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https://issues.apache.org/jira/browse/DRILL-5476?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Arina Ielchiieva updated DRILL-5476:
Description:
Currently when applying substring / substr / left / right / trim functions
Drill doesn't calculate return length. Since we know calculation rules for
these functions, we can predict return length.
For example:
substring(cast(col as varchar(10), 1, 5) -> varchar(5)
substring(cast(col as varchar(10), 5) -> varchar(5)
Similar changes has been done in DRILL-5419 for other string functions.
Note: should return the same value for regular queries and limit 0 queries
(when limit 0 optimization is enabled).
was:
Currently when applying substring / substr / left / right / trim functions
Drill doesn't calculate return length. Since we know calculation rules for
these functions, we can predict return length.
For example:
substring(cast(col as varchar(10), 1, 5) -> varchar(5)
substring(cast(col as varchar(10), 5) -> varchar(5)
Similar changes has been done in DRILL-5419 for other string functions.
> Calculate return type precision value for substring functions (substring,
> substr, left, right, trim)
> -
>
> Key: DRILL-5476
> URL: https://issues.apache.org/jira/browse/DRILL-5476
> Project: Apache Drill
> Issue Type: Improvement
>Affects Versions: 1.10.0
>Reporter: Arina Ielchiieva
>Priority: Minor
>
> Currently when applying substring / substr / left / right / trim functions
> Drill doesn't calculate return length. Since we know calculation rules for
> these functions, we can predict return length.
> For example:
> substring(cast(col as varchar(10), 1, 5) -> varchar(5)
> substring(cast(col as varchar(10), 5) -> varchar(5)
> Similar changes has been done in DRILL-5419 for other string functions.
> Note: should return the same value for regular queries and limit 0 queries
> (when limit 0 optimization is enabled).
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