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

Class AtomicMutationIndexMaintainer

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.AtomicMutationIndexMaintainer

@API(value=MAINTAINED)
public class AtomicMutationIndexMaintainer
extends StandardIndexMaintainer

An index that maintains an aggregate value in a low-contention way.

Normally, when two transactions read, modify, and write the same location, they conflict. This makes a straightforward implementation of most aggregate indexes inefficient. Ones that use the atomic mutation feature of FDB avoid this problem.

Field Summary

Fields

Modifier and Type	Field and Description
protected AtomicMutation	mutation

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

Modifier	Constructor and Description
	AtomicMutationIndexMaintainer(IndexMaintainerState state)
protected	AtomicMutationIndexMaintainer(IndexMaintainerState state, AtomicMutation mutation)

Method Summary

Modifier and Type	Method and Description
boolean	canEvaluateAggregateFunction(IndexAggregateFunction function) Get whether this index can be used to evaluate the given aggregate function.
protected Tuple	decodeValue(byte[] value) Decode value portion of key value pair.
CompletableFuture<Tuple>	evaluateAggregateFunction(IndexAggregateFunction function, TupleRange range, IsolationLevel isolationveLevel) Evaluate an aggregate function over the given range using this index.
protected static AtomicMutation	getAtomicMutation(Index index)
boolean	isIdempotent() Whether updating or removing a record on this index is idempotent.
protected boolean	matchesAggregateFunction(IndexAggregateFunction function)
RecordCursor<IndexEntry>	scan(IndexScanType scanType, TupleRange range, byte[] continuation, ScanProperties scanProperties) Scan entries in the index.
boolean	skipUpdateForUnchangedKeys()
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, canDeleteWhere, canDeleteWhere, canEvaluateRecordFunction, checkKeyValueSizes, commonKeys, deleteWhere, evaluateIndex, evaluateRecordFunction, filteredIndexEntries, getExecutor, getGroupedCount, getGroupingCount, getTimer, indexEntryKey, makeMutable, performOperation, saveIndexEntryAsKeyValue, scan, scanUniquenessViolations, trimTooLargeTuple, unpackKeyValue, unpackKeyValue, update, updateIndexKeysFunction, updateOneKey, updateUniquenessViolations, validateEntries, 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

Field Detail

mutation

protected final AtomicMutation mutation

Constructor Detail

AtomicMutationIndexMaintainer

public AtomicMutationIndexMaintainer(IndexMaintainerState state)

AtomicMutationIndexMaintainer

protected AtomicMutationIndexMaintainer(IndexMaintainerState state,
                                        AtomicMutation mutation)

Method Detail

getAtomicMutation

protected static AtomicMutation getAtomicMutation(@Nonnull
                                                  Index index)

scan

@Nonnull
public RecordCursor<IndexEntry> scan(@Nonnull
                                              IndexScanType scanType,
                                              @Nonnull
                                              TupleRange range,
                                              @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

range - 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

decodeValue

protected Tuple decodeValue(@Nonnull
                            byte[] value)

Description copied from class: StandardIndexMaintainer

Decode value portion of key value pair.

Overrides:

decodeValue in class StandardIndexMaintainer

Parameters:

value - the raw value portion of a key value pair

Returns:

a decoded tuple of any values stored in the value side of the index, which is usually empty

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 isolationveLevel)

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

isolationveLevel - the isolation level at which to perform the scan

Returns:

a future that completes with the aggregate result

matchesAggregateFunction

protected boolean matchesAggregateFunction(@Nonnull
                                           IndexAggregateFunction function)

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

skipUpdateForUnchangedKeys

public boolean skipUpdateForUnchangedKeys()

Overrides:

skipUpdateForUnchangedKeys in class StandardIndexMaintainer