package org.apache.spark.util
trait KnownSizeEstimation {
def estimatedSize: Long
}KnownSizeEstimation
KnownSizeEstimation is the contract that allows a class to give SizeEstimator a more accurate size estimation.
KnownSizeEstimation defines the single estimatedSize method.
estimatedSize is used when:
-
SizeEstimatoris requested to visitSingleObject -
BroadcastExchangeExecis requested for relationFuture -
BroadcastHashJoinExecis requested to execute -
ShuffledHashJoinExecis requested to buildHashedRelation
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Note
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KnownSizeEstimation is a private[spark] contract.
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Note
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HashedRelation is the only KnownSizeEstimation available.
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