Interface RelOptPlanner

  • All Known Implementing Classes:
    AbstractRelOptPlanner, HepPlanner, VolcanoPlanner

    public interface RelOptPlanner
    A RelOptPlanner is a query optimizer: it transforms a relational expression into a semantically equivalent relational expression, according to a given set of rules and a cost model.
    • Field Detail

      • LOGGER

        static final org.slf4j.Logger LOGGER
    • Method Detail

      • setRoot

        void setRoot​(RelNode rel)
        Sets the root node of this query.
        Parameters:
        rel - Relational expression
      • getRoot

        RelNode getRoot()
        Returns the root node of this query.
        Returns:
        Root node
      • addRelTraitDef

        boolean addRelTraitDef​(RelTraitDef relTraitDef)
        Registers a rel trait definition. If the RelTraitDef has already been registered, does nothing.
        Returns:
        whether the RelTraitDef was added, as per Collection.add(E)
      • clearRelTraitDefs

        void clearRelTraitDefs()
        Clear all the registered RelTraitDef.
      • getRelTraitDefs

        List<RelTraitDef> getRelTraitDefs()
        Returns the list of active trait types.
      • clear

        void clear()
        Removes all internal state, including all registered rules, materialized views, and lattices.
      • getRules

        List<RelOptRule> getRules()
        Returns the list of all registered rules.
      • addRule

        boolean addRule​(RelOptRule rule)
        Registers a rule.

        If the rule has already been registered, does nothing. This method determines if the given rule is a ConverterRule and pass the ConverterRule to all registered RelTraitDef instances.

        Returns:
        whether the rule was added, as per Collection.add(E)
      • getContext

        Context getContext()
        Provides the Context created when this planner was constructed.
        Returns:
        Never null; either an externally defined context, or a dummy context that returns null for each requested interface
      • setRuleDescExclusionFilter

        void setRuleDescExclusionFilter​(Pattern exclusionFilter)
        Sets the exclusion filter to use for this planner. Rules which match the given pattern will not be fired regardless of whether or when they are added to the planner.
        Parameters:
        exclusionFilter - pattern to match for exclusion; null to disable filtering
      • setCancelFlag

        @Deprecated
        void setCancelFlag​(CancelFlag cancelFlag)
        Deprecated.
        Previously, this method installed the cancellation-checking flag for this planner, but is now deprecated. Now, you should add a CancelFlag to the Context passed to the constructor.
        Does nothing.
        Parameters:
        cancelFlag - flag which the planner should periodically check
      • changeTraits

        RelNode changeTraits​(RelNode rel,
                             RelTraitSet toTraits)
        Changes a relational expression to an equivalent one with a different set of traits.
        Parameters:
        rel - Relational expression (may or may not have been registered; must not have the desired traits)
        toTraits - Trait set to convert the relational expression to
        Returns:
        Relational expression with desired traits. Never null, but may be abstract
      • chooseDelegate

        RelOptPlanner chooseDelegate()
        Negotiates an appropriate planner to deal with distributed queries. The idea is that the schemas decide among themselves which has the most knowledge. Right now, the local planner retains control.
      • addMaterialization

        void addMaterialization​(RelOptMaterialization materialization)
        Defines a pair of relational expressions that are equivalent.

        Typically tableRel is a LogicalTableScan representing a table that is a materialized view and queryRel is the SQL expression that populates that view. The intention is that tableRel is cheaper to evaluate and therefore if the query being optimized uses (or can be rewritten to use) queryRel as a sub-expression then it can be optimized by using tableRel instead.

      • getMaterializations

        List<RelOptMaterialization> getMaterializations()
        Returns the materializations that have been registered with the planner.
      • register

        RelNode register​(RelNode rel,
                         RelNode equivRel)
        Registers a relational expression in the expression bank.

        After it has been registered, you may not modify it.

        The expression must not already have been registered. If you are not sure whether it has been registered, call ensureRegistered(RelNode, RelNode).

        Parameters:
        rel - Relational expression to register (must not already be registered)
        equivRel - Relational expression it is equivalent to (may be null)
        Returns:
        the same expression, or an equivalent existing expression
      • ensureRegistered

        RelNode ensureRegistered​(RelNode rel,
                                 RelNode equivRel)
        Registers a relational expression if it is not already registered.

        If equivRel is specified, rel is placed in the same equivalence set. It is OK if equivRel has different traits; rel will end up in a different subset of the same set.

        It is OK if rel is a subset.

        Parameters:
        rel - Relational expression to register
        equivRel - Relational expression it is equivalent to (may be null)
        Returns:
        Registered relational expression
      • isRegistered

        boolean isRegistered​(RelNode rel)
        Determines whether a relational expression has been registered.
        Parameters:
        rel - expression to test
        Returns:
        whether rel has been registered
      • registerSchema

        void registerSchema​(RelOptSchema schema)
        Tells this planner that a schema exists. This is the schema's chance to tell the planner about all of the special transformation rules.
      • addListener

        void addListener​(RelOptListener newListener)
        Adds a listener to this planner.
        Parameters:
        newListener - new listener to be notified of events
      • registerMetadataProviders

        void registerMetadataProviders​(List<RelMetadataProvider> list)
        Gives this planner a chance to register one or more RelMetadataProviders in the chain which will be used to answer metadata queries.

        Planners which use their own relational expressions internally to represent concepts such as equivalence classes will generally need to supply corresponding metadata providers.

        Parameters:
        list - receives planner's custom providers, if any
      • getRelMetadataTimestamp

        long getRelMetadataTimestamp​(RelNode rel)
        Gets a timestamp for a given rel's metadata. This timestamp is used by CachingRelMetadataProvider to decide whether cached metadata has gone stale.
        Parameters:
        rel - rel of interest
        Returns:
        timestamp of last change which might affect metadata derivation
      • prune

        void prune​(RelNode rel)
        Prunes a node from the planner.

        When a node is pruned, the related pending rule calls are cancelled, and future rules will not fire. This can be used to reduce the search space.

        Parameters:
        rel - the node to prune.
      • registerClass

        void registerClass​(RelNode node)
        Registers a class of RelNode. If this class of RelNode has been seen before, does nothing.
        Parameters:
        node - Relational expression
      • emptyTraitSet

        RelTraitSet emptyTraitSet()
        Creates an empty trait set. It contains all registered traits, and the default values of any traits that have them.

        The empty trait set acts as the prototype (a kind of factory) for all subsequently created trait sets.

        Returns:
        Empty trait set
      • setExecutor

        void setExecutor​(RexExecutor executor)
        Sets the object that can execute scalar expressions.
      • getExecutor

        RexExecutor getExecutor()
        Returns the executor used to evaluate constant expressions.
      • onCopy

        void onCopy​(RelNode rel,
                    RelNode newRel)
        Called when a relational expression is copied to a similar expression.