wzhero1 commented on code in PR #6858: URL: https://github.com/apache/paimon/pull/6858#discussion_r2652125960
########## paimon-core/src/main/java/org/apache/paimon/table/source/KeyValueSystemFieldsRecordReader.java: ########## @@ -0,0 +1,254 @@ +/* + * 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.table.source; + +import org.apache.paimon.KeyValue; +import org.apache.paimon.data.BinaryString; +import org.apache.paimon.data.GenericRow; +import org.apache.paimon.data.InternalRow; +import org.apache.paimon.data.JoinedRow; +import org.apache.paimon.reader.RecordReader; +import org.apache.paimon.table.SpecialFields; +import org.apache.paimon.utils.ProjectedRow; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +/** + * A decorator for {@link RecordReader} that injects system fields into the output rows for + * KeyValue-based data sources. + * + * <p>This reader wraps a {@code RecordReader<KeyValue>} and produces {@code + * RecordReader<InternalRow>} with additional system fields extracted from the KeyValue metadata. + * + * <p><b>Naming:</b> This class is specifically designed for KeyValue format data (e.g., + * MergeFileSplitRead). For InternalRow readers (e.g., RawFileSplitRead), system fields are handled + * differently in {@link org.apache.paimon.io.DataFileRecordReader} using file metadata. + * + * <p><b>Field Ordering:</b> The output schema supports arbitrary field ordering. Internally, fields + * are assembled as [system fields... + physical fields...], then reordered using {@link + * ProjectedRow} to match the requested field order. + * + * <p><b>Performance:</b> Implementation uses {@link JoinedRow} for zero-copy concatenation of + * system fields and physical fields, then {@link ProjectedRow} for zero-copy field reordering. + */ +public class KeyValueSystemFieldsRecordReader implements RecordReader<InternalRow> { + + private final RecordReader<KeyValue> wrapped; + private final List<SystemFieldExtractor> systemFieldExtractors; + @Nullable private final int[] projection; + + /** + * Creates a KeyValueSystemFieldsRecordReader. + * + * @param wrapped the underlying KeyValue reader + * @param systemFieldExtractors extractors for system fields, in order + * @param projection optional projection to reorder fields. If null, fields are in natural order + * [system fields... + physical fields...]. If provided, projects from the natural order to + * the desired order. + */ + public KeyValueSystemFieldsRecordReader( + RecordReader<KeyValue> wrapped, + List<SystemFieldExtractor> systemFieldExtractors, + @Nullable int[] projection) { + this.wrapped = wrapped; + this.systemFieldExtractors = systemFieldExtractors; + this.projection = projection; + } + + @Nullable + @Override + public RecordIterator<InternalRow> readBatch() throws IOException { + RecordIterator<KeyValue> batch = wrapped.readBatch(); + if (batch == null) { + return null; + } + return new SystemFieldsRecordIterator(batch); + } + + @Override + public void close() throws IOException { + wrapped.close(); + } + + private class SystemFieldsRecordIterator implements RecordIterator<InternalRow> { + + private final RecordIterator<KeyValue> kvIterator; + private final JoinedRow joinedRow; + private final GenericRow systemFieldsRow; + @Nullable private final ProjectedRow projectedRow; + + private SystemFieldsRecordIterator(RecordIterator<KeyValue> kvIterator) { + this.kvIterator = kvIterator; + this.joinedRow = new JoinedRow(); + this.systemFieldsRow = new GenericRow(systemFieldExtractors.size()); + // If projection is provided, use ProjectedRow to reorder fields + this.projectedRow = projection != null ? ProjectedRow.from(projection) : null; + } + + @Nullable + @Override + public InternalRow next() throws IOException { + KeyValue kv = kvIterator.next(); + if (kv == null) { + return null; + } + + InternalRow value = kv.value(); + + // Extract system fields into the reusable row + for (int i = 0; i < systemFieldExtractors.size(); i++) { + SystemFieldExtractor extractor = systemFieldExtractors.get(i); + Object systemValue = extractor.extract(kv); + systemFieldsRow.setField(i, systemValue); + } + + // Join system fields first, then