Package org.infinispan.persistence.file

Class SingleFileStore<K,​V>

  • All Implemented Interfaces:
    NonBlockingStore<K,​V>
    public class SingleFileStore<K,​V>
extends Object
implements NonBlockingStore<K,​V>
    A filesystem-based implementation of a NonBlockingStore. This file store stores cache values in a single file <location>/<cache name>.dat, keys and file positions are kept in memory.

    Note: this CacheStore implementation keeps keys and file positions in memory! The current implementation needs about 100 bytes per cache entry, plus the memory for the key objects.

    So, the space taken by this cache store is both the space in the file itself plus the in-memory index with the keys and their file positions. With this in mind and to avoid the cache store leading to OutOfMemoryExceptions, you can optionally configure the maximum number of entries to maintain in this cache store, which affects both the size of the file and the size of the in-memory index. However, setting this maximum limit results in older entries in the cache store to be eliminated, and hence, it only makes sense configuring a maximum limit if Infinispan is used as a cache where loss of data in the cache store does not lead to data loss, and data can be recomputed or re-queried from the original data source.

    This class is fully thread safe, yet allows for concurrent load / store of individual cache entries.

    Since:
    6.0
    Author:
    Karsten Blees, Mircea Markus

    • Field Detail

      • MAGIC_BEFORE_11

        public static final byte[] MAGIC_BEFORE_11

      • MAGIC_11_0

        public static final byte[] MAGIC_11_0

      • MAGIC_12_0

        public static final byte[] MAGIC_12_0

      • MAGIC_12_1

        public static final byte[] MAGIC_12_1

      • MAGIC_LATEST

        public static final byte[] MAGIC_LATEST

    • Constructor Detail

      • SingleFileStore

        public SingleFileStore()

    • Method Detail

      • getStoreFile

        public static File getStoreFile​(String directoryPath,
                                String cacheName)

      • start

        public CompletionStage<Void> start​(InitializationContext ctx)
        Description copied from interface: NonBlockingStore
        The first method to invoke so that the store can be configured and additional steps, such as connecting through a socket or opening file descriptors, are performed.

        The provided InitializationContext contains many helpful objects, including the configuration of the cache and store, concurrency utilities such as BlockingManager or an executor reserved for non-blocking operations only InitializationContext.getNonBlockingExecutor().

        This method is guaranteed not to be invoked concurrently with other operations. This means other methods are not invoked on this store until after the returned Stage completes.

        It is expected that an implementation should be able to "restart" by invoking start a second time if NonBlockingStore.stop() has been invoked and allowed for its stage to complete.

        Specified by:
        start in interface NonBlockingStore<K,​V>
        Parameters:
        ctx - initialization context used to initialize this store.
        Returns:
        a stage that, when complete, indicates that this store has started successfully.

      • stop

        public CompletionStage<Void> stop()
        Description copied from interface: NonBlockingStore
        This method is invoked when the cache is being shutdown. It is expected that all resources related to the store are freed when the returned stage is complete.

        This method is guaranteed not to be invoked concurrently with other operations. This means other methods are not invoked on this store until after the returned Stage completes.

        It is expected that an implementation should be able to "restart" by invoking NonBlockingStore.start(InitializationContext) a second time if stop has been invoked and allowed for its stage to complete.

        Specified by:
        stop in interface NonBlockingStore<K,​V>
        Returns:
        a stage that, when complete, indicates that this store has stopped.

      • characteristics

        public Set<NonBlockingStore.Characteristic> characteristics()
        Description copied from interface: NonBlockingStore
        Returns a set of characteristics for this store and its elements. This method may be invoked multiple times to determine which methods of the store can be used and how the data in the store can be handled.

        Refer to NonBlockingStore.Characteristic and its values for descriptions of each characteristic for stores.

        Specified by:
        characteristics in interface NonBlockingStore<K,​V>
        Returns:
        the set of characteristics that this store supports.

      • isAvailable

        public CompletionStage<Boolean> isAvailable()
        Description copied from interface: NonBlockingStore
        Returns a stage that, when complete, returns a boolean indicating whether the current store can be accessed for requests. This can be useful for store implementations that rely on an external source, such as a remote database, that may become unreachable. This can reduce sending requests to a store that is not available, as subsequent cache requests will result in a StoreUnavailableException being thrown until the store becomes available again.

        Store availability is is polled periodically to update the status of stores if their availability changes. This method is not invoked concurrently with itself. In other words, this method is not invoked until after the previous stage has completed. However this method is invoked concurrently with other operations, except for NonBlockingStore.start(InitializationContext) and NonBlockingStore.stop().

