SQL Server Wait Type: LCK_M_U

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.

If you are having performance issues associated with this wait type and need some help, please contact us with our 30 minute consultation link.

The LCK_M_U wait type indicates that a task is waiting for a lock in an update mode on a database resource. This wait type is commonly seen when a task is trying to modify data in a database but is unable to do so because another task is currently holding a lock on the same resource. This wait type can also occur when a task is waiting for a lock in an update mode on a file, a table, an index, or another database object. The length of time that a task spends waiting on this wait type can be an indication of the level of concurrency in the database and the performance of the locking system.

More details avilable on this wait type here: http://DatabaseHealth.com/Waits/LCK_M_U.html

Do you have a favorite tool for monitoring your wait statistics on SQL Server over time? This is something that you can use Database Health monitor to do. More details at http://DatabaseHealth.com.

If you are having performance issues associated with this wait type and need some help, please contact us with our 30 minute consultation link.