From: Tom Lane <tgl@sss.pgh.pa.us>
To: Christian Ullrich <chris@chrullrich.net>
Cc: pgsql-admin@postgresql.org
Subject: Re: Why does the WAL writer sit on completed segments (on Windows)?
Date: Mon, 17 Apr 2017 12:06:44 -0400
Message-ID: <28442.1492445204@sss.pgh.pa.us> (raw)
In-Reply-To: <b53e3f50-54b4-49ad-9344-97494ab5cbbd@chrullrich.net>
References: <od2lad$df0$1@blaine.gmane.org>
<17213.1492442911@sss.pgh.pa.us>
<b53e3f50-54b4-49ad-9344-97494ab5cbbd@chrullrich.net>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-admin>
Christian Ullrich <chris@chrullrich.net> writes:
> So, just to be sure, you're saying that when the ".ready" file is
> created, it is guaranteed that no process will write to a location
> within that segment anymore even if it happens to have the file open?
> (That's actually completely obvious, but bear with me, please.)
Right.
> And further, that each such process will close the open file as soon as
> it, intending to write WAL, finds out that the next available location
> is not within the file?
Yes, I believe it will typically hold the file open until that happens.
(If short of file descriptors, it might close it sooner, but that's
probably not common.)
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, chris@chrullrich.net
Subject: Re: Why does the WAL writer sit on completed segments (on Windows)?
In-Reply-To: <28442.1492445204@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