[Tarantool-patches] [PATCH v4 4/4] box: start counting local space requests separately

[Konstantin Osipov]

* Serge Petrenko <sergepetrenko at tarantool.org> [20/03/27 18:08]:
> Moreover, it fixes the following bug with local spaces and replication.
> In a situation when there are a master and a replica set up, replica may
> still write to local spaces even if it's read-only. Local space
> operations used to promote instance's lsn before this patch. Eventually,
> master would have vclock {1:x} and replica'd have vclock {1:x, 2:y},
> where y > 0, due to local space requests performed by the replica.
> If a snapshot happens on replica side, replica will delete it's .xlog
> files prior to the snapshot, since no one replicates from it and thus it
> doesn't have any registered GC consumers.
> From this point, every attempt to configure replication from replica to
> master will fail, since master will try to fetch records which account
> for the difference in master's and replica's vclocks: {1:x} vs {1:x,2:y},
> even though master will never need the rows in range {2:1} - {2:y},
> since they'll be turned to NOPs during replication.

OK, got it.

Makes sense.

Then, I'm afraid, relay has to be using lexicographical vclock as
well.

Waiting a fix or clarification here.


-- 
Konstantin Osipov, Moscow, Russia