Module com.darkcollective.relix.plan

Package com.darkcollective.relix.plan

Record Class PhysicalNode.Cover

java.lang.Object

java.lang.Record

com.darkcollective.relix.plan.PhysicalNode.Cover

Record Components:

strength - the covering strength t: every t-column value combination occurring in the input must occur in the output

exact - when true, use MIP set-cover for an exact minimum suite

All Implemented Interfaces:

PhysicalNode

Enclosing interface:

PhysicalNode

public static record PhysicalNode.Cover(Schema schema, int strength, boolean exact, PhysicalNode input)
extends Record
implements PhysicalNode

Covering reduction (COVER): keeps a near-minimal subset of input rows such that every distinct t-column value combination (strength-way tuple) occurring in the input occurs in the output. Output schema equals the input schema (a windowed filter like PhysicalNode.TopK and PhysicalNode.Optimize).

When exact is false (default), executed in-engine by a greedy algorithm: buffer candidates, build the coverage universe (one set of demanded tuples per C(w,t) column subset), then repeatedly select the highest-scoring candidate (earliest-arrival tie-break) until the universe is empty.

When exact is true (COVER EXACT t (R)), uses a MIP set-cover formulation via ojAlgo to find a provably minimal suite.

Never pushed to a source.

Nested Class Summary

Nested classes/interfaces inherited from interface com.darkcollective.relix.plan.PhysicalNode

PhysicalNode.Aggregate, PhysicalNode.AsOfJoin, PhysicalNode.BernoulliSample, PhysicalNode.BuildSide, PhysicalNode.Closure, PhysicalNode.Cluster, PhysicalNode.ConstructiveCover, PhysicalNode.Cover, PhysicalNode.Distinct, PhysicalNode.Division, PhysicalNode.Downsample, PhysicalNode.Empty, PhysicalNode.Fixpoint, PhysicalNode.IntervalJoin, PhysicalNode.Iterate, PhysicalNode.Join, PhysicalNode.JoinAlgorithm, PhysicalNode.JoinKeys, PhysicalNode.JoinKind, PhysicalNode.LateralJoin, PhysicalNode.Limit, PhysicalNode.Optimize, PhysicalNode.Path, PhysicalNode.Pivot, PhysicalNode.Project, PhysicalNode.PushedScan, PhysicalNode.RecursiveRef, PhysicalNode.Rename, PhysicalNode.ReservoirSample, PhysicalNode.Scan, PhysicalNode.Select, PhysicalNode.Sessionize, PhysicalNode.SetKind, PhysicalNode.SetOp, PhysicalNode.Solve, PhysicalNode.Sort, PhysicalNode.Spool, PhysicalNode.TopK, PhysicalNode.Trace, PhysicalNode.Tree, PhysicalNode.Universal, PhysicalNode.Unnest, PhysicalNode.Unpivot, PhysicalNode.Why, PhysicalNode.Window

Constructor Summary

Constructors

Constructor	Description
Cover(Schema schema, int strength, boolean exact, PhysicalNode input)	Creates an instance of a Cover record class.

Method Summary

Modifier and Type	Method	Description
List<PhysicalNode>	children()	Direct child plans, left-to-right; empty for a PhysicalNode.Scan.
final boolean	equals(Object o)	Indicates whether some other object is "equal to" this one.
boolean	exact()	Returns the value of the exact record component.
final int	hashCode()	Returns a hash code value for this object.
PhysicalNode	input()	Returns the value of the input record component.
Schema	schema()	Returns the value of the schema record component.
int	strength()	Returns the value of the strength record component.
final String	toString()	Returns a string representation of this record class.

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.darkcollective.relix.plan.PhysicalNode

deliveredOrdering, mapChildren

Constructor Details

Cover

public Cover(Schema schema,
 int strength,
 boolean exact,
 PhysicalNode input)

Creates an instance of a Cover record class.

Parameters:

schema - the value for the schema record component

strength - the value for the strength record component

exact - the value for the exact record component

input - the value for the input record component

Method Details

children

public List<PhysicalNode> children()

Description copied from interface: PhysicalNode

Direct child plans, left-to-right; empty for a PhysicalNode.Scan.

Specified by:

children in interface PhysicalNode

toString

public final String toString()

Returns a string representation of this record class. The representation contains the name of the class, followed by the name and value of each of the record components.

Specified by:

toString in class Record

Returns:

a string representation of this object

hashCode

public final int hashCode()

Returns a hash code value for this object. The value is derived from the hash code of each of the record components.

Specified by:

hashCode in class Record

Returns:

a hash code value for this object

equals

public final boolean equals(Object o)

Indicates whether some other object is "equal to" this one. The objects are equal if the other object is of the same class and if all the record components are equal. Reference components are compared with Objects::equals(Object,Object); primitive components are compared with '=='.

Specified by:

equals in class Record

Parameters:

o - the object with which to compare

Returns:

true if this object is the same as the o argument; false otherwise.

schema

public Schema schema()

Returns the value of the schema record component.

Specified by:

schema in interface PhysicalNode

Returns:

the value of the schema record component

strength

public int strength()

Returns the value of the strength record component.

Returns:

the value of the strength record component

exact

public boolean exact()

Returns the value of the exact record component.

Returns:

the value of the exact record component

input

public PhysicalNode input()

Returns the value of the input record component.

Returns:

the value of the input record component