When you diagnose blocking issues, remember that external waits do not always imply that the worker is idle, because the worker may actively be running some external code. Queue waits may also periodically become active even if no new packets have been put on the queue.Įxternal waits occur when a SQL Server worker is waiting for an external event, such as an extended stored procedure call or a linked server query, to finish.

These tasks will wait for work requests to be placed into a work queue. Queue waits are most typically seen with system background tasks such as the deadlock monitor and deleted record cleanup tasks. Queue waits occur when a worker is idle, waiting for work to be assigned. Lock and latch waits are waits on synchronization objects Examples of resource waits are locks, latches, network, and disk I/O waits. Resource waits occur when a worker requests access to a resource that is not available because the resource is being used by some other worker or is not yet available. On all other SQL Database service objectives, either the VIEW DATABASE STATE permission on the database, or membership in the #MS_ServerStateReader# server role is required. On SQL Database Basic, S0, and S1 service objectives, and for databases in elastic pools, the server admin account, the Azure Active Directory admin account, or membership in the #MS_ServerStateReader# server role is required. On SQL Server and SQL Managed Instance, requires VIEW SERVER STATE permission. The identifier for the node that this distribution is on.Īpplies to: Azure Synapse Analytics, Analytics Platform System (PDW) This time is inclusive of signal_wait_time_ms.ĭifference between the time that the waiting thread was signaled and when it started running. Total wait time for this wait type in milliseconds. This counter is incremented at the start of each wait. For more information, see Types of Waits, later in this topic. This syntax is not supported by serverless SQL pool in Azure Synapse Analytics.

To call this from Azure Synapse Analytics or Analytics Platform System (PDW), use the name sys.dm_pdw_nodes_os_wait_stats.

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