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Posted to jira@arrow.apache.org by "Andy Grove (Jira)" <ji...@apache.org> on 2022/08/05 17:51:00 UTC

[jira] [Closed] (ARROW-17325) AQE should use available column statistics from completed query stages

     [ https://issues.apache.org/jira/browse/ARROW-17325?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Andy Grove closed ARROW-17325.
------------------------------
    Resolution: Invalid

> AQE should use available column statistics from completed query stages
> ----------------------------------------------------------------------
>
>                 Key: ARROW-17325
>                 URL: https://issues.apache.org/jira/browse/ARROW-17325
>             Project: Apache Arrow
>          Issue Type: Improvement
>          Components: SQL
>            Reporter: Andy Grove
>            Priority: Major
>
> In QueryStageExec.computeStats we copy partial statistics from materlized query stages by calling QueryStageExec#getRuntimeStatistics, which in turn calls ShuffleExchangeLike#runtimeStatistics or BroadcastExchangeLike#runtimeStatistics.
> Only dataSize and numOutputRows are copied into the new Statistics object:
>  {code:scala}
>   def computeStats(): Option[Statistics] = if (isMaterialized) {
>     val runtimeStats = getRuntimeStatistics
>     val dataSize = runtimeStats.sizeInBytes.max(0)
>     val numOutputRows = runtimeStats.rowCount.map(_.max(0))
>     Some(Statistics(dataSize, numOutputRows, isRuntime = true))
>   } else {
>     None
>   }
> {code}
> I would like to also copy over the column statistics stored in Statistics.attributeMap so that they can be fed back into the logical plan optimization phase. This is a small change as shown below:
> {code:scala}
>   def computeStats(): Option[Statistics] = if (isMaterialized) {
>     val runtimeStats = getRuntimeStatistics
>     val dataSize = runtimeStats.sizeInBytes.max(0)
>     val numOutputRows = runtimeStats.rowCount.map(_.max(0))
>     val attributeStats = runtimeStats.attributeStats
>     Some(Statistics(dataSize, numOutputRows, attributeStats, isRuntime = true))
>   } else {
>     None
>   }
> {code}
> The Spark implementations of ShuffleExchangeLike and BroadcastExchangeLike do not currently provide such column statistics, but other custom implementations can.



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