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https://issues.apache.org/jira/browse/SPARK-58993?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated SPARK-58993:
-----------------------------------
Labels: pull-request-available (was: )
> Use OpenHashMap for CountVectorizer vocabulary lookup
> -----------------------------------------------------
>
> Key: SPARK-58993
> URL: https://issues.apache.org/jira/browse/SPARK-58993
> Project: Spark
> Issue Type: Sub-task
> Components: ML
> Affects Versions: 5.0.0
> Reporter: Ruifeng Zheng
> Priority: Major
> Labels: pull-request-available
>
> CountVectorizerModel.transform builds and broadcasts an immutable Map[String,
> Int] for vocabulary
> lookups. Replace it with Spark's OpenHashMap[String, Int], storing index + 1
> so that zero can be
> used as the missing-key sentinel.
> A Java 17 microbenchmark with the default 262,144-entry vocabulary and 2
> million lookups (90%
> hits) measured approximately 69.5 ns/lookup for the current immutable Map.get
> match and 37.6
> ns/lookup for OpenHashMap.apply with the sentinel representation. The change
> should also avoid
> boxed vocabulary indexes and per-lookup Option allocation while preserving
> transform behavior.
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