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  1. Couchbase Server
  2. MB-61259

Race condition in ns_tick_agent that can cause stats not being gathered

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      init([]) ->
      		 
          Master = mb_master:master_node(),
      		 
       
      		 
          Self = self(),
      		 
          ns_pubsub:subscribe_link(leader_events,
      		 
                                   case _ of
      		 
                                       {new_leader, _} = Event ->
      		 
                                           Self ! Event;
      		 
                                       _ ->
      		 
                                           ok
      		 
                                   end),

      We can see here that there's a tiny race condition: new_leader event might come after mb_master:master_node() returned undefined, but before the subscription to the event is established. In this case the event is lost and ns_tick_agent won't get another notification until the new master election occures.

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            steve.watanabe Steve Watanabe
            artem Artem Stemkovski
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              Updated:
              Resolved:

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