Module org.elasticsearch.compute

Package org.elasticsearch.compute.operator.topn

Class TopNOperator

java.lang.Object

org.elasticsearch.compute.operator.topn.TopNOperator

All Implemented Interfaces:

Closeable, AutoCloseable, org.apache.lucene.util.Accountable, Operator, org.elasticsearch.core.Releasable

public class TopNOperator
extends Object
implements Operator, org.apache.lucene.util.Accountable

An operator that sorts "rows" of values by encoding the values to sort on, as bytes (using BytesRef). Each data type is encoded in a specific way, defined by methods of a TopNEncoder. All the values used to sort a specific row (think of column/block 3 and column/block 6) are converted/encoded in a byte array and the concatenated bytes are all compared in bulk. For now, the only values that have a special "treatment" when it comes to encoding are the text-based ones (text, keyword, ip, version). For each "special" encoding there is should be new TopNEncoder implementation. See TopNEncoder.UTF8 for encoding regular "text" and "keyword" data types. See LocalExecutionPlanner for which data type uses which encoder. This Operator will not be able to sort binary values (encoded as BytesRef) because the bytes used as separator and "null"s can appear as valid bytes inside a binary value.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static enum	TopNOperator.InputOrdering
static final record	TopNOperator.SortOrder
static final record	TopNOperator.TopNOperatorFactory

Nested classes/interfaces inherited from interface org.elasticsearch.compute.operator.Operator

Operator.OperatorFactory, Operator.Status

Field Summary

Fields inherited from interface org.apache.lucene.util.Accountable

NULL_ACCOUNTABLE

Fields inherited from interface org.elasticsearch.compute.operator.Operator

MIN_TARGET_PAGE_SIZE, NOT_BLOCKED, TARGET_PAGE_SIZE

Constructor Summary

Constructors

Constructor	Description
TopNOperator(BlockFactory blockFactory, CircuitBreaker breaker, int topCount, List<ElementType> elementTypes, List<TopNEncoder> encoders, List<TopNOperator.SortOrder> sortOrders, int maxPageRows, long jumboPageBytes, TopNOperator.InputOrdering inputOrdering, SharedMinCompetitive.Supplier minCompetitiveSupplier)

Method Summary

Modifier and Type	Method	Description
void	addInput(Page page)	adds an input page to the operator.
boolean	canProduceMoreDataWithoutExtraInput()	Returns true if the operator can produce more output pages without requiring additional input pages.
void	close()	notifies the operator that it won't be used anymore (i.e.
void	finish()	notifies the operator that it won't receive any more input pages
Page	getOutput()	returns non-null if output page available.
boolean	isFinished()	whether the operator has finished processing all input pages and made the corresponding output pages available
boolean	needsInput()	whether the given operator can accept more input pages
long	ramBytesUsed()
Operator.Status	status()	The status of the operator.
String	toString()

Methods inherited from class java.lang.Object

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

Methods inherited from interface org.apache.lucene.util.Accountable

getChildResources

Methods inherited from interface org.elasticsearch.compute.operator.Operator

isBlocked

Constructor Details

TopNOperator

public TopNOperator(BlockFactory blockFactory,
 CircuitBreaker breaker,
 int topCount,
 List<ElementType> elementTypes,
 List<TopNEncoder> encoders,
 List<TopNOperator.SortOrder> sortOrders,
 int maxPageRows,
 long jumboPageBytes,
 TopNOperator.InputOrdering inputOrdering,
 @Nullable
 SharedMinCompetitive.Supplier minCompetitiveSupplier)

Method Details

needsInput

public boolean needsInput()

Description copied from interface: Operator

whether the given operator can accept more input pages

Specified by:

needsInput in interface Operator

addInput

public void addInput(Page page)

Description copied from interface: Operator

adds an input page to the operator. only called when needsInput() == true and isFinished() == false

Specified by:

addInput in interface Operator

finish

public void finish()

Description copied from interface: Operator

notifies the operator that it won't receive any more input pages

Specified by:

finish in interface Operator

isFinished

public boolean isFinished()

Description copied from interface: Operator

whether the operator has finished processing all input pages and made the corresponding output pages available

Specified by:

isFinished in interface Operator

canProduceMoreDataWithoutExtraInput

public boolean canProduceMoreDataWithoutExtraInput()

Description copied from interface: Operator

Returns true if the operator can produce more output pages without requiring additional input pages. This is useful for operators that buffer data or have internal state that can produce multiple output pages.

Operators that do not buffer data should return false - they cannot produce pages out of thin air. Examples of operators that may return true:

• Operators with internal buffers (e.g., AsyncOperator with pending results)
• Operators processing a single input page into multiple output pages
• Aggregation operators that buffer partial results

Specified by:

canProduceMoreDataWithoutExtraInput in interface Operator

Returns:

true if the operator has buffered data that can produce output, false otherwise

getOutput

public Page getOutput()

Description copied from interface: Operator

returns non-null if output page available. Only called when isFinished() == false

Specified by:

getOutput in interface Operator

close

public void close()

Description copied from interface: Operator

notifies the operator that it won't be used anymore (i.e. none of the other methods called), and its resources can be cleaned up

Specified by:

close in interface AutoCloseable

Specified by:

close in interface Closeable

Specified by:

close in interface Operator

Specified by:

close in interface org.elasticsearch.core.Releasable

ramBytesUsed

public long ramBytesUsed()

Specified by:

ramBytesUsed in interface org.apache.lucene.util.Accountable

status

public Operator.Status status()

Description copied from interface: Operator

The status of the operator.

Specified by:

status in interface Operator

toString

public String toString()

Overrides:

toString in class Object