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https://issues.apache.org/jira/browse/FLINK-10897?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16747409#comment-16747409
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boshu Zheng edited comment on FLINK-10897 at 1/30/19 2:13 AM:
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I will try to follow the example that you presented at FlinkForwardChina.
Additionally, I propose to add two fields to `PojoSerializer`, namely
`previousFieldNames` and `previousFieldSerializers` which are snapshotted and
restored by a new `PojoSerializerSnapshot`. When restoring states via
`PojoSerializer#deserialize`, we should be able to figure out which fields have
been removed/added or have a new type with these additional fields.
What do you think? [~tzulitai]
was (Author: kisimple):
I will try to follow the example that you presented at FlinkForwardChain.
Additionally, I propose to add two fields to `PojoSerializer`, namely
`previousFieldNames` and `previousFieldSerializers` which are snapshotted and
restored by a new `PojoSerializerSnapshot`. When restoring states via
`PojoSerializer#deserialize`, we should be able to figure out which fields have
been removed/added or have a new type with these additional fields.
What do you think? [~tzulitai]
> Support POJO state schema evolution
> -----------------------------------
>
> Key: FLINK-10897
> URL: https://issues.apache.org/jira/browse/FLINK-10897
> Project: Flink
> Issue Type: Sub-task
> Components: Type Serialization System
> Reporter: Tzu-Li (Gordon) Tai
> Assignee: boshu Zheng
> Priority: Major
>
> Main action point for this is to implement a separate POJO serializer that is
> specifically used as the restore serializer.
> This restore POJO serializer should be able to read and dump values of fields
> that no longer exists in the updated POJO schema, and assign default values
> to newly added fields. Snapshot of the {{PojoSerializer}} should contain
> sufficient information so that on restore, the information can be compared
> with the adapted POJO class to figure out which fields have been removed /
> added.
> Changing fields types is out of scope and should not be supported.
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