Ignite serialization issue in QueryCursor

Question

I’m quite new to ignite and trying to 'seed' cache from EntryProcessor but can't traverse ScanQuery's results in application

I have ignite v2.6.0 cluster with two atomic partitioned caches and peer class loading enabled:

Cache A : IgniteCache<Long, A>
Cache B : IgniteCache<UUID, ScheduledTask>


interface ScheduledTask extends Serializable {
     Instant getExecuteAt()
}

one of classes that are stored in cache B:

class ExpirationTask implements ScheduledTask

Spring boot application (written in Kotlin) asynchronously invokes entry processor against cache A. Processor populates data in both caches (A and B). Then application queries cache B:

 val dueQuery = ScanQuery<UUID, ScheduledTask> { _, task -> task.executeAt <= now }

       bCache.query(dueQuery, { it.key }).use { taskKeys ->
            for (taskKey in taskKeys) {
   ………………………
          }
}

But query cursor throws ClassCastException:

Caused by: java.lang.ClassCastException: ExpirationTask cannot be cast to ScheduledTask
    at ….Scheduler$poll$dueQuery$1.apply(Scheduler:61)
    at org.apache.ignite.internal.processors.cache.query.GridCacheQueryManager$ScanQueryIterator.advance(GridCacheQueryManager.java:3089)
    at org.apache.ignite.internal.processors.cache.query.GridCacheQueryManager$ScanQueryIterator.onHasNext(GridCacheQueryManager.java:2982)
    at org.apache.ignite.internal.util.GridCloseableIteratorAdapter.hasNextX(GridCloseableIteratorAdapter.java:53)
    at org.apache.ignite.internal.util.lang.GridIteratorAdapter.hasNext(GridIteratorAdapter.java:45)
    at org.apache.ignite.internal.processors.cache.query.GridCacheQueryManager.runQuery(GridCacheQueryManager.java:1164)
    at org.apache.ignite.internal.processors.cache.query.GridCacheDistributedQueryManager.processQueryRequest(GridCacheDistributedQueryManager.java:230)
    at org.apache.ignite.internal.processors.cache.query.GridCacheDistributedQueryManager$2.apply(GridCacheDistributedQueryManager.java:108)
    at org.apache.ignite.internal.processors.cache.query.GridCacheDistributedQueryManager$2.apply(GridCacheDistributedQueryManager.java:106)
    at org.apache.ignite.internal.processors.cache.GridCacheIoManager.processMessage(GridCacheIoManager.java:1054)
    at org.apache.ignite.internal.processors.cache.GridCacheIoManager.onMessage0(GridCacheIoManager.java:579)
    at org.apache.ignite.internal.processors.cache.GridCacheIoManager.handleMessage(GridCacheIoManager.java:378)
    at org.apache.ignite.internal.processors.cache.GridCacheIoManager.handleMessage(GridCacheIoManager.java:304)
    at org.apache.ignite.internal.processors.cache.GridCacheIoManager.access$100(GridCacheIoManager.java:99)
    at org.apache.ignite.internal.processors.cache.GridCacheIoManager$1.onMessage(GridCacheIoManager.java:293)
    at org.apache.ignite.internal.managers.communication.GridIoManager.invokeListener(GridIoManager.java:1556)
    at org.apache.ignite.internal.managers.communication.GridIoManager.processRegularMessage0(GridIoManager.java:1184)
    at org.apache.ignite.internal.managers.communication.GridIoManager.access$4200(GridIoManager.java:125)
    at org.apache.ignite.internal.managers.communication.GridIoManager$9.run(GridIoManager.java:1091)
    ... 3 common frames omitted

Both A and B classes are marshaled by OptimizedMarshaller because of custom serialization like:

data class B(val dueTime: Instant, val id: Long) : ScheduledTask {

 override fun getExecuteAt(): Instant {
        return dueTime
    }
    private fun writeObject(stream: ObjectOutputStream) {
        // Only used to indicate custom serialization for Ignite. Real work done by writeReplace()
    }

    private fun readObject(stream: ObjectInputStream) {
        // Only used to indicate custom serialization for Ignite. Real work done by writeReplace()
    }

    private fun writeReplace(): Any = Serializer(this)

    class Serializer @JvmOverloads constructor(var source: B? = null) : Externalizable {
        override fun readExternal(stream: ObjectInput) {
            val dueTime = stream.readObject() as Instant
            val id = stream.readLong()
           source = B(dueTime, id)
        }

        override fun writeExternal(stream: ObjectOutput) {
            stream.writeObject(source!!.dueTime)
            stream.writeLong(source!!.id)
       }

        private fun readResolve(): Any = source!!

        companion object {
            private const val serialVersionUID: Long = 1
        }
    }

    companion object {
        private const val serialVersionUID: Long = 42
    }
}

So I'm looking for a way to perform polymorphic queries over cache values.

Thanks

alamar alamar · Accepted Answer · 2019-04-03T09:28:50

Ignite will not peer-class-load cache key/value types so you should not worry about that.
Is it possible that you have B loaded by different class loaders? You could debug that by checking getClass().getClassLoader() of B's.
Maybe Kotlin expects wrapped B type at some point?

Ignite serialization issue in QueryCursor

1 Answers