Received: from malur.postgresql.org ([2a02:16a8:dc51::56]) by arkaria.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fgMzN-0004LQ-1l for pgsql-hackers@arkaria.postgresql.org; Fri, 20 Jul 2018 04:25:58 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1fgMzL-0004zz-5x for pgsql-hackers@arkaria.postgresql.org; Fri, 20 Jul 2018 04:25:55 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fgMzJ-0004zi-Ep for pgsql-hackers@lists.postgresql.org; Fri, 20 Jul 2018 04:25:55 +0000 Received: from wout5-smtp.messagingengine.com ([64.147.123.21]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA384:256) (Exim 4.89) (envelope-from ) id 1fgMz6-0002D1-7n for pgsql-hackers@lists.postgresql.org; Fri, 20 Jul 2018 04:25:50 +0000 Received: from compute4.internal (compute4.nyi.internal [10.202.2.44]) by mailout.west.internal (Postfix) with ESMTP id 5A0F2395; Fri, 20 Jul 2018 00:25:36 -0400 (EDT) Received: from mailfrontend2 ([10.202.2.163]) by compute4.internal (MEProxy); Fri, 20 Jul 2018 00:25:37 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=paquier.xyz; h= cc:content-type:date:from:in-reply-to:message-id:mime-version :references:subject:to:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; bh=0MGqm8Oy08NWdrUp3i3RZFovktLSaEFxFxJ//yNDu8U=; b=nbwRYFLD CMBreUv0+PX8IoXzSzOfoPerQCqIe3PmH7QPMoDMoYHyBExSiDfUgNTwq33seW7o v1/A39IHyZLmwTeNyFL4LxZD4yRnvBDump2yY819gj1NkgS6npX+1oAdCfmvlOKL l1iGxkBSGW45i8QUmGX2+NJVonrsXf78XnI6bQu8v7htO+clbq/E/7ml1sIqKjZt 0KpfmTtjUygNznCtOyiy4bScDLU06xvO4QwHZtFc/ex70rXCvRQ+LK83G/0GHZgb xSj0woDbjIl9RV01U9/lTgEibHWie+izWGGc/yY28Il3axQH5S8GuGw9YA9dS1pi 2SjQouwxEzuM/w== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-type:date:from:in-reply-to :message-id:mime-version:references:subject:to:x-me-sender :x-me-sender:x-sasl-enc; s=fm3; bh=0MGqm8Oy08NWdrUp3i3RZFovktLSa EFxFxJ//yNDu8U=; b=H5yZQ5nlbHgxmuDmRpqy47Nqhs/6SEwoXQbB5iF7ds1xE ChaYR7zbg2hfQqaBk/EvXy+rKumUfPtr1MBgyCNjE1ckISHWwi7KQRqihAtTtp4H M3fPAfaiuGZnQJxwwQ+NeQcSENY2cQ4GVbrG09hP4ZElaPd8ZWtm6A0bTUOLIBcm 2HENx/LEj7+bED0WO9HFiTAhTcVM8M2q3PHEMywfGoMh5joTBZIxZZGX/SUz+STz EgY4/ULaID819EadPFb4ui7Azo03gwVv9jg884vpN+9vP5V02GQoDNAuo58DzE9M lpivtYcOYX2TUA+2CQR7wTRgjOcG3LbH1hD2/AU0g== X-ME-Proxy: X-ME-Sender: Received: from paquier.xyz (mp76f1f9fa.ap.nuro.jp [118.241.249.250]) by mail.messagingengine.com (Postfix) with ESMTPA id ED54210261; Fri, 20 Jul 2018 00:25:31 -0400 (EDT) Date: Fri, 20 Jul 2018 13:25:20 +0900 From: Michael Paquier To: Masahiko Sawada Cc: Kyotaro HORIGUCHI , PostgreSQL Hackers , Thomas Munro , sk@zsrv.org, Michael Paquier , Andres Freund , Peter Eisentraut Subject: Re: [HACKERS] Restricting maximum keep segments by repslots Message-ID: <20180720042520.GD7023@paquier.xyz> References: <20180709.144706.258526585.horiguchi.kyotaro@lab.ntt.co.jp> <20180713.174004.249224160.horiguchi.kyotaro@lab.ntt.co.jp> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="OaZoDhBhXzo6bW1J" Content-Disposition: inline In-Reply-To: List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk --OaZoDhBhXzo6bW1J Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Jul 20, 2018 at 10:13:58AM +0900, Masahiko Sawada wrote: > Also, I'm not sure it's a good way to show the distance as LSN. LSN is > a monotone increasing value but in your patch, a value of the "remain" > column can get decreased. If that can happen, I think that this is a very, very bad idea. A couple of code paths, including segment recycling and the new WAL advancing rely on such monotonic properties. That would be also very confusing for any monitoring job looking at pg_replication_slots. -- Michael --OaZoDhBhXzo6bW1J Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAABCgAdFiEEG72nH6vTowiyblFKnvQgOdbyQH0FAltRZDAACgkQnvQgOdby QH2Vpg/+Ij0I00vps7NHhx6YMTkslaNzK8lmTGygnK6f0y+89G7iPOfm8eFvKmdP 9k0ljX/AdNHtEHq9iVJMrTxSN51SNoeOn5udM5KuWe0BLMUiqPK1IeAULfxdNST1 phVWUs6R+DqrleJlYr40NFjm5B6jmhWACwgvz85SW4lzsBPGhU/k5mHNspqwnvcx Gpg8aVndqMHJAFxaVfObxrHgSDd5aWRa4xuFUCFAcFiza0eYch62G8bqsoQDHMR7 6894UUpXPwtPKFudIVnQmJrIuZY851Jk/KE2NUJ9YZJlF4qMRIOnGPB84ttAuj44 y8Krmff+qksSpCI5GW7UW9R+tomxXfvYfaf6FntR7kCSHzRzpwJZoEsv6AJ4NeU7 z/hcjjVRDpzrfgnPT8K85E0xiG00tQrvQW92EEA570eXP3YADe/uieEuEMoFgK1U A4iE70RcZbWz/otlFgDH/NxtGFS8TXtgxDi14ghQ4xDBmx+43tqAPVErFxLt3/xs EqKEHaxpYmLkPUQEuLvPveTYXC3Ty8UFkZeMDGF6zm5j1yXnZBptWEA1FjFO2Lgg 18zZksBT8mhMXZIcEoUL+bbYtnI6FgVF8ESxx2CckQ74l8ElsuBYmJLpE1GZduVb mfgmMz09tvBGKK8Llvbjz8MaJPoxdA8ECJo71Rs+Q8Dn+LaJeCI= =r/mM -----END PGP SIGNATURE----- --OaZoDhBhXzo6bW1J--