SQL Server, Latches object
Applies to: SQL Server (all supported versions)
The SQLServer:Latches object in Microsoft SQL Server provides counters to monitor internal SQL Server resource locks called latches. Monitoring the latches to determine user activity and resource usage can help you to identify performance bottlenecks.
This table describes the SQL Server Latches counters.
|SQL Server Latches counters||Description|
|Average Latch Wait Time (ms)||Average latch wait time (in milliseconds) for latch requests that had to wait.|
|Average Latch Wait Time Base||For internal use only.|
|Latch Waits/sec||Number of latch requests that could not be granted immediately.|
|Number of SuperLatches||Number of latches that are currently SuperLatches.|
|SuperLatch Demotions/sec||Number of SuperLatches that have been demoted to regular latches in the last second.|
|SuperLatch Promotions/sec||Number of latches that have been promoted to SuperLatches in the last second.|
|Total Latch Wait Time (ms)||Total latch wait time (in milliseconds) for latch requests in the last second.|
You begin to explore the query performance counters in this object using this T-SQL query on the sys.dm_os_performance_counters dynamic management view:
SELECT * FROM sys.dm_os_performance_counters WHERE object_name LIKE '%Latches%';