| The wait type LCK_M_U is ranked #11 by Stedman Solutions and Database Health Monitor. 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 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. Applies toRelated WaitsLCK_M_BULCK_M_BU_ABORT_BLOCKERS LCK_M_BU_LOW_PRIORITY LCK_M_IS LCK_M_IS_ABORT_BLOCKERS LCK_M_IS_LOW_PRIORITY LCK_M_IU LCK_M_IU_ABORT_BLOCKERS LCK_M_IU_LOW_PRIORITY LCK_M_IX LCK_M_IX_ABORT_BLOCKERS LCK_M_IX_LOW_PRIORITY LCK_M_RIn_NL LCK_M_RIn_NL_ABORT_BLOCKERS LCK_M_RIn_NL_LOW_PRIORITY LCK_M_RIn_S LCK_M_RIn_S_ABORT_BLOCKERS LCK_M_RIn_S_LOW_PRIORITY LCK_M_RIn_U LCK_M_RIn_U_ABORT_BLOCKERS LCK_M_RIn_U_LOW_PRIORITY LCK_M_RIn_X LCK_M_RIn_X_ABORT_BLOCKERS LCK_M_RIn_X_LOW_PRIORITY LCK_M_RS_S LCK_M_RS_S_ABORT_BLOCKERS LCK_M_RS_S_LOW_PRIORITY LCK_M_RS_U LCK_M_RS_U_ABORT_BLOCKERS LCK_M_RS_U_LOW_PRIORITY LCK_M_RX_S LCK_M_RX_S_ABORT_BLOCKERS LCK_M_RX_S_LOW_PRIORITY LCK_M_RX_U LCK_M_RX_U_ABORT_BLOCKERS LCK_M_RX_U_LOW_PRIORITY LCK_M_RX_X LCK_M_RX_X_ABORT_BLOCKERS LCK_M_RX_X_LOW_PRIORITY LCK_M_S LCK_M_S_ABORT_BLOCKERS LCK_M_S_LOW_PRIORITY LCK_M_SCH_M LCK_M_SCH_M_ABORT_BLOCKERS LCK_M_SCH_M_LOW_PRIORITY LCK_M_SCH_S LCK_M_SCH_S_ABORT_BLOCKERS LCK_M_SCH_S_LOW_PRIORITY LCK_M_SIU LCK_M_SIU_ABORT_BLOCKERS LCK_M_SIU_LOW_PRIORITY LCK_M_SIX LCK_M_SIX_ABORT_BLOCKERS LCK_M_SIX_LOW_PRIORITY LCK_M_U_ABORT_BLOCKERS LCK_M_U_LOW_PRIORITY LCK_M_UIX LCK_M_UIX_ABORT_BLOCKERS LCK_M_UIX_LOW_PRIORITY LCK_M_X LCK_M_X_ABORT_BLOCKERS LCK_M_X_LOW_PRIORITY See AlsoAll Wait Types |  |