org.apache.calcite.rel.rules

Class ValuesReduceRule

java.lang.Object

org.apache.calcite.plan.RelOptRule

org.apache.calcite.rel.rules.ValuesReduceRule

public abstract class ValuesReduceRule
extends RelOptRule

Planner rule that folds projections and filters into an underlying LogicalValues.

Returns a simplified Values, perhaps containing zero tuples if all rows are filtered away.

For example,

select a - b from (values (1, 2), (3, 5), (7, 11)) as t (a, b) where a + b > 4

becomes

select x from (values (-2), (-4))

Ignores an empty Values; this is better dealt with by PruneEmptyRules.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
private static class	ValuesReduceRule.MyRexShuttle Shuttle that converts inputs to literals.

Field Summary

Fields

Modifier and Type	Field and Description
static ValuesReduceRule	FILTER_INSTANCE Instance of this rule that applies to the pattern Filter(Values).
private static org.slf4j.Logger	LOGGER
static ValuesReduceRule	PROJECT_FILTER_INSTANCE Singleton instance of this rule that applies to the pattern Project(Filter(Values)).
static ValuesReduceRule	PROJECT_INSTANCE Instance of this rule that applies to the pattern Project(Values).

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

description, operands, relBuilderFactory

Constructor Summary

Constructors

Constructor and Description
ValuesReduceRule(RelOptRuleOperand operand, RelBuilderFactory relBuilderFactory, String desc) Creates a ValuesReduceRule.

Method Summary

Modifier and Type	Method and Description
protected void	apply(RelOptRuleCall call, LogicalProject project, LogicalFilter filter, LogicalValues values) Does the work.

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

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

Methods inherited from class java.lang.Object

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

Field Detail

LOGGER

private static final org.slf4j.Logger LOGGER

FILTER_INSTANCE

public static final ValuesReduceRule FILTER_INSTANCE

Instance of this rule that applies to the pattern Filter(Values).

PROJECT_INSTANCE

public static final ValuesReduceRule PROJECT_INSTANCE

Instance of this rule that applies to the pattern Project(Values).

PROJECT_FILTER_INSTANCE

public static final ValuesReduceRule PROJECT_FILTER_INSTANCE

Singleton instance of this rule that applies to the pattern Project(Filter(Values)).

Constructor Detail

ValuesReduceRule

public ValuesReduceRule(RelOptRuleOperand operand,
                        RelBuilderFactory relBuilderFactory,
                        String desc)

Creates a ValuesReduceRule.

Parameters:

operand - Class of rels to which this rule should apply

relBuilderFactory - Builder for relational expressions

desc - Description, or null to guess description

Method Detail

apply

protected void apply(RelOptRuleCall call,
                     LogicalProject project,
                     LogicalFilter filter,
                     LogicalValues values)

Does the work.

Parameters:

call - Rule call

project - Project, may be null

filter - Filter, may be null

values - Values rel to be reduced