RussellSpitzer commented on code in PR #7388: URL: https://github.com/apache/iceberg/pull/7388#discussion_r1186503285
########## spark/v3.3/spark/src/main/java/org/apache/iceberg/spark/ComputeUpdateIterator.java: ########## @@ -0,0 +1,144 @@ +/* + * 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.spark; + +import java.util.Arrays; +import java.util.Iterator; +import java.util.List; +import java.util.stream.Collectors; +import org.apache.iceberg.relocated.com.google.common.base.Preconditions; +import org.apache.spark.sql.Row; +import org.apache.spark.sql.RowFactory; +import org.apache.spark.sql.catalyst.expressions.GenericRow; +import org.apache.spark.sql.types.StructType; + +/** + * An iterator that finds delete/insert rows which represent an update, and converts them into + * update records from changelog tables within a single Spark task. It assumes that rows are sorted + * by identifier columns and change type. + * + * <p>For example, these two rows + * + * <ul> + * <li>(id=1, data='a', op='DELETE') + * <li>(id=1, data='b', op='INSERT') + * </ul> + * + * <p>will be marked as update-rows: + * + * <ul> + * <li>(id=1, data='a', op='UPDATE_BEFORE') + * <li>(id=1, data='b', op='UPDATE_AFTER') + * </ul> + */ +public class ComputeUpdateIterator extends ChangelogIterator { + + private final String[] identifierFields; + private final List<Integer> identifierFieldIdx; + + private Row cachedRow = null; + + ComputeUpdateIterator(Iterator<Row> rowIterator, StructType rowType, String[] identifierFields) { + super(rowIterator, rowType); + this.identifierFieldIdx = + Arrays.stream(identifierFields).map(rowType::fieldIndex).collect(Collectors.toList()); + this.identifierFields = identifierFields; + } + + @Override + public boolean hasNext() { + if (cachedRow != null) { + return true; + } + return rowIterator().hasNext(); + } + + @Override + public Row next() { + // if there is an updated cached row, return it directly + if (cachedUpdateRecord()) { + Row row = cachedRow; + cachedRow = null; + return row; + } + + Row currentRow = currentRow(); + + if (currentRow.getString(changeTypeIndex()).equals(DELETE) && rowIterator().hasNext()) { + Row nextRow = rowIterator().next(); + cachedRow = nextRow; + + if (sameLogicalRow(currentRow, nextRow)) { + String nextRowChangeType = nextRow.getString(changeTypeIndex()); + + Preconditions.checkState( + nextRowChangeType.equals(INSERT), + "The next row should be an INSERT row, but it is %s. That means there are multiple" + + " rows with the same value of identifier fields([%s]). Please make sure the rows are unique.", + nextRowChangeType, + String.join(",", identifierFields)); + + currentRow = modify(currentRow, changeTypeIndex(), UPDATE_BEFORE); + cachedRow = modify(nextRow, changeTypeIndex(), UPDATE_AFTER); + } + } + + return currentRow; + } + + private Row modify(Row row, int valueIndex, Object value) { + if (row instanceof GenericRow) { + GenericRow genericRow = (GenericRow) row; + genericRow.values()[valueIndex] = value; + return genericRow; + } else { + Object[] values = new Object[row.size()]; + for (int index = 0; index < row.size(); index++) { + values[index] = row.get(index); + } + values[valueIndex] = value; + return RowFactory.create(values); + } + } + + private boolean cachedUpdateRecord() { + return cachedRow != null Review Comment: can't this only be UPDATE_AFTER? -- 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: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org
