tzulitai commented on a change in pull request #7124: [FLINK-9574] [doc] Rework documentation for custom state serializers and state evolution URL: https://github.com/apache/flink/pull/7124#discussion_r236763803
########## File path: docs/dev/stream/state/schema_evolution.md ########## @@ -0,0 +1,92 @@ +--- +title: "State Schema Evolution" +nav-parent_id: streaming_state +nav-pos: 6 +--- +<!-- +Licensed to the Apache Software Foundation (ASF) under one +or more contributor license agreements. See the NOTICE file +distributed with this work for additional information +regarding copyright ownership. The ASF licenses this file +to you under the Apache License, Version 2.0 (the +"License"); you may not use this file except in compliance +with the License. You may obtain a copy of the License at + + http://www.apache.org/licenses/LICENSE-2.0 + +Unless required by applicable law or agreed to in writing, +software distributed under the License is distributed on an +"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +KIND, either express or implied. See the License for the +specific language governing permissions and limitations +under the License. +--> + +* ToC +{:toc} + +## Overview + +Apache Flink streaming applications are typically designed to run indefinitely for long periods of time. +As with all long-running services, the applications need to be updated to adapt to changing requirements. +This goes the same for data schemas that the applications work against; they evolve along with the application. + +This page provides an overview of how you can evolve your state type's data schema. +The current restrictions varies across different type's and state structures (et.c `ValueState`, `ListState`, etc.). + +Note that the information on this page is relevant only if you are using state serializers that is +generated by Flink's own [type serialization framework]({{ site.baseurl }}/dev/types_serialization.html). +That is, when declaring your state, the provided state descriptor is not configured to use a specific `TypeSerializer` +or `TypeInformation`, and therefore allowing Flink to infer information about the state type: Review comment: This should be more a tone of: The user doesn't want Flink to infer a serializer, instead use their own custom serializer ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services
