Azure SQL high wait time on "VDI_CLIENT_OTHER"

Question

We're benchmarking our app with different scales of an Azure SQL database, and we're having a hard time saturating the db. Among other things, we've executed this query:

SELECT *
FROM sys.dm_os_wait_stats
ORDER BY wait_time_ms DESC

The top row of the result was something like

wait_type        waiting_tasks_count    wait_time_ms    max_wait_time_ms    signal_wait_time_ms
VDI_CLIENT_OTHER         19560           409007428          60016                37281

What is this wait time? What exactly have we been waiting for during those 409000 seconds (almost 5 days)? Google doesn't seem to know what VDI_CLIENT_OTHER is.

Answer 1

VDI_CLIENT_OTHER is used in case of new replica seeding or any other user initiated workflow that triggers copies like update service tier and setting up geo relationship link. High wait time It likely just means we did seeding and the task remained running waiting for additional work items which aren’t arriving.