umehrot2 commented on a change in pull request #1702: URL: https://github.com/apache/hudi/pull/1702#discussion_r447566244
########## File path: hudi-spark/src/main/scala/org/apache/hudi/HudiBootstrapRDD.scala ########## @@ -0,0 +1,131 @@ +/* + * 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 + +import org.apache.spark.{Partition, TaskContext} +import org.apache.spark.rdd.RDD +import org.apache.spark.sql.SparkSession +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.execution.datasources.PartitionedFile +import org.apache.spark.sql.types.StructType +import org.apache.spark.sql.vectorized.ColumnarBatch + +class HudiBootstrapRDD(@transient spark: SparkSession, + dataReadFunction: PartitionedFile => Iterator[Any], + skeletonReadFunction: PartitionedFile => Iterator[Any], + regularReadFunction: PartitionedFile => Iterator[Any], + dataSchema: StructType, + skeletonSchema: StructType, + requiredColumns: Array[String], + tableState: HudiBootstrapTableState) + extends RDD[InternalRow](spark.sparkContext, Nil) { + + override def compute(split: Partition, context: TaskContext): Iterator[InternalRow] = { + val bootstrapPartition = split.asInstanceOf[HudiBootstrapPartition] + + if (log.isDebugEnabled) { + if (bootstrapPartition.split.skeletonFile.isDefined) { + logDebug("Got Split => Index: " + bootstrapPartition.index + ", Data File: " + + bootstrapPartition.split.dataFile.filePath + ", Skeleton File: " + + bootstrapPartition.split.skeletonFile.get.filePath) + } else { + logDebug("Got Split => Index: " + bootstrapPartition.index + ", Data File: " + + bootstrapPartition.split.dataFile.filePath) + } + } + + var partitionedFileIterator: Iterator[InternalRow] = null + + if (bootstrapPartition.split.skeletonFile.isDefined) { + // It is a bootstrap split. Check both skeleton and data files. + if (dataSchema.isEmpty) { + // No data column to fetch, hence fetch only from skeleton file + partitionedFileIterator = read(bootstrapPartition.split.skeletonFile.get, skeletonReadFunction) Review comment: That understanding is correct. But here **data schema** being empty does not mean that there is not data file. It means that in the **request schema** they have not requested any of the **data schema fields**. So this is kind of an optimization where depending on what schema the user has requested, if the request fields all only belong to either skeleton file or data file we only read from that file and avoid the expensive merge operation. ---------------------------------------------------------------- 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]
