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https://issues.apache.org/jira/browse/SPARK-58027?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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ASF GitHub Bot updated SPARK-58027:
-----------------------------------
Labels: pull-request-available (was: )
> Avoid unnecessary Matcher allocation in SparkDateTimeUtils.getZoneId for
> region-based zone IDs
> ----------------------------------------------------------------------------------------------
>
> Key: SPARK-58027
> URL: https://issues.apache.org/jira/browse/SPARK-58027
> Project: Spark
> Issue Type: Improvement
> Components: SQL
> Affects Versions: 5.0.0
> Reporter: Yang Jie
> Priority: Major
> Labels: pull-request-available
>
> `SparkDateTimeUtils.getZoneId` runs two regex `replaceFirst` calls on every
> invocation to normalize the legacy `(+|-)h:mm` and `(+|-)hh:m` zone-offset
> formats (supported before Spark 3.0):
> {code:scala}
> var formattedZoneId = singleHourTz.matcher(timeZoneId).replaceFirst("$10$2:")
> formattedZoneId =
> singleMinuteTz.matcher(formattedZoneId).replaceFirst("$1$2:0$3")
> ZoneId.of(formattedZoneId, ZoneId.SHORT_IDS)
> {code}
> Both patterns are anchored on a leading sign character `(+|-)`. Region-based
> IDs such as `UTC`, `America/New_York`, or `GMT+8` -- the overwhelming
> majority of inputs -- can never match, yet each call still allocates two
> `Matcher` instances and scans the string twice before `ZoneId.of` does the
> real work.
> This guards the normalization so the two regexes only run when the input
> starts with a sign character, skipping the `Matcher` allocations for the
> common region-id case. The change is behavior-preserving: since both patterns
> are anchored on the leading sign, an input that does not start with `+`/`-`
> is returned unchanged by `replaceFirst` today, which is exactly what the
> guarded `else` branch returns.
> This is a small clarity and allocation cleanup on the shared `getZoneId`
> helper, not a headline performance change.
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