[tarantool-patches] Re: [PATCH] [replication] introduce anonymous replicas.

[Konstantin Osipov]

* Serge Petrenko <sergepetrenko at tarantool.org> [18/10/15 10:15]:
> This patch makes it possible for a replica to join/subscribe
> anonymously, i.e. without being added to the _cluster table.
> This allows to have more than VCLOCK_MAX (currently 32) replicas in a
> replicaset, with a condition that some of them must be read only.
> 
> This is achieved by introducing a new field to JOIN/SUBSCRIBE
> requests: IPROTO_REPLICA_ANON. Upon recieving a request with the option
> set to true, master adds the newly connected replica to a replica hash,
> but does not register it in _cluster table and does not assign an id to
> it. The replica still appears in `box.info.replication` with
> 'anonymous` parameter set to true.
> To make replica send 'anonymous' JOIN/SUBSCRIBE requests, a new config
> option is introduced: `replica_anon`. It may only be set to true
> together with `read_only`.
> 
> Closes #3186

This feature seems to be easy to do now but I would like to
suspend any work on it before we implement promote(), proxy,
dynamic assignment of server ids, and smart filtering of relayed
rows (server id based filtering). 

We have been stuck with these features since the spring, they are
more important than this one, and they may have dramatic impact on
complexity of this feature. 


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