[tarantool-patches] Re: [PATCH 1/4] Fix races related to object outdating

[Alex Khatskevich <avkhatskevich@tarantool.org>]

>>>> diff --git a/vshard/router/init.lua b/vshard/router/init.lua
>>>> index 142ddb6..1a0ed2f 100644
>>>> --- a/vshard/router/init.lua
>>>> +++ b/vshard/router/init.lua
>>>> @@ -88,15 +94,18 @@ local function bucket_discovery(bucket_id)
>>>>       log.verbose("Discovering bucket %d", bucket_id)
>>>>       local last_err = nil
>>>>       local unreachable_uuid = nil
>>>> -    for uuid, replicaset in pairs(M.replicasets) do
>>>> -        local _, err =
>>>> -            replicaset:callrw('vshard.storage.bucket_stat', 
>>>> {bucket_id})
>>>> -        if err == nil then
>>>> -            bucket_set(bucket_id, replicaset)
>>>> -            return replicaset
>>>> -        elseif err.code ~= lerror.code.WRONG_BUCKET then
>>>> -            last_err = err
>>>> -            unreachable_uuid = uuid
>>>> +    for uuid, _ in pairs(M.replicasets) do
>>>> +        -- Handle reload/reconfigure.
>>>> +        replicaset = M.replicasets[uuid]
>>>> +        if replicaset then
>>>> +            local _, err =
>>>> + replicaset:callrw('vshard.storage.bucket_stat', {bucket_id})
>>>> +            if err == nil then
>>>> +                return bucket_set(bucket_id, replicaset.uuid)
>>>
>>> Do not return error immediately. You can continue iteration in the hope
>>> of finding the bucket out on one of next replicasets. So here you
>>> do 'if bucket_set ~= nil then return result end'. Else continue.
>> Please, read it again. It seems like you misunderstood something.
>> I did not change the behavior here.
>
> You changed the behavior here. Before bucket_set never failed when
> 'err ~= nil' always a non-nil result was returned, even though outdated.
> Now you return nil.
Discussed verbally.
Further iteration in case of the error do not speeds up anything.