Details
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Improvement
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Status: Open
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Minor
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Resolution: Unresolved
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1.10.0
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None
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None
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None
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).