org.apache.arrow.memory

Class AllocationManager

java.lang.Object

org.apache.arrow.memory.AllocationManager

Direct Known Subclasses:

NettyAllocationManager, UnsafeAllocationManager

public abstract class AllocationManager
extends Object

The abstract base class of AllocationManager.

Manages the relationship between one or more allocators and a particular UDLE. Ensures that one allocator owns the memory that multiple allocators may be referencing. Manages a BufferLedger between each of its associated allocators.

The only reason that this isn't package private is we're forced to put ArrowBuf in Netty's package which need access to these objects or methods.

Threading: AllocationManager manages thread-safety internally. Operations within the context of a single BufferLedger are lockless in nature and can be leveraged by multiple threads. Operations that cross the context of two ledgers will acquire a lock on the AllocationManager instance. Important note, there is one AllocationManager per UnsafeDirectLittleEndian buffer allocation. As such, there will be thousands of these in a typical query. The contention of acquiring a lock on AllocationManager should be very low.

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static interface	AllocationManager.Factory A factory interface for creating AllocationManager.

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	AllocationManager(BufferAllocator accountingAllocator)

Method Summary

Modifier and Type	Method and Description
abstract long	getSize() Return the size of underlying chunk of memory managed by this Allocation Manager.
protected abstract long	memoryAddress() Return the absolute memory address pointing to the fist byte of underlying memory chunk.
protected abstract void	release0() Release the underlying memory chunk.

Methods inherited from class java.lang.Object

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

Constructor Detail

AllocationManager

protected AllocationManager(BufferAllocator accountingAllocator)

Method Detail

getSize

public abstract long getSize()

Return the size of underlying chunk of memory managed by this Allocation Manager.

The underlying memory chunk managed can be different from the original requested size.

Returns:

size of underlying memory chunk

memoryAddress

protected abstract long memoryAddress()

Return the absolute memory address pointing to the fist byte of underlying memory chunk.

release0

protected abstract void release0()

Release the underlying memory chunk.