Re: [Tarantool-patches] [PATCH vshard 2/2] router: don't fallback RO to master right away

[Oleg Babin via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

Thanks for your fixes. LGTM.

On 07.12.2021 02:56, Vladislav Shpilevoy wrote:
> Thanks for the review!
>
> On 05.12.2021 18:53, Oleg Babin wrote:
>> Thanks for your patch. See one comment below.
>>
>> Also as I see CI is red on your branch. Is it related to your changes?
> Yes, I didn't update .result file in one of the tests. Done now.
>
>>> diff --git a/vshard/replicaset.lua b/vshard/replicaset.lua
>>> index 174c761..93f210e 100644
>>> --- a/vshard/replicaset.lua
>>> +++ b/vshard/replicaset.lua
>>> @@ -455,18 +455,25 @@ local function replicaset_template_multicallro(prefer_replica, balance)
>>>                        return r
>>>                    end
>>>                end
>>> -        elseif prefer_replica then
>>> -            r = replicaset.replica
>>> +        else
>>> +            local start_r = replicaset.replica
>>> +            r = start_r
>>>                while r do
>>> -                if r:is_connected() and r ~= master then
>>> +                if r:is_connected() and (not prefer_replica or r ~= master) then
>>>                        return r
>>>                    end
>>>                    r = r.next_by_priority
>>>                end
>>> -        else
>>> -            r = replicaset.replica
>>> -            if r and r:is_connected() then
>>> -                return r
>>> +            -- Iteration above could start not from the best prio replica.
>>> +            -- Check the beginning of the list too.
>>> +            for _, r in pairs(replicaset.priority_list) do
>> pairs can't be jitted (at least now until https://github.com/tarantool/tarantool/issues/6475).
>>
>> Also pairs don't give any guarantees about iteration order. Could it be replaced with ipairs?
> It can be. Replaced with ipairs on the branch.