Return-Path: Delivered-To: 2-oracle-l@orafaq.com Received: (qmail 13437 invoked from network); 10 Dec 2007 14:42:12 -0600 Received: from freelists-180.iquest.net (HELO turing.freelists.org) (206.53.239.180) by 69.64.49.119 with SMTP; 10 Dec 2007 14:42:12 -0600 Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 738567D6F71; Mon, 10 Dec 2007 15:42:12 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 02922-05; Mon, 10 Dec 2007 15:42:12 -0500 (EST) Received: from turing (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id C4A907D6F41; Mon, 10 Dec 2007 15:42:11 -0500 (EST) Received: with ECARTIS (v1.0.0; list oracle-l); Mon, 10 Dec 2007 14:55:14 -0500 (EST) Received: from localhost (localhost [127.0.0.1]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id A9F217D6C92 for ; Mon, 10 Dec 2007 14:55:14 -0500 (EST) Received: from turing.freelists.org ([127.0.0.1]) by localhost (turing.freelists.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 18614-04 for ; Mon, 10 Dec 2007 14:55:14 -0500 (EST) Received: from NT15.oneneck.corp (dot092host.oneneck.net [63.226.42.92]) by turing.freelists.org (Avenir Technologies Mail Multiplex) with ESMTP id 6DAD37D6BEE for ; Mon, 10 Dec 2007 14:55:12 -0500 (EST) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.3790.2992 Content-Class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C83B66.906169C6" Subject: RE: Operations that perform multiblock I/O and cluster factor Date: Mon, 10 Dec 2007 12:55:07 -0700 Message-ID: <04DDF147ED3A0D42B48A48A18D574C450999D439@NT15.oneneck.corp> In-Reply-To: <578806DDE66A3A45916740EB73C6982AB42BB5D391@M1EXCHANGE01.mmi.local> X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: Operations that perform multiblock I/O and cluster factor References: <578806DDE66A3A45916740EB73C6982AB42BB5D391@M1EXCHANGE01.mmi.local> Priority: normal From: "Allen, Brandon" To: , X-archive-position: 3817 X-ecartis-version: Ecartis v1.0.0 Sender: oracle-l-bounce@freelists.org Errors-to: oracle-l-bounce@freelists.org X-original-sender: Brandon.Allen@OneNeck.com Precedence: normal Reply-to: Brandon.Allen@OneNeck.com List-help: List-unsubscribe: List-software: Ecartis version 1.0.0 List-Id: oracle-l X-List-ID: oracle-l List-subscribe: List-owner: List-post: List-archive: X-list: oracle-l X-Virus-Scanned: Debian amavisd-new at localhost.localdomain ------_=_NextPart_001_01C83B66.906169C6 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I'm pretty sure you are correct - only FTS and FFS will perform "db file scattered read" (reference: http://download.oracle.com/docs/cd/B10501_01/server.920/a96533/instance_ tune.htm#15945). There are other multi-block I/Os though, for example direct path reads & writes to temp, but those show up under their own wait events, not "db file scattered read", and they do not occur on behalf of an index range scan. I think your co-worker is wrong and if s/he's going to make such claims in contradiction to the documentation - the burden of proof is on him so ask him/her to show you a 10046 trace file with "db file scattered read" wait events coming from an INDEX RANGE SCAN, or some other proof. =20 Regards, Brandon =20 ________________________________ From: oracle-l-bounce@freelists.org [mailto:oracle-l-bounce@freelists.org] On Behalf Of Josh Collier =20 =20 Are there any other access paths that are served by multiblock I/O? My co-worker contends: If the range scan is not a full scan, the query optimizer will decide whether to use a scattered read depending on the fraction of rows in the scan and the cluster factor of the index.=20 Privileged/Confidential Information may be contained in this message or = attachments hereto. Please advise immediately if you or your employer do = not consent to Internet email for messages of this kind. Opinions, = conclusions and other information in this message that do not relate to = the official business of this company shall be understood as neither = given nor endorsed by it. ------_=_NextPart_001_01C83B66.906169C6 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
I'm pretty sure you are correct - only FTS and = FFS will=20 perform "db file scattered read" (reference: http://download.oracle.com/docs/cd/B10501_01/serve= r.920/a96533/instance_tune.htm#15945). =20 There are other multi-block I/Os though, for example direct path reads = &=20 writes to temp, but those show up under their own wait events, not "db = file=20 scattered read", and they do not occur on behalf of an index range = scan.  I=20 think your co-worker is wrong and if s/he's going to make such claims in = contradiction to the documentation - the burden of proof is on him = so ask=20 him/her to show you a 10046 trace file with "db file scattered = read" wait=20 events coming from an INDEX RANGE SCAN, or some other = proof.
 
Regards,
Brandon
 

From: oracle-l-bounce@freelists.org=20 [mailto:oracle-l-bounce@freelists.org] On Behalf Of Josh=20 Collier
 
 
Are there any other access paths that are served by multiblock I/O? = My=20 co-worker contends:  If the = range scan=20 is not a full scan, the query optimizer will decide whether to use a = scattered=20 read depending on the fraction of rows in the scan and the cluster = factor of the=20 index. =

Privileged/Confidential Information may be contained in this message = or attachments hereto. Please advise immediately if you or your employer = do not consent to Internet email for messages of this kind. Opinions, = conclusions and other information in this message that do not relate to = the official business of this company shall be understood as neither = given nor endorsed by it.

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