sys.dm_os_memory_clerks (Transact-SQL)


THIS TOPIC APPLIES TO:yesSQL Server (starting with 2008)noAzure SQL DatabaseyesAzure SQL Data Warehouse yesParallel Data Warehouse

Returns the set of all memory clerks that are currently active in the instance of SQL Server.

System_CAPS_ICON_note.jpg Note

To call this from Azure SQL Data Warehouse or Parallel Data Warehouse, use the name sys.dm_pdw_nodes_os_memory_clerks.

Column nameData typeDescription
memory_clerk_addressvarbinary(8)Specifies the unique memory address of the memory clerk. This is the primary key column. Is not nullable.
typenvarchar(60)Specifies the type of memory clerk. Every clerk has a specific type, such as CLR Clerks MEMORYCLERK_SQLCLR. Is not nullable.
namenvarchar(256)Specifies the internally assigned name of this memory clerk. A component can have several memory clerks of a specific type. A component might choose to use specific names to identify memory clerks of the same type. Is not nullable.
memory_node_idsmallintSpecifies the ID of the memory node. Not nullable.
single_pages_kbbigintApplies to: SQL Server 2008 through SQL Server 2008 R2.
pages_kbbigintApplies to: SQL Server 2012 through SQL Server 2016.

Specifies the amount of page memory allocated in kilobytes (KB) for this memory clerk. Is not nullable.
multi_pages_kbbigintApplies to: SQL Server 2008 through SQL Server 2008 R2.

Amount of multipage memory allocated in KB. This is the amount of memory allocated by using the multiple page allocator of the memory nodes. This memory is allocated outside the buffer pool and takes advantage of the virtual allocator of the memory nodes. Is not nullable.
virtual_memory_reserved_kbbigintSpecifies the amount of virtual memory that is reserved by a memory clerk. Is not nullable.
virtual_memory_committed_kbbigintSpecifies the amount of virtual memory that is committed by a memory clerk. The amount of committed memory should always be less than the amount of reserved memory. Is not nullable.
awe_allocated_kbbigintSpecifies the amount of memory in kilobytes (KB) locked in the physical memory and not paged out by the operating system. Is not nullable.
shared_memory_reserved_kbbigintSpecifies the amount of shared memory that is reserved by a memory clerk. The amount of memory reserved for use by shared memory and file mapping. Is not nullable.
shared_memory_committed_kbbigintSpecifies the amount of shared memory that is committed by the memory clerk. Is not nullable.
page_size_in_bytesbigintSpecifies the granularity of the page allocation for this memory clerk. Is not nullable.
page_allocator_addressvarbinary(8)Specifies the address of the page allocator. This address is unique for a memory clerk and can be used in sys.dm_os_memory_objects to locate memory objects that are bound to this clerk. Is not nullable.
host_addressvarbinary(8)Specifies the memory address of the host for this memory clerk. For more information, see sys.dm_os_hosts (Transact-SQL). Components, such as Microsoft SQL Server Native Client, access SQL Server memory resources through the host interface.

0x00000000 = Memory clerk belongs to SQL Server.

Is not nullable.
pdw_node_idintApplies to: Azure SQL Data Warehouse, Parallel Data Warehouse

The identifier for the node that this distribution is on.

Requires VIEW SERVER STATE permission on the server.

The SQL Server memory manager consists of a three-layer hierarchy. At the bottom of the hierarchy are memory nodes. The middle level consists of memory clerks, memory caches, and memory pools. The top layer consists of memory objects. These objects are generally used to allocate memory in an instance of SQL Server.

Memory nodes provide the interface and the implementation for low-level allocators. Inside SQL Server, only memory clerks have access to memory nodes. Memory clerks access memory node interfaces to allocate memory. Memory nodes also track the memory allocated by using the clerk for diagnostics. Every component that allocates a significant amount of memory must create its own memory clerk and allocate all its memory by using the clerk interfaces. Frequently, components create their corresponding clerks at the time SQL Server is started.

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