Interface RelOptPlanner

All Known Implementing Classes:
AbstractRelOptPlanner, HepPlanner, MockRelOptPlanner, 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 Details

    • LOGGER

      static final org.slf4j.Logger LOGGER
  • Method Details

    • setRoot

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

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

      boolean addRelTraitDef(RelTraitDef relTraitDef)
      Registers a rel trait definition. If the RelTraitDef has already been registered, does nothing.
      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.

      whether the rule was added, as per Collection.add(E)
    • removeRule

      boolean removeRule(RelOptRule rule)
      Removes a rule.
      true if the rule was present, as per Collection.remove(Object)
    • getContext

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

      void setRuleDescExclusionFilter(@Nullable 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.
      exclusionFilter - pattern to match for exclusion; null to disable filtering
    • setCancelFlag

      @Deprecated void setCancelFlag(CancelFlag cancelFlag)
      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.
      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.
      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
      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.
    • addLattice

      void addLattice(RelOptLattice lattice)
      Defines a lattice.

      The lattice may have materializations; it is not necessary to call addMaterialization(org.apache.calcite.plan.RelOptMaterialization) for these; they are registered implicitly.

    • getLattice

      @Nullable RelOptLattice getLattice(RelOptTable table)
      Retrieves a lattice, given its star table.
    • findBestExp

      RelNode findBestExp()
      Finds the most efficient expression to implement this query.
      RelOptPlanner.CannotPlanException - if cannot find a plan
    • getCostFactory

      RelOptCostFactory getCostFactory()
      Returns the factory that creates RelOptCosts.
    • getCost

      @Nullable RelOptCost getCost(RelNode rel, RelMetadataQuery mq)
      Computes the cost of a RelNode. In most cases, this just dispatches to RelMetadataQuery.getCumulativeCost(org.apache.calcite.rel.RelNode).
      rel - Relational expression of interest
      mq - Metadata query
      estimated cost
    • getCost

      @Deprecated @Nullable RelOptCost getCost(RelNode rel)
    • register

      RelNode register(RelNode rel, @Nullable 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).

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

      RelNode ensureRegistered(RelNode rel, @Nullable 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.

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

      boolean isRegistered(RelNode rel)
      Determines whether a relational expression has been registered.
      rel - expression to test
      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.
      newListener - new listener to be notified of events
    • registerMetadataProviders

      @Deprecated 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.

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

      @Deprecated 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.
      rel - rel of interest
      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.

      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.
      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.

      Empty trait set
    • setExecutor

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

      @Nullable 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.