Wait Type DEADLOCK_ENUM_MUTEX

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.

A DEADLOCK_ENUM_MUTEX wait type in SQL Server occurs when a process is waiting for a mutex (short for mutual exclusion) lock to be released in order to access a resource.

A mutex is a synchronization object that is used to protect access to a shared resource. It allows only one process to access the resource at a time, ensuring that multiple processes do not try to modify the resource simultaneously and potentially cause data inconsistencies or corruption.

When a process tries to acquire a mutex lock on a resource, it may have to wait if the lock is already held by another process. If the process has to wait for an extended period of time, it may result in a DEADLOCK_ENUM_MUTEX wait type.

There are a few potential causes for DEADLOCK_ENUM_MUTEX wait types:

1. Insufficient resources: If the system does not have enough resources (e.g. memory, CPU, etc.), it may take longer for a process to acquire a mutex lock and result in a DEADLOCK_ENUM_MUTEX wait type.

2. Contention for resources: If multiple processes are trying to access the same resource simultaneously, it may result in a DEADLOCK_ENUM_MUTEX wait type as they all try to acquire the mutex lock.

3. Deadlocks: A deadlock is a situation where two or more processes are waiting for each other to release a mutex lock, resulting in a standstill. This can cause a DEADLOCK_ENUM_MUTEX wait type as each process waits for the other to release the lock.

To troubleshoot DEADLOCK_ENUM_MUTEX wait types, you can use the SQL Server Profiler tool to identify the cause of the wait type and take appropriate action to resolve it. This may involve optimizing queries, increasing system resources, or modifying the application logic to avoid contention for resources.

In summary, a DEADLOCK_ENUM_MUTEX wait type in SQL Server indicates that a process is waiting for a mutex lock to be released in order to access a resource. It can be caused by insufficient resources, contention for resources, or deadlocks, and can be troubleshooted using the SQL Server Profiler tool.

Applies to

Related Waits

See Also

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