Package org.apache.druid.query.groupby.epinephelinae

Class AbstractBufferHashGrouper<KeyType>

java.lang.Object

org.apache.druid.query.groupby.epinephelinae.AbstractBufferHashGrouper<KeyType>

All Implemented Interfaces:

Closeable, AutoCloseable, Grouper<KeyType>

Direct Known Subclasses:

BufferHashGrouper, LimitedBufferHashGrouper

public abstract class AbstractBufferHashGrouper<KeyType>
extends Object
implements Grouper<KeyType>

Nested Class Summary

Nested classes/interfaces inherited from interface org.apache.druid.query.groupby.epinephelinae.Grouper

Grouper.BufferComparator, Grouper.Entry<T>, Grouper.KeySerde<T>, Grouper.KeySerdeFactory<T>

Field Summary

Fields

Modifier and Type	Field	Description
protected final AggregatorAdapters	aggregators
protected final int	baseAggregatorOffset
protected int	bucketSize
protected final int	bufferGrouperMaxSize
protected final com.google.common.base.Supplier<ByteBuffer>	bufferSupplier
protected static final int	HASH_SIZE
protected ByteBufferHashTable	hashTable
protected ByteBuffer	hashTableBuffer
protected int	initialBuckets
protected final Grouper.KeySerde<KeyType>	keySerde
protected final int	keySize
protected static final Logger	log
protected float	maxLoadFactor

Constructor Summary

Constructors

Constructor	Description
AbstractBufferHashGrouper(com.google.common.base.Supplier<ByteBuffer> bufferSupplier, Grouper.KeySerde<KeyType> keySerde, AggregatorAdapters aggregators, int baseAggregatorOffset, int bufferGrouperMaxSize)

Method Summary

Modifier and Type	Method	Description
abstract void	afterAggregateHook(int bucketOffset)	Called after a row is aggregated.
AggregateResult	aggregate(KeyType key, int keyHash)	Aggregate the current row with the provided key.
abstract boolean	canSkipAggregate(int bucketOffset)	Called to check if it's possible to skip aggregation for a row.
void	close()	Close the grouper and release associated resources.
int	getBuckets()
int	getGrowthCount()
int	getMaxSize()
int	getSize()
abstract void	newBucketHook(int bucketOffset)	Called when a new bucket is used for an entry in the hash table.
protected Grouper.Entry<KeyType>	populateBucketEntryForOffset(ReusableEntry<KeyType> reusableEntry, int bucketOffset)	Populate a ReusableEntry with values from a particular bucket.

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.druid.query.groupby.epinephelinae.Grouper

aggregate, hashFunction, init, isInitialized, iterator, reset

Field Details

HASH_SIZE

protected static final int HASH_SIZE

See Also:

• Constant Field Values

log

protected static final Logger log

bufferSupplier

protected final com.google.common.base.Supplier<ByteBuffer> bufferSupplier

keySerde

protected final Grouper.KeySerde<KeyType> keySerde

keySize

protected final int keySize

aggregators

protected final AggregatorAdapters aggregators

baseAggregatorOffset

protected final int baseAggregatorOffset

bufferGrouperMaxSize

protected final int bufferGrouperMaxSize

maxLoadFactor

protected float maxLoadFactor

initialBuckets

protected int initialBuckets

bucketSize

protected int bucketSize

hashTable

protected ByteBufferHashTable hashTable

hashTableBuffer

protected ByteBuffer hashTableBuffer

Constructor Details

AbstractBufferHashGrouper

public AbstractBufferHashGrouper(com.google.common.base.Supplier<ByteBuffer> bufferSupplier,
 Grouper.KeySerde<KeyType> keySerde,
 AggregatorAdapters aggregators,
 int baseAggregatorOffset,
 int bufferGrouperMaxSize)

Method Details

newBucketHook

public abstract void newBucketHook(int bucketOffset)

Called when a new bucket is used for an entry in the hash table. An implementing BufferHashGrouper class can use this to update its own state, e.g. tracking bucket offsets in a structure outside of the hash table.

Parameters:

bucketOffset - offset of the new bucket, within the buffer returned by hashTable.getTableBuffer()

canSkipAggregate

public abstract boolean canSkipAggregate(int bucketOffset)

Called to check if it's possible to skip aggregation for a row.

Parameters:

bucketOffset - Offset of the bucket containing this row's entry in the hash table, within the buffer returned by hashTable.getTableBuffer()

Returns:

true if aggregation can be skipped, false otherwise.

afterAggregateHook

public abstract void afterAggregateHook(int bucketOffset)

Called after a row is aggregated. An implementing BufferHashGrouper class can use this to update its own state, e.g. reading the new aggregated values for the row's key and acting on that information.

Parameters:

bucketOffset - Offset of the bucket containing the row that was aggregated, within the buffer returned by hashTable.getTableBuffer()

getGrowthCount

public int getGrowthCount()

getSize

public int getSize()

getBuckets

public int getBuckets()

getMaxSize

public int getMaxSize()

aggregate

public AggregateResult aggregate(KeyType key,
 int keyHash)

Description copied from interface: Grouper

Aggregate the current row with the provided key. Some implementations are thread-safe and some are not.

Specified by:

aggregate in interface Grouper<KeyType>

Parameters:

key - key object

keyHash - result of Grouper.hashFunction() on the key

Returns:

result that is ok if the row was aggregated, not ok if a resource limit was hit

close

public void close()

Description copied from interface: Grouper

Close the grouper and release associated resources.

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface Grouper<KeyType>

populateBucketEntryForOffset

protected Grouper.Entry<KeyType> populateBucketEntryForOffset(ReusableEntry<KeyType> reusableEntry,
 int bucketOffset)

Populate a ReusableEntry with values from a particular bucket.