Waitopedia is a comprehensive resource of information about SQL Server waits.

The description shown below is the top answer as voted by the Spotlight community.

The charts are based on 2.1 TB of data collected from 4207 instances uploaded by 323 Spotlight users over an 8 week period.


Category: Other
SQL Server versions: 2005, 2008, 2008 R2, 2012, 2014, 2016, 2017


1 Answer


Occurs during synchronization of the garbage collection queue in the Query Notification Manager. Information from Microsoft®

Very rare

This wait never occurs for most instances

For each of 4207 instances, we ranked QUERY_NOTIFICATION_MGR_MUTEX on how frequent it is compared to all other recent waits. The chart shows the total of all rankings.

Prevalence of QUERY_NOTIFICATION_MGR_MUTEX across the Spotlight Population

For 66 % of hours with this wait, average wait time is less than 0.061 ms

For each instance, we found all the recent hours when it had a QUERY_NOTIFICATION_MGR_MUTEX wait. We found the average latency for each of those hours.

29 instances contributed data to this chart

Latency Distribution of QUERY_NOTIFICATION_MGR_MUTEX across the Spotlight Population