io.druid.segment.realtime.appenderator

Class BaseAppenderatorDriver

java.lang.Object

io.druid.segment.realtime.appenderator.BaseAppenderatorDriver

All Implemented Interfaces:

Closeable, AutoCloseable

Direct Known Subclasses:

BatchAppenderatorDriver, StreamAppenderatorDriver

public abstract class BaseAppenderatorDriver
extends Object
implements Closeable

A BaseAppenderatorDriver drives an Appenderator to index a finite stream of data. This class does not help you index unbounded streams. All handoff is done at the end of indexing.

This class helps with doing things that Appenderators don't, including deciding which segments to use (with a SegmentAllocator), publishing segments to the metadata store (with a SegmentPublisher).

This class has two child classes, i.e., BatchAppenderatorDriver and StreamAppenderatorDriver, which are for batch and streaming ingestion, respectively. This class provides some fundamental methods for making the child classes' life easier like pushInBackground(io.druid.segment.realtime.appenderator.BaseAppenderatorDriver.WrappedCommitter, java.util.Collection<io.druid.segment.realtime.appenderator.SegmentIdentifier>), dropInBackground(io.druid.segment.realtime.appenderator.SegmentsAndMetadata), or publishInBackground(io.druid.segment.realtime.appenderator.SegmentsAndMetadata, io.druid.segment.realtime.appenderator.TransactionalSegmentPublisher). The child classes can use these methods to achieve their goal.

Note that the commit metadata stored by this class via the underlying Appenderator is not the same metadata as you pass in. It's wrapped in some extra metadata needed by the driver.

Field Summary

Fields

Modifier and Type	Field and Description
protected Appenderator	appenderator
protected com.google.common.util.concurrent.ListeningExecutorService	executor
protected Map<String,io.druid.segment.realtime.appenderator.BaseAppenderatorDriver.SegmentsForSequence>	segments

Method Summary

Modifier and Type	Method and Description
protected AppenderatorDriverAddResult	append(InputRow row, String sequenceName, com.google.common.base.Supplier<Committer> committerSupplier, boolean skipSegmentLineageCheck, boolean allowIncrementalPersists) Add a row.
void	clear() Clears out all our state and also calls Appenderator.clear() on the underlying Appenderator.
void	close() Closes this driver.
abstract Object	startJob() Perform any initial setup and return currently persisted commit metadata.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

appenderator

protected final Appenderator appenderator

segments

protected final Map<String,io.druid.segment.realtime.appenderator.BaseAppenderatorDriver.SegmentsForSequence> segments

executor

protected final com.google.common.util.concurrent.ListeningExecutorService executor

Method Detail

startJob

@Nullable
public abstract Object startJob()

Perform any initial setup and return currently persisted commit metadata.

Note that this method returns the same metadata you've passed in with your Committers, even though this class stores extra metadata on disk.

Returns:

currently persisted commit metadata

append

protected AppenderatorDriverAddResult append(InputRow row,
                                             String sequenceName,
                                             @Nullable
                                             com.google.common.base.Supplier<Committer> committerSupplier,
                                             boolean skipSegmentLineageCheck,
                                             boolean allowIncrementalPersists)
                                      throws IOException

Add a row. Must not be called concurrently from multiple threads.

Parameters:

row - the row to add

sequenceName - sequenceName for this row's segment

committerSupplier - supplier of a committer associated with all data that has been added, including this row if is set to false then this will not be used

skipSegmentLineageCheck - if true, perform lineage validation using previousSegmentId for this sequence. Should be set to false if replica tasks would index events in same order

allowIncrementalPersists - whether to allow persist to happen when maxRowsInMemory or intermediate persist period threshold is hit

Returns:

AppenderatorDriverAddResult

Throws:

IOException - if there is an I/O error while allocating or writing to a segment

clear

public void clear()
           throws InterruptedException

Clears out all our state and also calls Appenderator.clear() on the underlying Appenderator.

Throws:

InterruptedException

close

public void close()

Closes this driver. Does not close the underlying Appenderator; you should do that yourself.

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable