Status
Current state: Under Discussion
Discussion thread: here (<- link to https://mail-archives.apache.org/mod_mbox/flink-dev/)
JIRA: here (<- link to https://issues.apache.org/jira/browse/FLINK-XXXX)
Released: <Flink Version>
Please keep the discussion on the mailing list rather than commenting on the wiki (wiki discussions get unwieldy fast).
Motivation
This FLIP proposes to promote the Unified Sink API V2 from PublicEvolving
to Public
and to mark the SinkFunction as Deprecated
. Since its introduction in Flink 1.12, the Unified Sink API has undergone extensive development and testing, evidenced by its evolution across multiple FLIPs and its adoption in major connectors like Kafka, Cassandra, and Elasticsearch since Flink 1.14 and beyond. Over more then four release cycles, the API has demonstrated stability and robustness, aligning with the criteria set forth in FLIP-197 for API stability graduation. This promotion is expected to encourage wider adoption by signaling the API’s maturity and reliability to the user base. This step is essential for standardizing Flink’s API landscape, much like the transition from SourceFunction to Source API, thereby enhancing the framework's overall functionality and maintainability.
The following table shows the relevant FLIPs that lead to the SinkV2 API as it has been released with Flink 1.19
FLIP | Note | API Annotation | Released with |
---|---|---|---|
FLIP-143: Unified Sink API | Introduction of new Unified Sink API | Experimental | Flink 1.12 |
FLIP-177: Extend Sink API | Extends Unified Sink API | Experimental | Flink 1.14 |
FLIP-171: Async Sink | Introduces generic Async Sink API, based on the Unified Sink API | PublicEvolving | Flink 1.15 |
FLIP-191: Extend unified Sink interface to support small file compaction | Extends Unified Sink API with introduction of SinkV2 | Sink: SinkV2: | Flink 1.15 |
FLIP-372: Enhance and synchronize Sink API to match the Source API | Changed the Sink V2 API so that it uses mixin interfaces to enhance the extendibility of the API, similar to the Source API. | SinkV2: | Flink 1.19 |
The following table shows the state of migration to SinkV2 for ASF supported and released connectors:
Status | Connector | Used Sink/SinkV2 since |
---|---|---|
FileSystem | ||
Kafka / Upsert-Kafka | ||
Cassandra | ||
DynamoDB | ||
Elasticsearch | ||
Firehose | ||
Kinesis | ||
MongoDB | ||
Opensearch | ||
RabbitMQ | ||
Google Cloud PubSub | ||
Pulsar | ||
JDBC | ||
HBase |
This topic has also been previously discussed on the Dev mailing list in https://lists.apache.org/thread/q62nj89rrz0t5xtggy5n65on95f2rmmx
Public Interfaces
Briefly list any new interfaces that will be introduced as part of this proposal or any existing interfaces that will be removed or changed. The purpose of this section is to concisely call out the public contract that will come along with this feature.
A public interface is any change to the following:
- DataStream and DataSet API, including classes related to that, such as StreamExecutionEnvironment
- Classes marked with the @Public annotation
- On-disk binary formats, such as checkpoints/savepoints
- User-facing scripts/command-line tools, i.e. bin/flink, Yarn scripts, Mesos scripts
- Configuration settings
- Exposed monitoring information
Proposed Changes
Describe the new thing you want to do in appropriate detail. This may be fairly extensive and have large subsections of its own. Or it may be a few sentences. Use judgement based on the scope of the change.
Compatibility, Deprecation, and Migration Plan
- What impact (if any) will there be on existing users?
- If we are changing behavior how will we phase out the older behavior?
- If we need special migration tools, describe them here.
- When will we remove the existing behavior?
Test Plan
Describe in few sentences how the FLIP will be tested. We are mostly interested in system tests (since unit-tests are specific to implementation details). How will we know that the implementation works as expected? How will we know nothing broke?
Rejected Alternatives
If there are alternative ways of accomplishing the same thing, what were they? The purpose of this section is to motivate why the design is the way it is and not some other way.