[Tarantool-patches] [RFC 4/4] qsync: allow to specify replication_synchro_quorum as a formula

[Cyrill Gorcunov]

On Fri, Nov 20, 2020 at 01:50:50PM +0300, Serge Petrenko wrote:
> > @@ -4216,6 +4217,7 @@ unregister_replica(struct trigger *trigger, void * /* event */)
> >   	struct replica *replica = replica_by_uuid(&old_uuid);
> >   	assert(replica != NULL);
> >   	replica_clear_id(replica);
> > +	replication_on_cluster_update();
> >   	return 0;
> >   }
> 
> We usually perform all the work related to replica register/unregister
> directly in replica_set_id
> and replica_clear_id.
> 
> Besides, these are the places where replicaset.registered_count is updated,
> so it'd be nice to call replication_on_cluster_update from there.

Sure.

> > --- a/src/box/box.cc
> > +++ b/src/box/box.cc
> > @@ -634,14 +634,6 @@ box_check_replication_synchro_quorum(void)
> >   		 */
> >   		int value = replication_synchro_quorum;
> >   		quorum = eval_replication_synchro_quorum(value);
> 
> > Pass replicaset.registered_count instead of replication_synchro_quorum here.

Wait, this is bootstrap, replicaset.registered_count is 0 at this moment, no?

> >   }
> > +/**
> > + * Evaluate the new synchro quorum number when replica
> > + * get registered/unregistered and the quorum depends on
> > + * their amount via formula in config.
> > + */
> > +void
> > +replication_on_cluster_update(void)
> > +{
> > +	if (!replication_synchro_quorum_eval)
> > +		return;
> > +
> > +	/*
> > +	 * Account only registered replicas when evaluating
> > +	 * quorum number from a fromula present in config.
> > +	 */
> > +	int value = replicaset.registered_count - replicaset.anon_count;
> 
> 
> registered_count stands for 'normal' replica count, so no need to subtract
> anon_count from it.

Yeah, thanks!

> > +
> > +	say_info("replication: evaluated quorum is %d", quorum);
> 
> 
> quorum -> replication_synchro_quorum

ok