cloud-fan commented on code in PR #49235: URL: https://github.com/apache/spark/pull/49235#discussion_r1891418567
########## sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/PushVariantIntoScan.scala: ########## @@ -0,0 +1,334 @@ +/* + * 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.spark.sql.execution.datasources + +import scala.collection.mutable.HashMap + +import org.apache.spark.sql.catalyst.InternalRow +import org.apache.spark.sql.catalyst.expressions._ +import org.apache.spark.sql.catalyst.expressions.variant.{VariantGet, VariantPathParser} +import org.apache.spark.sql.catalyst.planning.PhysicalOperation +import org.apache.spark.sql.catalyst.plans.logical.{Filter, LogicalPlan, Project, Subquery} +import org.apache.spark.sql.catalyst.rules.Rule +import org.apache.spark.sql.catalyst.util.ResolveDefaultColumns +import org.apache.spark.sql.errors.QueryExecutionErrors +import org.apache.spark.sql.execution.datasources.parquet.ParquetFileFormat +import org.apache.spark.sql.internal.SQLConf +import org.apache.spark.sql.types._ + +// A metadata class of a struct field. All struct fields in a struct must either all have this +// metadata, or all don't have it. +// We define a "variant struct" as: a special struct with its fields annotated with this metadata. +// It indicates that the struct should produce all requested fields of a variant type, and should be +// treated specially by the scan. +case class VariantMetadata( + // The `path` parameter of VariantGet. It has the same format as a JSON path, except that + // `[*]` is not supported. + path: String, + failOnError: Boolean, + timeZoneId: String) { + // Produce a metadata contain one key-value pair. The key is the special `METADATA_KEY`. + // The value contains three key-value pairs for `path`, `failOnError`, and `timeZoneId`. + def toMetadata: Metadata = + new MetadataBuilder().putMetadata( + VariantMetadata.METADATA_KEY, + new MetadataBuilder() + .putString(VariantMetadata.PATH_KEY, path) + .putBoolean(VariantMetadata.FAIL_ON_ERROR_KEY, failOnError) + .putString(VariantMetadata.TIME_ZONE_ID_KEY, timeZoneId) + .build() + ).build() + + def parsedPath(): Array[VariantPathParser.PathSegment] = { + VariantPathParser.parse(path).getOrElse { + val name = if (failOnError) "variant_get" else "try_variant_get" + throw QueryExecutionErrors.invalidVariantGetPath(path, name) + } + } +} + +object VariantMetadata { + val METADATA_KEY = "__VARIANT_METADATA_KEY" + val PATH_KEY = "path" + val FAIL_ON_ERROR_KEY = "failOnError" + val TIME_ZONE_ID_KEY = "timeZoneId" + + def isVariantStruct(s: StructType): Boolean = + s.fields.length > 0 && s.fields.forall(_.metadata.contains(METADATA_KEY)) + + def isVariantStruct(t: DataType): Boolean = t match { + case s: StructType => isVariantStruct(s) + case _ => false + } + + // Parse the `VariantMetadata` from a metadata produced by `toMetadata`. + def fromMetadata(metadata: Metadata): VariantMetadata = { + val value = metadata.getMetadata(METADATA_KEY) + VariantMetadata( + value.getString(PATH_KEY), + value.getBoolean(FAIL_ON_ERROR_KEY), + value.getString(TIME_ZONE_ID_KEY) + ) + } +} + +// Represent a requested field of a variant that the scan should produce. +// Each `RequestedVariantField` is corresponded to a variant path extraction in the plan. +case class RequestedVariantField(path: VariantMetadata, targetType: DataType) + +object RequestedVariantField { + def fullVariant: RequestedVariantField = + RequestedVariantField(VariantMetadata("$", failOnError = true, "UTC"), VariantType) + + def apply(v: VariantGet): RequestedVariantField = + RequestedVariantField( + VariantMetadata(v.path.eval().toString, v.failOnError, v.timeZoneId.get), v.dataType) + + def apply(c: Cast): RequestedVariantField = + RequestedVariantField( + VariantMetadata("$", c.evalMode != EvalMode.TRY, c.timeZoneId.get), c.dataType) +} + +// Extract a nested struct access path. Return the (root attribute id, a sequence of ordinals to +// access the field). For non-nested attribute access, the sequence is empty. +object StructPath { + def unapply(expr: Expression): Option[(ExprId, Seq[Int])] = expr match { + case GetStructField(StructPath(root, path), ordinal, _) => Some((root, path :+ ordinal)) + case a: Attribute => Some(a.exprId, Nil) + case _ => None + } +} + +// A collection of all eligible variants in a relation, which are in the root of the relation output +// schema, or only nested in struct types. +// The user should: +// 1. Call `addVariantFields` to add all eligible variants in a relation. +// 2. Call `collectRequestedFields` on all expressions depending on the relation. This process will +// add the requested fields of each variant and potentially remove non-eligible variants. See +// `collectRequestedFields` for details. +// 3. Call `rewriteType` to produce a new output schema for the relation. +// 4. Call `rewriteExpr` to rewrite the previously visited expressions by replacing variant +// extractions with struct accessed. +class VariantInRelation { + // First level key: root attribute id. + // Second level key: struct access paths to the variant type. + // Third level key: requested fields of a variant type. + // Final value: the ordinal of a requested field in the final struct of requested fields. + val mapping = new HashMap[ExprId, HashMap[Seq[Int], HashMap[RequestedVariantField, Int]]] + + // Extract the SQL-struct path where the leaf is a variant. + object StructPathToVariant { + def unapply(expr: Expression): Option[HashMap[RequestedVariantField, Int]] = expr match { + case StructPath(attrId, path) => + mapping.get(attrId).flatMap(_.get(path)) + case _ => None + } + } + + // Find eligible variants recursively. `attrId` is the root attribute id. + // `path` is the current struct access path. `dataType` is the child data type after extracting + // `path` from the root attribute struct. + def addVariantFields(attrId: ExprId, dataType: DataType, defaultValue: Any, + path: Seq[Int]): Unit = { Review Comment: ```suggestion def addVariantFields( attrId: ExprId, dataType: DataType, defaultValue: Any, path: Seq[Int]): Unit = { ``` -- This is an automated message from the Apache Git Service. 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