Details
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Bug
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Status: Resolved
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Blocker
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Resolution: Fixed
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3.2.4, 3.3.3, 3.4.1, 3.5.0, 4.0.0
Description
Decimal multiplication and division results may be inaccurate due to rounding issues.
Multiplication:
scala> sql("select -14120025096157587712113961295153.858047 * -0.4652").show(truncate=false) +----------------------------------------------------+ |(-14120025096157587712113961295153.858047 * -0.4652)| +----------------------------------------------------+ |6568635674732509803675414794505.574764 | +----------------------------------------------------+
The correct answer is
6568635674732509803675414794505.574763
Please note that the last digit is 3 instead of 4 as
scala> java.math.BigDecimal("-14120025096157587712113961295153.858047").multiply(java.math.BigDecimal("-0.4652")) val res21: java.math.BigDecimal = 6568635674732509803675414794505.5747634644
Since the factional part .574763 is followed by 4644, it should not be rounded up.
Division:
scala> sql("select -0.172787979 / 533704665545018957788294905796.5").show(truncate=false) +-------------------------------------------------+ |(-0.172787979 / 533704665545018957788294905796.5)| +-------------------------------------------------+ |-3.237521E-31 | +-------------------------------------------------+
The correct answer is
-3.237520E-31
Please note that the last digit is 0 instead of 1 as
scala> java.math.BigDecimal("-0.172787979").divide(java.math.BigDecimal("533704665545018957788294905796.5"), 100, java.math.RoundingMode.DOWN) val res22: java.math.BigDecimal = -3.237520489418037889998826491401059986665344697406144511563561222578738E-31
Since the factional part .237520 is followed by 4894..., it should not be rounded up.