Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1f0x8d-0002Fd-Tu for pgsql-hackers@arkaria.postgresql.org; Tue, 27 Mar 2018 22:32:20 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1f0x8c-00028l-QJ for pgsql-hackers@arkaria.postgresql.org; Tue, 27 Mar 2018 22:32:18 +0000 Received: from makus.postgresql.org ([2001:4800:1501:1::229]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1f0x8c-00028b-3K for pgsql-hackers@lists.postgresql.org; Tue, 27 Mar 2018 22:32:18 +0000 Received: from bay.acenet.us ([173.230.252.50]) by makus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1f0x8Z-0002H6-8Z for pgsql-hackers@postgresql.org; Tue, 27 Mar 2018 22:32:16 +0000 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=anastigmatix.net; s=default; h=Content-Transfer-Encoding:Content-Type: In-Reply-To:MIME-Version:Date:Message-ID:From:Cc:References:To:Subject:Sender :Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=QAaqifUS61UsVtM0kDSmHjQAZ/78HzRA9KK9215IlSw=; b=DRcJ/sUD9Pk3ejyHMpYsrySI6f EYYLDPp8WEEAjlhF4iaJoiVZCO8av6qDi16turpwBqIZjaKO/4Nh2LGH/mStIL0Ymfu+zFQCLFfkp gxM3v43xlWVdMlCOqKstwK+qQ1F0/9cc67+CuS9T5IM+ah/i/M7H61JZpiZ9m22/vmjeeYxJcX5lO XSPmRC4QciZ3r1lGCQJ9ciDzeYPYiSK8u0x6s/7VtYOdGp+Ot+WR37/alMqWYiFsegn3+nqKI2vq5 LPv5UriO9+4GkEGaN+vWEKVMSpAf6XvTe/zhqd1+fOvla116Io9DOlJsJm5leYiquq6f3Is/hHQzP D/UcKQpw==; Received: from [192.182.57.106] (port=55215) by bay.acenet.us with esmtpsa (TLSv1.2:ECDHE-RSA-AES128-GCM-SHA256:128) (Exim 4.89_1) (envelope-from ) id 1f0x8T-001R6r-Li; Tue, 27 Mar 2018 18:32:11 -0400 Subject: Re: [HACKERS] AdvanceXLInsertBuffer vs. WAL segment compressibility To: Michael Paquier , Stephen Frost References: <5A92F0C0.7070706@anastigmatix.net> <5AADB130.2020206@anastigmatix.net> <4597.1521338981@sss.pgh.pa.us> <46FFB930-B0F3-400A-85ED-D9948C97FADF@yesql.se> <5AAEE00E.9050503@anastigmatix.net> <21C25ED8-4ED8-4AD4-B551-3E3987ECB18F@yesql.se> <5AAEFF11.3070903@anastigmatix.net> <20180326032731.GM24540@tamriel.snowman.net> <20180326054354.GB2759@paquier.xyz> Cc: Daniel Gustafsson , Tom Lane , Michael Paquier , Heikki Linnakangas , Robert Haas , Bruce Momjian , PostgreSQL Hackers From: Chapman Flack Message-ID: <5ABAC668.5080203@anastigmatix.net> Date: Tue, 27 Mar 2018 18:32:08 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: <20180326054354.GB2759@paquier.xyz> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit X-OutGoing-Spam-Status: No, score=-99.5 X-AntiAbuse: This header was added to track abuse, please include it with any abuse report X-AntiAbuse: Primary Hostname - bay.acenet.us X-AntiAbuse: Original Domain - postgresql.org X-AntiAbuse: Originator/Caller UID/GID - [47 12] / [47 12] X-AntiAbuse: Sender Address Domain - anastigmatix.net X-Get-Message-Sender-Via: bay.acenet.us: authenticated_id: chap+anastigmatix.net/only user confirmed/virtual account not confirmed X-Authenticated-Sender: bay.acenet.us: chap@anastigmatix.net X-Source: X-Source-Args: X-Source-Dir: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk On 03/26/18 01:43, Michael Paquier wrote: > Have a look at BKP_REMOVABLE then. This was moved to page headers in > 2dd9322, still it seems to me that the small benefits outlined on this > thread don't justify breaking tools relying on this flag set, especially > if there is no replacement for it. Is 2dd9322 a commit? I'm having difficulty finding it: https://git.postgresql.org/gitweb/?p=postgresql.git&a=search&h=HEAD&st=commit&s=2dd9322 Am I searching wrong? I probably won't have more time to look at this tonight, but could I ask in advance for examples of tools that would need this bit when encountering unwritten pages at the end of a segment? I don't mean that as snark; it's just nonobvious to me and I might need a little nudge where to look. -Chap