leonardBang commented on code in PR #4387: URL: https://github.com/apache/flink-cdc/pull/4387#discussion_r3308108620
########## flink-cdc-connect/flink-cdc-source-connectors/flink-connector-postgres-cdc/src/main/java/org/apache/flink/cdc/connectors/postgres/source/reader/PostgresSourceStreamFetcher.java: ########## @@ -0,0 +1,58 @@ +/* + * 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.cdc.connectors.postgres.source.reader; + +import org.apache.flink.cdc.connectors.base.source.reader.external.FetchTask; +import org.apache.flink.cdc.connectors.base.source.reader.external.IncrementalSourceStreamFetcher; + +import io.debezium.data.Envelope; +import org.apache.kafka.connect.data.Struct; +import org.apache.kafka.connect.source.SourceRecord; + +/** + * Stream fetcher for Postgres. When {@code includeLogicalMessages} is enabled, lets {@code + * pg_logical_emit_message} records (op="m") bypass table-based watermark filtering, since logical + * messages are not bound to a table. + */ +public class PostgresSourceStreamFetcher extends IncrementalSourceStreamFetcher { Review Comment: @eskabetxe @loserwang1024 I'd suggest following the `FetchTask.Context` approach rather than introducing a PostgresSourceStreamFetcher subclass. Two reasons: 1. Better cohesion. The Context abstraction already serves as the dialect-specific extension point — `isDataChangeRecord()` lives there for exactly this reason. Adding `shouldEmit()` to Context keeps all Postgres-specific decision logic in one place (`PostgresSourceFetchTaskContext`), rather than splitting it between a new StreamFetcher subclass and the existing context. 2. Avoids a double-check path. The current implementation introduces `shouldEmit(record) && context.shouldEmit(record)`, which creates ambiguity about which layer owns the emit decision. If we consolidate everything into `Context.shouldEmit()`, the base `IncrementalSourceStreamFetcher` would simply call `context.shouldEmit(record)` with no subclass override needed: ```java // IncrementalSourceStreamFetcher — no subclass needed if (context.shouldEmit(record)) { // emit } // PostgresSourceFetchTaskContext — single decision point @Override public boolean shouldEmit(SourceRecord record) { if (isLogicalMessage(record)) { return matchesPrefix(record, prefixes); } return super.shouldEmit(record); } ``` -- 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]
