrent.forkjoin.ForkJoinTask.doExec(ForkJoinTask.java:260)
> at
> scala.concurrent.forkjoin.ForkJoinPool$WorkQueue.runTask(ForkJoinPool.java:1339)
> at
> scala.concurrent.forkjoin.ForkJoinPool.runWorker(ForkJoinPool.java:1979)
> at
> scala.concurrent.forkjoin.ForkJoinWorkerThread.run(ForkJoinWorkerThread.java:107)
>
> Am I missing something grossly ?
>
>
>
> Regards
>
> Muthu
>
>
>
>
>
> --
> >>>>>>>>>> Read the docs: http://akka.io/docs/
> >>>>>>>>>> Check the FAQ: http://doc.akka.io/docs/akka/
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