Struct datafusion_execution::memory_pool::MemoryReservation

pub struct MemoryReservation { /* private fields */ }

A MemoryReservation tracks an individual reservation of a number of bytes of memory in a MemoryPool that is freed back to the pool on drop.

The reservation can be grown or shrunk over time.

Implementations

impl MemoryReservation

pub fn size(&self) -> usize

Returns the size of this reservation in bytes

pub fn consumer(&self) -> &MemoryConsumer

Returns MemoryConsumer for this MemoryReservation

pub fn free(&mut self) -> usize

Frees all bytes from this reservation back to the underlying pool, returning the number of bytes freed.

pub fn shrink(&mut self, capacity: usize)

Frees capacity bytes from this reservation

Panics

Panics if capacity exceeds Self::size

pub fn try_shrink(&mut self, capacity: usize) -> Result<usize>

Tries to free capacity bytes from this reservation if capacity does not exceed Self::size Returns new reservation size or error if shrinking capacity is more than allocated size

pub fn resize(&mut self, capacity: usize)

Sets the size of this reservation to capacity

pub fn try_resize(&mut self, capacity: usize) -> Result<()>

Try to set the size of this reservation to capacity

pub fn grow(&mut self, capacity: usize)

Increase the size of this reservation by capacity bytes

pub fn try_grow(&mut self, capacity: usize) -> Result<()>

Try to increase the size of this reservation by capacity bytes, returning error if there is insufficient capacity left in the pool.

pub fn split(&mut self, capacity: usize) -> MemoryReservation

Splits off capacity bytes from this MemoryReservation into a new MemoryReservation with the same MemoryConsumer.

This can be useful to free part of this reservation with RAAI style dropping

Panics

Panics if capacity exceeds Self::size

pub fn new_empty(&self) -> Self

Returns a new empty MemoryReservation with the same MemoryConsumer

pub fn take(&mut self) -> MemoryReservation

Splits off all the bytes from this MemoryReservation into a new MemoryReservation with the same MemoryConsumer

Trait Implementations

impl Debug for MemoryReservation

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Drop for MemoryReservation

fn drop(&mut self)

Executes the destructor for this type.