org.apache.spark.sql.catalyst.plans.logical.statsEstimation.ProjectEstimation.scala Maven / Gradle / Ivy
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* 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
*
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package org.apache.spark.sql.catalyst.plans.logical.statsEstimation
import org.apache.spark.sql.catalyst.expressions.{Alias, Attribute, AttributeMap}
import org.apache.spark.sql.catalyst.plans.logical.{Project, Statistics}
object ProjectEstimation {
import EstimationUtils._
def estimate(project: Project): Option[Statistics] = {
if (rowCountsExist(project.child)) {
val childStats = project.child.stats
val inputAttrStats = childStats.attributeStats
// Match alias with its child's column stat
val aliasStats = project.expressions.collect {
case alias @ Alias(attr: Attribute, _) if inputAttrStats.contains(attr) =>
alias.toAttribute -> inputAttrStats(attr)
}
val outputAttrStats =
getOutputMap(AttributeMap(inputAttrStats.toSeq ++ aliasStats), project.output)
Some(childStats.copy(
sizeInBytes = getOutputSize(project.output, childStats.rowCount.get, outputAttrStats),
attributeStats = outputAttrStats))
} else {
None
}
}
}