Return-Path: Received: from ensim.rackshack.net (root@localhost) by orafaq.net (8.11.6/8.11.6) with ESMTP id h8PFExl02544 for ; Thu, 25 Sep 2003 10:14:59 -0500 X-ClientAddr: 66.27.56.213 Received: from www2.fatcity.com (rrcs-west-66-27-56-213.biz.rr.com [66.27.56.213]) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id h8PFEsc02538 for ; Thu, 25 Sep 2003 10:14:54 -0500 Received: (from root@localhost) by www2.fatcity.com (8.11.6/8.11.6) id h8PCa8v25367 for oracle-l@orafaq.net; Thu, 25 Sep 2003 05:36:08 -0700 Received: by fatcity.com (05-Jun-2003/v1.0g-b73/bab) via fatcity.com id 005D10B7; Thu, 25 Sep 2003 05:34:43 -0800 Message-ID: Date: Thu, 25 Sep 2003 05:34:43 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: "Khedr, Waleed" Sender: ml-errors@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: "Khedr, Waleed" Subject: RE: Oracle Compress Option Organization: Fat City Network Services, San Diego, California X-ListServer: v1.0g, build 73; ListGuru (c) 1996-2003 Bruce A. Bergman Precedence: bulk Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="----=_NextPartTM-000-42413039-1db9-4a68-932e-7ad662a23baf" ------=_NextPartTM-000-42413039-1db9-4a68-932e-7ad662a23baf Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C38361.2E561B09" ------_=_NextPart_001_01C38361.2E561B09 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable Disk is not cheap if you pay for high availability configuration. I = compress historical data on daily basis and was able to save 70 percent of the = disk space. Imagine the amount of savings for five TB. =20 Two major issues: =20 1) Oracle says updates will be slow on compressed tables, but I say = don't even try to update a compressed table, uncompress first otherwise you = will end up with a segment that is not good at all for scattered reads. =20 2) You can not add columns to the table when it's compressed, so if you compressed a big table and need a new column you need to recreate the = table without compression. So adding many extra columns before compression is = a good idea. =20 It's mainly good for data warehouses applications. =20 Regards, =20 Waleed =20 -----Original Message----- Sent: Thursday, September 25, 2003 9:05 AM To: Multiple recipients of list ORACLE-L I think 9202 doesn't like to export compressed tables in direct mode = ... so watch out for that ... I implemented, tested and next day reverted back = to regular tables due to this export issue. Disk is cheap. A BAARF party member wannabe !!=20 Raj=20 ------------------------------------------------------------------------= ---- ----=20 Rajendra dot Jamadagni at nospamespn dot com=20 All Views expressed in this email are strictly personal.=20 QOTD: Any clod can have facts, having an opinion is an art !=20 -----Original Message-----=20 ]=20 Sent: Wednesday, September 24, 2003 10:05 PM=20 To: Multiple recipients of list ORACLE-L=20 "Compress to impress?" by Julian Dyke is a good presentation on this=20 topic (see for instance http://www.ukoug.org/calendar/jan03/jan30ab.htm ).=20 I do have the article - 202 K with no compression, 147 K with=20 compression :).=20 Let me know if you're interested, and I'll email it directly to you.=20 Mogens=20 Avnish.Rastogi@providence.org wrote:=20 >Does anybody has any experience with Oracle 9I compression option. I = did some test on 9202 with a table of more 14 million rows. Table has total = 7 indexes. Surprising both table and indexes are using more space after compression. Before compression space used is 13064MB and after = compression 13184MB. In both the cases I did export from source table and stored in = two different tablespaces. Any insight on that and any disadvantages of = using that. >=20 >Thanks=20 ------_=_NextPart_001_01C38361.2E561B09 Content-Type: text/html; charset="ISO-8859-1" Content-Transfer-Encoding: quoted-printable RE: Oracle Compress Option
Disk is not cheap=20 if you pay for high availability configuration. I compress historical = data on=20 daily basis and was able to save 70 percent of the disk space. Imagine = the=20 amount of savings for five TB.
 
Two major=20 issues:
 
1) = Oracle says=20 updates will be slow on compressed tables, but I say don't even try to = update a=20 compressed table, uncompress first otherwise you will end up with a = segment that=20 is not good at all for scattered reads.
 
2) = You can not=20 add columns to the table when it's compressed, so if you compressed a = big table=20 and need a new column you need to recreate the table without = compression. So=20 adding many extra columns before compression is a good = idea.
 
It's mainly good=20 for data warehouses applications.
 
Regards,
 
Waleed
 
-----Original Message-----
From: Jamadagni, = Rajendra=20 [mailto:Rajendra.Jamadagni@espn.com]
Sent: Thursday, = September 25,=20 2003 9:05 AM
To: Multiple recipients of list=20 ORACLE-L
Subject: RE: Oracle Compress = Option

I think 9202 doesn't like to export compressed = tables in=20 direct mode ... so watch out for that ... I implemented, tested and = next day=20 reverted back to regular tables due to this export issue. Disk is=20 cheap.

A BAARF party member wannabe !!
Raj
---------------------------------------------------------------= -----------------=20
Rajendra dot Jamadagni at nospamespn dot = com
All Views expressed in this email are strictly = personal.=20
QOTD: Any clod can have facts, having an opinion = is an art=20 !


-----Original Message-----
From:=20 Mogens N=F8rgaard [mailto:mln@miracleas.dk] =
Sent: Wednesday, September 24, 2003 10:05 PM =
To: Multiple recipients of list ORACLE-L
Subject: Re: Oracle Compress Option


"Compress to impress?" by Julian Dyke is a good = presentation=20 on this
topic (see for instance http://www.ukoug.org/calendar/jan03/jan30ab.htm).=20

I do have the article - 202 K with no compression, = 147 K with=20
compression :).

Let me know if you're interested, and I'll email it = directly=20 to you.

Mogens

Avnish.Rastogi@providence.org wrote:

>Does anybody has any experience with Oracle 9I = compression=20 option. I did some test on 9202 with a table of more 14 million rows. = Table=20 has total 7 indexes. Surprising both table and indexes are using more = space=20 after compression. Before compression space used is 13064MB and after = compression 13184MB. In both the cases I did export from source table = and=20 stored in two different tablespaces. Any insight on that and any = disadvantages=20 of using that.

>
>Thanks=20

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