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This wait type is when a thread is waiting for more work when seeding a new availability group replica, or in Azure when something triggers a database copy, like changing a service tier or setting up geo-replication.
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Added in SQL Server version:
Removed in SQL Server version:
Extended Events wait_type value:
The map_key value in sys.dm_xe_map_values is 912 in 2014 RTM. After 2014 RTM, you must check the DMV to get the latest value as some map_key values have changed in later builds.
I have not seen this wait type be a noticeable source of contention. High wait times indicate that one of the copy threads is waiting for more work.
Note: There is a ‘by-design’ behavior where the system threads that are created for the seeding (on the primary and other replicas) will remain until the instances are rebooted, even after seeding has completed. They will continue to accrue VDI_CLIENT_OTHER wait time but do nothing. This wait type can be safely ignored and is one that my scripts filter out.
Known occurrences in SQL Server (list number matches call stack list):
Abbreviated call stacks (list number matches known occurrences list):