Interface Convention

All Superinterfaces:
RelTrait
All Known Implementing Classes:
BindableConvention, Convention.Impl, EnumerableConvention, InterpretableConvention, JdbcConvention

public interface Convention
extends RelTrait
Calling convention trait.
  • Field Details

    • NONE

      static final Convention NONE
      Convention that for a relational expression that does not support any convention. It is not implementable, and has to be transformed to something else in order to be implemented.

      Relational expressions generally start off in this form.

      Such expressions always have infinite cost.

  • Method Details

    • getInterface

      Class getInterface()
    • getName

      String getName()
    • enforce

      default RelNode enforce​(RelNode input, RelTraitSet required)
      Given an input and required traits, returns the corresponding enforcer rel nodes, like physical Sort, Exchange etc.
      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

      default boolean canConvertConvention​(Convention toConvention)
      Returns whether we should convert from this convention to toConvention. Used by ConventionTraitDef.
      Parameters:
      toConvention - Desired convention to convert to
      Returns:
      Whether we should convert from this convention to toConvention
    • useAbstractConvertersForConversion

      default boolean useAbstractConvertersForConversion​(RelTraitSet fromTraits, RelTraitSet toTraits)
      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.

      Parameters:
      fromTraits - Traits of the RelNode that we are converting from
      toTraits - Target traits
      Returns:
      Whether we should add converters
    • getRelFactories

      default RelFactories.Struct getRelFactories()
      Return RelFactories struct for this convention. It can can be used to build RelNode.