org.apache.druid.query.topn

Class HeapBasedTopNAlgorithm

java.lang.Object

org.apache.druid.query.topn.BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

org.apache.druid.query.topn.HeapBasedTopNAlgorithm

All Implemented Interfaces:

TopNAlgorithm<Aggregator[][],TopNParams>

public class HeapBasedTopNAlgorithm
extends BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

Heap based topn algorithm that handles aggregates on dimension extractions and numeric typed dimension columns. This has to be its own strategy because the pooled topn algorithm assumes each index is unique, and cannot handle multiple index numerals referencing the same dimension value.

Nested Class Summary

Nested classes/interfaces inherited from class org.apache.druid.query.topn.BaseTopNAlgorithm

BaseTopNAlgorithm.AggregatorArrayProvider, BaseTopNAlgorithm.BaseArrayProvider<T>

Field Summary

Fields inherited from class org.apache.druid.query.topn.BaseTopNAlgorithm

storageAdapter

Fields inherited from interface org.apache.druid.query.topn.TopNAlgorithm

EMPTY_ARRAY, INIT_POSITION_VALUE, SKIP_POSITION_VALUE

Constructor Summary

Constructors

Constructor and Description
HeapBasedTopNAlgorithm(StorageAdapter storageAdapter, TopNQuery query)

Method Summary

Modifier and Type	Method and Description
void	cleanup(TopNParams params)
protected void	closeAggregators(TopNColumnAggregatesProcessor processor)
protected TopNColumnAggregatesProcessor	makeDimValAggregateStore(TopNParams params)
protected Aggregator[][]	makeDimValSelector(TopNParams params, int numProcessed, int numToProcess)
TopNParams	makeInitParams(ColumnSelectorPlus<TopNColumnAggregatesProcessor> selectorPlus, Cursor cursor)
protected long	scanAndAggregate(TopNParams params, Aggregator[][] rowSelector, TopNColumnAggregatesProcessor processor) Returns the number of processed rows (i.
protected Aggregator[][]	updateDimValSelector(Aggregator[][] aggregators, int numProcessed, int numToProcess)
protected void	updateResults(TopNParams params, Aggregator[][] aggregators, TopNColumnAggregatesProcessor processor, TopNResultBuilder resultBuilder)

Methods inherited from class org.apache.druid.query.topn.BaseTopNAlgorithm

computeNewLength, makeAggregators, makeBufferAggregators, makeResultBuilder, run

Methods inherited from class java.lang.Object

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

Constructor Detail

HeapBasedTopNAlgorithm

public HeapBasedTopNAlgorithm(StorageAdapter storageAdapter,
                              TopNQuery query)

Method Detail

makeInitParams

public TopNParams makeInitParams(ColumnSelectorPlus<TopNColumnAggregatesProcessor> selectorPlus,
                                 Cursor cursor)

makeDimValSelector

protected Aggregator[][] makeDimValSelector(TopNParams params,
                                            int numProcessed,
                                            int numToProcess)

Specified by:

makeDimValSelector in class BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

updateDimValSelector

protected Aggregator[][] updateDimValSelector(Aggregator[][] aggregators,
                                              int numProcessed,
                                              int numToProcess)

Specified by:

updateDimValSelector in class BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

makeDimValAggregateStore

protected TopNColumnAggregatesProcessor makeDimValAggregateStore(TopNParams params)

Specified by:

makeDimValAggregateStore in class BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

scanAndAggregate

protected long scanAndAggregate(TopNParams params,
                                Aggregator[][] rowSelector,
                                TopNColumnAggregatesProcessor processor)

Description copied from class: BaseTopNAlgorithm

Returns the number of processed rows (i. e. after postFilters are applied inside the cursor being processed).

Specified by:

scanAndAggregate in class BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

updateResults

protected void updateResults(TopNParams params,
                             Aggregator[][] aggregators,
                             TopNColumnAggregatesProcessor processor,
                             TopNResultBuilder resultBuilder)

Specified by:

updateResults in class BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

closeAggregators

protected void closeAggregators(TopNColumnAggregatesProcessor processor)

Specified by:

closeAggregators in class BaseTopNAlgorithm<Aggregator[][],TopNColumnAggregatesProcessor,TopNParams>

cleanup

public void cleanup(TopNParams params)