fix: follower prefers older voter status

rabbitmq · Sep 13, 2023 · ac707d3 · ac707d3
1 parent 221a016
commit ac707d3
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Showing 3 changed files with 19 additions and 17 deletions.
diff --git a/src/ra.erl b/src/ra.erl
@@ -1135,7 +1135,7 @@ key_metrics({Name, N} = ServerId) when N == node() ->
     case whereis(Name) of
         undefined ->
             Counters#{state => noproc,
-                      voter_status => unknown};
+                      voter_status => noproc};
         _ ->
             case ets:lookup(ra_state, Name) of
                 [] ->

diff --git a/src/ra_server.erl b/src/ra_server.erl
@@ -197,7 +197,7 @@
                               max_pipeline_count => non_neg_integer(),
                               ra_event_formatter => {module(), atom(), [term()]},
                               counter => counters:counters_ref(),
-                              voter_status => ra_voter_status(),
+                              init_non_voter => ra_nvid(),
                               system_config => ra_system:config()}.
 
 -type mutable_config() :: #{cluster_name => ra_cluster_name(),
@@ -2367,7 +2367,7 @@ apply_with({Idx, Term, {'$ra_cluster_change', CmdMeta, NewCluster, ReplyType}},
                            [log_id(State0), maps:keys(NewCluster)]),
                     %% we are recovering and should apply the cluster change
                     State0#{cluster => NewCluster,
-                            voter_status => voter_status(id(State0), NewCluster),
+                            voter_status => current_voter_status(NewCluster, State0),
                             cluster_change_permitted => true,
                             cluster_index_term => {Idx, Term}};
                 _  ->
@@ -2574,15 +2574,8 @@ pre_append_log_follower({Idx, Term, Cmd} = Entry,
     end;
 pre_append_log_follower({Idx, Term, {'$ra_cluster_change', _, Cluster, _}},
                         State) ->
-    OldStatus = {_, NewState} = voter_status(State),
-    NewStatus = {_, OldState} = voter_status(id(State), Cluster),
-    Self = maps:get(nvid, OldState, undefined),
-    MyStatus = case maps:get(nvid, NewState, undefined) of
-                   Self -> NewStatus;
-                   _ -> OldStatus
-               end,
     State#{cluster => Cluster,
-           voter_status => MyStatus,
+           voter_status => current_voter_status(Cluster, State),
            cluster_index_term => {Idx, Term}};
 pre_append_log_follower(_, State) ->
     State.
@@ -2961,6 +2954,15 @@ voter_status(PeerId, Cluster) ->
             maps:get(voter_status, Peer, {voter, #{}})
     end.
 
+current_voter_status(Cluster, State) ->
+    {_, NReason} = New = voter_status(id(State), Cluster),
+    {_, CReason} = Current = voter_status(State),
+    Self = maps:get(nvid, CReason, undefined),
+    case maps:get(nvid, NReason, undefined) of
+        Self -> New;
+        _ -> Current
+    end.
+
 -spec required_quorum(ra_cluster()) -> pos_integer().
 required_quorum(Cluster) ->
     Voters = count_voters(Cluster),

diff --git a/src/ra_server_proc.erl b/src/ra_server_proc.erl
@@ -786,16 +786,16 @@ follower({call, From}, {log_fold, Fun, Term}, State) ->
     fold_log(From, Fun, Term, State);
 follower(EventType, Msg, #state{conf = #conf{name = Name},
                                 server_state = SS0} = State0) ->
-    Voter0 = ra_server:voter_status(SS0),
+    VoterStatus0 = ra_server:voter_status(SS0),
     case handle_follower(Msg, State0) of
         {follower, State1, Effects} ->
             {State2, Actions} = ?HANDLE_EFFECTS(Effects, EventType, State1),
             State = #state{server_state = SS} = follower_leader_change(State0, State2),
             case ra_server:voter_status(SS) of
-                Voter0 ->
+                VoterStatus0 ->
                     ok;
-                Voter ->
-                    true = ets:update_element(ra_state, Name, {3, Voter})
+                VoterStatus ->
+                    true = ets:update_element(ra_state, Name, {3, VoterStatus})
             end,
             {keep_state, State, Actions};
         {pre_vote, State1, Effects} ->
@@ -1037,8 +1037,8 @@ format_status(Opt, [_PDict, StateName,
 handle_enter(RaftState, OldRaftState,
              #state{conf = #conf{name = Name},
                     server_state = ServerState0} = State) ->
-    Voter = ra_server:voter_status(ServerState0),
-    true = ets:insert(ra_state, {Name, RaftState, Voter}),
+    VoterStatus = ra_server:voter_status(ServerState0),
+    true = ets:insert(ra_state, {Name, RaftState, VoterStatus}),
     {ServerState, Effects} = ra_server:handle_state_enter(RaftState,
                                                           ServerState0),
     case RaftState == leader orelse OldRaftState == leader of