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https://issues.apache.org/jira/browse/IMPALA-14551?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18037945#comment-18037945
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woosuk.ro commented on IMPALA-14551:
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* Root Cause
** The alias mapping logic checks if the expression can serve as an identifier
via HiveLexer. With ANTLR 3.3, recovery does not consume input after a
RecognitionException, leading to an infinite loop. Hive 3.1.3’s allowQuotedId
default further hinders quoted Unicode identifier handling.
* Proposed Fixes
** Upgrade ANTLR runtime to 3.5.x so recover() consumes input
> Query hangs when selecting an expression that contains Unicode Letters
> -----------------------------------------------------------------------
>
> Key: IMPALA-14551
> URL: https://issues.apache.org/jira/browse/IMPALA-14551
> Project: IMPALA
> Issue Type: Bug
> Components: Frontend
> Reporter: woosuk.ro
> Priority: Major
> Fix For: Impala 4.4.0
>
>
> * Summary
> ** When a complex expression that contains Unicode Letters is selected
> without an alias, an error during alias mapping causes the query to hang
> before the planning phase. CANCEL QUERY is ineffective.
> * Environment
> ** Impala 4.4.0, Hive 3.1.3.
> * Steps to Reproduce
> ** In the SELECT list, use an expression containing Unicode Letters without
> an alias.
> ** Example : `select 누적합 - lag (누적합) over (partition by day order by day)
> from base`
> * Actual Behavior
> ** During alias mapping, invoking HiveLexer triggers repeated retries
> without consuming input, and the query hangs. Threads remain RUNNABLE and
> cannot be canceled
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