A momentary session is used during queries and edit operations. This is the default session type. The server creates an exclusive lock upon an editor's ServiceGeodatabase.applyEdits() operation and holds the lock only for the duration that it takes that operation to occur. An exclusive lock prevents readers and editors from accessing (connecting to and viewing) the rows affected by the edit in the ServiceGeodatabase version during this time, but they can access (connect to, view, query, and edit) other rows in the ServiceGeodatabase version. Use the transient type when concurrency is more important than data consistency between queries or between concurrent users.