Refactor: columnvalues to use strings builder#353
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micyen wants to merge 3 commits intodatabricks:mainfrom
Open
Refactor: columnvalues to use strings builder#353micyen wants to merge 3 commits intodatabricks:mainfrom
micyen wants to merge 3 commits intodatabricks:mainfrom
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…ValueContainer.Value() Signed-off-by: Michael Yen <29710093+micyen@users.noreply.github.com>
…alueContainer.Value() Signed-off-by: Michael Yen <29710093+micyen@users.noreply.github.com>
…ctValueContainer.Value() Signed-off-by: Michael Yen <29710093+micyen@users.noreply.github.com>
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Summary
Replace repeated string concatenation with strings.Builder in complex type Value() methods to improve performance.
Problem
listValueContainer, mapValueContainer, and structValueContainer build strings using + inside loops, resulting in O(n^2) time complexity.
In cases like COLLECT_SET(...) returning many elements, this can make rows.Next() / rows.Scan() hang, with most time spent in runtime.concatstring2.
Observed Workaround
Changing the SQL from COLLECT_SET() (array type) to ARRAY_JOIN(COLLECT_SET(...), '\n') (string type) bypasses the problem because the driver reads the column as a plain string value, avoiding calls to the complex type Value() methods.
Fix
Use strings.Builder for string construction in all three Value() methods, which reduces time complexity from O(n^2) to O(n).
Testing
Pre-existing unit tests passed, no tests added.
Notes
No behavioral changes, output format identical.
Signed-off-by: Michael Yen 29710093+micyen@users.noreply.github.com