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https://issues.apache.org/jira/browse/SPARK-30847?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Hyukjin Kwon updated SPARK-30847:
---------------------------------
Description:
See the issue in https://github.com/scala/bug/issues/10495 and fix
https://github.com/scala/scala/pull/7648.
Currently, different expressions with same children can produce the same hash
as below:
{code}
scala> spark.range(1).selectExpr("id -
1").queryExecution.analyzed.semanticHash()
res0: Int = -565572825
scala> spark.range(1).selectExpr("id +
1").queryExecution.analyzed.semanticHash()
res1: Int = -565572825
{code}
The reason seems to be it doesn't take the product's class itself
was:
Potentially a correctness issue. See the issue in
https://github.com/scala/bug/issues/10495 and fix
https://github.com/scala/scala/pull/7648.
Currently, different expressions with same children can produce the same hash
as below:
{code}
scala> spark.range(1).selectExpr("id -
1").queryExecution.analyzed.semanticHash()
res0: Int = -565572825
scala> spark.range(1).selectExpr("id +
1").queryExecution.analyzed.semanticHash()
res1: Int = -565572825
{code}
The reason seems to be it doesn't take the product's class itself
> Take productPrefix into account in MurmurHash3.productHash
> ----------------------------------------------------------
>
> Key: SPARK-30847
> URL: https://issues.apache.org/jira/browse/SPARK-30847
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 2.4.5, 3.0.0
> Reporter: Hyukjin Kwon
> Priority: Critical
>
> See the issue in https://github.com/scala/bug/issues/10495 and fix
> https://github.com/scala/scala/pull/7648.
> Currently, different expressions with same children can produce the same hash
> as below:
> {code}
> scala> spark.range(1).selectExpr("id -
> 1").queryExecution.analyzed.semanticHash()
> res0: Int = -565572825
> scala> spark.range(1).selectExpr("id +
> 1").queryExecution.analyzed.semanticHash()
> res1: Int = -565572825
> {code}
> The reason seems to be it doesn't take the product's class itself
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