physical fields + // Natural order: [system fields...] + [physical fields...] + joinedRow.replace(systemFieldsRow, value); + joinedRow.setRowKind(kv.valueKind()); + + // If projection is provided, reorder to match requested order + if (projectedRow != null) { + return projectedRow.replaceRow(joinedRow); + } + return joinedRow; + } + + @Override + public void releaseBatch() { + kvIterator.releaseBatch(); + } + } + + /** + * Wraps a KeyValue reader with system field injection if needed. + * + * @param reader the KeyValue reader + * @param systemFieldExtractors extractors for system fields (empty if no system fields needed) + * @param projection optional projection to reorder fields from natural order [system fields... + * + physical fields...] to desired order + * @return a reader producing InternalRow with system fields, or a simple unwrapped reader if no + * system fields + */ + public static RecordReader<InternalRow> wrap( + RecordReader<KeyValue> reader, + List<SystemFieldExtractor> systemFieldExtractors, + @Nullable int[] projection) { + if (systemFieldExtractors.isEmpty()) { + // No system fields, use the default unwrap logic + return KeyValueTableRead.unwrap(reader); Review Comment: Done. I've moved the logic into `KeyValueTableRead.java`. The method structure is now: * `unwrap(RecordReader<KeyValue> reader, List<SpecialFieldExtractor> specialFieldExtractors, @Nullable int[] projection)` as public method for extensibility * `unwrap(RecordReader<KeyValue> reader)` as private method for internal use ########## paimon-core/src/main/java/org/apache/paimon/table/source/KeyValueSystemFieldsRecordReader.java: ########## @@ -0,0 +1,254 @@ +/* + * 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.table.source; + +import org.apache.paimon.KeyValue; +import org.apache.paimon.data.BinaryString; +import org.apache.paimon.data.GenericRow; +import org.apache.paimon.data.InternalRow; +import org.apache.paimon.data.JoinedRow; +import org.apache.paimon.reader.RecordReader; +import org.apache.paimon.table.SpecialFields; +import org.apache.paimon.utils.ProjectedRow; + +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.HashMap; +import java.util.List; +import java.util.Map; + +/** + * A decorator for {@link RecordReader} that injects system fields into the output rows for + * KeyValue-based data sources. + * + * <p>This reader wraps a {@code RecordReader<KeyValue>} and produces {@code + * RecordReader<InternalRow>} with additional system fields extracted from the KeyValue metadata. + * + * <p><b>Naming:</b> This class is specifically designed for KeyValue format data (e.g., + * MergeFileSplitRead). For InternalRow readers (e.g., RawFileSplitRead), system fields are handled + * differently in {@link org.apache.paimon.io.DataFileRecordReader} using file metadata. + * + * <p><b>Field Ordering:</b> The output schema supports arbitrary field ordering. Internally, fields + * are assembled as [system fields... + physical fields...], then reordered using {@link + * ProjectedRow} to match the requested field order. + * + * <p><b>Performance:</b> Implementation uses {@link JoinedRow} for zero-copy concatenation of + * system fields and physical fields, then {@link ProjectedRow} for zero-copy field reordering. + */ +public class KeyValueSystemFieldsRecordReader implements RecordReader<InternalRow> { + + private final RecordReader<KeyValue> wrapped; + private final List<SystemFieldExtractor> systemFieldExtractors; + @Nullable private final int[] projection; + + /** + * Creates a KeyValueSystemFieldsRecordReader. + * + * @param wrapped the underlying KeyValue reader + * @param systemFieldExtractors extractors for system fields, in order + * @param projection optional projection to reorder fields. If null, fields are in natural order + * [system fields... + physical fields...]