From: Joe Conway <mail@joeconway.com>
To: Heikki Linnakangas <hlinnakangas@vmware.com>
To: Andres Freund <andres@2ndquadrant.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Hackers (PostgreSQL) <pgsql-hackers@postgresql.org>
Subject: Re: Excessive WAL generation and related performance issue
Date: Tue, 15 Apr 2014 14:21:53 -0700
Message-ID: <534DA2F1.4000606@joeconway.com> (raw)
In-Reply-To: <534DA179.7010305@vmware.com>
References: <534C540F.4030905@joeconway.com>
<20140414215059.GA4161@awork2.anarazel.de>
<3627.1397517449@sss.pgh.pa.us>
<534C6DC8.7000004@joeconway.com>
<20140414232532.GB4161@awork2.anarazel.de>
<534C70A0.6070805@joeconway.com>
<534D9C49.5080007@joeconway.com>
<534DA179.7010305@vmware.com>
List-Unsubscribe: <mailto:majordomo@postgresql.org?body=unsub%20pgsql-hackers>
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1
On 04/15/2014 02:15 PM, Heikki Linnakangas wrote:
> You're counting XLogRecData structs, not backup blocks. Each
> backup block typically consists of three XLogRecData structs, one
> to record a BkpBlock struct, one to record the data before the
> unused "hole" in the middle of the page, and one for after.
> Sometimes just two, if there is no hole to skip. See the loop just
> before the CRC calculation, that's where the XLogRecData entries
> for backup blocks are created.
>
> - Heikki
Ah, thanks for the explanation!
Joe
- --
Joe Conway
credativ LLC: http://www.credativ.us
Linux, PostgreSQL, and general Open Source
Training, Service, Consulting, & 24x7 Support
-----BEGIN PGP SIGNATURE-----
Version: GnuPG v1.4.14 (GNU/Linux)
Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/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=Y+m4
-----END PGP SIGNATURE-----
--
Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-hackers
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-hackers@postgresql.org
Cc: mail@joeconway.com, hlinnakangas@vmware.com, andres@2ndquadrant.com, tgl@sss.pgh.pa.us
Subject: Re: Excessive WAL generation and related performance issue
In-Reply-To: <534DA2F1.4000606@joeconway.com>
* 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