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https://issues.apache.org/jira/browse/SPARK-34115?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17267126#comment-17267126
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Norbert Schultz commented on SPARK-34115:
-----------------------------------------
Just tried it
{code:java}
diff --git a/core/src/main/scala/org/apache/spark/util/Utils.scala
b/core/src/main/scala/org/apache/spark/util/Utils.scala
index 926f3a3c11..cc15481b4b 100644
--- a/core/src/main/scala/org/apache/spark/util/Utils.scala
+++ b/core/src/main/scala/org/apache/spark/util/Utils.scala
@@ -1891,7 +1891,7 @@ private[spark] object Utils extends Logging {
/**
* Indicates whether Spark is currently running unit tests.
*/
- def isTesting: Boolean = {
+ lazy val isTesting: Boolean = {
sys.env.contains("SPARK_TESTING") || sys.props.contains("spark.testing")
}
{code}
Solves the problem.
The lookup time of the contains call in sys.env.contains(..) is indeed
constant, however sys.env recreates the immutable map on each call and thus is
slow.
> Long runtime on many environment variables
> ------------------------------------------
>
> Key: SPARK-34115
> URL: https://issues.apache.org/jira/browse/SPARK-34115
> Project: Spark
> Issue Type: Bug
> Components: Spark Core, SQL
> Affects Versions: 2.4.0, 2.4.7, 3.0.1
> Environment: Spark 2.4.0 local[2] on a Kubernetes Pod
> Reporter: Norbert Schultz
> Priority: Major
> Attachments: spark-bug-34115.tar.gz
>
>
> I am not sure if this is a bug report or a feature request. The code is is
> the same in current versions of Spark and maybe this ticket saves someone
> some time for debugging.
> We migrated some older code to Spark 2.4.0, and suddently the integration
> tests on our build machine were much slower than expected.
> On local machines it was running perfectly.
> At the end it turned out, that Spark was wasting CPU Cycles during DataFrame
> analyzing in the following functions
> * AnalysisHelper.assertNotAnalysisRule calling
> * Utils.isTesting
> Utils.isTesting is traversing all environment variables.
> The offending build machine was a Kubernetes Pod which automatically exposed
> all services as environment variables, so it had more than 3000 environment
> variables.
> As Utils.isTesting is called very often throgh
> AnalysisHelper.assertNotAnalysisRule (via AnalysisHelper.transformDown,
> transformUp).
>
> Of course we will restrict the number of environment variables, on the other
> side Utils.isTesting could also use a lazy val for
>
> {code:java}
> sys.env.contains("SPARK_TESTING") {code}
>
> to not make it that expensive.
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