JingsongLi commented on code in PR #8380: URL: https://github.com/apache/paimon/pull/8380#discussion_r3490720767
########## paimon-core/src/main/java/org/apache/paimon/deletionvectors/DataEvolutionApplyDvReader.java: ########## @@ -0,0 +1,217 @@ +/* + * 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.paimon.deletionvectors; + +import org.apache.paimon.data.InternalRow; +import org.apache.paimon.fs.FileIO; +import org.apache.paimon.reader.RecordReader; +import org.apache.paimon.table.SpecialFields; +import org.apache.paimon.table.source.DeletionFile; +import org.apache.paimon.types.RowType; +import org.apache.paimon.utils.Preconditions; +import org.apache.paimon.utils.ProjectedRow; +import org.apache.paimon.utils.Range; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.ArrayList; +import java.util.Collections; +import java.util.Comparator; +import java.util.List; +import java.util.Map; + +/** + * Applies deletion vectors to data-evolution reads. The underlying reader is asked to include + * {@code _ROW_ID} when needed, and this reader projects it away again unless the caller requested + * it. + */ +public class DataEvolutionApplyDvReader implements RecordReader<InternalRow> { + + private final RecordReader<InternalRow> reader; + private final List<RowRangeDeletionVector> deletionVectors; + @Nullable private final ProjectedRow projectedRow; + private final int rowIdIndex; + + private long lastRowId = -1; + private int nextDvIndex; + @Nullable private RowRangeDeletionVector currentDv; + + public DataEvolutionApplyDvReader(RecordReader<InternalRow> reader, Info info) { + this.reader = reader; + this.deletionVectors = new ArrayList<>(info.deletionVectors); + this.deletionVectors.sort(Comparator.comparingLong(dv -> dv.range.from)); + this.rowIdIndex = info.rowIdIndex; + this.projectedRow = info.projectedRow; + + this.nextDvIndex = 1; + this.currentDv = deletionVectors.get(0); + } + + @Nullable + @Override + public RecordIterator<InternalRow> readBatch() throws IOException { + RecordIterator<InternalRow> iterator = reader.readBatch(); + if (iterator == null) { + return null; + } + + return new RecordIterator<InternalRow>() { + + @Nullable + @Override + public InternalRow next() throws IOException { + while (true) { + InternalRow row = iterator.next(); + if (row == null) { + return null; + } + + if (!isDeleted(row)) { + return projectedRow == null ? row : projectedRow.replaceRow(row); + } + } + } + + @Override + public void releaseBatch() { + iterator.releaseBatch(); + } + }; + } + + private boolean isDeleted(InternalRow row) { + long rowId = row.getLong(rowIdIndex); + checkRowIdMonotonicity(rowId); + moveToPossibleDv(rowId); + + if (currentDv == null || !currentDv.mayContain(rowId)) { + return false; + } + + return currentDv.isDeleted(rowId); + } + + private void checkRowIdMonotonicity(long rowId) { + if (lastRowId >= 0) { + Preconditions.checkState( + rowId > lastRowId, + "This reader works only if underlying reader produces incremental _ROW_IDs."); + } + lastRowId = rowId; + } + + private void moveToPossibleDv(long rowId) { + while (currentDv != null && rowId > currentDv.range.to) { + if (nextDvIndex >= deletionVectors.size()) { + currentDv = null; + return; + } + currentDv = deletionVectors.get(nextDvIndex); + nextDvIndex++; + } + } + + @Override + public void close() throws IOException { + reader.close(); + } + + public static Info readInfo( + FileIO fileIO, RowType readRowType, @Nullable Map<Range, DeletionFile> deletionFiles) + throws IOException { + if (deletionFiles == null || deletionFiles.isEmpty()) { + return Info.noDeletionVectors(readRowType); + } + + List<RowRangeDeletionVector> deletionVectors = new ArrayList<>(deletionFiles.size()); + for (Map.Entry<Range, DeletionFile> entry : deletionFiles.entrySet()) { + DeletionVector deletionVector = DeletionVector.read(fileIO, entry.getValue()); + if (!deletionVector.isEmpty()) { + deletionVectors.add(new RowRangeDeletionVector(entry.getKey(), deletionVector)); + } + } + if (deletionVectors.isEmpty()) { + return Info.noDeletionVectors(readRowType); + } + + int rowIdIndex = readRowType.getFieldIndex(SpecialFields.ROW_ID.name()); + RowType actualReadType = readRowType; + ProjectedRow projectedRow = null; + if (rowIdIndex == -1) { + actualReadType = SpecialFields.rowTypeWithRowId(readRowType); Review Comment: Maybe we can try putting this `ApplyDeletionVectorReader` at the bottom of a single file to implement it? -- This is an automated message from the Apache Git Service. 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