fix round() handling of scale, precision, and nulls#2187
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max-hoffman
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Dec 6, 2023
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this looks OK, the variable naming in Round.Eval() kind of makes it kind of hard to tell what's going on though
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This PR has
ROUND()behavior match MySQL more closely specifically when handling NULLs.Additionally, it refactors the function to no longer use custom logic, and rely on
decimal.Decimallibrary for conversions.The slowness from the original issues stems from the
math.Pow()function that is attempting to raise precision to some huge negative number. This PR solves that problem by constraining the precision values to ourDecimalMaxScale(30).A better constraint would be
-308since that's the max scale of a float supported by MySQL. However, we don't go nearly as far. If we knew the scale of the passed in value we could also constrain the precision that way.This PR also rewrites the
ROUND()unit tests to be structured like other unit tests for functions, and fixes their handling of null arguments.fixes: dolthub/dolt#7073