I have been using AGS for many years in conjunction with SDE data. As such I have found that SDE feature classes in mapservices put a lock on the SDE data when the mapservice is running.
Recently, my organization created a query layer from a SDE feature class and a table. When performing maintenance on the domains for the SDE feature class all locks needed to be cleared. All mapservices hitting the SDE feature class were stopped, but not a mapservice hitting the query layer, so I thought there would be 1 lock left, but there were none.
So my question is do Query Layers in SDE no longer generate lock files in mapservices like feature classes from SDE would?
Any help or hints on this topic are greatly appreciated.
"Query Layers in SDE" is a bit of a non-sequitur, because Query Layers exist outside of enterprise geodatabases, and SDE no longer exists (repeat after me: There is no more SDE. There is no more SDE...). The tables of an enterprise geodatabase are visible as Query Layers, but because they are Query Layers, the rowid column is prompted, and none of the geodatabase behavior is available (including geodatabase locking).
The main drawback to replacing all your feature classes with Query Layers is that, since the geodatabase envelope property is not available, ArcGIS can't tell when a full table scan query would be more efficient than a spatial extent query, so, if you have feature classes rendered at the top scale levels, they will be slower to execute than an equivalent enterprise geodatabase feature class at the same scale.