From: Tom Lane <tgl@sss.pgh.pa.us>
To: Ravi Krishna <s.ravikrishna@aim.com>
Cc: pgsql-admin@postgresql.org
Subject: Re: WAL and O_DIRECT
Date: Thu, 14 May 2015 12:25:28 -0400
Message-ID: <4614.1431620728@sss.pgh.pa.us> (raw)
In-Reply-To: <14d532dde85-2108-310a1@webstg-m03.mail.aol.com>
References: <21483.1431618933@sss.pgh.pa.us>
<14d532dde85-2108-310a1@webstg-m03.mail.aol.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-admin>
Ravi Krishna <s.ravikrishna@aim.com> writes:
> Am I right in concluding that PG WAL writes without underlying h/w caching is not crash proof.
We expect that the hardware+OS honors fsync() correctly, ie puts the data
on durable storage before fsync returns. That does not mean anything one
way or the other about caching, it just means that the filesystem stack
has to be correctly implemented.
regards, tom lane
--
Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Reply to all the recipients using the --to and --cc options:
reply via email
To: pgsql-admin@postgresql.org
Cc: tgl@sss.pgh.pa.us, s.ravikrishna@aim.com
Subject: Re: WAL and O_DIRECT
In-Reply-To: <4614.1431620728@sss.pgh.pa.us>
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
This inbox is served by DDX for PostgreSQL; see mirroring instructions
for how to clone and mirror all data and code used for this inbox