        If a store is configured to be StoreConfiguration.async() and the store becomes unavailable, then it is possible for the cache operations to be accepted in the interim period between the loss of availability and the modification-queue becoming full. This allows for this store to be unavailable for short periods of time without a StoreUnavailableException being thrown; however if the store does not become available before the queue fills, then a StoreUnavailableException is thrown.

        Specified by:
        isAvailable in interface NonBlockingStore<K,​V>
        Returns:
        stage that, when complete, indicates if the store is available.

      • containsKey

        public CompletionStage<Boolean> containsKey​(int segment,
                                            Object key)
        The base class implementation calls load(int, Object) for this, we can do better because we keep all keys in memory.
        Specified by:
        containsKey in interface NonBlockingStore<K,​V>
        Parameters:
        segment - the segment for the given key if segmentation is enabled, otherwise 0.
        key - key of the entry to check.
        Returns:
        a stage that, when complete, contains a boolean stating if the value is contained in the store.

      • delete

        public CompletionStage<Boolean> delete​(int segment,
                                       Object key)
        Description copied from interface: NonBlockingStore
        Removes the entry for given key and segment from the store and optionally report if the entry was actually removed or not.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.READ_ONLY This method will never be invoked.
        NonBlockingStore.Characteristic.SEGMENTABLE When this is not set or segmentation is disabled in the configuration, the segment parameter may be ignored.

        If a problem is encountered, it is recommended to wrap any created/caught Throwable in a PersistenceException and the stage be completed exceptionally.

        Specified by:
        delete in interface NonBlockingStore<K,​V>
        Parameters:
        segment - the segment for the given key if segmentation is enabled, otherwise 0.
        key - key of the entry to delete from the store.
        Returns:
        a stage that completes with TRUE if the key existed in the store, FALSE if the key did not exist in the store, or null if the store does not report this information.

      • publishKeys

        public org.reactivestreams.Publisher<K> publishKeys​(IntSet segments,
                                                    Predicate<? super K> filter)
        Description copied from interface: NonBlockingStore
        Publishes keys from this store that are in one of the provided segments and also pass the provided filter. The returned publisher must support being subscribed to any number of times. That is subsequent invocations of Publisher.subscribe(Subscriber) should provide independent views of the underlying keys to the Subscribers. Keys should not retrieved until a given Subscriber requests them via the Subscription.request(long) method.

        Subscribing to the returned Publisher should not block the invoking thread. It is the responsibility of the store implementation to ensure this occurs. If however the store must block to perform an operation it is recommended to wrap your Publisher before returning with the BlockingManager.blockingPublisher(Publisher) method and it will handle subscription and observation on the blocking and non blocking executors respectively.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.BULK_READ This method is only invoked if the store has this characteristic.
        NonBlockingStore.Characteristic.EXPIRATION When set the returned publisher must not return expired keys.
        NonBlockingStore.Characteristic.SEGMENTABLE When this is not set or segmentation is disabled in the configuration, the segment parameter may be ignored.

        Specified by:
        publishKeys in interface NonBlockingStore<K,​V>
        Parameters:
        segments - a set of segments to filter keys by. This will always be non null.
        filter - a filter to filter they keys by. If this is null then no additional filtering should be done after segments.
        Returns:
        a publisher that provides the keys from the store.

      • publishEntries

        public org.reactivestreams.Publisher<MarshallableEntry<K,​V>> publishEntries​(IntSet segments,
                                                                                  Predicate<? super K> filter,
                                                                                  boolean includeValues)
        Description copied from interface: NonBlockingStore
        Publishes entries from this store that are in one of the provided segments and also pass the provided filter. The returned publisher must support being subscribed to any number of times. That is subsequent invocations of Publisher.subscribe(Subscriber) should provide independent views of the underlying entries to the Subscribers. Entries should not retrieved until a given Subscriber requests them via the Subscription.request(long) method.

        Subscribing to the returned Publisher should not block the invoking thread. It is the responsibility of the store implementation to ensure this occurs. If however the store must block to perform an operation it is recommended to wrap your Publisher before returning with the BlockingManager.blockingPublisher(Publisher) method and it will handle subscription and observation on the blocking and non-blocking executors respectively.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.BULK_READ This method is only invoked if the store has this characteristic.
        NonBlockingStore.Characteristic.EXPIRATION When set the returned publisher must not return expired entries.
        NonBlockingStore.Characteristic.SEGMENTABLE When this is not set or segmentation is disabled in the configuration, the segment parameter may be ignored.
        Specified by:
        publishEntries in interface NonBlockingStore<K,​V>
        Parameters:
        segments - a set of segments to filter entries by. This will always be non null.
        filter - a filter to filter they keys by. If this is null then no additional filtering should be done after segments.
        Returns:
        a publisher that provides the keys from the store.

