Details
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Improvement
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Status: Resolved
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Critical
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Resolution: Done
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1.12.0
Description
Problem Description -
- Apache Drill allows users to specify columns even for SELECT STAR queries
- From my discussion with paul-rogers, Apache Calcite has a limitation where the, extra columns are not provided
- The workaround has been to always include all implicit columns for SELECT STAR queries
- Unfortunately, the current implementation is very inefficient as implicit column values get duplicated; this leads to substantial performance degradation when the number of rows are large
Suggested Optimization -
- The NullableVarChar vector should be enhanced to efficiently store duplicate values
- This will not only address the current Calcite limitations (for SELECT STAR queries) but also optimize all queries with implicit columns
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Issue Links
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