From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-lj1-f194.google.com (mail-lj1-f194.google.com [209.85.208.194]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by dev.tarantool.org (Postfix) with ESMTPS id 59C8A4696C3 for ; Sat, 28 Mar 2020 19:23:30 +0300 (MSK) Received: by mail-lj1-f194.google.com with SMTP id r7so5719496ljg.13 for ; Sat, 28 Mar 2020 09:23:30 -0700 (PDT) Date: Sat, 28 Mar 2020 19:23:28 +0300 From: Konstantin Osipov Message-ID: <20200328162328.GC20621@atlas> References: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [Tarantool-patches] [PATCH v4 4/4] box: start counting local space requests separately List-Id: Tarantool development patches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Serge Petrenko Cc: tarantool-patches@dev.tarantool.org, v.shpilevoy@tarantool.org * Serge Petrenko [20/03/27 18:08]: > Moreover, it fixes the following bug with local spaces and replication. > In a situation when there are a master and a replica set up, replica may > still write to local spaces even if it's read-only. Local space > operations used to promote instance's lsn before this patch. Eventually, > master would have vclock {1:x} and replica'd have vclock {1:x, 2:y}, > where y > 0, due to local space requests performed by the replica. > If a snapshot happens on replica side, replica will delete it's .xlog > files prior to the snapshot, since no one replicates from it and thus it > doesn't have any registered GC consumers. > From this point, every attempt to configure replication from replica to > master will fail, since master will try to fetch records which account > for the difference in master's and replica's vclocks: {1:x} vs {1:x,2:y}, > even though master will never need the rows in range {2:1} - {2:y}, > since they'll be turned to NOPs during replication. OK, got it. Makes sense. Then, I'm afraid, relay has to be using lexicographical vclock as well. Waiting a fix or clarification here. -- Konstantin Osipov, Moscow, Russia