Package org.apache.druid.segment.realtime.appenderator

Interface Appenderator

    • Method Detail

      • getId

        String getId()
        Return the identifier of this Appenderator; useful for log messages and such.

      • getDataSource

        String getDataSource()
        Return the name of the dataSource associated with this Appenderator.

      • startJob

        Object startJob()
        Perform any initial setup. Should be called before using any other methods.
        Returns:
        currently persisted commit metadata

      • add

        Appenderator.AppenderatorAddResult add​(SegmentIdWithShardSpec identifier,
                                       org.apache.druid.data.input.InputRow row,
                                       @Nullable
                                       com.google.common.base.Supplier<org.apache.druid.data.input.Committer> committerSupplier,
                                       boolean allowIncrementalPersists)
                                throws org.apache.druid.segment.incremental.IndexSizeExceededException,
                                       SegmentNotWritableException
        Add a row. Must not be called concurrently from multiple threads.

        If no pending segment exists for the provided identifier, a new one will be created.

        This method may trigger a persistAll(Committer) using the supplied Committer. If it does this, the Committer is guaranteed to be *created* synchronously with the call to add, but will actually be used asynchronously.

        If committer is not provided, no metadata is persisted.

        Parameters:
        identifier - the segment into which this row should be added
        row - the row to add
        committerSupplier - supplier of a committer associated with all data that has been added, including this row if allowIncrementalPersists is set to false then this will not be used as no persist will be done automatically
        allowIncrementalPersists - indicate whether automatic persist should be performed or not if required. If this flag is set to false then the return value should have Appenderator.AppenderatorAddResult.isPersistRequired set to true if persist was skipped because of this flag and it is assumed that the responsibility of calling persistAll(Committer) is on the caller.
        Returns:
        Appenderator.AppenderatorAddResult
        Throws:
        org.apache.druid.segment.incremental.IndexSizeExceededException - if this row cannot be added because it is too large
        SegmentNotWritableException - if the requested segment is known, but has been closed

      • getRowCount

        int getRowCount​(SegmentIdWithShardSpec identifier)
        Returns the number of rows in a particular pending segment.
        Parameters:
        identifier - segment to examine
        Returns:
        row count
        Throws:
        IllegalStateException - if the segment is unknown

      • getTotalRowCount

        int getTotalRowCount()
        Returns the number of total rows in this appenderator of all segments pending push.
        Returns:
        total number of rows

      • clear

        void clear()
    throws InterruptedException
        Drop all in-memory and on-disk data, and forget any previously-remembered commit metadata. This could be useful if, for some reason, rows have been added that we do not actually want to hand off. Blocks until all data has been cleared. This may take some time, since all pending persists must finish first.
        Throws:
        InterruptedException

      • drop

        com.google.common.util.concurrent.ListenableFuture<?> drop​(SegmentIdWithShardSpec identifier)
        Schedule dropping all data associated with a particular pending segment. Unlike clear()), any on-disk commit metadata will remain unchanged. If there is no pending segment with this identifier, then this method will do nothing.

        You should not write to the dropped segment after calling "drop". If you need to drop all your data and re-write it, consider clear() instead. This method might be called concurrently from a thread different from the "main data appending / indexing thread", from where all other methods in this class (except those inherited from QuerySegmentWalker) are called. This typically happens when drop() is called in an async future callback. drop() itself is cheap and relays heavy dropping work to an internal executor of this Appenderator.

        Parameters:
        identifier - the pending segment to drop
        Returns:
        future that resolves when data is dropped

      • persistAll

        com.google.common.util.concurrent.ListenableFuture<Object> persistAll​(@Nullable
                                                                      org.apache.druid.data.input.Committer committer)
        Persist any in-memory indexed data to durable storage. This may be only somewhat durable, e.g. the machine's local disk. The Committer will be made synchronously with the call to persistAll, but will actually be used asynchronously. Any metadata returned by the committer will be associated with the data persisted to disk.

        If committer is not provided, no metadata is persisted.

        Parameters:
        committer - a committer associated with all data that has been added so far
        Returns:
        future that resolves when all pending data has been persisted, contains commit metadata for this persist

      • push

        com.google.common.util.concurrent.ListenableFuture<SegmentsAndCommitMetadata> push​(Collection<SegmentIdWithShardSpec> identifiers,
                                                                                   @Nullable
                                                                                   org.apache.druid.data.input.Committer committer,
                                                                                   boolean useUniquePath)
        Merge and push particular segments to deep storage. This will trigger an implicit persistAll(Committer) using the provided Committer.

        After this method is called, you cannot add new data to any segments that were previously under construction.

        If committer is not provided, no metadata is persisted.

        Parameters:
        identifiers - list of segments to push
        committer - a committer associated with all data that has been added so far
        useUniquePath - true if the segment should be written to a path with a unique identifier
        Returns:
        future that resolves when all segments have been pushed. The segment list will be the list of segments that have been pushed and the commit metadata from the Committer.

      • close

        void close()
        Stop any currently-running processing and clean up after ourselves. This allows currently running persists and pushes to finish. This will not remove any on-disk persisted data, but it will drop any data that has not yet been persisted.

      • closeNow

        void closeNow()
        Stop all processing, abandoning current pushes, currently running persist may be allowed to finish if they persist critical metadata otherwise shutdown immediately. This will not remove any on-disk persisted data, but it will drop any data that has not yet been persisted. Since this does not wait for pushes to finish, implementations have to make sure if any push is still happening in background thread then it does not cause any problems.