Re: [PATCH v2 08/11] replication: rebootstrap instance on startup if it fell behind

[Konstantin Osipov <kostja@tarantool.org>]

* Vladimir Davydov <vdavydov.dev@gmail.com> [18/06/08 20:38]:
> If a replica fell too much behind its peers in the cluster and xlog
> files needed for it to get up to speed have been removed, it won't be
> able to proceed without rebootstrap. This patch makes the recovery
> procedure detect such cases and initiate rebootstrap procedure if
> necessary.
> 
> Note, rebootstrap is currently only supported by memtx engine. If there
> are vinyl spaces on the replica, rebootstrap will fail. This is fixed by
> the following patches.

A nitpick, but this makes the whole point of factoring out local
recovery less valid.


If local_recovery() can fall back to bootstrap_from_master(), then
the name is misleading.

Please make sure the control flow and decision making stays in box_cfg().

>  
> +bool
> +replicaset_needs_rejoin(struct replica **master)
> +{
> +	replicaset_foreach(replica) {
> +		if (replica->applier != NULL &&
> +		    vclock_compare(&replica->applier->gc_vclock,
> +				   &replicaset.vclock) > 0) {
> +			*master = replica;
> +			return true;
> +		}
> +	}
> +	*master = NULL;
> +	return false;
> +}

Intuitively this function should return true only if none of the
masters can provide it with necessary logs, not *any* of the
masters.

-- 
Konstantin Osipov, Moscow, Russia, +7 903 626 22 32
http://tarantool.io - www.twitter.com/kostja_osipov