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https://issues.apache.org/jira/browse/NIFI-5801?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16763129#comment-16763129
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Joseph Witt commented on NIFI-5801:
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[~markap14] since this appears to be improvement only and not about a defect
and since there is no review traction I've removed the fix version. It looks
promising so lets not lose track. let me know if a problem. thanks
> Evaluating Expression Language can in many cases be made much more efficient
> ----------------------------------------------------------------------------
>
> Key: NIFI-5801
> URL: https://issues.apache.org/jira/browse/NIFI-5801
> Project: Apache NiFi
> Issue Type: Improvement
> Components: Core Framework
> Reporter: Mark Payne
> Assignee: Mark Payne
> Priority: Major
> Time Spent: 20m
> Remaining Estimate: 0h
>
> When a StandardPropertyValue is obtained and evaluateAttributeExpressions is
> called, it builds the entire Evaluator Tree each time. This was done to
> ensure that Evaluator.evaluate() is called only once. However, the
> requirement to call this only once was introduced as a way to have
> anyMatchingAttribute, anyAttribute, allMatchingAttributes, allAttributes,
> etc. methods work, and these are rarely used. I.e., we introduced semantics
> that significantly slow performance in order to provide functionality that is
> used maybe 1% of the time. Instead, we should optimize for the 99% use case
> and incur a penalty, if necessary, in the 1% use case instead. Profiling the
> ConsumeKafkaRecord processor shows that 80% of the time in that method is
> evaluating Expression Language for `${schema.name}` to determine which schema
> should be used. We can likely make this evaluation just as quick as
> attributeMap.get("schema.name") by pre-building the Evaluators and re-using
> them.
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