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 1er6QS-0000WM-R2 for pgsql-admin@arkaria.postgresql.org; Wed, 28 Feb 2018 18:26:00 +0000 Received: from localhost ([127.0.0.1] helo=malur.postgresql.org) by malur.postgresql.org with esmtp (Exim 4.89) (envelope-from ) id 1er6QR-000260-Hi for pgsql-admin@arkaria.postgresql.org; Wed, 28 Feb 2018 18:25:59 +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 1er6QR-00025a-AM for pgsql-admin@lists.postgresql.org; Wed, 28 Feb 2018 18:25:59 +0000 Received: from mr28p48im-tydg10101201.me.com ([17.110.88.44]) by magus.postgresql.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_CBC_SHA1:256) (Exim 4.89) (envelope-from ) id 1er6QJ-0006yt-Q9 for pgsql-admin@lists.postgresql.org; Wed, 28 Feb 2018 18:25:58 +0000 Received: from process-dkim-sign-daemon.mr28p48im-tydg10101201.me.com by mr28p48im-tydg10101201.me.com (Oracle Communications Messaging Server 8.0.1.2.20170607 64bit (built Jun 7 2017)) id <0P4V00600HJSPP00@mr28p48im-tydg10101201.me.com> for pgsql-admin@lists.postgresql.org; Wed, 28 Feb 2018 18:25:47 +0000 (GMT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=icloud.com; s=04042017; t=1519842347; bh=IGy7o/K6IfcHbHFhCPugEHB0BphygLM9owyapMyR9UA=; h=From:Message-id:Content-type:MIME-version:Subject:Date:To; b=K1ao4TSv1QP9F+TcD8g4IhhE32xlG6oeH5OYz0MNtB25f0MahQ3Wqx7usieMbjQzD oOQis8jFl1lOGl9/WG4ZZrhRG93vSXWo3Ep7SemMaRqUIDq8mgdjBOB/ps/f8VrDgq AvLx3Fg5on9wq48CLcOPT1j5h3H4NMRnyCPYRj7f4Sic6Chym/zEQyIcgPTvLwDY/b KMLAjnYeinYfizZk7PVehASWQqI1ikfAeZlWgBNFijLZ44ftocovqMEGT+/SEMS0w8 QEs4WGxg1c3Hgo++3xa4KHuCSjeS/+4duaK1H8Rp6BaoihmaHJRxQVXfZVAfwMMTiF chsGRQ0ZQCAOg== Received: from icloud.com ([127.0.0.1]) by mr28p48im-tydg10101201.me.com (Oracle Communications Messaging Server 8.0.1.2.20170607 64bit (built Jun 7 2017)) with ESMTPSA id <0P4V00C4PHUXC860@mr28p48im-tydg10101201.me.com>; Wed, 28 Feb 2018 18:25:47 +0000 (GMT) X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10432:,, definitions=2018-02-28_10:,, signatures=0 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 clxscore=1015 suspectscore=0 malwarescore=0 phishscore=0 adultscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1707230000 definitions=main-1802280224 From: Rui DeSousa Message-id: <45F65094-CF9C-4BC4-AF56-2FE299F79EFF@icloud.com> Content-type: multipart/alternative; boundary="Apple-Mail=_08AD1635-8D13-4471-87EB-CF0150E48DC4" MIME-version: 1.0 (Mac OS X Mail 11.2 \(3445.5.20\)) Subject: Re: Reliable WAL file shipping over unreliable network Date: Wed, 28 Feb 2018 13:25:45 -0500 In-reply-to: <9BE48599-5417-42BF-A7D3-554590878841@elevated-dev.com> Cc: =?utf-8?Q?Nagy_L=C3=A1szl=C3=B3_Zsolt?= , pgsql-admin@lists.postgresql.org To: scott ribe References: <400AC9CD-1E43-422C-A689-70BDBAFF231E@elevated-dev.com> <954e01b6-b240-eb9a-5feb-8efd202fef5a@shopzeus.com> <9BE48599-5417-42BF-A7D3-554590878841@elevated-dev.com> X-Mailer: Apple Mail (2.3445.5.20) List-Id: List-Help: List-Subscribe: List-Post: List-Owner: List-Archive: Precedence: bulk --Apple-Mail=_08AD1635-8D13-4471-87EB-CF0150E48DC4 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=utf-8 > On Feb 28, 2018, at 1:12 PM, scott ribe = wrote: >=20 > There seem to be 2 fundamental misunderstandings here: >=20 > 1) That other processes cannot see data written to a file until it is = flushed to disk; this is not true; while file data is still in file = cache, it is visible to other processes. >=20 > 2) That rsync writes the file on the destination directly; it does = not; it writes into a temporary file and renames that file when it is = complete. >=20 While you=E2=80=99re correct; I never made either of those assumptions=20= --Apple-Mail=_08AD1635-8D13-4471-87EB-CF0150E48DC4 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=utf-8

On Feb 28, 2018, at 1:12 PM, scott ribe <scott_ribe@elevated-dev.com> wrote:

There seem to be 2 fundamental = misunderstandings here:

1) That other processes cannot see data written = to a file until it is flushed to disk; this is not true; while file data = is still in file cache, it is visible to other processes.
2) That rsync writes the file on the destination = directly; it does not; it writes into a temporary file and renames that = file when it is complete.


While you=E2=80=99= re correct; I never made either of those assumptions 

= --Apple-Mail=_08AD1635-8D13-4471-87EB-CF0150E48DC4--