sys.dm_os_memory_objects (Transact-SQL)
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 (Transact-SQL). |
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