Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jzwsm-0000X0-IE for pgsql-hackers@arkaria.postgresql.org; Mon, 27 Jul 2020 06:45:09 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1jzwsk-0003NO-Mt for pgsql-hackers@arkaria.postgresql.org; Mon, 27 Jul 2020 06:45:06 +0000 Received: from makus.postgresql.org ([2001:4800:3e1:1::229]) by malur.postgresql.org with esmtps (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1jzwsk-0003NH-Be for pgsql-hackers@lists.postgresql.org; Mon, 27 Jul 2020 06:45:06 +0000 Received: from mail.postgrespro.ru ([93.174.131.139]) by makus.postgresql.org with esmtp (Exim 4.92) (envelope-from ) id 1jzwsd-0000Lg-56 for pgsql-hackers@postgresql.org; Mon, 27 Jul 2020 06:45:05 +0000 Received: from localhost (localhost [127.0.0.1]) by mail.postgrespro.ru (Postfix) with ESMTP id C2B8D21C2BEC; Mon, 27 Jul 2020 09:44:56 +0300 (MSK) X-Virus-Scanned: Debian amavisd-new at postgrespro.ru X-Spam-Flag: NO X-Spam-Score: 0 X-Spam-Level: X-Spam-Status: No, score=x tagged_above=-99 required=4 WHITELISTED tests=[] autolearn=unavailable Received: from [192.168.129.197] (unknown [94.25.177.8]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mail.postgrespro.ru (Postfix) with ESMTPSA id CDE5621C2BEB; Mon, 27 Jul 2020 09:44:55 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=postgrespro.ru; s=mail; t=1595832296; bh=dqoJyDAn7X04k20lcgvlSN5G96xZlyMGDGBpB74D3xA=; h=Subject:To:Cc:References:From:Date:In-Reply-To; b=p43jp4JxE9cGlQwm/sKZ3jRdTUPTGHX1RmEWRzI2n2JgU9HY6zLGXuQKyPQRoOm+0 zFQ1vbYL/Qv7R7NRMwhmEQs+zEpoggMY59MsuVZUp80tH8eELrF6ZMN7nF7zdONLZz uykjdutJQA6G0QOfUnfBbEOnpcbJ4LHoU0G+SmZw= Subject: Re: Global snapshots To: "tsunakawa.takay@fujitsu.com" , "movead.li@highgo.ca" Cc: 'Amit Kapila' , Masahiko Sawada , Fujii Masao , PostgreSQL-Dev References: <07b2c899-4ed0-4c87-1327-23c750311248@postgrespro.ru> <4d13207c-43ba-1db3-1459-e7d4bc0e47ad@oss.nttdata.com> <9964cf46-9294-34b9-4858-971e9029f5c7@postgrespro.ru> From: "Andrey V. Lepikhov" Organization: Postgres Professional Message-ID: <806c3708-26ea-b94d-87b1-d48e41e93726@postgrespro.ru> Date: Mon, 27 Jul 2020 11:44:54 +0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On 7/27/20 11:22 AM, tsunakawa.takay@fujitsu.com wrote: > Hi Andrey san, Movead san, > > > From: tsunakawa.takay@fujitsu.com >> While Clock-SI seems to be considered the best promising for global >> serializability here, >> >> * Why does Clock-SI gets so much attention? How did Clock-SI become the >> only choice? >> >> * Clock-SI was devised in Microsoft Research. Does Microsoft or some other >> organization use Clock-SI? > > Could you take a look at this patent? I'm afraid this is the Clock-SI for MVCC. Microsoft holds this until 2031. I couldn't find this with the keyword "Clock-SI."" > > > US8356007B2 - Distributed transaction management for database systems with multiversioning - Google Patents > https://patents.google.com/patent/US8356007 > > > If it is, can we circumvent this patent? > > > Regards > Takayuki Tsunakawa > > Thank you for the research (and previous links too). I haven't seen this patent before. This should be carefully studied. -- regards, Andrey Lepikhov Postgres Professional