Re: [Tarantool-patches] [PATCH v2 01/11] applier: store instance_id in struct applier

[Serge Petrenko <sergepetrenko@tarantool.org>]

19.09.2020 18:44, Vladislav Shpilevoy пишет:
> The patch was reworked from the scratch. It appeared, that we can't
> rely on getting an id when an applier is assigned to a struct replica.
> Because that moment is not clearly defined. Sometimes applier starts
> serving rows, but still wasn't assigned to a struct replica.
>
> Then I realized, that SUBSCRIBE response contains replica_id of the
> sender. It is sent in box_process_subscribe(). So I started fetching
> that ID in applier_subscribe().
>
> ====================


LGTM.

>      applier: store instance_id in struct applier
>      
>      Applier is going to need its numeric ID in order to tell the
>      future Raft module who is a sender of a Raft message. An
>      alternative would be to add sender ID to each Raft message, but
>      this looks like a crutch. Moreover, applier still needs to know
>      its numeric ID in order to notify Raft about heartbeats from the
>      peer node.
>      
>      Needed for #1146
>
> diff --git a/src/box/applier.cc b/src/box/applier.cc
> index e272a7af6..1a0b55640 100644
> --- a/src/box/applier.cc
> +++ b/src/box/applier.cc
> @@ -1118,6 +1118,7 @@ applier_subscribe(struct applier *applier)
>   		vclock_create(&applier->remote_vclock_at_subscribe);
>   		xrow_decode_subscribe_response_xc(&row, &cluster_id,
>   					&applier->remote_vclock_at_subscribe);
> +		applier->instance_id = row.replica_id;
>   		/*
>   		 * If master didn't send us its cluster id
>   		 * assume that it has done all the checks.
> diff --git a/src/box/applier.h b/src/box/applier.h
> index 6e979a806..15ca1fcfd 100644
> --- a/src/box/applier.h
> +++ b/src/box/applier.h
> @@ -95,6 +95,8 @@ struct applier {
>   	ev_tstamp lag;
>   	/** The last box_error_code() logged to avoid log flooding */
>   	uint32_t last_logged_errcode;
> +	/** Remote instance ID. */
> +	uint32_t instance_id;
>   	/** Remote instance UUID */
>   	struct tt_uuid uuid;
>   	/** Remote URI (string) */

-- 
Serge Petrenko