Github user yhuai commented on a diff in the pull request:
https://github.com/apache/spark/pull/10541#discussion_r49041161
--- Diff:
sql/hive/src/main/scala/org/apache/spark/sql/hive/SQLBuilder.scala ---
@@ -0,0 +1,236 @@
+/*
+ * 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.hive
+
+import java.util.concurrent.atomic.AtomicLong
+
+import org.apache.spark.Logging
+import org.apache.spark.sql.catalyst.expressions.{Expression, Attribute,
NamedExpression, SortOrder}
+import org.apache.spark.sql.catalyst.optimizer.ProjectCollapsing
+import org.apache.spark.sql.catalyst.plans.logical._
+import org.apache.spark.sql.catalyst.rules.{Rule, RuleExecutor}
+import org.apache.spark.sql.catalyst.util.sequenceOption
+import org.apache.spark.sql.execution.datasources.LogicalRelation
+import org.apache.spark.sql.execution.datasources.parquet.ParquetRelation
+import org.apache.spark.sql.{DataFrame, SQLContext}
+
+class SQLBuilder(logicalPlan: LogicalPlan, sqlContext: SQLContext) extends
Logging {
+ def this(df: DataFrame) = this(df.queryExecution.analyzed, df.sqlContext)
+
+ def toSQL: Option[String] = {
+ val canonicalizedPlan = Canonicalizer.execute(logicalPlan)
+ val maybeSQL = toSQL(canonicalizedPlan)
+
+ if (maybeSQL.isDefined) {
+ logDebug(
+ s"""Built SQL query string successfully from given logical plan:
+ |
+ |# Original logical plan:
+ |${logicalPlan.treeString}
+ |# Canonicalized logical plan:
+ |${canonicalizedPlan.treeString}
+ |# Built SQL query string:
+ |${maybeSQL.get}
+ """.stripMargin)
+ } else {
+ logDebug(
+ s"""Failed to build SQL query string from given logical plan:
+ |
+ |# Original logical plan:
+ |${logicalPlan.treeString}
+ |# Canonicalized logical plan:
+ |${canonicalizedPlan.treeString}
+ """.stripMargin)
+ }
+
+ maybeSQL
+ }
+
+ private def projectToSQL(
+ projectList: Seq[NamedExpression],
+ child: LogicalPlan,
+ isDistinct: Boolean): Option[String] = {
+ for {
+ listSQL <- sequenceOption(projectList.map(_.sql))
+ childSQL <- toSQL(child)
+ from = child match {
+ case OneRowRelation => ""
+ case _ => " FROM "
+ }
+ distinct = if (isDistinct) " DISTINCT" else ""
+ } yield s"SELECT$distinct ${listSQL.mkString(", ")}$from$childSQL"
+ }
+
+ private def aggregateToSQL(
+ groupingExprs: Seq[Expression],
+ aggExprs: Seq[Expression],
+ child: LogicalPlan): Option[String] = {
+ for {
+ aggSQL <- sequenceOption(aggExprs.map(_.sql))
+ groupingSQL <- sequenceOption(groupingExprs.map(_.sql))
+ maybeGroupBy = if (groupingSQL.isEmpty) "" else " GROUP BY "
+ maybeFrom = child match {
+ case OneRowRelation => ""
+ case _ => " FROM "
+ }
+ childSQL <- toSQL(child).map(maybeFrom + _)
+ } yield {
+ s"SELECT ${aggSQL.mkString(",
")}$childSQL$maybeGroupBy${groupingSQL.mkString(", ")}"
+ }
+ }
+
+ private def toSQL(node: LogicalPlan): Option[String] = node match {
+ case Distinct(Project(list, child)) =>
+ projectToSQL(list, child, isDistinct = true)
+
+ case Project(list, child) =>
+ projectToSQL(list, child, isDistinct = false)
+
+ case Aggregate(groupingExprs, aggExprs, Aggregate(_, _, Expand(_, _,
child))) =>
+ aggregateToSQL(groupingExprs, aggExprs, child)
+
+ case Aggregate(groupingExprs, aggExprs, child) =>
+ aggregateToSQL(groupingExprs, aggExprs, child)
+
+ case Limit(limit, child) =>
+ for {
+ limitSQL <- limit.sql
+ childSQL <- toSQL(child)
+ } yield s"$childSQL LIMIT $limitSQL"
+
+ case Filter(condition, child) =>
+ for {
+ conditionSQL <- condition.sql
+ childSQL <- toSQL(child)
+ whereOrHaving = child match {
+ case _: Aggregate => "HAVING"
+ case _ => "WHERE"
+ }
+ } yield s"$childSQL $whereOrHaving $conditionSQL"
+
+ case Union(left, right) =>
+ for {
+ leftSQL <- toSQL(left)
+ rightSQL <- toSQL(right)
+ } yield s"$leftSQL UNION ALL $rightSQL"
+
+ // ParquetRelation converted from Hive metastore table
+ case Subquery(alias, LogicalRelation(r: ParquetRelation, _)) =>
+ Some(s"`$alias`")
+
+ case Subquery(alias, child) =>
+ toSQL(child).map(childSQL => s"($childSQL) AS $alias")
+
+ case Join(left, right, joinType, condition) =>
+ for {
+ leftSQL <- toSQL(left)
+ rightSQL <- toSQL(right)
+ joinTypeSQL = joinType.sql
+ conditionSQL = condition.flatMap(_.sql).map(" ON " +
_).getOrElse("")
+ } yield s"$leftSQL $joinTypeSQL JOIN $rightSQL$conditionSQL"
+
+ case MetastoreRelation(database, table, alias) =>
+ val aliasSQL = alias.map(a => s" AS `$a`").getOrElse("")
+ Some(s"`$database`.`$table`$aliasSQL")
+
+ case Sort(orders, _, RepartitionByExpression(partitionExprs, child, _))
+ if orders.map(_.child) == partitionExprs =>
+ for {
+ partitionExprsSQL <- sequenceOption(partitionExprs.map(_.sql))
+ childSQL <- toSQL(child)
+ } yield s"$childSQL CLUSTER BY ${partitionExprsSQL.mkString(", ")}"
+
+ case Sort(orders, global, child) =>
+ for {
+ childSQL <- toSQL(child)
+ ordersSQL <- sequenceOption(orders.map { case SortOrder(e, dir) =>
+ e.sql.map(sql => s"$sql ${dir.sql}")
+ })
+ orderOrSort = if (global) "ORDER" else "SORT"
+ } yield s"$childSQL $orderOrSort BY ${ordersSQL.mkString(", ")}"
+
+ case RepartitionByExpression(partitionExprs, child, _) =>
+ for {
+ partitionExprsSQL <- sequenceOption(partitionExprs.map(_.sql))
+ childSQL <- toSQL(child)
+ } yield s"$childSQL DISTRIBUTE BY ${partitionExprsSQL.mkString(",
")}"
+
+ case OneRowRelation =>
+ Some("")
+
+ case _ => None
+ }
+
+ object Canonicalizer extends RuleExecutor[LogicalPlan] {
+ override protected def batches: Seq[Batch] = Seq(
+ Batch("Normalizer", FixedPoint(100),
+ // The `WidenSetOperationTypes` analysis rule may introduce extra
`Project`s over
+ // `Aggregate`s to perform type casting. This rule merges these
`Project`s into
+ // `Aggregate`s.
+ ProjectCollapsing,
--- End diff --
Do we have to have this rule? I mean should we just create a sub-query
block to wrap the aggregate?
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