From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 3DB4F2D867 for ; Mon, 3 Dec 2018 15:20:15 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id jzEIE7XjUq1G for ; Mon, 3 Dec 2018 15:20:15 -0500 (EST) Received: from smtp58.i.mail.ru (smtp58.i.mail.ru [217.69.128.38]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTPS id ED5DA2D7EF for ; Mon, 3 Dec 2018 15:20:14 -0500 (EST) Received: from [185.6.245.178] (port=54704 helo=atlas.local) by smtp58.i.mail.ru with esmtpa (envelope-from ) id 1gTuhR-0006YR-C5 for tarantool-patches@freelists.org; Mon, 03 Dec 2018 23:20:13 +0300 Date: Mon, 3 Dec 2018 23:20:13 +0300 From: Konstantin Osipov Subject: [tarantool-patches] Re: [PATCH 8/9] wal: pass struct instead of vclock to checkpoint methods Message-ID: <20181203202013.GH2890@chai> References: <20181130090014.GH5760@chai> <20181130094332.6asjty7ahazfv5dm@esperanza> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181130094332.6asjty7ahazfv5dm@esperanza> Sender: tarantool-patches-bounce@freelists.org Errors-to: tarantool-patches-bounce@freelists.org Reply-To: tarantool-patches@freelists.org List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: tarantool-patches List-subscribe: List-owner: List-post: List-archive: To: tarantool-patches@freelists.org * Vladimir Davydov [18/11/30 13:17]: > On Fri, Nov 30, 2018 at 12:00:14PM +0300, Konstantin Osipov wrote: > > * Vladimir Davydov [18/11/28 19:16]: > > > Currently, we only need to pass a vclock between TX and WAL during > > > checkpointing. However, in order to implement auto-checkpointing > > > triggered when WAL size exceeds a certain threshold, we will need to > > > pass some extra info so that we can properly reset the counter > > > accounting the WAL size in the WAL thread. To make it possible,let's > > > move wal_checkpoint struct, which is used internally by WAL to pass a > > > checkpoint vclock, to the header and require the caller to pass it to > > > wal_begin/commit_checkpoint instead of just a vclock. > > > > wal is a singleton and there could be only one ongoing checkpoint. > > > > I am ok with this change but I don't understand the purpose of it: > > why not simply store wal_checkpoint in struct wal then you don't > > have to pass it around at all? > > Yeah, we could store the vclock in the WAL thread, but IMO that would > look ugly, because the new member of the wal_writer struct would only be > used during checkpointing and would be meaningless for the rest of the > WAL operation. OK, it's bikeshed. -- Konstantin Osipov, Moscow, Russia, +7 903 626 22 32 http://tarantool.io - www.twitter.com/kostja_osipov