Package org.elasticsearch.xpack.esql.core.expression

Class FoldContext

java.lang.Object

org.elasticsearch.xpack.esql.core.expression.FoldContext

public class FoldContext
extends Object

Context passed to Expression.fold(org.elasticsearch.xpack.esql.core.expression.FoldContext). This is not thread safe.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	FoldContext.FoldTooMuchMemoryException

Constructor Summary

Constructors

Constructor	Description
FoldContext(long allowedBytes)

Method Summary

Modifier and Type	Method	Description
CircuitBreaker	circuitBreakerView(Source source)	Adapt this into a CircuitBreaker suitable for building bounded local DriverContext.
boolean	equals(Object o)
int	hashCode()
long	initialAllowedBytes()	The maximum allowed bytes.
static FoldContext	small()	Expression.fold(org.elasticsearch.xpack.esql.core.expression.FoldContext) using less than 5% of heap.
String	toString()
void	trackAllocation(Source source, long bytes)	Track an allocation.

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Constructor Details

FoldContext

public FoldContext(long allowedBytes)

Method Details

small

public static FoldContext small()

Expression.fold(org.elasticsearch.xpack.esql.core.expression.FoldContext) using less than 5% of heap. Fine in tests but otherwise calling this is a signal that you either, shouldn't be calling Expression.fold(org.elasticsearch.xpack.esql.core.expression.FoldContext) at all, or should pass in a shared FoldContext made by Configuration.

initialAllowedBytes

public long initialAllowedBytes()

The maximum allowed bytes. allowedBytes() will be the same as this for an unused context.

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object

trackAllocation

public void trackAllocation(Source source,
 long bytes)

Track an allocation. Best to call this before allocating if possible, but after is ok if the allocation is small.

Note that, unlike CircuitBreaker, you don't have to free this allocation later. This is important because the query plan doesn't implement Releasable so it can't free consistently. But when you have to allocate big chunks of memory during folding and know that you are returning the memory it is kindest to call this with a negative number, effectively giving those bytes back.

circuitBreakerView

public CircuitBreaker circuitBreakerView(Source source)

Adapt this into a CircuitBreaker suitable for building bounded local DriverContext. This is absolutely an abuse of the CircuitBreaker contract and only methods used by BlockFactory are implemented. And this'll throw a FoldContext.FoldTooMuchMemoryException instead of the standard CircuitBreakingException. This works for the common folding implementation though.