You are viewing a plain text version of this content. The canonical link for it is here.
Posted to issues@spark.apache.org by "Sunitha Kambhampati (Jira)" <ji...@apache.org> on 2020/02/18 23:33:00 UTC
[jira] [Commented] (SPARK-27213) Unexpected results when filter is
used after distinct
[ https://issues.apache.org/jira/browse/SPARK-27213?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17039556#comment-17039556 ]
Sunitha Kambhampati commented on SPARK-27213:
---------------------------------------------
I tried it now on master trunk, synced up to Feb11, 2020 commit
45db48e2d29359591a4ebc3db4625dd2158e446e and I see the same behavior as mentioned in the description.
{code:java}
>>> df = spark.createDataFrame([['a','123','12.3','n'],['a','123','12.3','y'],['a','123','12.4','y']],['x','y','z','y_n'])
>>> df.show(5)
+---+---+----+---+
| x| y| z|y_n|
+---+---+----+---+
| a|123|12.3| n|
| a|123|12.3| y|
| a|123|12.4| y|
+---+---+----+---+
>>> df.filter("y_n='y'").select('x','y','z').distinct().show()
+---+---+----+
| x| y| z|
+---+---+----+
| a|123|12.3|
| a|123|12.4|
+---+---+----+
>>> df.select('x','y','z').distinct().filter("y_n='y'").show()
+---+---+----+
| x| y| z|
+---+---+----+
| a|123|12.4|
+---+---+----+
{code}
> Unexpected results when filter is used after distinct
> -----------------------------------------------------
>
> Key: SPARK-27213
> URL: https://issues.apache.org/jira/browse/SPARK-27213
> Project: Spark
> Issue Type: Bug
> Components: PySpark
> Affects Versions: 2.3.2, 2.4.0
> Reporter: Rinaz Belhaj
> Priority: Blocker
> Labels: correctness, distinct, filter
>
> The following code gives unexpected output due to the filter not getting pushed down in catalyst optimizer.
> {code:java}
> df = spark.createDataFrame([['a','123','12.3','n'],['a','123','12.3','y'],['a','123','12.4','y']],['x','y','z','y_n'])
> df.show(5)
> df.filter("y_n='y'").select('x','y','z').distinct().show()
> df.select('x','y','z').distinct().filter("y_n='y'").show()
> {code}
> {panel:title=Output}
> |x|y|z|y_n|
> |a|123|12.3|n|
> |a|123|12.3|y|
> |a|123|12.4|y|
>
> |x|y|z|
> |a|123|12.3|
> |a|123|12.4|
>
> |x|y|z|
> |a|123|12.4|
> {panel}
> Ideally, the second statement should result in an error since the column used in the filter is not present in the preceding select statement. But the catalyst optimizer is using first() on column y_n and then applying the filter.
> Even if the filter was pushed down, the result would have been accurate.
> {code:java}
> df = spark.createDataFrame([['a','123','12.3','n'],['a','123','12.3','y'],['a','123','12.4','y']],['x','y','z','y_n'])
> df.filter("y_n='y'").select('x','y','z').distinct().explain(True)
> df.select('x','y','z').distinct().filter("y_n='y'").explain(True)
> {code}
> {panel:title=Output}
>
> == Parsed Logical Plan ==
> Deduplicate [x#74, y#75, z#76|#74, y#75, z#76]
> +- AnalysisBarrier
> +- Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- Filter (y_n#77 = y)
> +- LogicalRDD [x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77], false
>
> == Analyzed Logical Plan ==
> x: string, y: string, z: string
> Deduplicate [x#74, y#75, z#76|#74, y#75, z#76]
> +- Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- Filter (y_n#77 = y)
> +- LogicalRDD [x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77], false
>
> == Optimized Logical Plan ==
> Aggregate [x#74, y#75, z#76|#74, y#75, z#76], [x#74, y#75, z#76|#74, y#75, z#76]
> +- Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- Filter (isnotnull(y_n#77) && (y_n#77 = y))
> +- LogicalRDD [x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77], false
>
> == Physical Plan ==
> *(2) HashAggregate(keys=[x#74, y#75, z#76|#74, y#75, z#76], functions=[], output=[x#74, y#75, z#76|#74, y#75, z#76])
> +- Exchange hashpartitioning(x#74, y#75, z#76, 10)
> +- *(1) HashAggregate(keys=[x#74, y#75, z#76|#74, y#75, z#76], functions=[], output=[x#74, y#75, z#76|#74, y#75, z#76])
> +- *(1) Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- *(1) Filter (isnotnull(y_n#77) && (y_n#77 = y))
> +- Scan ExistingRDD[x#74,y#75,z#76,y_n#77|#74,y#75,z#76,y_n#77]
>
> -------------------------------------------------------------------------------------------------------------------
>
> == Parsed Logical Plan ==
> 'Filter ('y_n = y)
> +- AnalysisBarrier
> +- Deduplicate [x#74, y#75, z#76|#74, y#75, z#76]
> +- Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- LogicalRDD [x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77], false
>
> == Analyzed Logical Plan ==
> x: string, y: string, z: string
> Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- Filter (y_n#77 = y)
> +- Deduplicate [x#74, y#75, z#76|#74, y#75, z#76]
> +- Project [x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77]
> +- LogicalRDD [x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77], false
>
> == Optimized Logical Plan ==
> Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- Filter (isnotnull(y_n#77) && (y_n#77 = y))
> +- Aggregate [x#74, y#75, z#76|#74, y#75, z#76], [x#74, y#75, z#76, first(y_n#77, false) AS y_n#77|#74, y#75, z#76, first(y_n#77, false) AS y_n#77]
> +- LogicalRDD [x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77], false
>
> == Physical Plan ==
> *(3) Project [x#74, y#75, z#76|#74, y#75, z#76]
> +- *(3) Filter (isnotnull(y_n#77) && (y_n#77 = y))
> +- SortAggregate(key=[x#74, y#75, z#76|#74, y#75, z#76], functions=[first(y_n#77, false)|#77, false)], output=[x#74, y#75, z#76, y_n#77|#74, y#75, z#76, y_n#77])
> +- *(2) Sort [x#74 ASC NULLS FIRST, y#75 ASC NULLS FIRST, z#76 ASC NULLS FIRST|#74 ASC NULLS FIRST, y#75 ASC NULLS FIRST, z#76 ASC NULLS FIRST], false, 0
> +- Exchange hashpartitioning(x#74, y#75, z#76, 10)
> +- SortAggregate(key=[x#74, y#75, z#76|#74, y#75, z#76], functions=[partial_first(y_n#77, false)|#77, false)], output=[x#74, y#75, z#76, first#95, valueSet#96|#74, y#75, z#76, first#95, valueSet#96])
> +- *(1) Sort [x#74 ASC NULLS FIRST, y#75 ASC NULLS FIRST, z#76 ASC NULLS FIRST|#74 ASC NULLS FIRST, y#75 ASC NULLS FIRST, z#76 ASC NULLS FIRST], false, 0
> +- Scan ExistingRDD[x#74,y#75,z#76,y_n#77|#74,y#75,z#76,y_n#77]
>
> {panel}
> The second query. ie *"df.select('x','y','z').distinct().filter("y_n='y'").explain(True)"* should result in error rather than giving wrong output.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)
---------------------------------------------------------------------
To unsubscribe, e-mail: issues-unsubscribe@spark.apache.org
For additional commands, e-mail: issues-help@spark.apache.org