Contents
How to tell if a task is waiting?
Name of the wait type. Address of the resource for which the task is waiting. ID of the session that is blocking the request. If this column is NULL, the request is not blocked, or the session information of the blocking session is not available (or cannot be identified). -2 = The blocking resource is owned by an orphaned distributed transaction.
What happens when a log is sent to a mirror server?
In high-performance mode, as soon as the principal server sends a log record to the mirror server, the principal server sends a confirmation to the client. It does not wait for an acknowledgement from the mirror server. This means that transactions commit without waiting for the mirror server to write the log to disk.
How to call sys.dm.pdw.waiting-tasks?
sys.dm_os_waiting_tasks (Transact-SQL) Returns information about the wait queue of tasks that are waiting on some resource. For more information about tasks, see the Thread and Task Architecture Guide. To call this from Azure Synapse Analytics (SQL DW) or Parallel Data Warehouse, use the name sys.dm_pdw_nodes_os_waiting_tasks.
How does role switching work in database mirroring?
Within the context of a database mirroring session, the principal and mirror roles are typically interchangeable in a process known as role switching. Role switching involves transferring the principal role to the mirror server.
How to create sys.dm.waiting-tasks ( Transact-SQL )?
For METADATA: metadatalock subresource= classid= dbid= For ALLOCATION_UNIT: allocunitlock hobtid= subresource= dbid=
How does the alert feature work in SQL Server?
Alerting in SQL Server is available via Alerts. This feature allows you to be notified when the metric reaches a specific threshold value. SQL Server Agent can send messages, launch applications, or execute tasks if an alert is triggered.
How to be proactively alerted of SQL Server performance problems?
Note that for sending emails, Database Mail in SQL Server Management Studio has to be configured. SQL Server Alerts provide a mechanism to be proactively notified of any performance issues on your SQL Server instance. They provide granular configuration of SQL Server performance metrics and multiple actions for each triggered alert.