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sys.dm_os_memory_objects

SQL Server 2005

Returns memory objects that are currently allocated by SQL Server. sys.dm_os_memory_objects is primarily used to analyze memory use and to identify possible memory leaks.

Column name	Data type	Description
memory_object_address	varbinary(8)	Address of the memory object. Is not nullable.
parent_address	varbinary(8)	Address of the parent memory object. Is nullable.
pages_allocated_count	int	Number of pages that are allocated by this object. Is not nullable.
creation_options	int	Internal use only. Is nullable.
bytes_used	bigint	Internal use only. Is nullable.
type	nvarchar(60)	Type of memory object. This indicates a component that this memory object belongs to, or the function of the memory object. Is nullable.
name	varchar(128)	Internal use only. Is nullable.
memory_node_id	smallint	ID of a memory node that is being used by this memory object. Is not nullable.
creation_time	datetime	Internal only. NULLABLE.
page_size_in_bytes	int	Size of pages allocated by this object. Is not nullable.
max_pages_allocated_count	int	Maximum number of pages allocated by this memory object. Is not nullable.
page_allocator_address	varbinary(8)	Memory address of page allocator. Is not nullable. For more information, see sys.dm_os_memory_clerks.
creation_stack_address	varbinary(8)	Internal use only. Is nullable.
sequence_num	int	Internal use only. Is nullable.

Permissions

Requires VIEW SERVER STATE permission on the server.

Remarks

Memory objects are heaps. They provide allocations that have a finer granularity than those provided by memory clerks. SQL Server components use memory objects instead of memory clerks. Memory objects use the page allocator interface of the memory clerk to allocate pages. Memory objects do not use virtual or shared memory interfaces. Depending on the allocation patterns, components can create different types of memory objects to allocate regions of arbitrary size.

The typical page size for a memory object is 8-KB. However, incremental memory objects can have page sizes that range from 512 bytes to 8 kilobytes.

Note:
Page size is not a maximum allocation. Instead, page size is allocation granularity that is supported by a page allocator and that is implemented by a memory clerk. You can request allocations of 16 KB and larger from memory objects, and the request is eventually directed to the multipage allocator of the memory node.

Examples

The following example returns the amount of memory allocated by each memory object type.

SELECT SUM (pages_allocated_count * page_size_in_bytes) as 'Bytes Used', type 
FROM sys.dm_os_memory_objects
GROUP BY type 
ORDER BY 1 DESC;
GO

Reference

Dynamic Management Views and Functions
SQL Server Operating System Related Dynamic Management Views
sys.dm_os_memory_clerks

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