Return-Path: Received: from ensim.rackshack.net (root@localhost) by orafaq.net (8.11.6/8.11.6) with ESMTP id h8PGhVX10500 for ; Thu, 25 Sep 2003 11:43:31 -0500 X-ClientAddr: 66.27.56.210 Received: from ns3.fatcity.com (rrcs-west-66-27-56-210.biz.rr.com [66.27.56.210]) by ensim.rackshack.net (8.11.6/8.11.6) with ESMTP id h8PGhPc10490 for ; Thu, 25 Sep 2003 11:43:30 -0500 Received: from ns3.fatcity.com (localhost.localdomain [127.0.0.1]) by ns3.fatcity.com (8.12.8/8.12.8) with ESMTP id h8PE1HCY032203 for ; Thu, 25 Sep 2003 07:04:44 -0700 Received: (from root@localhost) by ns3.fatcity.com (8.12.8/8.12.5/Submit) id h8PDoP0Z030350 for oracle-l@orafaq.net; Thu, 25 Sep 2003 06:50:25 -0700 Received: by fatcity.com (05-Jun-2003/v1.0g-b73/bab) via fatcity.com id 005D10C5; Thu, 25 Sep 2003 06:49:47 -0800 Message-ID: Date: Thu, 25 Sep 2003 06:49:47 -0800 To: Multiple recipients of list ORACLE-L X-Comment: Oracle RDBMS Community Forum X-Sender: "Tanel Poder" Sender: ml-errors@fatcity.com Reply-To: ORACLE-L@fatcity.com Errors-To: ML-ERRORS@fatcity.com From: "Tanel Poder" 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/alternative; boundary="----=_NextPart_000_132D_01C38384.C4250CB0" ------=_NextPart_000_132D_01C38384.C4250CB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: Oracle Compress OptionHi! I think in DW style environments, compressed fact tables and indexes on = them can give more benefit than just saved disk storage -> if you save = 50% in space due compression, then 100% more data can be read in single = IO as well. Tanel. ----- Original Message -----=20 From: Khedr, Waleed=20 To: Multiple recipients of list ORACLE-L=20 Sent: Thursday, September 25, 2003 4:34 PM Subject: RE: Oracle Compress Option 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. Two major issues: 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. 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. It's mainly good for data warehouses applications. Regards, Waleed -----Original Message----- From: Jamadagni, Rajendra [mailto:Rajendra.Jamadagni@espn.com] Sent: Thursday, September 25, 2003 9:05 AM To: Multiple recipients of list ORACLE-L Subject: RE: Oracle Compress Option 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 From: Mogens N=F8rgaard [mailto:mln@miracleas.dk]=20 Sent: Wednesday, September 24, 2003 10:05 PM=20 To: Multiple recipients of list ORACLE-L=20 Subject: Re: Oracle Compress Option=20 "Compress to impress?" by Julian Dyke is a good presentation 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 :).=20 Let me know if you're interested, and I'll email it directly to you. = 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_000_132D_01C38384.C4250CB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable RE: Oracle Compress Option
Hi!
 
I think in DW style environments, = compressed fact=20 tables and indexes on them can give more benefit than just saved disk = storage=20 -> if you save 50% in space due compression, then 100% more data can = be read=20 in single IO as well.
 
Tanel.
 
----- Original Message -----
From:=20 Khedr,=20 Waleed
Sent: Thursday, September 25, = 2003 4:34=20 PM
Subject: RE: Oracle Compress = Option

Disk is not=20 cheap if you pay for high availability configuration. I compress = historical=20 data on daily basis and was able to save 70 percent of the disk space. = Imagine=20 the 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=20 a compressed table, uncompress first otherwise you will end up with a = segment=20 that 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=20 table and need a new column you need to recreate the table without=20 compression. So adding many extra columns before compression is a good = idea.
 
It's mainly=20 good 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=20
All Views expressed in this email are strictly=20 personal.
QOTD: Any clod can have facts, = having an=20 opinion is an art !


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

>
>Thanks=20

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