Wait Type LATCH_EX

The wait type LATCH_EX is ranked #42 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 LATCH_EX wait type in SQL Server occurs when a session is waiting to acquire an exclusive latch on a resource. Latch is a lightweight synchronization mechanism that is used to protect shared data structures in SQL Servers memory.

Exclusive latches are used to protect resources that can be accessed by only one session at a time. For example, when a session wants to update a page in the database, it needs to acquire an exclusive latch on the page in order to prevent other sessions from modifying it at the same time.

When a session tries to acquire an exclusive latch on a resource but is unable to do so because it is already held by another session, the session will enter a LATCH_EX wait state. This means that the session will be paused until the latch is released by the other session and becomes available for the waiting session to acquire.

LATCH_EX wait types can be caused by a variety of factors, including high concurrency and resource contention in the database. To address LATCH_EX waits, it is important to identify the specific resources that are causing the waits and to optimize the database design and queries to reduce contention for those resources. This may involve indexing strategies, query optimization, and other techniques to improve the performance of the database.

Overall, LATCH_EX wait types are an important aspect of SQL Server performance, and understanding and addressing them can help improve the efficiency and scalability of a database.

Applies to

Related Waits

LATCH_DT
LATCH_KP
LATCH_NL
LATCH_SH
LATCH_UP

See Also


All Wait Types