Guards a replication set against client application updates in preparation for a MOVE SET command.
This command must be the first in a possible statement group (try). The reason for this is that it needs to commit the changes made to the tables (adding a special trigger function) before it can wait for every concurrent transaction to finish. At the same time it cannot hold an open transaction to the same database itself since this would result in blocking itself forever.
Note that this is a locking operation, which means that it can get stuck behind other database activity.
ID of the set to lock
Node ID of the current set origin