. If provided, projects from the natural order to + * the desired order. + */ + public KeyValueSystemFieldsRecordReader( + RecordReader<KeyValue> wrapped, + List<SystemFieldExtractor> systemFieldExtractors, + @Nullable int[] projection) { + this.wrapped = wrapped; + this.systemFieldExtractors = systemFieldExtractors; + this.projection = projection; + } + + @Nullable + @Override + public RecordIterator<InternalRow> readBatch() throws IOException { + RecordIterator<KeyValue> batch = wrapped.readBatch(); + if (batch == null) { + return null; + } + return new SystemFieldsRecordIterator(batch); + } + + @Override + public void close() throws IOException { + wrapped.close(); + } + + private class SystemFieldsRecordIterator implements RecordIterator<InternalRow> { + + private final RecordIterator<KeyValue> kvIterator; + private final JoinedRow joinedRow; + private final GenericRow systemFieldsRow; + @Nullable private final ProjectedRow projectedRow; + + private SystemFieldsRecordIterator(RecordIterator<KeyValue> kvIterator) { + this.kvIterator = kvIterator; + this.joinedRow = new JoinedRow(); + this.systemFieldsRow = new GenericRow(systemFieldExtractors.size()); + // If projection is provided, use ProjectedRow to reorder fields + this.projectedRow = projection != null ? ProjectedRow.from(projection) : null; + } + + @Nullable + @Override + public InternalRow next() throws IOException { + KeyValue kv = kvIterator.next(); + if (kv == null) { + return null; + } + + InternalRow value = kv.value(); + + // Extract system fields into the reusable row + for (int i = 0; i < systemFieldExtractors.size(); i++) { + SystemFieldExtractor extractor = systemFieldExtractors.get(i); + Object systemValue = extractor.extract(kv); + systemFieldsRow.setField(i, systemValue); + } + + // Join system fields first, then physical fields + // Natural order: [system fields...] + [physical fields...] + joinedRow.replace(systemFieldsRow, value); + joinedRow.setRowKind(kv.valueKind()); + + // If projection is provided, reorder to match requested order + if (projectedRow != null) { + return projectedRow.replaceRow(joinedRow); + } + return joinedRow; + } + + @Override + public void releaseBatch() { + kvIterator.releaseBatch(); + } + } + + /** + * Wraps a KeyValue reader with system field injection if needed. + * + * @param reader the KeyValue reader + * @param systemFieldExtractors extractors for system fields (empty if no system fields needed) + * @param projection optional projection to reorder fields from natural order [system fields... + * + physical fields...] to desired order + * @return a reader producing InternalRow with system fields, or a simple unwrapped reader if no + * system fields + */ + public static RecordReader<InternalRow> wrap( + RecordReader<KeyValue> reader, + List<SystemFieldExtractor> systemFieldExtractors, + @Nullable int[] projection) { + if (systemFieldExtractors.isEmpty()) { + // No system fields, use the default unwrap logic + return KeyValueTableRead.unwrap(reader); + } + return new KeyValueSystemFieldsRecordReader(reader, systemFieldExtractors, projection); + } + + // ========== Internal Extractor Interface ========== + + /** + * Internal interface for extracting system fields from {@link KeyValue} objects. + * + * <p>System fields are metadata fields like {@code _SEQUENCE_NUMBER}, {@code _LEVEL}, {@code + * rowkind} that are derived from the KeyValue container itself rather than the stored data. + * + * <p><b>Note:</b> This interface is specifically for KeyValue-based extraction. For InternalRow + * readers (e.g., RawFileSplitRead), system fields are handled differently in {@link + * org.apache.paimon.io.DataFileRecordReader} using file metadata. + * + * <p>All field definitions are sourced from {@link SpecialFields} to maintain consistency + * across the codebase. + * + * <p>Each extractor is stateless and thread-safe. + */ + @FunctionalInterface + public interface SystemFieldExtractor { + + /** + * Extracts the system field value from a KeyValue object. + * + * @param kv the KeyValue to extract from + * @return the extracted value, or null if not applicable + */ + @Nullable + Object extract(KeyValue kv); + + // ========== Built-in Extractors ========== + + /** + * Extractor for {@code _SEQUENCE_NUMBER} system field. + * + * <p>Extracts the sequence number from KeyValue metadata. + */ + SystemFieldExtractor SEQUENCE_NUMBER = kv -> kv.sequenceNumber(); Review Comment: done -- 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]
