Package dev.frostlake.executor.operators

Class AsofJoinOperator

java.lang.Object

dev.frostlake.executor.operators.AsofJoinOperator

All Implemented Interfaces:

Operator

public class AsofJoinOperator
extends Object
implements Operator

Snowflake ASOF JOIN: for every left row, the single CLOSEST right row that satisfies the MATCH_CONDITION — the newest right row at or before the left row's timestamp, and the mirror-image for the < / <= directions.

Live-verified semantics (probed against a real account):

• The result is LEFT OUTER: a left row with no qualifying right row survives, null-extended over the right table's columns.
• >= / > pick the right row with the GREATEST match value among those satisfying the condition; <= / < pick the SMALLEST. Those four are the only operators Snowflake allows in a MATCH_CONDITION.
• A NULL on either side of the comparison never matches, so such right rows are skipped.
• The optional ON / USING equality clause narrows the candidate set per left row (it partitions the join); without it every right row is a candidate.

Constructor Summary

Constructors

Constructor	Description
AsofJoinOperator(Table leftTable, Table rightTable, List<Row> rightRows, BinaryOperator matchOperator, Expression leftMatchExpression, RowExpressionEvaluator leftMatchEvaluator, Expression rightMatchExpression, RowExpressionEvaluator rightMatchEvaluator, JoinConditionEvaluator partitionEvaluator)

Method Summary

Modifier and Type	Method	Description
List<Row>	execute(List<Row> leftRows, OperatorContext context)	Execute this operator on the input rows.
String	getDescription()	Get a description of this operator for debugging/logging.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Details

AsofJoinOperator

public AsofJoinOperator(Table leftTable,
 Table rightTable,
 List<Row> rightRows,
 BinaryOperator matchOperator,
 Expression leftMatchExpression,
 RowExpressionEvaluator leftMatchEvaluator,
 Expression rightMatchExpression,
 RowExpressionEvaluator rightMatchEvaluator,
 JoinConditionEvaluator partitionEvaluator)

Parameters:

leftTable - left input metadata

rightTable - right input metadata

rightRows - the right input's rows

matchOperator - the MATCH_CONDITION comparison (>=, >, <=, <)

leftMatchExpression - the condition's left operand, evaluated against a LEFT row

leftMatchEvaluator - evaluator bound to the left input

rightMatchExpression - the condition's right operand, evaluated against a RIGHT row

rightMatchEvaluator - evaluator bound to the right input

partitionEvaluator - the ON / USING equality test over a (left, right) pair, or null when absent

Method Details

execute

public List<Row> execute(List<Row> leftRows,
 OperatorContext context)

Description copied from interface: Operator

Execute this operator on the input rows.

Specified by:

execute in interface Operator

Parameters:

leftRows - The input rows from the previous operator

context - The execution context containing table metadata and other information

Returns:

The output rows after applying this operator

getDescription

public String getDescription()

Description copied from interface: Operator

Get a description of this operator for debugging/logging.

Specified by:

getDescription in interface Operator

Returns:

A human-readable description of the operator