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https://issues.apache.org/jira/browse/IMPALA-13411?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Yida Wu resolved IMPALA-13411.
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Fix Version/s: Impala 4.5.0
Assignee: Yida Wu (was: Michael Smith)
Resolution: Fixed
> DCHECK can fire for scan nodes that produce zero-length tuples
> --------------------------------------------------------------
>
> Key: IMPALA-13411
> URL: https://issues.apache.org/jira/browse/IMPALA-13411
> Project: IMPALA
> Issue Type: Bug
> Components: Backend
> Affects Versions: Impala 4.5.0
> Reporter: Joe McDonnell
> Assignee: Yida Wu
> Priority: Major
> Fix For: Impala 4.5.0
>
>
> This query crashes when using the tuple cache:
> {noformat}
> select count(*) from functional.alltypes;{noformat}
> It hits this assert:
> [https://github.com/apache/impala/blob/6121c4f7d61fb9f2341cf14e1be3404325fb35b9/be/src/exec/tuple-file-writer.cc#L105]
> {noformat}
> DCHECK_GT(tuple_data_len, 0);{noformat}
> For this count(*) query, it is not actually returning any columns. Instead,
> only the row count matters and the count does not require any tuple data. So,
> the tuple data is empty.
> We can revisit this DCHECK and either remove it or modify the condition to
> check if the tuple size is zero.
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