Package com.apple.foundationdb.record.provider.foundationdb.storestate

Interface FDBRecordStoreStateCache

All Known Implementing Classes:

MetaDataVersionStampStoreStateCache, PassThroughRecordStoreStateCache, ReadVersionRecordStoreStateCache

@API(EXPERIMENTAL)
public interface FDBRecordStoreStateCache

A cache for FDBRecordStoreStateCacheEntry objects. These cache entries contain information necessary to initialize a record store, so caching this information can make accessing a record store multiple times in quick succession cheaper both in that latency is saved at record store creation time. Additionally, in scenarios when a client is connecting to a very small number of record stores, loading this information from disk can load potential hot keys which can generally degrade cluster performance. Caching this information avoids performing those reads.

Note that if the client is connecting to multiple clusters, there should be one cache per cluster. In general, as there is one FDBDatabase object per cluster, it is sufficient to provide a FDBRecordStoreStateCacheFactory to the FDBDatabaseFactory singleton. One can also provide a cache instance to an FDBRecordStore at build time.

Clients should generally not call methods defined on this interface, as they are intended mainly for internal use within the Record Layer.

See Also:

FDBDatabaseFactory.setStoreStateCacheFactory(FDBRecordStoreStateCacheFactory), FDBRecordStoreBase.BaseBuilder.setStoreStateCache(FDBRecordStoreStateCache)

Method Summary

Modifier and Type	Method	Description
void	clear()	Remove all entries from the cache.
CompletableFuture<FDBRecordStoreStateCacheEntry>	get(FDBRecordStore recordStore, FDBRecordStoreBase.StoreExistenceCheck existenceCheck)	Load the record store state for the record store stored at the given location.
default void	validateContext(FDBRecordContext context)
void	validateDatabase(FDBDatabase database)

Method Detail

get

@API(INTERNAL)
@Nonnull
CompletableFuture<FDBRecordStoreStateCacheEntry> get(@Nonnull
                                                     FDBRecordStore recordStore,
                                                     @Nonnull
                                                     FDBRecordStoreBase.StoreExistenceCheck existenceCheck)

Load the record store state for the record store stored at the given location. If this information is available in the cache, it will be served from memory without communicating with the database. Otherwise, the information may require performing network and disk I/O. Note that the cache entry returned should be consistent with the view of the database as viewed by the transaction provided as input. The cache implementations are generally differentiated by the manner in which they invalidate data to ensure that the value returned is consistent with this contract.

This method should generally not be called by clients importing the Record Layer.

Parameters:

recordStore - the record store to load the store state of

existenceCheck - whether to error if the store does or does not exist

Returns:

a future that will complete with the cached store state

validateDatabase

@API(INTERNAL)
void validateDatabase(@Nonnull
                      FDBDatabase database)

validateContext

@API(INTERNAL)
default void validateContext(@Nonnull
                             FDBRecordContext context)

clear

void clear()

Remove all entries from the cache.