spark Command 源码
spark Command 代码
文件路径：/sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/Command.scala
/*
* 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.plans.logical
import org.apache.spark.sql.catalyst.analysis.AnalysisContext
import org.apache.spark.sql.catalyst.expressions.{Attribute, AttributeSet}
import org.apache.spark.sql.catalyst.plans.QueryPlan
import org.apache.spark.sql.catalyst.trees.{BinaryLike, LeafLike, UnaryLike}
import org.apache.spark.sql.catalyst.trees.TreePattern.{COMMAND, TreePattern}
/**
* A logical node that represents a non-query command to be executed by the system. For example,
* commands can be used by parsers to represent DDL operations. Commands, unlike queries, are
* eagerly executed.
*/
trait Command extends LogicalPlan {
override def output: Seq[Attribute] = Seq.empty
override def producedAttributes: AttributeSet = outputSet
// Commands are eagerly executed. They will be converted to LocalRelation after the DataFrame
// is created. That said, the statistics of a command is useless. Here we just return a dummy
// statistics to avoid unnecessary statistics calculation of command's children.
override def stats: Statistics = Statistics.DUMMY
final override val nodePatterns: Seq[TreePattern] = Seq(COMMAND)
}
trait LeafCommand extends Command with LeafLike[LogicalPlan]
trait UnaryCommand extends Command with UnaryLike[LogicalPlan]
trait BinaryCommand extends Command with BinaryLike[LogicalPlan]
/**
* A logical node that can be used for a command that requires its children to be only analyzed,
* but not optimized.
*/
trait AnalysisOnlyCommand extends Command {
val isAnalyzed: Boolean
def childrenToAnalyze: Seq[LogicalPlan]
override final def children: Seq[LogicalPlan] = if (isAnalyzed) Nil else childrenToAnalyze
override def innerChildren: Seq[QueryPlan[_]] = if (isAnalyzed) childrenToAnalyze else Nil
// After the analysis finished, we give the command a chance to update it's state based
// on the `AnalysisContext`
def markAsAnalyzed(analysisContext: AnalysisContext): LogicalPlan
}
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