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 LATCH_SH wait type in SQL Server indicates that a task is waiting to acquire a shared (SH) latch on a resource. Latches are lightweight locks that are used by SQL Server to protect shared data structures in memory, such as pages in the buffer pool and allocation bitmaps.
When a query is executed in SQL Server, it may need to access data that is currently being used by another query. In order to prevent multiple queries from modifying the same data at the same time, SQL Server uses latches to ensure that only one query can access the data at a given time. The LATCH_SH wait type occurs when a query is waiting to acquire a shared latch on a resource in order to access the data.
The presence of the LATCH_SH wait type does not necessarily indicate a problem with SQL Server. However, if this wait type is occurring frequently and for long periods of time, it could indicate that the server is experiencing a high workload or that there is contention for shared resources. In these cases, it may be necessary to optimize the queries being executed or to add additional hardware resources to the server to improve performance.
In summary, the LATCH_SH wait type in SQL Server indicates that a task is waiting to acquire a shared latch on a resource in order to access data. While this is a normal part of the operation of SQL Server, frequent occurrences of this wait type could indicate a potential performance issue that should be addressed.
More details avilable on this wait type here: http://DatabaseHealth.com/Waits/LATCH_SH.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.
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