openinx commented on a change in pull request #1663: URL: https://github.com/apache/iceberg/pull/1663#discussion_r526708985
########## File path: core/src/main/java/org/apache/iceberg/io/BaseDeltaWriter.java ########## @@ -0,0 +1,248 @@ +/* + * 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.iceberg.io; + +import java.io.IOException; +import java.util.List; +import java.util.function.Function; +import org.apache.iceberg.DataFile; +import org.apache.iceberg.DeleteFile; +import org.apache.iceberg.Schema; +import org.apache.iceberg.StructLike; +import org.apache.iceberg.deletes.PositionDelete; +import org.apache.iceberg.relocated.com.google.common.base.MoreObjects; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.apache.iceberg.relocated.com.google.common.collect.Sets; +import org.apache.iceberg.types.TypeUtil; +import org.apache.iceberg.util.StructLikeMap; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +public class BaseDeltaWriter<T> implements DeltaWriter<T> { + private static final Logger LOG = LoggerFactory.getLogger(BaseDeltaWriter.class); + + private final RollingContentFileWriter<DataFile, T> dataWriter; + private final RollingContentFileWriter<DeleteFile, T> equalityDeleteWriter; + private final RollingContentFileWriter<DeleteFile, PositionDelete<T>> posDeleteWriter; + + private final PositionDelete<T> positionDelete = new PositionDelete<>(); + private final StructLikeMap<List<FilePos>> insertedRowMap; + + // Function to convert the generic data to a StructLike. + private final Function<T, StructLike> structLikeFun; + + public BaseDeltaWriter(RollingContentFileWriter<DataFile, T> dataWriter) { + this(dataWriter, null); + } + + public BaseDeltaWriter(RollingContentFileWriter<DataFile, T> dataWriter, + RollingContentFileWriter<DeleteFile, PositionDelete<T>> posDeleteWriter) { + this(dataWriter, posDeleteWriter, null, null, null, null); + } + + public BaseDeltaWriter(RollingContentFileWriter<DataFile, T> dataWriter, + RollingContentFileWriter<DeleteFile, PositionDelete<T>> posDeleteWriter, + RollingContentFileWriter<DeleteFile, T> equalityDeleteWriter, + Schema tableSchema, + List<Integer> equalityFieldIds, + Function<T, StructLike> structLikeFun) { + + Preconditions.checkNotNull(dataWriter, "Data writer should always not be null."); + + if (posDeleteWriter == null) { + // Only accept INSERT records. + Preconditions.checkArgument(equalityDeleteWriter == null); + } + + if (posDeleteWriter != null && equalityDeleteWriter == null) { + // Only accept INSERT records and position deletion. + Preconditions.checkArgument(tableSchema == null); + Preconditions.checkArgument(equalityFieldIds == null); + } + + if (equalityDeleteWriter != null) { + // Accept insert records, position deletion, equality deletions. + Preconditions.checkNotNull(posDeleteWriter, + "Position delete writer shouldn't be null when writing equality deletions."); + Preconditions.checkNotNull(tableSchema, "Iceberg table schema shouldn't be null"); + Preconditions.checkNotNull(equalityFieldIds, "Equality field ids shouldn't be null"); + Preconditions.checkNotNull(structLikeFun, "StructLike function shouldn't be null"); + + Schema deleteSchema = TypeUtil.select(tableSchema, Sets.newHashSet(equalityFieldIds)); + this.insertedRowMap = StructLikeMap.create(deleteSchema.asStruct()); + this.structLikeFun = structLikeFun; + } else { + this.insertedRowMap = null; + this.structLikeFun = null; + } + + this.dataWriter = dataWriter; + this.equalityDeleteWriter = equalityDeleteWriter; + this.posDeleteWriter = posDeleteWriter; + } + + @Override + public void writeRow(T row) throws IOException { + if (enableEqualityDelete()) { + FilePos filePos = FilePos.create(dataWriter.currentPath(), dataWriter.currentPos()); + insertedRowMap.compute(structLikeFun.apply(row), (k, v) -> { + if (v == null) { + return Lists.newArrayList(filePos); + } else { + v.add(filePos); + return v; Review comment: Let's consider the three cases: Case.1 : Import CDC data whose table has an unique key to iceberg table. In this case, it's impossible to have duplicated records with the same key to INSERT. Case.2 : Import CDC data whose table does not have an unique key to iceberg table, the equality fields should be all columns in the table, but it be possible that we will encounter duplicated rows because database such as mysql would allow to write the same record twice. But that's not a common case, more people will create a table with unique keys, I think it's OK to not address this case. Case.3: upsert records in the iceberg table. it must have primary keys. The `UPSERT` will be executed as an `DELETE` and an `INSERT`, then we could also ensure that duplicated keys won't happen in the `writeRow` method ( which will be called when `INSERT` row). So in general, I think it's OK to expect that we don't have multiple inserts for the same key. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
