From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from [87.239.111.99] (localhost [127.0.0.1]) by dev.tarantool.org (Postfix) with ESMTP id AB7096EC55; Thu, 17 Jun 2021 12:58:20 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org AB7096EC55 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=tarantool.org; s=dev; t=1623923900; bh=O1IKdhyMUowZ2XLJkLqfh0wBOpGosQgaEZ01h0qT06c=; h=Date:To:References:In-Reply-To:Subject:List-Id:List-Unsubscribe: List-Archive:List-Post:List-Help:List-Subscribe:From:Reply-To:Cc: From; b=MXYTZpsZ5Hzsr7SxiGPypTjkmxqRrYEfAJWHLAcX9bwTR259TONeiHXmK08VOwC0s uvPcx+FtFYSOLRm9SqUoGswUSjyRkbhAIUGxt9sSEmrq6orrY3qKP2fDTpRlFcBfvg ehhOMV+4lXIOhtGcOnH/wmgC8keGbvFOUM5fytDw= Received: from mail-lf1-f41.google.com (mail-lf1-f41.google.com [209.85.167.41]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 4FB516EC55 for ; Thu, 17 Jun 2021 12:58:19 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 dev.tarantool.org 4FB516EC55 Received: by mail-lf1-f41.google.com with SMTP id m21so9450467lfg.13 for ; Thu, 17 Jun 2021 02:58:19 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=8Pbe8ySxZEHZ7bt3AY7lSeB+vRfa5BxpYyBzkkAycvo=; b=i3/n6pgR5w4kCWUOnjWziSuQ1SYxnC9vK52ueGzf9/X1NmSa7fwuxGMks0PT5AZ24H LAdZWow4ygduD04htqWXhTPI1yGIxf+1bB4sVv7/4TJRobcj4++aGT2t3ILlevoZWgtx qd7/1OLbW7ghdOYU29kRZ6w0bm8Wfl93ZglgoaLshJO45WWk33npxwsEAj8BpCpoh/5f K1o3NlBDakem+QrsBZy0DeT/BVvge8mxgs4E6ZtclnG0ny0joYwHWMmvAux5QTjo9Gul Ou2elO7oGtwpIsZvm2jO63/pAqf08Bxqco7imEU6nZhXgPSrTfsbeyeobLT14UWSAmpj Mm+w== X-Gm-Message-State: AOAM530OZO7mdDND2N8tQIDhoGwVqy+0oa4tv0YaICtoq9AtzwjLzump JEm14cAuaCJcBEpSKdsx5LoTPFUTO68= X-Google-Smtp-Source: ABdhPJx04/Xx9DeAf22yL5QtcERZUdu2VVvfP3ZATG1UBQWlrDo/Ws1uqJt/ZPbW/9NNDFj/jDZIWQ== X-Received: by 2002:a05:6512:54b:: with SMTP id h11mr3507650lfl.236.1623923898086; Thu, 17 Jun 2021 02:58:18 -0700 (PDT) Received: from grain.localdomain ([5.18.171.94]) by smtp.gmail.com with ESMTPSA id q21sm579251lfm.240.2021.06.17.02.58.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 17 Jun 2021 02:58:16 -0700 (PDT) Received: by grain.localdomain (Postfix, from userid 1000) id 04A535A002A; Thu, 17 Jun 2021 12:58:15 +0300 (MSK) Date: Thu, 17 Jun 2021 12:58:15 +0300 To: Serge Petrenko Message-ID: References: <20210607155519.109626-1-gorcunov@gmail.com> <20210607155519.109626-3-gorcunov@gmail.com> <73be2a27-dacf-c750-7bb6-da777b9c2f5a@tarantool.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/2.0.7 (2021-05-04) Subject: Re: [Tarantool-patches] [PATCH v8 2/2] relay: provide information about downstream lag X-BeenThere: tarantool-patches@dev.tarantool.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: Cyrill Gorcunov via Tarantool-patches Reply-To: Cyrill Gorcunov Cc: Vladislav Shpilevoy , tml Errors-To: tarantool-patches-bounces@dev.tarantool.org Sender: "Tarantool-patches" On Thu, Jun 17, 2021 at 12:01:32PM +0300, Serge Petrenko wrote: > I think I understand what you mean now. But still, this description is > confusing. > > When you're saying it's "time delta when data is already written to a > replica's WAL" it sounds like the delta is taken on replica, not on master. > And that's not true. > It's also unclear from this description that packet travel time (ack from > replica to master) is included into downstream.lag > > So I would reformulate the description to something like > > "Downstream.lag is the lag between the main node writes a certain > transaction to it's own WAL and the moment it receives an ack for > this transaction from a replica". Thanks, Serge! I'll update the description.