From: Vladislav Shpilevoy via Tarantool-patches <tarantool-patches@dev.tarantool.org> To: Serge Petrenko <sergepetrenko@tarantool.org>, Cyrill Gorcunov <gorcunov@gmail.com> Cc: tml <tarantool-patches@dev.tarantool.org> Subject: Re: [Tarantool-patches] [PATCH v27 2/3] qsync: order access to the limbo terms Date: Wed, 12 Jan 2022 22:30:14 +0100 [thread overview] Message-ID: <63f0bdcc-4ab1-6fa9-411f-ddce6e0aa215@tarantool.org> (raw) In-Reply-To: <77b533c1-0c2f-c11d-0aa6-4109674a7025@tarantool.org> Hi! On 12.01.2022 15:01, Serge Petrenko wrote: > > > 11.01.2022 23:39, Cyrill Gorcunov пишет: >> On Mon, Jan 10, 2022 at 05:28:43PM +0300, Serge Petrenko wrote: >>> Hi! Thanks for the patch! >>> box_issue_promote() and box_issue_demote() need fine-grained locking >>> anyway. >>> Otherwise it’s possible that promote() is already issued, but not yet >>> written to WAL, and some >>> outdated request is applied by applier at that exact moment. >> True. And in previous series Vlad has asked to not move in code which is >> not covered by tests. So I think this is a task for the next part. Currently >> we cover only the race between appliers. > > Let's ask Vlad, then. > > I feel like we should fix this now, not waiting for a full fine-grained locking > patch. > > First of all, this is a known bug (and fine-grained locking was meant to > cover everything we don't know of, just in case). I am not sure I understand what you both are talking about here. Sergey, do you mean 'fine-grained locking' as big critical sections covering a lot of code at once or as many small critical sections? I am confused because of this sentence. "Cover everything we don't know" is rather opposite to fine-grained locking. I voted for big locks because apparently it was too hard to implement smaller more precise locks. > Besides, simply locking issue_promote/issue_demote should be > much easier than implementing the fine-grained locking patch. Yes. I remember the proposal was to lock entire promote/demote and other qsync/raft functions from beginning to end. Because it should be relatively easy. I didn't look at the code in this patch though, can't comment it.
next prev parent reply other threads:[~2022-01-12 21:30 UTC|newest] Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-30 20:23 [Tarantool-patches] [PATCH v27 0/3] qsync: implement packet filtering (part 1) Cyrill Gorcunov via Tarantool-patches 2021-12-30 20:23 ` [Tarantool-patches] [PATCH v27 1/3] latch: add latch_is_locked helper Cyrill Gorcunov via Tarantool-patches 2021-12-30 20:23 ` [Tarantool-patches] [PATCH v27 2/3] qsync: order access to the limbo terms Cyrill Gorcunov via Tarantool-patches 2022-01-10 14:28 ` Serge Petrenko via Tarantool-patches 2022-01-11 20:39 ` Cyrill Gorcunov via Tarantool-patches 2022-01-12 14:01 ` Serge Petrenko via Tarantool-patches 2022-01-12 21:30 ` Vladislav Shpilevoy via Tarantool-patches [this message] 2022-01-13 10:13 ` Serge Petrenko via Tarantool-patches 2022-01-13 23:32 ` Vladislav Shpilevoy via Tarantool-patches 2022-01-14 10:20 ` Serge Petrenko via Tarantool-patches 2022-01-14 10:33 ` Cyrill Gorcunov via Tarantool-patches 2021-12-30 20:23 ` [Tarantool-patches] [PATCH v27 3/3] test: add gh-6036-qsync-order test Cyrill Gorcunov via Tarantool-patches 2022-01-10 14:29 ` Serge Petrenko via Tarantool-patches 2022-01-11 20:41 ` Cyrill Gorcunov via Tarantool-patches
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