+1 Best Yuan
On Mon, Oct 31, 2022 at 5:01 PM Dawid Wysakowicz <dwysakow...@apache.org> wrote: > +1 > > On 28/10/2022 16:57, Piotr Nowojski wrote: > > Hi, > > > > As discussed on the dev mailing list [0] I would like to start a vote to > > drop support of older savepoint formats (for Flink versions older than > > 1.8). You can find the original explanation from the aforementioned dev > > mailing list thread at the bottom of this message. > > > > Draft PR containing the proposed change you can find here: > > https://github.com/apache/flink/pull/21056 > > > > Vote will be open at least until Wednesday, November 2nd 18:00 CET. > > > > Best, > > Piotrek > > > > [0] https://lists.apache.org/thread/v1q28zg5jhxcqrpq67pyv291nznd3n0w > > > > I would like to open a discussion to remove the long deprecated > > (@PublicEvolving) TypeSerializerConfigSnapshot class [1] and the related > > code. > > > > 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 [2]. 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 [3], 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 [4] and [5]. 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 a side effect, we could also drop support for some of the legacy > > metadata serializers from LegacyStateMetaInfoReaders and potentially > other > > places that we are keeping for the sake of compatibility with old > > savepoints. > > > > [1] > > > https://nightlies.apache.org/flink/flink-docs-master/api/java/org/apache/flink/api/common/typeutils/TypeSerializerConfigSnapshot.html > > [2] https://issues.apache.org/jira/browse/FLINK-29379 > > [3] https://issues.apache.org/jira/browse/FLINK-9377 > > [4] https://issues.apache.org/jira/browse/FLINK-9376 > > [5] https://issues.apache.org/jira/browse/FLINK-11323 > > >
