Package com.apple.foundationdb.record.query.plan.plans

Class RecordQueryUnorderedDistinctPlan

java.lang.Object

com.apple.foundationdb.record.query.plan.plans.RecordQueryUnorderedDistinctPlan

All Implemented Interfaces:

PlanHashable, QueryPlan<FDBQueriedRecord<Message>>, RecordQueryPlan, RecordQueryPlanWithChild, RecordQueryPlanWithChildren, Bindable, PlannerGraphRewritable, RelationalExpressionWithChildren, RelationalExpression

@API(MAINTAINED)
public class RecordQueryUnorderedDistinctPlan
extends Object
implements RecordQueryPlanWithChild

A query plan that removes duplicates by means of a hash table of previously seen values.

Field Summary

Fields

Modifier and Type	Field	Description
static org.slf4j.Logger	LOGGER

Constructor Summary

Constructors

Constructor	Description
RecordQueryUnorderedDistinctPlan(RecordQueryPlan inner, KeyExpression comparisonKey)

Method Summary

Modifier and Type	Method	Description
boolean	equals(Object o)
boolean	equalsWithoutChildren(RelationalExpression otherExpression)
<M extends Message> RecordCursor<FDBQueriedRecord<M>>	execute(FDBRecordStoreBase<M> store, EvaluationContext context, byte[] continuation, ExecuteProperties executeProperties)	Execute this query plan.
RecordQueryPlan	getChild()
int	getComplexity()	Returns an integer representing the "complexity" of the generated plan.
List<? extends Quantifier>	getQuantifiers()	Return an iterator of references to the children of this planner expression.
int	hashCode()
boolean	isReverse()	Indicates whether this plan will return values in "reverse" order from the natural order of results of this plan.
void	logPlanStructure(StoreTimer timer)	Adds one to an appropriate StoreTimer counter for each plan and subplan of this plan, allowing tracking of which plans are being chosen (e.g.
int	planHash()	Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.
PlannerGraph	rewritePlannerGraph(List<? extends PlannerGraph> childGraphs)	Method to rewrite the planner graph.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface com.apple.foundationdb.record.query.plan.plans.QueryPlan

execute, execute

Methods inherited from interface com.apple.foundationdb.record.query.plan.plans.RecordQueryPlan

execute, execute, execute, getQueryPlanChildren

Methods inherited from interface com.apple.foundationdb.record.query.plan.plans.RecordQueryPlanWithChild

getChildren, getRelationalChildCount, getUsedIndexes, hasFullRecordScan, hasIndexScan, hasLoadBykeys, hasRecordScan

Methods inherited from interface com.apple.foundationdb.record.query.plan.temp.RelationalExpression

acceptPropertyVisitor, bindTo, show

Field Detail

LOGGER

public static final org.slf4j.Logger LOGGER

Constructor Detail

RecordQueryUnorderedDistinctPlan

public RecordQueryUnorderedDistinctPlan(@Nonnull
                                        RecordQueryPlan inner,
                                        @Nonnull
                                        KeyExpression comparisonKey)

Method Detail

execute

@Nonnull
public <M extends Message> RecordCursor<FDBQueriedRecord<M>> execute(@Nonnull
                                                                     FDBRecordStoreBase<M> store,
                                                                     @Nonnull
                                                                     EvaluationContext context,
                                                                     @Nullable
                                                                     byte[] continuation,
                                                                     @Nonnull
                                                                     ExecuteProperties executeProperties)

Description copied from interface: RecordQueryPlan

Execute this query plan.

Specified by:

execute in interface RecordQueryPlan

Type Parameters:

M - type used to represent stored records

Parameters:

store - record store from which to fetch records

context - evaluation context containing parameter bindings

continuation - continuation from a previous execution of this same plan

executeProperties - limits on execution

Returns:

a cursor of records that match the query criteria

isReverse

public boolean isReverse()

Description copied from interface: QueryPlan

Indicates whether this plan will return values in "reverse" order from the natural order of results of this plan. The return value is true if the plan returns elements in descending order and false if the elements are returned in ascending order.

Specified by:

isReverse in interface QueryPlan<FDBQueriedRecord<Message>>

Returns:

true if this plan returns elements in reverse order

getChild

@Nonnull
public RecordQueryPlan getChild()

Specified by:

getChild in interface RecordQueryPlanWithChild

getQuantifiers

@Nonnull
@API(EXPERIMENTAL)
public List<? extends Quantifier> getQuantifiers()

Description copied from interface: RelationalExpression

Return an iterator of references to the children of this planner expression. The iterators returned by different calls are guaranteed to be independent (i.e., advancing one will not advance another). However, they might point to the same object, as when Collections.emptyIterator() is returned. The returned iterator should be treated as an immutable object and may throw an exception if Iterator.remove() is called. The iterator must return its elements in a consistent order.

Specified by:

getQuantifiers in interface RelationalExpression

Returns:

an iterator of references to the children of this planner expression

toString

public String toString()

Overrides:

toString in class Object

equalsWithoutChildren

@API(EXPERIMENTAL)
public boolean equalsWithoutChildren(@Nonnull
                                     RelationalExpression otherExpression)

Specified by:

equalsWithoutChildren in interface RelationalExpression

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

planHash

public int planHash()

Description copied from interface: PlanHashable

Return a hash similar to hashCode, but with the additional guarantee that is is stable across JVMs.

Specified by:

planHash in interface PlanHashable

Returns:

a stable hash code

logPlanStructure

public void logPlanStructure(StoreTimer timer)

Description copied from interface: QueryPlan

Adds one to an appropriate StoreTimer counter for each plan and subplan of this plan, allowing tracking of which plans are being chosen (e.g. index scan vs. full scan).

Specified by:

logPlanStructure in interface QueryPlan<FDBQueriedRecord<Message>>

Parameters:

timer - the counters to increment

getComplexity

public int getComplexity()

Description copied from interface: QueryPlan

Returns an integer representing the "complexity" of the generated plan. Currently, this should simply be the number of plans in the plan tree with this plan as the root (i.e. the number of descendants of this plan, including itself).

Specified by:

getComplexity in interface QueryPlan<FDBQueriedRecord<Message>>

Returns:

the complexity of this plan

rewritePlannerGraph

@Nonnull
public PlannerGraph rewritePlannerGraph(@Nonnull
                                        List<? extends PlannerGraph> childGraphs)

Description copied from interface: PlannerGraphRewritable

Method to rewrite the planner graph.

Specified by:

rewritePlannerGraph in interface PlannerGraphRewritable

Parameters:

childGraphs - planner graphs of children expression that already have been computed

Returns:

a new planner graph that can combine the childGraphs in a meaningful way. Note that there is no obligation to use the childGraphs at all, this method can create a new independent planner graph completely from scratch.