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 F2417265B5 for ; Mon, 19 Aug 2019 16:49:14 -0400 (EDT) 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 PMth-OpRJSdJ for ; Mon, 19 Aug 2019 16:49:14 -0400 (EDT) Received: from smtp46.i.mail.ru (smtp46.i.mail.ru [94.100.177.106]) (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 B0888265B0 for ; Mon, 19 Aug 2019 16:49:14 -0400 (EDT) Received: by smtp46.i.mail.ru with esmtpa (envelope-from ) id 1hzoaX-0006gO-9K for tarantool-patches@freelists.org; Mon, 19 Aug 2019 23:49:13 +0300 Date: Mon, 19 Aug 2019 23:49:13 +0300 From: Konstantin Osipov Subject: [tarantool-patches] Re: [PATCH v2 3/7] vinyl: get rid of vy_env::join_lsn Message-ID: <20190819204913.GD21602@atlas> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 [19/08/19 19:57]: > This fake LSN counter, which is used for assigning LSNs to Vinyl > statements during the initial join stage, was introduced a long time > ago, when LSNs were used as identifiers for lsregion allocations and > hence were supposed to grow strictly monotonically with each new > transaction. Later on, they were reused for assigning unique LSNs to > identify indexes in vylog. > > These days, we don't need initial join LSNs to be unique, as we switched > to generations for lsregion allocations while in vylog we now use LSNs > only as an incarnation counter, not as a unique identifier. That said, > let's zap vy_env::join_lsn and simply assign 0 to all statements > received during the initial join stage. > > To achieve that, we just need to relax an assertion in vy_tx_commit() > and remove the assumption that an LSN can't be zero in the write > iterator implementation. lgtm -- Konstantin Osipov, Moscow, Russia