Module com.darkcollective.relix.ast
Package com.darkcollective.relix.ast

Record Class SampleNode

java.lang.Object
java.lang.Record
com.darkcollective.relix.ast.SampleNode
Record Components:
probability - the per-row keep probability, in [0, 1]
seed - the optional RNG seed for reproducible sampling; empty = non-deterministic
input - the relation to sample; must not be null
location - the source location of this node; never null
All Implemented Interfaces:
RelNode
public record SampleNode(double probability, Optional<Long> seed, RelNode input, SourceLocation location) extends Record implements RelNode
Bernoulli sampling (SAMPLE) — independently keeps each row of input with probability probability (a fraction in [0, 1]).

It is the streaming, composable form of TABLESAMPLE: every row is an independent coin flip, so the result size is approximately probability × |input| and varies from run to run.

Reproducibility: when seed is present the sampling is deterministic — identical runs produce identical row selections. Without a seed, fresh randomness is drawn each run.

Examples:

  • SAMPLE 0.1 (Events) — keeps roughly 10% of the rows (non-deterministic)
  • SAMPLE 0.8 SEED 42 (HistoricalData) — reproducible 80% sample

  • Constructor Details

    • SampleNode

      public SampleNode(double probability, Optional<Long> seed, RelNode input, SourceLocation location)
      Creates an instance of a SampleNode record class.
      Parameters:
      probability - the value for the probability record component
      seed - the value for the seed record component
      input - the value for the input record component
      location - the value for the location record component

    • SampleNode

      public SampleNode(double probability, RelNode input, SourceLocation location)
      Convenience constructor without seed (non-deterministic); uses provided location.

    • SampleNode

      public SampleNode(double probability, 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. 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.

    • probability

      public double probability()
      Returns the value of the probability record component.
      Returns:
      the value of the probability record component

    • 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