[jira] [Commented] (FLINK-17486) ClassCastException when checkpointing AVRO SpecificRecord with decimal fields

["Sivaprasanna Sethuraman (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-17486?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17103754#comment-17103754 ] 

Sivaprasanna Sethuraman commented on FLINK-17486:
-------------------------------------------------

This seems to be because when when we do `serializer.copy(s1)`, the logical type conversion informations are lost. I did a quick test which updates the AvroSerializer#copy() to something like:

 
{code:java}
// code placeholder@Override
public T copy(T from) {
   if (CONCURRENT_ACCESS_CHECK) {
      enterExclusiveThread();
   }

   try {
      checkAvroInitialized();

      if (from instanceof SpecificRecord) {
         Collection<Conversion<?>> conversions = ((SpecificRecordBase) from).getSpecificData().getConversions();
         conversions.forEach(avroData::addLogicalTypeConversion);
      }

      return avroData.deepCopy(runtimeSchema, from);
   }
   finally {
      if (CONCURRENT_ACCESS_CHECK) {
         exitExclusiveThread();
      }
   }
}
{code}
This fixes this bug and the user code runs as expected. However, the thing is `.getConversions()` are added to SpecificRecordBases from Avro 1.9.x so I updated the avro version to 1.9.2 from 1.8.2 which causes a lot of other problems in test cases. I have updated quite a lot of them but they seem to fail in AvroSerializerMigrationTest with InvalidClassException.

I have attached the patch. The link to the changes in my forked repo: [https://github.com/zenfenan/flink/tree/FLINK-17486]

> ClassCastException when checkpointing AVRO SpecificRecord with decimal fields
> -----------------------------------------------------------------------------
>
>                 Key: FLINK-17486
>                 URL: https://issues.apache.org/jira/browse/FLINK-17486
>             Project: Flink
>          Issue Type: Bug
>          Components: Formats (JSON, Avro, Parquet, ORC, SequenceFile)
>    Affects Versions: 1.10.0
>         Environment: Flink 1.10.0
> AVRO 1.9.2
> Java 1.8.0 (but also Java 14)
> Scala binary 2.11
>            Reporter: Lorenzo Nicora
>            Priority: Critical
>              Labels: AVRO, confluent-kafka, kafka
>
> When consuming from a Kafka source AVRO SpecificRecord containing a {{decimal}} (logical type) field, copying the record fails with:
> {{java.lang.ClassCastException: class java.math.BigDecimal cannot be cast to class java.nio.ByteBuffer}}
> I understand the problem arises when Flink tries to make a deep-copy of the record for checkpointing.
> This code reproduces the problem ([https://github.com/nicusX/flink-avro-bug/blob/master/src/test/java/example/TestDeepCopy.java]):
>  
> {code:java}
> AvroSerializer<Sample> serializer = new AvroSerializer<>(Sample.class);
> Sample s1 = Sample.newBuilder()
>    .setPrice(BigDecimal.valueOf(42.32))
>    .setId("A12345")
>    .build();
> Sample s2 = serializer.copy(s1);
> {code}
>  
>  
> The AVRO SpecificRecord is generated from this IDL (using the maven-avro-plugin):
> {code:java}
> @namespace("example.avro")
>  protocol SampleProtocol {
>    record Sample{
>      string id;
>      decimal(9,2) price;
>      timestamp_ms eventTime;
>     }
>  }{code}
> In particular, I had the problem after attaching an AssignerWithPeriodicWatermark to a Kafka Source consuming AVRO SpecificRecord and using Confluent Schema Registry. The assigned extracts the event time from the record and enabling bookmarking (not sure whether this is related).
>  A simplified version of the application is here: [https://github.com/nicusX/flink-avro-bug/blob/master/src/main/java/example/StreamJob.java]
>  
> The problem looks similar to AVRO-1895 but that issue has been fixed since AVRO 1.8.2.
> In fact, the following code does deep-copy only relying on AVRO and does work:  
> {code:java}
> Sample s1 = Sample.newBuilder()
>    .setPrice(BigDecimal.valueOf(42.32))
>    .setId("A12345")
>    .build();
>  Sample s2 = Sample.newBuilder(s1).build();{code}
>  
> Code of the two tests and simplified application: [https://github.com/nicusX/flink-avro-bug|https://github.com/nicusX/flink-avro-bug/blob/master/src/main/java/example/StreamJob.java]
>  



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