title
SQL Server Operating System Related Dynamic Management Views (Transact-SQL)
description
Dynamic management views (DMVs) associated with SQL Server Operating System (SQLOS).
author
rwestMSFT
ms.author
randolphwest
ms.date
01/19/2026
ms.service
sql
ms.subservice
system-objects
ms.topic
reference
ms.custom
helpviewer_keywords
operating systems [SQL Server], dynamic management objects
SQL Operating System dynamic management objects [SQL Server]
SQL OS dynamic management objects [SQL Server]
dynamic management objects [SQL Server], SQL OS
dev_langs
SQL Server Operating System related dynamic management views (Transact-SQL) [!INCLUDE SQL Server ]
This section documents dynamic management views (DMVs) that are associated with [!INCLUDE ssNoVersion ] Operating System (SQLOS). SQLOS manages operating system resources that are specific to [!INCLUDE ssNoVersion ].
Memory management and memory topology These DMVs show how SQL Server allocates, tracks, caches, and structures memory across clerks, caches, NUMA nodes, and virtual address spaces.
Dynamic management view
Description
sys.dm_os_memory_clerks Reports memory usage by memory clerks - internal SQLOS objects allocating memory - useful for pinpointing memory consumers.
sys.dm_os_memory_nodes Displays memory distribution across NUMA nodes, showing how memory is allocated per node.
sys.dm_os_nodes Returns NUMA node information visible to SQL Server, including node IDs and memory partitioning.
sys.dm_os_memory_brokers Shows memory broker objects within SQLOS that manage allocation units for different consumers.
sys.dm_os_memory_cache_clock_hands Provides clock sweep positions for memory cache objects, useful for diagnosing cache eviction behavior.
sys.dm_os_memory_cache_counters Returns size and usage metrics for memory caches, aiding analysis of cache utilization patterns.
sys.dm_os_memory_cache_entries Shows details about individual entries in memory caches, enabling granular analysis of what data and objects are cached.
sys.dm_os_memory_cache_hash_tables Lists hash tables used by memory caches and shows metrics for distribution and load factors.
sys.dm_os_sys_memory Provides system memory metrics reported from the OS that SQLOS uses for memory allocation decisions.
sys.dm_os_process_memory Provides process-level memory metrics such as physical and virtual memory usage for SQL Server.
sys.dm_os_virtual_address_dump Offers a dump of virtual address descriptors, helpful in low-level memory diagnostics.
Buffer pool and storage cache These DMVs report on the buffer pool, data pages in cache, and buffer pool extension (BPE) configurations.
Dynamic management view
Description
sys.dm_os_buffer_descriptors Returns metadata for all data pages currently cached in the SQL Server buffer pool, including database and file associations and page type details. This view is useful for analyzing cache usage and distribution.
sys.dm_os_buffer_pool_extension_configuration Provides configuration and state for the buffer pool extension (BPE), which allows the buffer pool to extend to disk storage. This view is useful for understanding how extended cache is configured.
Scheduling, workers, tasks, and concurrency These DMVs describe SQLOS scheduling, worker threads, tasks, queues, dispatcher pools, spinlocks, latches, and low-level concurrency mechanisms.
Dynamic management view
Description
sys.dm_os_schedulers Displays scheduler state and run queue lengths for CPU scheduling by SQLOS. This view is critical for CPU and parallelism diagnostics.
sys.dm_os_workers Lists workers managed by SQLOS, including state and flags that indicate exceptions or execution conditions.
sys.dm_os_threads Returns information about worker threads within SQLOS, useful for thread and scheduler analysis.
sys.dm_os_tasks Shows tasks currently managed by SQLOS, providing state and scheduling details.
sys.dm_os_dispatcher_pools Provides statistics about internal dispatcher pools that handle work distribution across schedulers. This view helps you analyze parallelism and scheduling load.
sys.dm_os_spinlock_stats Aggregates spinlock contention statistics, which helps identify low-level synchronization bottlenecks.
sys.dm_os_latch_stats Aggregates latch wait statistics, showing contention and distribution of low-level synchronization primitives.
sys.dm_os_waiting_tasks Shows tasks that are currently waiting along with wait types and resource details, enabling real-time wait analysis.
Waits and performance diagnostics These DMVs expose wait statistics, ring buffer diagnostics, counters, or server-level data that you can use to troubleshoot performance problems.
Dynamic management view
Description
sys.dm_os_wait_stats Aggregates wait statistics for thread waits across the instance, a foundational view for diagnosing CPU, memory, or I/O bottlenecks.
sys.dm_os_ring_buffers Returns entries from the internal ring buffer, useful for diagnosing system-level events like memory pressure or scheduler alerts.
sys.dm_os_performance_counters Exposes performance counter values for SQL Server - often used to correlate SQL-level activity with Windows performance monitoring metrics.
sys.dm_os_server_diagnostics_log_configurations Shows configuration for server diagnostics logs, which capture critical internal events and diagnostics.
Host, cluster, and environment information These DMVs provide information about host OS characteristics, cluster configuration, multihost participation, and general instance and system metadata.
Dynamic management view
Description
sys.dm_os_host_info Exposes host OS details, such as OS version and configuration, relevant to the local SQL Server instance.
sys.dm_os_hosts Returns a row for each host known to the SQL Server instance, useful in multihost or clustered environments.
sys.dm_os_cluster_nodes Returns information about cluster node names and roles when SQL Server is running in a Windows failover cluster.
sys.dm_os_cluster_properties Shows cluster-level properties and settings relevant to the SQL Server node, such as cluster state and configured behaviors.
sys.dm_os_sys_info Returns high-level SQL Server instance information such as CPU count, memory configuration, and SQLOS version.
sys.dm_os_windows_info Provides OS-specific information about the Windows environment hosting SQL Server, such as version and machine characteristics.
sys.dm_os_child_instances Lists resource and state information about child SQLOS instances in environments like distributed or multi-instance deployments.
Disk, volume, and I/O environment These DMVs relate to storage devices, available volumes, and file-level or volume-level statistics.
Dynamic management view
Description
sys.dm_os_enumerate_fixed_drives Returns a list of fixed disk drives accessible to the SQL Server instance, along with basic space information.
sys.dm_os_volume_stats Returns I/O statistics for database files by volume, helpful in analyzing disk activity and performance.
Loaded modules (executable code context) This DMV exposes DLLs and modules currently loaded and active execution components.
Dynamic management view
Description
sys.dm_os_loaded_modules Lists modules (DLLs/assemblies) that SQL Server workers load, providing insight into code executing within the server.
Low-level debugging and diagnostics This DMV is useful primarily for escalation, debugging, crash analysis, or deep SQL Server engine troubleshooting.
Dynamic management view
Description
sys.dm_os_stacks Displays stack information for workers, often used in deep troubleshooting or crash dump analysis.
Internal and unsupported DMVs The following [!INCLUDE ssNoVersion ] operating system-related dynamic management views are [!INCLUDE ssInternalOnly ]:
sys.dm_os_function_symbolic_namesys.dm_os_memory_allocationssys.dm_os_sublatchessys.dm_os_worker_local_storage