Module com.darkcollective.relix.ast

Package com.darkcollective.relix.ast

Record Class ShuffleNode

java.lang.Object

java.lang.Record

com.darkcollective.relix.ast.ShuffleNode

Record Components:

seed - the optional RNG seed for a reproducible permutation; empty = non-deterministic

input - the relation to permute; must not be null

location - the source location of this node; never null

All Implemented Interfaces:

RelNode

public record ShuffleNode(Optional<Long> seed, RelNode input, SourceLocation location)
extends Record
implements RelNode

Random permutation (SHUFFLE) — returns every row of input exactly once, in a uniformly random order. It is the random-ordering sibling of τ (SORT): where sort imposes a deterministic key order, shuffle imposes a random one.

Cardinality is unchanged — this is the distinction from SAMPLE n ROWS, which also returns rows out of input order but changes the row count. A full permutation requires holding every row, so SHUFFLE is a blocking operator (Fisher–Yates over the buffered rows) and, like SORT, is rejected over a provably unbounded input by the plan-time blocking-operator check.

Reproducibility: when seed is present the permutation is deterministic — identical runs produce the identical order. Without a seed, fresh randomness is drawn each run, exactly as unseeded SAMPLE does.

Examples:

• SHUFFLE (Deck) — a random permutation (non-deterministic)
• SHUFFLE SEED 42 (Deck) — a reproducible permutation

Constructor Summary

Constructors

Constructor	Description
ShuffleNode(RelNode input)	Convenience constructor for tests; uses SourceLocation.UNKNOWN and no seed.
ShuffleNode(Optional<Long> seed, RelNode input, SourceLocation location)	Creates an instance of a ShuffleNode record class.

Method Summary

Modifier and Type	Method	Description
<R> R	accept(RelNodeVisitor<R> visitor)
final boolean	equals(Object o)	Indicates whether some other object is "equal to" this one.
final int	hashCode()	Returns a hash code value for this object.
RelNode	input()	Returns the value of the input record component.
SourceLocation	location()	Returns the value of the location record component.
Optional<Long>	seed()	Returns the value of the seed 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.ast.RelNode

children, mapChildren, materializationMode, prettyPrint

Constructor Details

ShuffleNode

public ShuffleNode(Optional<Long> seed,
 RelNode input,
 SourceLocation location)

Creates an instance of a ShuffleNode record class.

Parameters:

seed - the value for the seed record component

input - the value for the input record component

location - the value for the location record component

ShuffleNode

public ShuffleNode(RelNode input)

Convenience constructor for tests; uses SourceLocation.UNKNOWN and no seed.

Method Details

accept

public <R> R accept(RelNodeVisitor<R> visitor)

Specified by:

accept in interface RelNode

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. All components in this record class are compared with Objects::equals(Object,Object).

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.

seed

public Optional<Long> seed()

Returns the value of the seed record component.

Returns:

the value of the seed record component

input

public RelNode input()

Returns the value of the input record component.

Returns:

the value of the input record component

location

public SourceLocation location()

Returns the value of the location record component.

Specified by:

location in interface RelNode

Returns:

the value of the location record component