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https://issues.apache.org/jira/browse/CALCITE-2703?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16705762#comment-16705762
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Stamatis Zampetakis commented on CALCITE-2703:
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That's right! I am using many parts of it but not Calcite as a server.
> Reduce code generation and class loading overhead when executing queries in
> the EnumerableConvention
> ----------------------------------------------------------------------------------------------------
>
> Key: CALCITE-2703
> URL: https://issues.apache.org/jira/browse/CALCITE-2703
> Project: Calcite
> Issue Type: Improvement
> Components: core
> Affects Versions: 1.17.0
> Reporter: Stamatis Zampetakis
> Assignee: Julian Hyde
> Priority: Major
> Labels: performance
> Fix For: 1.18.0
>
>
> The queries using Calcite's EnumerableConvention always end-up generating new
> java classes at runtime (using Janino) that are then instantiated using
> reflection. This combination of class generation and class loading introduces
> a big overhead in query response time.
> A quick profiling on our Company's internal test suite consisting in 4000
> tests with roughly 430000 SQL queries passing through Calcite we observed
> that a big amount of time is spend on code generation and class loading
> making the EnumerableInterpretable#toBindable method a performance
> bottleneck.
> Among the 430000 SQL queries there are many duplicates which are going to
> lead to the generation of exactly the same code Java. Introducing, a small
> cache at the level of EnumerableInterpretable class could avoid generating
> and loading the same code over and over again.
> A simple implementation based on Guava improved the overall execution time of
> the afforementioned test suite by more than 50%.
>
>
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