From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from smtpng3.m.smailru.net (smtpng3.m.smailru.net [94.100.177.149]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 179E9445320 for ; Mon, 6 Jul 2020 16:50:06 +0300 (MSK) References: <1593757997-4145-1-git-send-email-alyapunov@tarantool.org> <1593757997-4145-10-git-send-email-alyapunov@tarantool.org> From: Aleksandr Lyapunov Message-ID: <53be5df2-5136-6e4a-0aac-bc39e90a627e@tarantool.org> Date: Mon, 6 Jul 2020 16:50:05 +0300 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Subject: Re: [Tarantool-patches] [PATCH 09/15] tx: introduce prepare sequence number List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladislav Shpilevoy , tarantool-patches@dev.tarantool.org On 05.07.2020 20:05, Vladislav Shpilevoy wrote: > Thanks for the patch! > > What are these psns? What are the difference with txn->id and > with lsn? I need an ID for ordering transactions, for answering a simple question - which TX is earlier in order of serialization. txn->id gives us order of creation of TXs, it's not suitable because TXs could be prepared in different order. LSN is good, it give us a correct order, but there's a problem with it: it becomes known after wal writer call, and I need that order before wal writer finishes.