Make state change logic atomic

lib/galaxy/jobs/__init__.py

@@ -1550,9 +1550,10 @@ def change_state(self, state, info=False, flush=True, job=None):
             return
         if info:
             job.info = info
-        job.set_state(state)
+        state_changed = job.set_state(state)
         self.sa_session.add(job)
-        job.update_output_states(self.app.application_stack.supports_skip_locked())
+        if state_changed:
+            job.update_output_states(self.app.application_stack.supports_skip_locked())
         if flush:
             with transaction(self.sa_session):
                 self.sa_session.commit()

lib/galaxy/model/__init__.py

@@ -1640,10 +1640,27 @@ def all_entry_points_configured(self):
 
     def set_state(self, state):
         """
-        Save state history
+        Save state history. Returns True if stat has changed, else False
         """
-        self.state = state
-        self.state_history.append(JobStateHistory(self))
+        if self.state == state:
+            # Nothing changed, no action needed
+            return False
+        session = object_session(self)
+        if session and self.id and not state in Job.terminal_states:
+            # generate statement that will not revert DELETING or DELETED back to anything non-terminal
+            rval = session.execute(update(Job.table).where(
+                Job.table.c.id == self.id,
+                ~Job.table.c.state.in_((Job.states.DELETING, Job.states.DELETED))
+            ).values(state=state))
+            if rval.rowcount == 1:
+                self.state_history.append(JobStateHistory(self))
+                return True
+            else:
+                return False
+        else:
+            self.state = state
+            self.state_history.append(JobStateHistory(self))
+            return True
 
     def get_param_values(self, app, ignore_errors=False):
         """