[GitHub] [iceberg] aokolnychyi commented on a change in pull request #1852: Spark: Add plans & rules for DELETE

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aokolnychyi commented on a change in pull request #1852:
URL: https://github.com/apache/iceberg/pull/1852#discussion_r533406571



##########
File path: spark3-extensions/src/main/scala/org/apache/spark/sql/catalyst/optimizer/RewriteDelete.scala
##########
@@ -0,0 +1,152 @@
+/*
+ * 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.catalyst.optimizer
+
+import java.util.UUID
+import org.apache.spark.internal.Logging
+import org.apache.spark.sql.{sources, AnalysisException}
+import org.apache.spark.sql.catalyst.expressions.{Alias, Ascending, Attribute, AttributeReference, EqualNullSafe, Expression, InputFileName, Literal, Not, PredicateHelper, SortOrder, SubqueryExpression}
+import org.apache.spark.sql.catalyst.plans.logical.{Aggregate, DeleteFromTable, DynamicFileFilter, Filter, LogicalPlan, Project, RepartitionByExpression, ReplaceData, Sort}
+import org.apache.spark.sql.catalyst.rules.Rule
+import org.apache.spark.sql.connector.catalog.Table
+import org.apache.spark.sql.connector.iceberg.catalog.ExtendedSupportsDelete
+import org.apache.spark.sql.connector.iceberg.read.SupportsFileFilter
+import org.apache.spark.sql.connector.iceberg.write.MergeBuilder
+import org.apache.spark.sql.connector.write.{LogicalWriteInfo, LogicalWriteInfoImpl}
+import org.apache.spark.sql.execution.datasources.DataSourceStrategy
+import org.apache.spark.sql.execution.datasources.v2.{DataSourceV2Relation, DataSourceV2ScanRelation, PushDownUtils}
+import org.apache.spark.sql.internal.SQLConf
+import org.apache.spark.sql.types.{BooleanType, StructType}
+import org.apache.spark.sql.util.CaseInsensitiveStringMap
+
+// TODO: should be part of early scan push down after the delete condition is optimized
+object RewriteDelete extends Rule[LogicalPlan] with PredicateHelper with Logging {
+
+  import org.apache.spark.sql.execution.datasources.v2.ExtendedDataSourceV2Implicits._
+
+  private val FILE_NAME_COL = "_file"
+
+  override def apply(plan: LogicalPlan): LogicalPlan = plan resolveOperators {
+    // don't rewrite deletes that can be answered by passing filters to deleteWhere in SupportsDelete
+    case d @ DeleteFromTable(r: DataSourceV2Relation, Some(cond)) if isDeleteWhereCase(r, cond) =>
+      d
+
+    // rewrite all operations that require reading the table to delete records
+    case DeleteFromTable(r: DataSourceV2Relation, Some(cond)) =>
+      // TODO: do a switch based on whether we get BatchWrite or DeltaBatchWrite
+      val writeInfo = newWriteInfo(r.schema)
+      val mergeBuilder = r.table.asMergeable.newMergeBuilder(writeInfo)
+
+      val scanPlan = buildScanPlan(r.table, r.output, mergeBuilder, cond)
+
+      val remainingRowFilter = Not(EqualNullSafe(cond, Literal(true, BooleanType)))
+      val remainingRowsPlan = Filter(remainingRowFilter, scanPlan)
+
+      val batchWrite = mergeBuilder.asWriteBuilder.buildForBatch()
+      val writePlan = buildWritePlan(remainingRowsPlan, r.output)
+      ReplaceData(r, batchWrite, writePlan)
+  }
+
+  private def buildScanPlan(
+      table: Table,
+      output: Seq[AttributeReference],
+      mergeBuilder: MergeBuilder,
+      cond: Expression): LogicalPlan = {
+
+    val scanBuilder = mergeBuilder.asScanBuilder
+
+    val predicates = splitConjunctivePredicates(cond)
+    val normalizedPredicates = DataSourceStrategy.normalizeExprs(predicates, output)
+    PushDownUtils.pushFilters(scanBuilder, normalizedPredicates)
+
+    val scan = scanBuilder.build()
+    val scanRelation = DataSourceV2ScanRelation(table, scan, output)
+
+    val scanPlan = scan match {
+      case _: SupportsFileFilter =>
+        val matchingFilePlan = buildFileFilterPlan(cond, scanRelation)
+        val dynamicFileFilter = DynamicFileFilter(scanRelation, matchingFilePlan)
+        dynamicFileFilter
+      case _ =>
+        scanRelation
+    }
+
+    // include file name so that we can group data back
+    val fileNameExpr = Alias(InputFileName(), FILE_NAME_COL)()
+    Project(scanPlan.output :+ fileNameExpr, scanPlan)
+  }
+
+  private def buildWritePlan(
+      remainingRowsPlan: LogicalPlan,
+      output: Seq[AttributeReference]): LogicalPlan = {
+
+    // TODO: sort by _pos to keep the original ordering of rows
+    // TODO: consider setting a file size limit
+
+    val fileNameCol = findOutputAttr(remainingRowsPlan, FILE_NAME_COL)
+    val numShufflePartitions = SQLConf.get.numShufflePartitions
+    val repartition = RepartitionByExpression(Seq(fileNameCol), remainingRowsPlan, numShufflePartitions)
+    val sort = Sort(Seq(SortOrder(fileNameCol, Ascending)), global = false, repartition)
+    Project(output, sort)
+  }
+
+  private def isDeleteWhereCase(relation: DataSourceV2Relation, cond: Expression): Boolean = {
+    relation.table match {
+      case t: ExtendedSupportsDelete if !SubqueryExpression.hasSubquery(cond) =>
+        val predicates = splitConjunctivePredicates(cond)
+        val normalizedPredicates = DataSourceStrategy.normalizeExprs(predicates, relation.output)
+        val dataSourceFilters = toDataSourceFilters(normalizedPredicates)
+        val allPredicatesTranslated = normalizedPredicates.size == dataSourceFilters.length

Review comment:
       Yeah, this logic is present in all places where the translation is done.




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