Re: [Tarantool-patches] [PATCH 1/5] box: update comment describing join protocol

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Thanks for the patch!

See 1 question below.

On 15/12/2019 21:58, sergepetrenko wrote:
> From: Serge Petrenko <sergepetrenko@tarantool.org>
> 
> The comment states that relay sends the latest snapshot to replica
> during initial join, however, this was changed in commit
> 6332aca655ae7f95d391bdc0109e79915f6e6ad0 (relay: join new replicas off
> read view).
> Now relay sends rows from the read view created at the moment of join.
> Update the comment to match.
> 
> Follow-up #1271
> ---
>  src/box/box.cc | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/src/box/box.cc b/src/box/box.cc
> index b119c927b..76fe0d534 100644
> --- a/src/box/box.cc
> +++ b/src/box/box.cc
> @@ -1391,13 +1391,14 @@ box_process_join(struct ev_io *io, struct xrow_header *header)
>  	 * => JOIN { INSTANCE_UUID: replica_uuid }
>  	 * <= OK { VCLOCK: start_vclock }
>  	 *    Replica has enough permissions and master is ready for JOIN.
> -	 *     - start_vclock - vclock of the latest master's checkpoint.
> +	 *     - start_vclock - master's vclock at the time of join.
>  	 *
>  	 * <= INSERT
>  	 *    ...
>  	 *    Initial data: a stream of engine-specifc rows, e.g. snapshot
> -	 *    rows for memtx or dirty cursor data for Vinyl. Engine can
> -	 *    use REPLICA_ID, LSN and other fields for internal purposes.
> +	 *    rows for memtx or dirty cursor data for Vinyl fed from a read-view.
> +	 *    Engine can use REPLICA_ID, LSN and other fields for internal
> +	 *    purposes.

Rule of 66's ship has already sailed here, but lets at least
keep it in 80.

Also I have a question about what are the internal purposes?
I really don't know. From what I see in the next commits,
purposes of REPLICA_ID and LSN didn't change in this patchset.

>  	 *    ...
>  	 * <= INSERT
>  	 * <= OK { VCLOCK: stop_vclock } - end of initial JOIN stage.
>