Wait Type PREEMPTIVE_HADR_LEASE_MECHANISM

Wait statistics, in the context of SQL Server, refer to the amount of time that a query spends waiting to access data in the database. When a client application requests data from the database, the request is placed in a queue and the client application must wait for its turn to access the data. The time that the query spends waiting is called a "wait" and is tracked by SQL Server. This information can be used to identify potential performance bottlenecks and optimize the performance of the database. Wait statistics are commonly used by database administrators to diagnose and troubleshoot performance issues in SQL Server.

In Microsoft SQL Server, a wait type is a type of event that occurs when a task has to wait for a resource or for an event to complete before it can continue processing. One of the wait types that can occur in SQL Server is PREEMPTIVE_HADR_LEASE_MECHANISM.

PREEMPTIVE_HADR_LEASE_MECHANISM is a wait type that occurs when a task is waiting for a lease renewal to occur in a SQL Server Always On Availability Group (AG). An AG is a feature in SQL Server that allows you to configure a group of databases to fail over together to another server in the event of a failure. In an AG, a lease is a mechanism that is used to determine which server is the primary server and which servers are the secondary servers.

The PREEMPTIVE_HADR_LEASE_MECHANISM wait type occurs when a task is waiting for the lease renewal process to complete. This can happen if the primary server is unavailable or if there is an issue with the lease renewal process.

It is important to monitor for the PREEMPTIVE_HADR_LEASE_MECHANISM wait type, as it can indicate that there is an issue with the AG that needs to be addressed. If this wait type occurs frequently or for a long duration, it can potentially impact the performance and availability of the AG.

To resolve issues with the PREEMPTIVE_HADR_LEASE_MECHANISM wait type, you may need to troubleshoot the cause of the issue and take appropriate action, such as fixing the primary server or resolving any issues with the lease renewal process. It is also important to ensure that the AG is properly configured and that all servers in the AG are functioning correctly. By monitoring for and addressing issues with the PREEMPTIVE_HADR_LEASE_MECHANISM wait type, you can ensure that your AG is performing optimally and providing high availability for your databases.

Applies to

Related Waits

See Also

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