Re: [Tarantool-patches] [PATCH v3 08/10] Support manual elections in `box.ctl.clear_synchro_queue()`

[Serge Petrenko via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

16.04.2021 18:40, Serge Petrenko via Tarantool-patches пишет:
>
>
> 16.04.2021 18:38, Serge Petrenko via Tarantool-patches пишет:
>>
>>
>> 16.04.2021 02:30, Vladislav Shpilevoy пишет:
>>>> diff --git a/src/box/raft.h b/src/box/raft.h
>>>> index 15f4e80d9..8fce423e1 100644
>>>> --- a/src/box/raft.h
>>>> +++ b/src/box/raft.h
>>>> @@ -97,6 +97,9 @@ box_raft_checkpoint_remote(struct raft_request 
>>>> *req);
>>>>   int
>>>>   box_raft_process(struct raft_request *req, uint32_t source);
>>>>   +void
>>>> +box_raft_wait_leader_found();
>>>> +
>>>>   void
>>>>   box_raft_init(void);
>>>>   diff --git a/src/lib/raft/raft.c b/src/lib/raft/raft.c
>>>> index e9ce8cade..7b77e05ea 100644
>>>> --- a/src/lib/raft/raft.c
>>>> +++ b/src/lib/raft/raft.c
>>>> @@ -846,7 +846,7 @@ raft_cfg_is_enabled(struct raft *raft, bool 
>>>> is_enabled)
>>>>   }
>>>>     void
>>>> -raft_cfg_is_candidate(struct raft *raft, bool is_candidate)
>>>> +raft_cfg_is_candidate(struct raft *raft, bool is_candidate, bool 
>>>> demote)
>>> 5. I know it might lead to some code duplication, but probably
>>> better move that to other functions. For example,
>>>
>>>     raft_cfg_is_temporary_candidate()
>>>
>>> or something like that. Otherwise it appears surprisingly hard
>>> to follow these 2 flags together. Although I might be wrong and
>>> it would look worse. Did you try?
>>>
>>> Or another option:
>>>
>>>     raft_cfg_is_candidate(box_raft(), true, false);
>>>     raft_cfg_is_candidate(box_raft(), false, false);
>>>
>>> turns into
>>>
>>>     raft_start_candidate(box_raft())
>>>     raft_stop_candidate(box_raft())
>>>
>>> Also it would be good to have unit tests for the changes in raft.h
>>> and raft.c.
>>
>> This variant sounds good. I'll implement in in a new commit.
>
> The commit I was talking about:

Incremental diff on top:

=====================================

diff --git a/src/lib/raft/raft.c b/src/lib/raft/raft.c
index 8deb06eb5..b21693642 100644
--- a/src/lib/raft/raft.c
+++ b/src/lib/raft/raft.c
@@ -862,7 +862,13 @@ raft_start_candidate(struct raft *raft)
         if (raft->is_candidate)
                 return;
         raft->is_candidate = true;
-       assert(raft->state == RAFT_STATE_FOLLOWER);
+       assert(raft->state != RAFT_STATE_CANDIDATE);
+       /*
+        * May still be the leader after raft_stop_candidate
+        * with demote = false.
+        */
+       if (raft->state == RAFT_STATE_LEADER)
+               return;
         if (raft->is_write_in_progress) {
                 /*
                  * If there is an on-going WAL write, it means there was


-- 
Serge Petrenko