You're right, all RavenDB indexing operations (including Map/Reduce) are done on background threads. When you query, it returns a flag (as you say) indicating if the index is currently stale or not.
You're right, all RavenDB indexing operations (including Map/Reduce) are done on background threads. When you query, it returns a flag (as you say) indicating if the index is currently stale or not.