io.prestosql.sql.planner.iterative.rule

Class ImplementOffset

java.lang.Object

io.prestosql.sql.planner.iterative.rule.ImplementOffset

All Implemented Interfaces:

Rule<OffsetNode>

public class ImplementOffset
extends Object
implements Rule<OffsetNode>

Transforms:

 - Offset (row count = x)
    - Source
 

Into:

 - Project (prune rowNumber symbol)
    - Filter (rowNumber > x)
       - RowNumber
          - Source
 

Relies on RowNumberNode's property of keeping order of its input. If the query contains an ORDER BY clause, the sorted order will be respected when leading rows are removed.

Nested Class Summary

Nested classes/interfaces inherited from interface io.prestosql.sql.planner.iterative.Rule

Rule.Context, Rule.Result

Constructor Summary

Constructors

Constructor and Description
ImplementOffset()

Method Summary

Modifier and Type	Method and Description
Rule.Result	apply(OffsetNode parent, Captures captures, Rule.Context context)
Pattern<OffsetNode>	getPattern() Returns a pattern to which plan nodes this rule applies.

Methods inherited from class java.lang.Object

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

Methods inherited from interface io.prestosql.sql.planner.iterative.Rule

isEnabled

Constructor Detail

ImplementOffset

public ImplementOffset()

Method Detail

getPattern

public Pattern<OffsetNode> getPattern()

Description copied from interface: Rule

Returns a pattern to which plan nodes this rule applies.

Specified by:

getPattern in interface Rule<OffsetNode>

apply

public Rule.Result apply(OffsetNode parent,
                         Captures captures,
                         Rule.Context context)

Specified by:

apply in interface Rule<OffsetNode>