Packages

object DecimalPrecision extends Rule[LogicalPlan] with TypeCoercionRule

Calculates and propagates precision for fixed-precision decimals. Hive has a number of rules for this based on the SQL standard and MS SQL: https://cwiki.apache.org/confluence/download/attachments/27362075/Hive_Decimal_Precision_Scale_Support.pdf https://msdn.microsoft.com/en-us/library/ms190476.aspx

In particular, if we have expressions e1 and e2 with precision/scale p1/s2 and p2/s2 respectively, then the following operations have the following precision / scale:

Operation Result Precision Result Scale ------------------------------------------------------------------------ e1 union e2 max(s1, s2) + max(p1-s1, p2-s2) max(s1, s2)

To implement the rules for fixed-precision types, we introduce casts to turn them to unlimited precision, do the math on unlimited-precision numbers, then introduce casts back to the required fixed precision. This allows us to do all rounding and overflow handling in the cast-to-fixed-precision operator.

In addition, when mixing non-decimal types with decimals, we use the following rules: - BYTE gets turned into DECIMAL(3, 0) - SHORT gets turned into DECIMAL(5, 0) - INT gets turned into DECIMAL(10, 0) - LONG gets turned into DECIMAL(20, 0) - FLOAT and DOUBLE cause fixed-length decimals to turn into DOUBLE - Literals INT and LONG get turned into DECIMAL with the precision strictly needed by the value

Linear Supertypes
TypeCoercionRule, Rule[LogicalPlan], Logging, SQLConfHelper, AnyRef, Any
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  1. DecimalPrecision
  2. TypeCoercionRule
  3. Rule
  4. Logging
  5. SQLConfHelper
  6. AnyRef
  7. Any
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Value Members

  1. final def !=(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  2. final def ##: Int
    Definition Classes
    AnyRef → Any
  3. final def ==(arg0: Any): Boolean
    Definition Classes
    AnyRef → Any
  4. def apply(plan: LogicalPlan): LogicalPlan

    Applies any changes to AttributeReference data types that are made by the transform method to instances higher in the query tree.

    Applies any changes to AttributeReference data types that are made by the transform method to instances higher in the query tree.

    Definition Classes
    TypeCoercionRule → Rule
  5. final def asInstanceOf[T0]: T0
    Definition Classes
    Any
  6. def clone(): AnyRef
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.CloneNotSupportedException]) @native()
  7. def conf: SQLConf

    The active config object within the current scope.

    The active config object within the current scope. See SQLConf.get for more information.

    Definition Classes
    SQLConfHelper
  8. final def eq(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  9. def equals(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef → Any
  10. def finalize(): Unit
    Attributes
    protected[lang]
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.Throwable])
  11. final def getClass(): Class[_ <: AnyRef]
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  12. def hashCode(): Int
    Definition Classes
    AnyRef → Any
    Annotations
    @native()
  13. def initializeLogIfNecessary(isInterpreter: Boolean, silent: Boolean): Boolean
    Attributes
    protected
    Definition Classes
    Logging
  14. def initializeLogIfNecessary(isInterpreter: Boolean): Unit
    Attributes
    protected
    Definition Classes
    Logging
  15. final def isInstanceOf[T0]: Boolean
    Definition Classes
    Any
  16. def isTraceEnabled(): Boolean
    Attributes
    protected
    Definition Classes
    Logging
  17. def log: Logger
    Attributes
    protected
    Definition Classes
    Logging
  18. def logDebug(msg: => String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  19. def logDebug(msg: => String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  20. def logError(msg: => String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  21. def logError(msg: => String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  22. def logInfo(msg: => String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  23. def logInfo(msg: => String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  24. def logName: String
    Attributes
    protected
    Definition Classes
    Logging
  25. def logTrace(msg: => String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  26. def logTrace(msg: => String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  27. def logWarning(msg: => String, throwable: Throwable): Unit
    Attributes
    protected
    Definition Classes
    Logging
  28. def logWarning(msg: => String): Unit
    Attributes
    protected
    Definition Classes
    Logging
  29. final def ne(arg0: AnyRef): Boolean
    Definition Classes
    AnyRef
  30. final def notify(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  31. final def notifyAll(): Unit
    Definition Classes
    AnyRef
    Annotations
    @native()
  32. lazy val ruleId: RuleId
    Attributes
    protected
    Definition Classes
    Rule
  33. val ruleName: String

    Name for this rule, automatically inferred based on class name.

    Name for this rule, automatically inferred based on class name.

    Definition Classes
    Rule
  34. final def synchronized[T0](arg0: => T0): T0
    Definition Classes
    AnyRef
  35. def toString(): String
    Definition Classes
    AnyRef → Any
  36. def transform: PartialFunction[Expression, Expression]
    Definition Classes
    DecimalPrecision → TypeCoercionRule
  37. final def wait(): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  38. final def wait(arg0: Long, arg1: Int): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException])
  39. final def wait(arg0: Long): Unit
    Definition Classes
    AnyRef
    Annotations
    @throws(classOf[java.lang.InterruptedException]) @native()
  40. def widerDecimalType(p1: Int, s1: Int, p2: Int, s2: Int): DecimalType
  41. def widerDecimalType(d1: DecimalType, d2: DecimalType): DecimalType

Inherited from TypeCoercionRule

Inherited from Rule[LogicalPlan]

Inherited from Logging

Inherited from SQLConfHelper

Inherited from AnyRef

Inherited from Any

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