From: Kirill Yukhin via Tarantool-patches <tarantool-patches@dev.tarantool.org>
To: Serge Petrenko <sergepetrenko@tarantool.org>
Cc: tarantool-patches@dev.tarantool.org, v.shpilevoy@tarantool.org
Subject: Re: [Tarantool-patches] [PATCH v3] wal: introduce limits on simultaneous writes
Date: Fri, 19 Mar 2021 15:36:06 +0000 [thread overview]
Message-ID: <20210319153606.ccbnnvje3eb6mzil@tarantool.org> (raw)
In-Reply-To: <20210224193549.70017-1-sergepetrenko@tarantool.org>
Hello,
On 24 фев 22:35, Serge Petrenko via Tarantool-patches wrote:
> Since the introduction of asynchronous commit, which doesn't wait for a
> WAL write to succeed, it's quite easy to clog WAL with huge amounts
> write requests. For now, it's only possible from an applier, since it's
> the only user of async commit at the moment.
>
> This happens when replica is syncing with master and reads new
> transactions at a pace higher than it can write them to WAL (see docbot
> request for detailed explanation).
>
> To ameliorate such behavior, we need to introduce some limit on
> not-yet-finished WAL write requests. This is what this commit is trying
> to do.
> Two new counters are added to wal writer: queue_size (in bytes) and
> queue_len (in wal messages) together with configuration settings:
> `wal_queue_max_size` and `wal_queue_max_len`.
> Size and length are increased on every new submitted request, and are
> decreased once the tx receives a confirmation that a specific request
> was written.
> Actually, the limits are added to an abstract journal, but take effect
> only for wal writer.
>
> Once size or length reach their maximum values, applier is blocked until
> some of the write requests are finished.
>
> The size limit isn't strict, i.e. if there's at least one free byte, the
> whole write request fits and no blocking is involved.
>
> The feature is ready for `box.commit{is_async=true}`. Once it's
> implemented, it should check whether the queue is full and let the user
> decide what to do next. Either wait or roll the tx back.
>
> Part of #5536
I've checked your patch into 2.6, 2.7 and master.
--
Regards, Kirill Yukhin
prev parent reply other threads:[~2021-03-19 15:36 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-24 19:35 Serge Petrenko via Tarantool-patches
2021-02-24 19:40 ` Serge Petrenko via Tarantool-patches
2021-02-25 13:05 ` Konstantin Osipov via Tarantool-patches
2021-02-26 0:57 ` Vladislav Shpilevoy via Tarantool-patches
2021-02-26 7:18 ` Konstantin Osipov via Tarantool-patches
2021-02-26 20:23 ` Vladislav Shpilevoy via Tarantool-patches
2021-02-26 21:20 ` Konstantin Osipov via Tarantool-patches
2021-02-26 22:44 ` Vladislav Shpilevoy via Tarantool-patches
2021-02-27 13:27 ` Konstantin Osipov via Tarantool-patches
2021-03-01 19:15 ` Serge Petrenko via Tarantool-patches
2021-03-01 21:46 ` Konstantin Osipov via Tarantool-patches
2021-02-26 0:56 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-01 19:08 ` Serge Petrenko via Tarantool-patches
2021-03-01 22:05 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-02 17:51 ` Serge Petrenko via Tarantool-patches
2021-03-03 20:59 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-09 15:10 ` Serge Petrenko via Tarantool-patches
2021-03-09 19:49 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-10 8:18 ` Konstantin Osipov via Tarantool-patches
2021-03-12 17:10 ` Serge Petrenko via Tarantool-patches
2021-03-13 19:14 ` Konstantin Osipov via Tarantool-patches
2021-03-15 23:42 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-16 6:45 ` Konstantin Osipov via Tarantool-patches
2021-03-16 20:27 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-16 10:19 ` Serge Petrenko via Tarantool-patches
2021-03-16 20:48 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-17 12:14 ` Serge Petrenko via Tarantool-patches
2021-03-17 21:02 ` Vladislav Shpilevoy via Tarantool-patches
2021-03-19 11:32 ` Serge Petrenko via Tarantool-patches
2021-03-19 15:36 ` Kirill Yukhin via Tarantool-patches [this message]
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