wombatu-kun commented on code in PR #19110: URL: https://github.com/apache/hudi/pull/19110#discussion_r3497791469
########## hudi-utilities/src/main/java/org/apache/hudi/utilities/transform/debezium/MysqlDebeziumTransformer.java: ########## @@ -0,0 +1,82 @@ +/* + * 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.hudi.utilities.transform.debezium; + +import org.apache.hudi.common.model.debezium.DebeziumConstants; +import org.apache.hudi.common.util.Option; + +import org.apache.spark.sql.Column; +import org.apache.spark.sql.Dataset; +import org.apache.spark.sql.Row; +import org.apache.spark.sql.functions; + +import java.util.Arrays; +import java.util.List; + +/** + * {@link AbstractDebeziumTransformer} for MySQL Debezium change events. + * + * <p>Surfaces the MySQL binlog coordinates ({@code file}, {@code pos}, {@code row}) as the flattened + * {@code _event_bin_file}, {@code _event_pos} and {@code _event_row} columns, and derives the + * {@code _event_seq} ordering column as {@code "<binlog-file-suffix>.<pos>"} (e.g. {@code "000001.100"} + * for a binlog file {@code "mysql-bin.000001"} at position {@code 100}). {@code _event_seq} is the + * precombine/ordering field consumed by {@code MySqlDebeziumAvroPayload}. + * + * <p>Metadata is flattened to the root level by default; set + * {@code hoodie.streamer.transformer.debezium.nested.fields.enable=true} to group it under a + * {@code _debezium_metadata} struct instead. + */ +public class MysqlDebeziumTransformer extends AbstractDebeziumTransformer { + + private static final List<Column> MYSQL_METADATA = Arrays.asList( + new Column(DebeziumConstants.INCOMING_SOURCE_FILE_FIELD).alias(DebeziumConstants.FLATTENED_FILE_COL_NAME), + new Column(DebeziumConstants.INCOMING_SOURCE_POS_FIELD).alias(DebeziumConstants.FLATTENED_POS_COL_NAME), + new Column(DebeziumConstants.INCOMING_SOURCE_ROW_FIELD).alias(DebeziumConstants.FLATTENED_ROW_COL_NAME)); + + public MysqlDebeziumTransformer() { + super(MYSQL_METADATA, Option.of(MysqlDebeziumTransformer::applySeqNo)); + } + + /** + * Builds the {@code _event_seq} ordering column from the binlog file and position. The file column + * holds a name like {@code "mysql-bin.000001"}; only the numeric suffix after the last dot is used, + * yielding a sequence such as {@code "000001.100"}. Handles both the flat and nested metadata + * layouts (reading {@code file}/{@code pos} from the {@code _debezium_metadata} struct when nested). + * + * @param dataset flattened MySQL Debezium dataset. + * @return dataset with the {@code _event_seq} column added. + */ + private static Dataset<Row> applySeqNo(Dataset<Row> dataset) { + boolean isNested = Arrays.asList(dataset.columns()).contains(DEBEZIUM_METADATA_FIELD); + + Column fileCol = isNested + ? dataset.col(DEBEZIUM_METADATA_FIELD + "." + DebeziumConstants.FLATTENED_FILE_COL_NAME) + : dataset.col(DebeziumConstants.FLATTENED_FILE_COL_NAME); + + Column posCol = isNested + ? dataset.col(DEBEZIUM_METADATA_FIELD + "." + DebeziumConstants.FLATTENED_POS_COL_NAME) + : dataset.col(DebeziumConstants.FLATTENED_POS_COL_NAME); + + return dataset.withColumn(DebeziumConstants.ADDED_SEQ_COL_NAME, functions.concat( Review Comment: Confirmed: the original `MysqlDebeziumSource.generateUniqueSequence` threw `HoodieReadFromSourceException` on `file == null || file.trim().isEmpty() || pos == null || pos < 0` before building the key. `applySeqNo` drops that guard, and since Spark `concat` returns null when any argument is null, a malformed event yields a null `_event_seq` - the precombine field - which only surfaces later in `MySqlDebeziumAvroPayload`. Restoring an equivalent fail-fast check (or a `coalesce` plus assertion) in `applySeqNo` keeps the early, descriptive failure. -- 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]
