wForget commented on code in PR #3221: URL: https://github.com/apache/datafusion-comet/pull/3221#discussion_r2719315607
########## spark/src/main/scala/org/apache/comet/NativeColumnarToRowConverter.scala: ########## @@ -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.comet + +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.catalyst.expressions.UnsafeRow +import org.apache.spark.sql.types.StructType +import org.apache.spark.sql.vectorized.ColumnarBatch + +import org.apache.comet.serde.QueryPlanSerde +import org.apache.comet.vector.NativeUtil + +/** + * Native converter that converts Arrow columnar data to Spark UnsafeRow format. + * + * This converter maintains a native handle that holds the conversion context and output buffer. + * The buffer is reused across conversions to minimize allocations. + * + * Memory Management: + * - The native side owns the output buffer + * - UnsafeRow objects returned by convert() point directly to native memory (zero-copy) + * - The buffer is valid until the next convert() call or close() + * - Always call close() when done to release native resources + * + * @param schema + * The schema of the data to convert + * @param batchSize + * Maximum number of rows per batch (used for buffer pre-allocation) + */ +class NativeColumnarToRowConverter(schema: StructType, batchSize: Int) extends AutoCloseable { + + private val nativeLib = new Native() + private val nativeUtil = new NativeUtil() + + // Serialize the schema for native initialization + private val serializedSchema: Array[Array[Byte]] = schema.fields.map { field => + QueryPlanSerde.serializeDataType(field.dataType) match { + case Some(dataType) => dataType.toByteArray + case None => + throw new UnsupportedOperationException( + s"Data type ${field.dataType} is not supported for native columnar to row conversion") + } + } + + // Initialize native context - handle is 0 if initialization failed + private var c2rHandle: Long = nativeLib.columnarToRowInit(serializedSchema, batchSize) + + // Reusable UnsafeRow for iteration + private val unsafeRow = new UnsafeRow(schema.fields.length) + + /** + * Converts a ColumnarBatch to an iterator of InternalRows. + * + * The returned iterator yields UnsafeRow objects that point directly to native memory. These + * rows are valid only until the next call to convert() or close(). + * + * @param batch + * The columnar batch to convert + * @return + * An iterator of InternalRows + */ + def convert(batch: ColumnarBatch): Iterator[InternalRow] = { + if (c2rHandle == 0) { + throw new IllegalStateException("NativeColumnarToRowConverter has been closed") + } + + val numRows = batch.numRows() + if (numRows == 0) { + return Iterator.empty + } + + // Export the batch to Arrow FFI and get memory addresses + val (arrayAddrs, schemaAddrs, exportedNumRows) = nativeUtil.exportBatchToAddresses(batch) + + // Call native conversion + val info = nativeLib.columnarToRowConvert(c2rHandle, arrayAddrs, schemaAddrs, exportedNumRows) Review Comment: Do we need to consider `exportedNumRows > batchSize`? -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
