Package com.apple.foundationdb.record.provider.foundationdb.indexes

Class RankIndexMaintainer

java.lang.Object

com.apple.foundationdb.record.provider.foundationdb.IndexMaintainer

com.apple.foundationdb.record.provider.foundationdb.indexes.StandardIndexMaintainer

com.apple.foundationdb.record.provider.foundationdb.indexes.RankIndexMaintainer

@API(MAINTAINED)
public class RankIndexMaintainer
extends StandardIndexMaintainer

An index maintainer for keeping a RankedSet of record field values. A rank index is used to implement these operations in queries:

• rank: Given a record, where would its field value be in an ordered enumeration of all record's values.
• select: Given a range of ranks, return (the primary keys for) the records with values in that range.

Any number of fields in the index can optionally separate records into non-overlapping groups. Each group, determined by the values of those fields, has separate ranking.

Physical layout:

• primary subspace: an ordinary B-tree index by [group, ..., score, ...].
• secondary subspace: a ranked set per group, that is, with any group key as a prefix.

Field Summary

Fields inherited from class com.apple.foundationdb.record.provider.foundationdb.indexes.StandardIndexMaintainer

TOO_LARGE_VALUE_MESSAGE_LIMIT

Fields inherited from class com.apple.foundationdb.record.provider.foundationdb.IndexMaintainer

state

Constructor Summary

Constructors

Constructor	Description
RankIndexMaintainer(IndexMaintainerState state)

Method Summary

Modifier and Type	Method	Description
boolean	canEvaluateAggregateFunction(IndexAggregateFunction function)	Get whether this index can be used to evaluate the given aggregate function.
boolean	canEvaluateRecordFunction(IndexRecordFunction<?> function)	Return true if this index be used to evaluate the given record function.
CompletableFuture<Void>	deleteWhere(Transaction tr, Tuple prefix)	Clear index storage associated with the given key prefix.
CompletableFuture<Tuple>	evaluateAggregateFunction(IndexAggregateFunction function, TupleRange range, IsolationLevel isolationLevel)	Evaluate an aggregate function over the given range using this index.
<T,M extends Message> CompletableFuture<T>	evaluateRecordFunction(EvaluationContext context, IndexRecordFunction<T> function, FDBRecord<M> record)	Evaluate a record function on the given record.
boolean	isIdempotent()	Whether updating or removing a record on this index is idempotent.
<M extends Message> CompletableFuture<Long>	rank(FDBRecord<M> record)
RecordCursor<IndexEntry>	scan(IndexScanType scanType, TupleRange rankRange, byte[] continuation, ScanProperties scanProperties)	Scan entries in the index.
protected <M extends Message> CompletableFuture<Void>	updateIndexKeys(FDBIndexableRecord<M> savedRecord, boolean remove, List<IndexEntry> indexEntries)	Update index according to record keys.

Methods inherited from class com.apple.foundationdb.record.provider.foundationdb.indexes.StandardIndexMaintainer

addedRangeWithKey, addUniquenessViolation, canDeleteWhere, canDeleteWhere, checkKeyValueSizes, checkUniqueness, commonKeys, decodeValue, evaluateIndex, filteredIndexEntries, getExecutor, getGroupedCount, getGroupingCount, getTimer, indexEntryKey, makeMutable, performOperation, removeUniquenessViolationsAsync, saveIndexEntryAsKeyValue, scan, scanUniquenessViolations, skipUpdateForUnchangedKeys, trimTooLargeTuple, unpackKeyValue, unpackKeyValue, update, updateIndexKeysFunction, updateOneKeyAsync, validateEntries, validateMissingEntries, validateOrphanEntries

Methods inherited from class com.apple.foundationdb.record.provider.foundationdb.IndexMaintainer

getIndexSubspace, getSecondarySubspace, unsupportedAggregateFunction, unsupportedRecordFunction

Methods inherited from class java.lang.Object

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

Constructor Detail

RankIndexMaintainer

public RankIndexMaintainer(IndexMaintainerState state)

Method Detail

scan

@Nonnull
public RecordCursor<IndexEntry> scan(@Nonnull
                                     IndexScanType scanType,
                                     @Nonnull
                                     TupleRange rankRange,
                                     @Nullable
                                     byte[] continuation,
                                     @Nonnull
                                     ScanProperties scanProperties)

Description copied from class: IndexMaintainer

Scan entries in the index.

