dwsmith1983 commented on code in PR #5365: URL: https://github.com/apache/datafusion-comet/pull/5365#discussion_r3826305642
########## contrib/delta-spark/src/main/scala/org/apache/comet/contrib/delta/CometDeltaNativeScan.scala: ########## @@ -0,0 +1,450 @@ +/* + * 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.contrib.delta + +import scala.jdk.CollectionConverters._ + +import org.apache.hadoop.fs.Path +import org.apache.spark.internal.Logging +import org.apache.spark.sql.catalyst.expressions.Literal +import org.apache.spark.sql.comet.{CometScanExec, DeltaPlanDataInjector} +import org.apache.spark.sql.delta.DeltaParquetFileFormat +import org.apache.spark.sql.delta.RowIndexFilterType +import org.apache.spark.sql.delta.actions.DeletionVectorDescriptor +import org.apache.spark.sql.execution.{FileSourceScanExec, ScalarSubquery => ExecScalarSubquery} +import org.apache.spark.sql.execution.datasources.{FilePartition, PartitionedFile} +import org.apache.spark.sql.types.{ByteType, LongType, MetadataBuilder, StructField, StructType} + +import org.apache.comet.serde.OperatorOuterClass +import org.apache.comet.serde.OperatorOuterClass.Operator +import org.apache.comet.serde.QueryPlanSerde.{exprToProto, serializeDataType} +import org.apache.comet.serde.operator.{literalToProto, partition2Proto, schema2Proto, CometNativeScan} +import org.apache.comet.shims.ShimFileFormat + +/** + * Serde for the native Delta scan. Two shapes: + * - Plain reads reuse core's `NativeScanCommon` builder wholesale. + * - Deletion-vector reads: Delta's planner appends `__delta_internal_is_row_deleted` (tinyint) + * and Spark's row-index temp column (bigint) to the read schema and filters on is_row_deleted + * above the scan. The native reader applies the DV as a row selection, so surviving rows are + * by construction not deleted: both internal columns are emitted as per-file constants (0), + * the parquet read schema is stripped to the real data columns, and the DV descriptor ships + * per file for the native side to fetch and decode. + */ +object CometDeltaNativeScan + extends Logging + with org.apache.spark.sql.catalyst.expressions.PredicateHelper { + + val IsRowDeletedColumn: String = DeltaParquetFileFormat.IS_ROW_DELETED_COLUMN_NAME + val RowIndexColumn: String = ShimFileFormat.ROW_INDEX_TEMPORARY_COLUMN_NAME + + private[delta] val internalColumnNames: Set[String] = Set(IsRowDeletedColumn, RowIndexColumn) + + // Prefix for the internal columns' slots in the partition schema, mirroring core's + // _comet_metadata_ prefix rationale: DataFusion matches partition columns by name. + private val deltaConstFieldPrefix = "_comet_delta_" + + def isDvShape(scanExec: FileSourceScanExec): Boolean = + scanExec.requiredSchema.exists(f => internalColumnNames.contains(f.name)) + + private def deltaFormat(scanExec: FileSourceScanExec): DeltaParquetFileFormat = + scanExec.relation.fileFormat.asInstanceOf[DeltaParquetFileFormat] + + private def columnMappingMode(scanExec: FileSourceScanExec): String = + deltaFormat(scanExec).metadata.columnMappingMode.name + + /** + * Under column mapping, parquet files store physical column names (stable UUIDs / ids), so the + * schemas passed to the native parquet reader must be physical. Positions and structure are + * preserved, so all positional output binding and projection are unaffected. The scan's + * internal DV columns are not part of the table schema and must be stripped before calling + * this. + */ + private def toPhysical(scanExec: FileSourceScanExec, schema: StructType): StructType = { + val format = deltaFormat(scanExec) + if (format.metadata.columnMappingMode.name == "none") { + schema + } else { + // Name mode matches file columns by physical NAME. createPhysicalSchema also stamps + // parquet.field.id metadata, but files written before the column-mapping upgrade have + // no field ids and would fail the reader's id expectations, strip the ids so the + // reader stays purely name-based (id mode, when enabled, will keep them). + stripFieldIds(org.apache.spark.sql.delta.DeltaColumnMapping + .createPhysicalSchema(schema, format.metadata.schema, format.metadata.columnMappingMode)) + } + } + + private def stripFieldIds(schema: StructType): StructType = { + import org.apache.spark.sql.types._ + def stripType(dt: DataType): DataType = dt match { + case s: StructType => stripFieldIds(s) + case a: ArrayType => a.copy(elementType = stripType(a.elementType)) + case m: MapType => + m.copy(keyType = stripType(m.keyType), valueType = stripType(m.valueType)) + case other => other + } + StructType(schema.fields.map { f => + val metadata = new MetadataBuilder() + .withMetadata(f.metadata) + .remove("parquet.field.id") + // Sibling key Delta stamps on array/map fields under IcebergCompat/Uniform. + .remove("parquet.field.nested.ids") + .build() + f.copy(dataType = stripType(f.dataType), metadata = metadata) + }) + } + + /** + * Build the planning-time `DeltaScan` operator (common data only; file partitions are injected + * lazily at execution). Returns None when an output data type cannot be serialized or the plan + * shape is not one we can translate faithfully. + */ + def convert(scanExec: FileSourceScanExec, scanHelper: CometScanExec): Option[Operator] = { + val relation = scanExec.relation + + val firstFileUri = scanHelper.selectedPartitions + .flatMap(_.files.headOption) + .headOption + .map(_.getPath.toUri) Review Comment: Went with derive rather than decline: options are now unioned over the data-file authority, the table root, and every on-disk DV authority, deduped per authority. The extracted prefixes are scheme-disjoint so the union can't collide. Cross-provider coverage is a unit test (S3 data plus ABFS sidecar, asserting both prefixes appear and that an S3-only set gets no azure keys), since a same-scheme MinIO scenario wouldn't prove anything, option extraction is scheme-global. -- This is an automated message from the Apache Git Service. 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