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https://issues.apache.org/jira/browse/FLINK-29807?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Piotr Nowojski updated FLINK-29807:
-----------------------------------
Release Note:
Savepoints using `TypeSerializerConfigSnapshot` are no longer supported. That
means, all savepoints from Flink < 1.8.0 are no longer supported. Furthermore,
savepoints from Flink < 1.17.0 created with custom serialiser using deprecated
since Flink 1.8.0 class `TypeSerializerConfigSnapshot` are also no longer
supported.
If you are only using built-in serialisers (Pojo, Kryo, Avro, Tuple, ...), and
your savepoint is from 1.8.0 <= Flink, you don't have to do anything.
If you are only using built-in serialisers (Pojo, Kryo, Avro, Tuple, ...), and
your savepoint is from Flink < 1.8.0, please first upgrade your job to 1.8.x <=
Flink <= 1.16.x, before upgrading in the second step to Flink >= 1.17.x.
If previously you were using a custom serialiser that depends on
`TypeSerializerConfigSnapshot`, please first while still using 1.8.x <= Flink
<= 1.16.x upgrade your serialiser to `TypeSerializerSnapshot`, take a savepoint
and restore from that savepoint in Flink >= 1.7.0
> Drop TypeSerializerConfigSnapshot and savepoint support from Flink versions <
> 1.8.0
> -----------------------------------------------------------------------------------
>
> Key: FLINK-29807
> URL: https://issues.apache.org/jira/browse/FLINK-29807
> Project: Flink
> Issue Type: Improvement
> Components: Runtime / Checkpointing
> Affects Versions: 1.17
> Reporter: Piotr Nowojski
> Assignee: Piotr Nowojski
> Priority: Major
> Fix For: 1.17
>
>
> The motivation behind this move is two fold. One reason is that it
> complicates our code base unnecessarily and creates confusion on how to
> actually implement custom serializers. The immediate reason is that I wanted
> to clean up Flink's configuration stack a bit and refactor the
> ExecutionConfig class FLINK-29379. This refactor would keep the API
> compatibility of the ExecutionConfig, but it would break savepoint
> compatibility with snapshots written with some of the old serializers, which
> had ExecutionConfig as a field and were serialized in the snapshot. This
> issue has been resolved by the introduction of TypeSerializerSnapshot in
> Flink 1.7 FLINK-9377, where serializers are no longer part of the snapshot.
> TypeSerializerConfigSnapshot has been deprecated and no longer used by
> built-in serializers since Flink 1.8 FLINK-9376 and FLINK-11323. Users were
> encouraged to migrate to TypeSerializerSnapshot since then with their own
> custom serializers. That has been plenty of time for the migration.
> This proposal would have the following impact for the users:
> 1. we would drop support for recovery from savepoints taken with Flink <
> 1.7.0 for all built in types serializers
> 2. we would drop support for recovery from savepoints taken with Flink <
> 1.8.0 for built in kryo serializers
> 3. we would drop support for recovery from savepoints taken with Flink < 1.17
> for custom serializers using deprecated TypeSerializerConfigSnapshot
> 1. and 2. would have a simple migration path. Users migrating from those old
> savepoints would have to first start his job using a Flink version from the
> [1.8, 1.16] range, and take a new savepoint that would be compatible with
> Flink 1.17.
> 3. This is a bit more problematic, because users would have to first migrate
> their own custom serializers to use TypeSerializerSnapshot (using a Flink
> version from the [1.8, 1.16]), take a savepoint, and only then migrate to
> Flink 1.17. However users had already 4 years to migrate, which in my opinion
> has been plenty of time to do so.
> *As discussed and vote is currently in progress:*
> https://lists.apache.org/thread/x5d0p08pf2wx47njogsgqct0k5rpfrl4
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