KnownSizeEstimation

2013-06-30 分类：spark-sql 阅读(1624) 评论(0)

KnownSizeEstimation is the contract that allows a class to give SizeEstimator a more accurate size estimation.

KnownSizeEstimation defines the single estimatedSize method.



package org.apache.spark.util

trait KnownSizeEstimation {
  def estimatedSize: Long
}

package org.apache.spark.util

trait KnownSizeEstimation {

def estimatedSize: Long

}

estimatedSize is used when:

Note	`KnownSizeEstimation` is a `private[spark]` contract.

Note	HashedRelation is the only `KnownSizeEstimation` available.

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