From: Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Serge Petrenko <sergepetrenko@tarantool.org>, gorcunov@gmail.com Cc: tarantool-patches@dev.tarantool.org Subject: Re: [Tarantool-patches] [PATCH 3/7] txn_limbo: fix promote term filtering Date: Sat, 19 Jun 2021 00:49:21 +0200 [thread overview] Message-ID: <d309c8a4-3cbb-c3b1-7d75-a162b63ab6fe@tarantool.org> (raw) In-Reply-To: <ac4faddb-5579-06b0-bde0-049a99f87a9e@tarantool.org> Hi! Thanks for the fixes! > 15.06.2021 23:57, Vladislav Shpilevoy пишет: >> Thanks for the patch! >> >> On 10.06.2021 15:32, Serge Petrenko via Tarantool-patches wrote: >>> txn_limbo_process() used to filter out promote requests whose term was >>> equal to the greatest term seen. This wasn't correct for PROMOTE entries >>> with term 1. >>> >>> Such entries appear after box.ctl.promote() is issued on an instance >>> with disabled elections. Every PROMOTE entry from such an instance has >>> term 1, but should still be applied. Fix this in the patch. >> Didn't we agree that PROMOTE should bump the term always? I see no purpose >> for the PROMOTE which never bumps the term except for the tests, but for >> such occasion it would be better to have internal.make_leader() or something >> which bypasses everything. Although the best option would to bump the term >> always. >> >> I see you did something in the last commit about that, but the part >> about `limbo->promote_greatest_term > 1` still remains. It looks very >> illegal to point out some terms as "special". > > What about old instances? > They may issue multiple promotes for the same term when elections are off. What if they issue multiple promotes for the same term > 1? They could have elections enabled, then the term was bumped a few times, then elections were turned off again. Next promotes will use the current term which is > 1, won't they? > Previous behaviour (wrong, because we forgot to filter out too old promotes at all) > made the instance apply all such promotes. > > I thought we should allow multiple promotes, at least for the default term (1), which > happen only when elections are turned off and have never been turned on. > > Otherwise, having a new instance together with the old one in the same cluster, > you'll have one of them apply all the promotes for one term, and have one dataset, > and the other ignore all but the first promote, and have possibly different data.> I did fix the issue in the last commit. All the new instances will issue promotes with > increasing term each time, and the term will be >= 2. > > So all the promotes with term == 1 surely will be from the old instances.
next prev parent reply other threads:[~2021-06-18 22:49 UTC|newest] Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-06-10 13:32 [Tarantool-patches] [PATCH 0/7] forbid implicit limbo ownership transition Serge Petrenko via Tarantool-patches 2021-06-10 13:32 ` [Tarantool-patches] [PATCH 1/7] replication: always send raft state to subscribers Serge Petrenko via Tarantool-patches 2021-06-10 16:47 ` Cyrill Gorcunov via Tarantool-patches 2021-06-11 8:43 ` Serge Petrenko via Tarantool-patches 2021-06-11 8:44 ` Cyrill Gorcunov via Tarantool-patches 2021-06-15 20:53 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-17 21:00 ` Serge Petrenko via Tarantool-patches 2021-06-10 13:32 ` [Tarantool-patches] [PATCH 2/7] replication: forbid implicit limbo owner transition Serge Petrenko via Tarantool-patches 2021-06-15 20:55 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-17 21:00 ` Serge Petrenko via Tarantool-patches 2021-06-18 22:49 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-21 10:13 ` Serge Petrenko via Tarantool-patches 2021-06-10 13:32 ` [Tarantool-patches] [PATCH 3/7] txn_limbo: fix promote term filtering Serge Petrenko via Tarantool-patches 2021-06-15 20:57 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-17 21:00 ` Serge Petrenko via Tarantool-patches 2021-06-18 22:49 ` Vladislav Shpilevoy via Tarantool-patches [this message] 2021-06-21 8:55 ` Serge Petrenko via Tarantool-patches 2021-06-10 13:32 ` [Tarantool-patches] [PATCH 4/7] txn_limbo: persist the latest effective promote in snapshot Serge Petrenko via Tarantool-patches 2021-06-15 20:59 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-17 21:00 ` Serge Petrenko via Tarantool-patches 2021-06-10 13:32 ` [Tarantool-patches] [PATCH 5/7] replication: send latest effective promote in initial join Serge Petrenko via Tarantool-patches 2021-06-15 21:00 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-17 21:00 ` Serge Petrenko via Tarantool-patches 2021-06-18 22:52 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-21 10:12 ` Serge Petrenko via Tarantool-patches 2021-06-10 13:32 ` [Tarantool-patches] [PATCH 6/7] box: introduce `box.ctl.demote` Serge Petrenko via Tarantool-patches 2021-06-18 22:52 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-21 14:56 ` Serge Petrenko via Tarantool-patches 2021-06-10 13:32 ` [Tarantool-patches] [PATCH 7/7] box: make promote/demote always bump the term Serge Petrenko via Tarantool-patches 2021-06-15 21:00 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-17 21:00 ` Serge Petrenko via Tarantool-patches 2021-06-18 22:53 ` Vladislav Shpilevoy via Tarantool-patches 2021-06-21 15:02 ` Serge Petrenko via Tarantool-patches 2021-06-15 20:53 ` [Tarantool-patches] [PATCH 0/7] forbid implicit limbo ownership transition Vladislav Shpilevoy via Tarantool-patches
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