sys.dm_os_sys_memory (Transact-SQL)

  • Article

Returns memory information from the operating system.

SQL Server is bounded by, and responds to, external memory conditions at the operating system level and the physical limits of the underlying hardware. Determining the overall system state is an important part of evaluating SQL Server memory usage.

Column name

Data type

Description

total_physical_memory_kb

bigint

Total size of physical memory available to the operating system, in kilobytes (KB).

available_physical_memory_kb

bigint

Size of physical memory available, in KB.

total_page_file_kb

bigint

Size of the commit limit reported by the operating system in KB

available_page_file_kb

bigint

Total amount of page file thatis not being used, in KB.

system_cache_kb

bigint

Total amount of system cache memory, in KB.

kernel_paged_pool_kb

bigint

Total amount of the paged kernel pool, in KB.

kernel_nonpaged_pool_kb

bigint

Total amount of the nonpaged kernel pool, in KB.

system_high_memory_signal_state

bit

State of the system high memory resource notification. A value of 1 indicates the high memory signal has been set by Windows. For more information, see CreateMemoryResourceNotification in the MSDN library.

system_low_memory_signal_state

bit

State of the system low memory resource notification. A value of 1 indicates the low memory signal has been set by Windows. For more information, see CreateMemoryResourceNotification in the MSDN library.

system_memory_state_desc

nvarchar(256)

Description of the memory state.

Condition

Value

system_high_memory_signal_state = 1

and

system_low_memory_signal_state = 0

Available physical memory is high

system_high_memory_signal_state = 0

and

system_low_memory_signal_state = 1

Available physical memory is low

system_high_memory_signal_state = 0

and

system_low_memory_signal_state = 0

Physical memory usage is steady

system_high_memory_signal_state = 1

and

system_low_memory_signal_state = 1

Physical memory state is transitioning

The high and low signal should never be on at the same time. However, rapid changes at the operating system level can cause both values to appear to be on to a user mode application. The appearance of both signals being on will be interpreted as a transition state.

Permissions

Requires VIEW SERVER STATE permission on the server.

See Also

Reference

Dynamic Management Views and Functions (Transact-SQL)

SQL Server Operating System Related Dynamic Management Views (Transact-SQL)