org.apache.calcite.rel.rules

Class ReduceExpressionsRule.CalcReduceExpressionsRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.ReduceExpressionsRule

org.apache.calcite.rel.rules.ReduceExpressionsRule.CalcReduceExpressionsRule

Enclosing class:

ReduceExpressionsRule

public static class ReduceExpressionsRule.CalcReduceExpressionsRule
extends ReduceExpressionsRule

Rule that reduces constants inside a Calc.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.calcite.rel.rules.ReduceExpressionsRule

ReduceExpressionsRule.CalcReduceExpressionsRule, ReduceExpressionsRule.CaseShuttle, ReduceExpressionsRule.FilterReduceExpressionsRule, ReduceExpressionsRule.JoinReduceExpressionsRule, ReduceExpressionsRule.ProjectReduceExpressionsRule, ReduceExpressionsRule.ReducibleExprLocator, ReduceExpressionsRule.RexReplacer

Field Summary

Fields inherited from class org.apache.calcite.rel.rules.ReduceExpressionsRule

CALC_INSTANCE, EXCLUSION_PATTERN, FILTER_INSTANCE, JOIN_INSTANCE, matchNullability, PROJECT_INSTANCE

Fields inherited from class org.apache.calcite.plan.RelOptRule

description, operands, relBuilderFactory

Constructor Summary

Constructors

Constructor and Description
CalcReduceExpressionsRule(Class<? extends Calc> calcClass, boolean matchNullability, RelBuilderFactory relBuilderFactory)
CalcReduceExpressionsRule(Class<? extends Calc> calcClass, RelBuilderFactory relBuilderFactory) Deprecated.

Method Summary

Modifier and Type	Method and Description
protected RelNode	createEmptyRelOrEquivalent(RelOptRuleCall call, Calc input) For static schema systems, a filter that is always false or null can be replaced by a values operator that produces no rows, as the schema information can just be taken from the input Rel.
void	onMatch(RelOptRuleCall call) Receives notification about a rule match.

Methods inherited from class org.apache.calcite.rel.rules.ReduceExpressionsRule

findReducibleExps, predicateConstants, pushPredicateIntoCase, reduceExpressions, reduceExpressions, reduceExpressions, reduceExpressionsInternal, substitute

Methods inherited from class org.apache.calcite.plan.RelOptRule

any, convert, convert, convertList, convertOperand, equals, equals, getOperand, getOperands, getOutConvention, getOutTrait, hashCode, matches, none, operand, operand, operand, operand, operand, some, toString, unordered

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Detail

CalcReduceExpressionsRule

@Deprecated
public CalcReduceExpressionsRule(Class<? extends Calc> calcClass,
                                             RelBuilderFactory relBuilderFactory)

Deprecated.

CalcReduceExpressionsRule

public CalcReduceExpressionsRule(Class<? extends Calc> calcClass,
                                 boolean matchNullability,
                                 RelBuilderFactory relBuilderFactory)

Method Detail

onMatch

public void onMatch(RelOptRuleCall call)

Description copied from class: RelOptRule

Receives notification about a rule match. At the time that this method is called, call.rels holds the set of relational expressions which match the operands to the rule; call.rels[0] is the root expression.

Typically a rule would check that the nodes are valid matches, creates a new expression, then calls back RelOptRuleCall.transformTo(org.apache.calcite.rel.RelNode, java.util.Map<org.apache.calcite.rel.RelNode, org.apache.calcite.rel.RelNode>) to register the expression.

Specified by:

onMatch in class RelOptRule

Parameters:

call - Rule call

See Also:

RelOptRule.matches(RelOptRuleCall)

createEmptyRelOrEquivalent

protected RelNode createEmptyRelOrEquivalent(RelOptRuleCall call,
                                             Calc input)

For static schema systems, a filter that is always false or null can be replaced by a values operator that produces no rows, as the schema information can just be taken from the input Rel. In dynamic schema environments, the filter might have an unknown input type, in these cases they must define a system specific alternative to a Values operator, such as inserting a limit 0 instead of a filter on top of the original input.

The default implementation of this method is to call RelBuilder.empty(), which for the static schema will be optimized to an empty Values.

Parameters:

input - rel to replace, assumes caller has already determined equivalence to Values operation for 0 records or a false filter.

Returns:

equivalent but less expensive replacement rel