Received: from malur.postgresql.org ([217.196.149.56]) by arkaria.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WaAnp-0002gG-6r for pgsql-hackers@arkaria.postgresql.org; Tue, 15 Apr 2014 21:22:01 +0000 Received: from localhost ([127.0.0.1] helo=postgresql.org) by malur.postgresql.org with smtp (Exim 4.80) (envelope-from ) id 1WaAno-0000Nm-FT for pgsql-hackers@arkaria.postgresql.org; Tue, 15 Apr 2014 21:22:00 +0000 Received: from magus.postgresql.org ([2a02:c0:301:0:ffff::29]) by malur.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WaAnn-0000Nd-4F for pgsql-hackers@postgresql.org; Tue, 15 Apr 2014 21:21:59 +0000 Received: from wsip-72-214-29-243.sd.sd.cox.net ([72.214.29.243] helo=joeconway.com) by magus.postgresql.org with esmtp (Exim 4.80) (envelope-from ) id 1WaAnj-0002aY-R0 for pgsql-hackers@postgresql.org; Tue, 15 Apr 2014 21:21:58 +0000 Received: from [192.168.4.41] (account jconway [192.168.4.41] verified) by joeconway.com (CommuniGate Pro SMTP 4.1.8) with ESMTP-TLS id 13933295; Tue, 15 Apr 2014 14:23:04 -0700 Message-ID: <534DA2F1.4000606@joeconway.com> Date: Tue, 15 Apr 2014 14:21:53 -0700 From: Joe Conway User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.4.0 MIME-Version: 1.0 To: Heikki Linnakangas , Andres Freund CC: Tom Lane , "Hackers (PostgreSQL)" Subject: Re: Excessive WAL generation and related performance issue 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> In-Reply-To: <534DA179.7010305@vmware.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Pg-Spam-Score: -0.9 (/) List-Archive: List-Help: List-ID: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: X-Mailing-List: pgsql-hackers Precedence: bulk Sender: pgsql-hackers-owner@postgresql.org -----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/ iQIcBAEBAgAGBQJTTaLxAAoJEDfy90M199hlwuQP/3Tuea1TUe+4L21ZdProNIIF fUtejFNUwqhkyWNcnePlubgSyTEIfHGEG9hatrB5/MWdzpiyEvXdDkvV1ODakEhJ CVKZbnQ4dmnrevypy2f2YdhlbB9du/DDFhFcPOZGbn+vLywwM9oMPS8tQmsol37e aITe2GnD5LpEcmCSqzz04OL+xAxKLe8fXaI9dDsTRWXb9qdj4pDHI706CeixwSFb sGsGcIHXmnWieMby9qfWc0WGpc38iMRRkE+LeaEULhsycFP/2x09irXdhbl5T1SH 4PItwX0/ZgLskklG2gaD4HpNe75+Emj1i22PHDYhXSoAzpykHUf+kZZwMUr0AbaF 5QVCer071jHaMacpaVC7/qwUt8zISx4/1wtJuQzfk5H3P2q4L+b/xPmod5/cqs9z /wFp+9kjMT4349sSMe1eDPTDoIZKgRh8Eiag5IfJtrOAjoK+FN+k8uWNikiyFDMu z/3l+6mbfrl7FAmfeXLFC9fqhhGOiGLHoZufB/4qFgEikj4S94Hx9Q0nHqkMsFvM Fcd3qcpLI06Xku7LmBPRvdZ8OVFGWAirH1jBlrdsvC9E5VoZxgByxg90EaTlwjAQ 1ZaGOsbQoXdOPOwe/rGx2ONGwgZp8uFwHSXzUY+CJucvfYQh2AD67AlEhS7Jb9NC ummpulzJ6arce0815KaT =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