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https://issues.apache.org/jira/browse/SPARK-45959?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot reassigned SPARK-45959:
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Assignee: (was: Apache Spark)
> Abusing DataSet.withColumn can cause huge tree with severe perf degradation
> ---------------------------------------------------------------------------
>
> Key: SPARK-45959
> URL: https://issues.apache.org/jira/browse/SPARK-45959
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 3.5.1
> Reporter: Asif
> Priority: Minor
> Labels: pull-request-available
>
> Though documentation clearly recommends to add all columns in a single shot,
> but in reality is difficult to expect customer to modify their code, as in
> spark2 the rules in analyzer were such that they did not do deep tree
> traversal. Moreover in Spark3 , the plans are cloned before giving to
> analyzer , optimizer etc which was not the case in Spark2.
> All these things have resulted in query time being increased from 5 min to 2
> - 3 hrs.
> Many times the columns are added to plan via some for loop logic which just
> keeps adding new computation based on some rule.
> So, my suggestion is to do some intial check in the withColumn api, before
> creating a new projection, like if all the existing columns are still being
> projected, and the new column being added has an expression which is not
> depending on the output of the top node , but its child, then instead of
> adding a new project, the column can be added to the existing node.
> For starts, may be we can just handle Project node ..
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