Class Convention.Impl

    • Method Detail

      • toString

        public String toString()
        Description copied from interface: RelTrait
        Returns a succinct name for this trait. The planner may use this String to describe the trait.
        Specified by:
        toString in interface RelTrait
        Overrides:
        toString in class Object
      • register

        public void register​(RelOptPlanner planner)
        Description copied from interface: RelTrait
        Registers a trait instance with the planner.

        This is an opportunity to add rules that relate to that trait. However, typical implementations will do nothing.

        Specified by:
        register in interface RelTrait
        Parameters:
        planner - Planner
      • satisfies

        public boolean satisfies​(RelTrait trait)
        Description copied from interface: RelTrait
        Returns whether this trait satisfies a given trait.

        A trait satisfies another if it is the same or stricter. For example, ORDER BY x, y satisfies ORDER BY x.

        A trait's satisfies relation must be a partial order (reflexive, anti-symmetric, transitive). Many traits cannot be "loosened"; their satisfies is an equivalence relation, where only X satisfies X.

        If a trait has multiple values (see RelCompositeTrait) a collection (T0, T1, ...) satisfies T if any Ti satisfies T.

        Specified by:
        satisfies in interface RelTrait
        Parameters:
        trait - Given trait
        Returns:
        Whether this trait subsumes a given trait
      • getTraitDef

        public RelTraitDef getTraitDef()
        Description copied from interface: RelTrait
        Returns the RelTraitDef that defines this RelTrait.
        Specified by:
        getTraitDef in interface RelTrait
        Returns:
        the RelTraitDef that defines this RelTrait
      • enforce

        public RelNode enforce​(RelNode input,
                               RelTraitSet required)
        Description copied from interface: Convention
        Given an input and required traits, returns the corresponding enforcer rel nodes, like physical Sort, Exchange etc.
        Specified by:
        enforce in interface Convention
        Parameters:
        input - The input RelNode
        required - The required traits
        Returns:
        Physical enforcer that satisfies the required traitSet, or null if trait enforcement is not allowed or the required traitSet can't be satisfied.
      • canConvertConvention

        public boolean canConvertConvention​(Convention toConvention)
        Description copied from interface: Convention
        Returns whether we should convert from this convention to toConvention. Used by ConventionTraitDef.
        Specified by:
        canConvertConvention in interface Convention
        Parameters:
        toConvention - Desired convention to convert to
        Returns:
        Whether we should convert from this convention to toConvention
      • useAbstractConvertersForConversion

        public boolean useAbstractConvertersForConversion​(RelTraitSet fromTraits,
                                                          RelTraitSet toTraits)
        Description copied from interface: Convention
        Returns whether we should convert from this trait set to the other trait set.

        The convention decides whether it wants to handle other trait conversions, e.g. collation, distribution, etc. For a given convention, we will only add abstract converters to handle the trait (convention, collation, distribution, etc.) conversions if this function returns true.

        Specified by:
        useAbstractConvertersForConversion in interface Convention
        Parameters:
        fromTraits - Traits of the RelNode that we are converting from
        toTraits - Target traits
        Returns:
        Whether we should add converters