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.
The PREEMPTIVE_OS_AUTHENTICATIONOPS wait type in SQL Server is a type of wait that occurs when a task is waiting for a security operation to complete. In SQL Server, security operations are used to authenticate users and enforce access controls. When a task is in the PREEMPTIVE_OS_AUTHENTICATIONOPS wait state, it is waiting for a security operation to complete before it can continue execution. This wait type is typically only seen when security operations are being performed in the database.
