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

Interface QueryPlan<T>

Type Parameters:

T - the type of element produced by executing this plan

All Superinterfaces:

Bindable, PlanHashable, PlannerExpression, RelationalPlannerExpression

All Known Subinterfaces:

RecordQueryPlan, RecordQueryPlanWithChild, RecordQueryPlanWithChildren, RecordQueryPlanWithComparisons, RecordQueryPlanWithIndex, RecordQueryPlanWithNoChildren

All Known Implementing Classes:

RecordQueryCoveringIndexPlan, RecordQueryFilterPlan, RecordQueryIndexPlan, RecordQueryInJoinPlan, RecordQueryInParameterJoinPlan, RecordQueryIntersectionPlan, RecordQueryInValuesJoinPlan, RecordQueryLoadByKeysPlan, RecordQueryScanPlan, RecordQueryScoreForRankPlan, RecordQueryTextIndexPlan, RecordQueryTypeFilterPlan, RecordQueryUnionPlan, RecordQueryUnorderedDistinctPlan, RecordQueryUnorderedPrimaryKeyDistinctPlan, RecordQueryUnorderedUnionPlan

@API(value=EXPERIMENTAL)
public interface QueryPlan<T>
extends PlanHashable, RelationalPlannerExpression

An executable query plan. A query plan can be executed against a record store to get a stream of items. Unlike a RecordQueryPlan (which extends this interface), implementations are not required to return records but might instead return items of an arbitrary type. Note that QueryPlanners always return RecordQueryPlans, but the query plan tree might contain intermediate plans that return something other than records.

Method Summary

Modifier and Type	Method and Description
default RecordCursor<T>	execute(FDBRecordStore store) Execute this query plan.
default RecordCursor<T>	execute(FDBRecordStore store, EvaluationContext context) Execute this query plan.
RecordCursor<T>	execute(FDBRecordStore store, EvaluationContext context, byte[] continuation, ExecuteProperties executeProperties) Execute this query plan.
int	getComplexity() Returns an integer representing the "complexity" of the generated plan.
List<? extends QueryPlan<?>>	getQueryPlanChildren() Returns the (zero or more) child QueryPlans of this plan.
Set<String>	getUsedIndexes() Returns a set of names of the indexes used by this plan (and its sub-plans).
boolean	hasFullRecordScan() Indicates whether this plan (or one of its components) must perform a scan over all records in the store directly rather than going through a secondary index.
boolean	hasIndexScan(String indexName) Indicates whether this plan scans the given index.
boolean	hasRecordScan() Indicates whether this plan (or one of its components) scans at least a subset of the record range directly rather than going through a secondary index.
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.

Methods inherited from interface com.apple.foundationdb.record.PlanHashable

iterablePlanHash, objectPlanHash, objectsPlanHash, planHash, planHash, planHash

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

fromRecordQuery

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

acceptPropertyVisitor, bindTo, getPlannerExpressionChildren

Method Detail

execute

@Nonnull
RecordCursor<T> execute(@Nonnull
                                 FDBRecordStore store,
                                 @Nonnull
                                 EvaluationContext context,
                                 @Nullable
                                 byte[] continuation,
                                 @Nonnull
                                 ExecuteProperties executeProperties)

Execute this query plan.

Parameters:

store - record store from which to fetch items

context - evaluation context containing parameter bindings

continuation - continuation from a previous execution of this same plan

executeProperties - limits on execution

Returns:

a cursor of items that match the query criteria

execute

@Nonnull
default RecordCursor<T> execute(@Nonnull
                                         FDBRecordStore store)

Execute this query plan.

Parameters:

store - record store from which to fetch items

Returns:

a cursor of items that match the query criteria

execute

@Nonnull
default RecordCursor<T> execute(@Nonnull
                                         FDBRecordStore store,
                                         @Nonnull
                                         EvaluationContext context)

Execute this query plan.

Parameters:

store - record store to access

context - evaluation context containing parameter bindings

Returns:

a cursor of items that match the query criteria

isReverse

boolean isReverse()

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.

Returns:

true if this plan returns elements in reverse order

hasRecordScan

boolean hasRecordScan()

Indicates whether this plan (or one of its components) scans at least a subset of the record range directly rather than going through a secondary index. A plan may only scan over a subset of all records. Someone might not use any secondary indexes explicitly, but they might make use of the primary key index. For example, if they had a compound primary key, and they issued a query for all records that had some value for the first element of their primary key, the planner will produce a plan which scans over a subset of all records.

Returns:

true if this plan (or one of its components) scans at least a subset of the records directly

hasFullRecordScan

boolean hasFullRecordScan()

Indicates whether this plan (or one of its components) must perform a scan over all records in the store directly rather than going through a secondary index. See hasRecordScan for the comparison between two methods.

Returns:

true if this plan (or one of its components) must perform a scan over all records in the store directly

hasIndexScan

boolean hasIndexScan(@Nonnull
                     String indexName)

Indicates whether this plan scans the given index.

Parameters:

indexName - the name of the index to check for

Returns:

true if this plan (or one of its children) scans the given index

getUsedIndexes

@Nonnull
Set<String> getUsedIndexes()

Returns a set of names of the indexes used by this plan (and its sub-plans).

Returns:

an set of indexes used by this plan

logPlanStructure

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. index scan vs. full scan).

Parameters:

timer - the counters to increment

getComplexity

int getComplexity()

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).

Returns:

the complexity of this plan

getQueryPlanChildren

List<? extends QueryPlan<?>> getQueryPlanChildren()

Returns the (zero or more) child QueryPlans of this plan. These children may or may not return elements of the same type as their parent plan.

Warning: This part of the API is currently undergoing active development. At some point in the future, this will be renamed getChildren(). This cannot be done at current, however, as it would require an incompatible change to RecordQueryPlan.getChildren(). That method has been marked API.Status#UNSTABLE as of version 2.5.

Returns:

the child plans of this plan