From: Konstantin Osipov <kostja.osipov@gmail.com> To: Olga Arkhangelskaia <arkholga@tarantool.org> Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH rfc 0/1] replication: stop resetting existing connections Date: Thu, 2 Apr 2020 19:43:11 +0300 [thread overview] Message-ID: <20200402164311.GA9239@atlas> (raw) In-Reply-To: <1d29a21b-78bd-d3a8-0210-fb8f9690aea4@tarantool.org> * Olga Arkhangelskaia <arkholga@tarantool.org> [20/04/02 19:07]: > 02.04.2020 16:47, Konstantin Osipov пишет: > > * Olga Arkhangelskaia <arkholga@tarantool.org> [20/04/02 16:30]: > > > > Could you please explain the idea of the patch? > > > > As far I can see, you do some strcmp magic to understand if the > > uri is the same. > Yes. > > > > Why not use instance uuids? > > I did not think of uuids in such a way. But after reading your description > it > > seems good idea (As I understand even if we have 3301 and localhost:3301 > they will have the same uuid). > > But I am not sure about appliers that should be removed. > > If there is no UUIDS of existing applier in new appliers pool it should be > removed? > > And we still need to do all this work even if we just changed order in the > config. We could perhaps optimize things based on some heuristics, like old and new uri match 100%, but first we need to settle on the main algorithm. E.g. one variation could be that, given appliers are ref-counted, we do not create a new applier for a 100% match, but simply add it directly to the new uuid -> applier hash. Please suggest an edit to this: > > > 0) Introduce uuid -> applier hash. > > 1) Create new appliers for all entries in replication. > > 2) Establish connections, but do not issue SUBSCRIBE yet. > > 3) Look at connection server uuids. If this uuid is already > > connected to, then (easy) quietly close the new connection, > > and add existing connection to the new instance of uuid hash. > > 4) Add the new connection to the new instance of uuid hash. > > If there is a duplicate in the *new* instance of the uuid hash, > > produce "duplicate connection" error. Otherwise remove/delete all > > appliers that are left in the old uuid hash. > > > > Perhaps we need applier reference counting to make this work > > smoothly -- Konstantin Osipov, Moscow, Russia
prev parent reply other threads:[~2020-04-02 16:43 UTC|newest] Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-04-02 13:29 Olga Arkhangelskaia 2020-04-02 13:29 ` [Tarantool-patches] [PATCH rfc 1/1] " Olga Arkhangelskaia 2020-04-02 13:47 ` [Tarantool-patches] [PATCH rfc 0/1] " Konstantin Osipov 2020-04-02 16:05 ` Olga Arkhangelskaia 2020-04-02 16:43 ` Konstantin Osipov [this message]
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