[jira] [Commented] (FLINK-5397) Fail to deserialize savepoints in v1.1 when there exist missing fields in class serialization descriptors

["ASF GitHub Bot (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-5397?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15801720#comment-15801720 ] 

ASF GitHub Bot commented on FLINK-5397:
---------------------------------------

Github user StephanEwen commented on the issue:

    https://github.com/apache/flink/pull/3050
  
    Looks good, merging this...


> Fail to deserialize savepoints in v1.1 when there exist missing fields in class serialization descriptors
> ---------------------------------------------------------------------------------------------------------
>
>                 Key: FLINK-5397
>                 URL: https://issues.apache.org/jira/browse/FLINK-5397
>             Project: Flink
>          Issue Type: Bug
>          Components: State Backends, Checkpointing
>            Reporter: Xiaogang Shi
>            Assignee: Stefan Richter
>
> To restore from the savepoints in previous versions, Flink now keeps all classes whose serialization is changed and put them in a separated package ("migration"). 
> When deserializing the old savepoints, flink will look up correct descriptors ({{ObjectStreamClass}}) for these classes, without using those ones written in serialized data. The implementation however is problematic when there exist missing field descriptors in the serialized data. 
> When serializing an object, Java will only write the descriptors of those non-null fields. But when we look up class descriptors with given classes, all fields will be put into the descriptors. As a result, we will deserialize the savepoints with incorrect descriptors, leading to serialization exceptions.
> A simple resolution is to update the name of read descriptors using Reflections, without using different descriptors.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)