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Liang-Chi Hsieh commented on SPARK-26205: ----------------------------------------- [~cloud_fan]. I see now. Created SPARK-29100. > Optimize InSet expression for bytes, shorts, ints, dates > -------------------------------------------------------- > > Key: SPARK-26205 > URL: https://issues.apache.org/jira/browse/SPARK-26205 > Project: Spark > Issue Type: Improvement > Components: SQL > Affects Versions: 3.0.0 > Reporter: Anton Okolnychyi > Assignee: Anton Okolnychyi > Priority: Major > Fix For: 3.0.0 > > > {{In}} expressions are compiled into a sequence of if-else statements, which > results in O\(n\) time complexity. {{InSet}} is an optimized version of > {{In}}, which is supposed to improve the performance if the number of > elements is big enough. However, {{InSet}} actually degrades the performance > in many cases due to various reasons (benchmarks were created in SPARK-26203 > and solutions to the boxing problem are discussed in SPARK-26204). > The main idea of this JIRA is to use Java {{switch}} statements to > significantly improve the performance of {{InSet}} expressions for bytes, > shorts, ints, dates. All {{switch}} statements are compiled into > {{tableswitch}} and {{lookupswitch}} bytecode instructions. We will have > O\(1\) time complexity if our case values are compact and {{tableswitch}} can > be used. Otherwise, {{lookupswitch}} will give us O\(log n\). Our local > benchmarks show that this logic is more than two times faster even on 500+ > elements than using primitive collections in {{InSet}} expressions. As Spark > is using Scala {{HashSet}} right now, the performance gain will be is even > bigger. > See > [here|https://docs.oracle.com/javase/specs/jvms/se7/html/jvms-3.html#jvms-3.10] > and > [here|https://stackoverflow.com/questions/10287700/difference-between-jvms-lookupswitch-and-tableswitch] > for more information. -- This message was sent by Atlassian Jira (v8.3.2#803003) --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@spark.apache.org For additional commands, e-mail: issues-h...@spark.apache.org