Package com.tangosol.io.journal

Class AbstractJournalRM.CollectorDaemon.CollectionCoordinator

  • Enclosing class:
    AbstractJournalRM.CollectorDaemon
    protected class AbstractJournalRM.CollectorDaemon.CollectionCoordinator
extends Object
    A CollectionCoordinator is responsible for shaping an evacuation as well as managing any reserved files created to ensure the journal continues to operate. The CollectionCoordinator is notified of any actions performed during the evacuation thus can suggest when the next evacuation should execute.

    The CollectionCoordinator is also responsible for finalizing a collection which in this context acts as a barrier to clients exposing the memory reclaimed during the evacuation.

    • Constructor Detail

      • CollectionCoordinator

        protected CollectionCoordinator()

    • Method Detail

      • getFinalJournalFile

        public AbstractJournalRM.JournalFile getFinalJournalFile()
        Return a AbstractJournalRM.JournalFile based on the context of the calling thread or null if it is determined that an exhaustive evacuation will not reclaim sufficient memory. This method should only be invoked in a "depleted" state when:
        • the maximum number of files is used
        • all those files are non-appending
        When called on a client thread, any operation against this file will block until the full compaction is performed. There is no guarantee that compaction will result in available memory therefore an out of memory error is still possible.

        When called on the CollectorDaemon thread this method returns a normal JournalFile, with the only exception that it will be in excess to the maximum number of permitted journal files and used exclusively by the CollectorDaemon to perform evacuation in a depleted state.

        Returns:
        a JournalFile either triggering a full collection or a file used exclusively by the CollectorDaemon. null may be returned if it is determined that an exhaustive evacuation will not reclaim sufficient memory

      • exhaustiveEvac

        public void exhaustiveEvac​(int cBytes,
                           boolean fWait)
        Request the CollectorDaemon to perform an exhaustive evacuation and block this thread until the collection is complete.
        Parameters:
        cBytes - the number of bytes required by this store request
        fWait - whether to block the calling thread until sufficient memory has been reclaimed

      • onReleased

        public void onReleased​(int cbReleased,
                       int nFileId)
        Notify the CollectionCoordinator that a AbstractJournalRM.JournalFile has released the provided amount of memory.
        Parameters:
        cbReleased - the number of bytes released
        nFileId - the journal file id that was released from

      • getReservedFileId

        public int getReservedFileId()
        Return the reserved file id.
        Returns:
        the reserved file id

      • getEvacuatedFileCount

        public int getEvacuatedFileCount()
        Return the number of files evacuated since the statistics were reset.
        Returns:
        the number of files evacuated

      • getExhaustiveCompactionCount

        public int getExhaustiveCompactionCount()
        Return the total number of exhaustive evacuations performed by the collector.
        Returns:
        the total number of exhaustive evacuations performed by the collector

      • getExhaustiveCompactionTime

        public long getExhaustiveCompactionTime()
        Return the number of milliseconds it took to perform exhaustive evacuations by the collector.
        Returns:
        the total number of milliseconds spent in performing exhaustive evacuations

      • getAvgEvacuationMillis

        public int getAvgEvacuationMillis()
        Determine the average number of milliseconds to evacuate a file.
        Returns:
        the average number of milliseconds to perform evacuation

      • getMaxEvacuationMillis

        public int getMaxEvacuationMillis()
        Determine the maximum number of milliseconds to evacuate a file.
        Returns:
        the number of milliseconds of the longest evacuation

      • resetStatistics

        public void resetStatistics()
        Reset the collector statistics.

      • ensureReservedFile

        public AbstractJournalRM.JournalFile ensureReservedFile()
        Return a reserved file.

        This method is only invoked in a 'depleted' state in which no more journal files can be created thus the reserved slot in the JournalFile[] must be used. This slot is reserved exclusively for the CollectorDaemon.

        Returns:
        a usable file from the survivor pool

      • onStart

        public void onStart()
        Inform the CollectionCoordinator that a collection is about to commence.

      • finalizeCollection

        protected void finalizeCollection()
        Inform the CollectionCoordinator that a collection is complete and changes should be exposed.

      • getWaitTime

        protected long getWaitTime()
        Return the amount of time the collector should wait prior to the next collection.
        Returns:
        the amount of time prior to the next collection

      • actionable

        protected void actionable​(AbstractJournalRM.JournalFile jrnlFile)
        Inform the CollectionCoordinator of an item that could be actioned if the CollectorDaemon was to execute. This may influence the interval before the next CollectorDaemon execution.

      • isExhaustiveEvacuation

        protected boolean isExhaustiveEvacuation()
        Return whether this is an exhaustive evacuation.
        Returns:
        whether this is an exhaustive evacuation

      • hasReclaimedMemory

        public boolean hasReclaimedMemory()
        Return true if memory has been reclaimed by evacuating a journal file or discarding of a garbage file.
        Returns:
        whether any files have been discarded during the collection

      • calculateCurrentLoadFactor

        protected double calculateCurrentLoadFactor()
        Calculate current load factor for compaction (GC).
        Returns:
        calculated load factor

      • release

        protected void release()
        Release the reserved file(s) used thus far into the RM's AbstractJournalRM.JournalFile pool so that they are linked appropriately. Additionally expose the slots that were free'd allowing clients awoken to carry out store requests.

        Calls to release when in exhaustive evacuation mode must hold the lock f_lockClientGC prior to calling release.

      • shouldExecuteFullGc

        protected boolean shouldExecuteFullGc()
        Return whether an exhaustive evacuation should be executed.
        Returns:
        whether an exhaustive evacuation should be executed