Specified by:

scan in class IndexMaintainer

Parameters:

scanType - the type of scan to perform

rankRange - the range to scan

continuation - any continuation from a previous scan invocation

scanProperties - skip, limit and other properties of the scan

Returns:

a cursor over index entries in the given range

updateIndexKeys

protected <M extends Message> CompletableFuture<Void> updateIndexKeys(@Nonnull
                                                                      FDBIndexableRecord<M> savedRecord,
                                                                      boolean remove,
                                                                      @Nonnull
                                                                      List<IndexEntry> indexEntries)

Description copied from class: StandardIndexMaintainer

Update index according to record keys. Often this operation returns an already completed future because there is no asynchronous work to be done.

Overrides:

updateIndexKeys in class StandardIndexMaintainer

Type Parameters:

M - the message type of the record

Parameters:

savedRecord - the record being indexed

remove - true if removing from index

indexEntries - the result of StandardIndexMaintainer.evaluateIndex(FDBRecord)

Returns:

a future completed when update is done

isIdempotent

public boolean isIdempotent()

Description copied from class: IndexMaintainer

Whether updating or removing a record on this index is idempotent. In principle, all index updates in the normal case are idempotent as long as the index update and the record insertion or deletion is atomic. However, certain indexes (mostly aggregate indexes) have the property that the index update on its own are not idempotent.

Overrides:

isIdempotent in class StandardIndexMaintainer

Returns:

whether updating this index is idempotent

canEvaluateRecordFunction

public boolean canEvaluateRecordFunction(@Nonnull
                                         IndexRecordFunction<?> function)

Description copied from class: IndexMaintainer

Return true if this index be used to evaluate the given record function.

Overrides:

canEvaluateRecordFunction in class StandardIndexMaintainer

Parameters:

function - requested function

Returns:

true if this index can be used to evaluate the given function

evaluateRecordFunction

@Nonnull
public <T,M extends Message> CompletableFuture<T> evaluateRecordFunction(@Nonnull
                                                                               EvaluationContext context,
                                                                               @Nonnull
                                                                               IndexRecordFunction<T> function,
                                                                               @Nonnull
                                                                               FDBRecord<M> record)

Description copied from class: IndexMaintainer

Evaluate a record function on the given record.

Overrides:

evaluateRecordFunction in class StandardIndexMaintainer

Type Parameters:

T - the result type of the function

M - the message type of the record

Parameters:

context - context for evaluation

function - the record function to apply to the given record

record - record against which to evaluate

Returns:

a future that completes with the result of evaluation

rank

public <M extends Message> CompletableFuture<Long> rank(@Nonnull
                                                        FDBRecord<M> record)

deleteWhere

public CompletableFuture<Void> deleteWhere(Transaction tr,
                                           @Nonnull
                                           Tuple prefix)

Description copied from class: IndexMaintainer

Clear index storage associated with the given key prefix.

Overrides:

deleteWhere in class StandardIndexMaintainer

Parameters:

tr - transaction in which to access the database

prefix - prefix of primary key to clear

Returns:

a future that is complete when the given prefix has been cleared from this index

canEvaluateAggregateFunction

public boolean canEvaluateAggregateFunction(@Nonnull
                                            IndexAggregateFunction function)

Description copied from class: IndexMaintainer

Get whether this index can be used to evaluate the given aggregate function.

Overrides:

canEvaluateAggregateFunction in class StandardIndexMaintainer

Parameters:

function - the requested aggregate function

Returns:

true if this index be used to evaluate the given aggregate function

evaluateAggregateFunction

@Nonnull
public CompletableFuture<Tuple> evaluateAggregateFunction(@Nonnull
                                                          IndexAggregateFunction function,
                                                          @Nonnull
                                                          TupleRange range,
                                                          @Nonnull
                                                          IsolationLevel isolationLevel)

Description copied from class: IndexMaintainer

Evaluate an aggregate function over the given range using this index.

Overrides:

evaluateAggregateFunction in class StandardIndexMaintainer

Parameters:

function - the aggregate function to evaluate

range - the range over which to accumulate the aggregate

isolationLevel - the isolation level at which to perform the scan

Returns:

a future that completes with the aggregate result