      • purgeExpired

        public org.reactivestreams.Publisher<MarshallableEntry<K,​V>> purgeExpired()
        Description copied from interface: NonBlockingStore
        Returns a Publisher that, after it is subscribed to, removes any expired entries from the store and publishes them to the returned Publisher.

        When the Publisher is subscribed to, it is expected to do point-in-time expiration and should not return a Publisher that has infinite entries or never completes.

        Subscribing to the returned Publisher should not block the invoking thread. It is the responsibility of the store implementation to ensure this occurs. If however the store must block to perform an operation it is recommended to wrap your Publisher before returning with the BlockingManager.blockingPublisher(Publisher) method and it will handle subscription and observation on the blocking and non blocking executors respectively.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.EXPIRATION This method is only invoked if the store has this characteristic.

        If a problem is encountered, it is recommended to wrap any created/caught Throwable in a PersistenceException and the stage be completed exceptionally.

        Specified by:
        purgeExpired in interface NonBlockingStore<K,​V>
        Returns:
        a Publisher that publishes the entries that are expired at the time of subscription.

      • size

        public CompletionStage<Long> size​(IntSet segments)
        Description copied from interface: NonBlockingStore
        Returns the amount of entries that map to the given segments in the store.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.BULK_READ This method is only invoked if the store has this characteristic.
        NonBlockingStore.Characteristic.SEGMENTABLE When this is not set or segmentation is disabled in the configuration, the segments parameter may be ignored.

        If a problem is encountered, it is recommended to wrap any created/caught Throwable in a PersistenceException and the stage be completed exceptionally.

        Specified by:
        size in interface NonBlockingStore<K,​V>
        Parameters:
        segments - the segments for which the entries are counted.
        Returns:
        a stage that, when complete, contains the count of how many entries are present for the given segments.

      • approximateSize

        public CompletionStage<Long> approximateSize​(IntSet segments)
        Description copied from interface: NonBlockingStore
        Returns an estimation of the amount of entries that map to the given segments in the store. This is similar to NonBlockingStore.size(IntSet) except that it is not strict about the returned size. For instance, this method might ignore if an entry is expired or if the store has some underlying optimizations to eventually have a consistent size.

        The implementations should be O(1). If a size approximation cannot be returned without iterating over all the entries in the store, the implementation should return -1L.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.BULK_READ This method is only invoked if the store has this characteristic.
        NonBlockingStore.Characteristic.SEGMENTABLE When the store does not have this characteristic or segmentation is disabled in the configuration, the segment parameter is always IntSets.immutableRangeSet(numSegments).

        If a problem is encountered, it is recommended to wrap any created/caught Throwable in a PersistenceException and the stage be completed exceptionally.

        Specified by:
        approximateSize in interface NonBlockingStore<K,​V>
        Parameters:
        segments - the segments for which the entries are counted.
        Returns:
        a stage that, when complete, contains the approximate count of the entries in the given segments, or -1L if an approximate count cannot be provided.

      • addSegments

        public CompletionStage<Void> addSegments​(IntSet segments)
        Description copied from interface: NonBlockingStore
        Invoked when a node becomes an owner of the given segments. Some store implementations may require initializing additional resources when a new segment is required. For example a store could store entries in a different file per segment.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.SHAREABLE If the store has this characteristic and is configured to be StoreConfiguration.shared(), this method will never be invoked.
        NonBlockingStore.Characteristic.SEGMENTABLE This method is invoked only if the store has this characteristic and is configured to be segmented.

        If a problem is encountered, it is recommended to wrap any created/caught Throwable in a PersistenceException and the stage be completed exceptionally.

        Specified by:
        addSegments in interface NonBlockingStore<K,​V>
        Parameters:
        segments - the segments to add.
        Returns:
        a stage that, when complete, indicates that the segments have been added.

      • removeSegments

        public CompletionStage<Void> removeSegments​(IntSet segments)
        Description copied from interface: NonBlockingStore
        Invoked when a node loses ownership of the given segments. A store must then remove any entries that map to the given segments and can remove any resources related to the given segments. For example, a database store can delete rows of the given segment or a file-based store can delete files related to the given segments.

        Summary of Characteristics Effects

        Characteristic Effect
        NonBlockingStore.Characteristic.SHAREABLE If the store has this characteristic and is configured to be shared, this method will never be invoked.
        NonBlockingStore.Characteristic.SEGMENTABLE This method is invoked only if the store has this characteristic and is configured to be segmented.

        If a problem is encountered, it is recommended to wrap any created/caught Throwable in a PersistenceException and the stage be completed exceptionally.

        Specified by:
        removeSegments in interface NonBlockingStore<K,​V>
        Parameters:
        segments - the segments to remove.
        Returns:
        a stage that, when complete, indicates that the segments have been removed.