fqshopify commented on code in PR #174: URL: https://github.com/apache/flink-connector-kafka/pull/174#discussion_r2755948694
########## flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/config/FormatProjectionPushdownLevel.java: ########## @@ -0,0 +1,38 @@ +/* + * 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. + */ + +package org.apache.flink.streaming.connectors.kafka.config; + +import org.apache.flink.annotation.Internal; + +/** + * Projection pushdown mode for {@link + * org.apache.flink.streaming.connectors.kafka.table.KafkaDynamicSource}. + */ +@Internal +public enum FormatProjectionPushdownLevel { + + /** The format does not support any kind of projection pushdown. */ + NONE, + + /** The format supports projection pushdown for top-level fields only. */ + TOP_LEVEL, + + /** The format supports projection pushdown for top-level and nested fields. */ + ALL Review Comment: No, we don't validate format compatibility at configuration time. This was intentional. Although I've done some of the work to figure out what level of projection is supported by some formats (`avro`, `csv`, `json`, `avro-confluent`, `debezium-avro-confluent`), the fact is there are more formats out there beyond those maintained by Flink or even in the open source ecosystem (we have some custom formats at my company for example). Even for the formats I've figured out, it's possible the support could potentially vary by version e.g. if the avro format projection pushdown [bugs](https://issues.apache.org/jira/browse/FLINK-35324) are fixed. Something we _could_ consider long-term is adding a method to `ProjectableDecodingFormat` to indicate its supported projection level. However, even that wouldn't fully solve the problem e.g. the avro format implements `ProjectableDecodingFormat` but doesn't actually support all projection pushdowns (as documented in https://issues.apache.org/jira/browse/FLINK-35324). In the short-term, I've chosen to simply document the appropriate combinations in the flink-connector-kafka config docs [here](https://github.com/apache/flink-connector-kafka/blob/1f283ee629c03b8c1a35a7a64217c40fe314a4d1/flink-connector-kafka/src/main/java/org/apache/flink/streaming/connectors/kafka/table/KafkaConnectorOptions.java#L116). -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
