Class Convention.Impl

All Implemented Interfaces:
Convention, RelTrait
Direct Known Subclasses:
Enclosing interface:

public static class Convention.Impl extends Object implements Convention
Default implementation.
  • Constructor Details

  • Method Details

    • 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
      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
      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
      trait - Given trait
      Whether this trait subsumes a given trait
    • getInterface

      public Class getInterface()
      Specified by:
      getInterface in interface Convention
    • getName

      public String getName()
      Specified by:
      getName in interface Convention
    • getTraitDef

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

      public @Nullable 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
      input - The input RelNode
      required - The required traits
      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
      toConvention - Desired convention to convert to
      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
      fromTraits - Traits of the RelNode that we are converting from
      toTraits - Target traits
      Whether we should add converters