RE: Fav. Urban Legend...

On Tue, 12 Mar 2002, John Kanagaraj wrote:

> I believe Jeremiah Wilton presented on a similar topic at OOW.

I did do a similar presenatation, and Rachel Carmichael did a similar one the year before. Also, Gaja has a tuning myths paper/presentation.

Robert, you are welcome to consult my paper in doing your work. Just don't forget to correctly attribute material you use.

http://www.speakeasy.net/~jwilton/oracle

> One thing I will note though - there's bound to be lots of fire and
> flak erupting in your presentation. There are *lots* of so-called
> experienced DataBase Baby Sitters out there fed exclusively on
> 'Oracle for Dummies' books who had adopted these myths as reality
> and will be prepared to defend their position. You will need
> documented evidence in the form of logs or timings to make your
> stand for exploding some of these myths.

There wasn't much flak in my presentation, just mostly good questions. But I was pretty keyed up, and some people might have just thought I was deranged and wanted to avoid provoking me :-/

--
Jeremiah Wilton
http://www.speakeasy.net/~jwilton




> >I'm doing Oracle Urban 


> > Legends. I've got 

> > several in my presentation but I thought I'd ask here, before 

> > I put the

> > presentation to bed, what your favorite (or the one you find the most

> > irritating) Oracle Urban legend was....

> 

> Robert,

> 

> 

> * You *have* to take a COLD backup of the database after using resetlogs.

> (Not required - a Hot backup and archive logs is adequate. All hot backups /

> archive logs prior to that are invalid, though...)

> * You *have* to create an additional Rollback segment in the SYSTEM

> tablespace before creating *any* object in a tablespace other than SYSTEM

> (even additional Rbs in a non-SYSTEM tablespace). This used to be true in V6

> and before, not anymore.

> * Backup the online redologs along with the datafiles/controlfiles in a Hot

> backup (Disaster strikes when the redologs are restored on the current

> online redo logs!!)

> * Continuously run ALTER TABLESPACE COALESCE

> * Allocate different values of INITIAL/NEXT extent sizes for large objects

> depending on the 'expected growth pattern' - this makes sure that the number

> of extents for large objects is kept down. (Sheesh!)

> * COMPRESS=Y during Export compresses the extents into 1 huge extent, and

> that's GOOD!

> * Make sure that all your Tablespaces have at least 15% (or whatever) free

> (i.e. stress the percentage rather than making sure that the largest free

> fragment is larger than the largest NEXT extent at the least)

> * You are absolutely protected from Redolog file corruption by hardware

> multiplexing it. (i.e. What if you fat-fingered an online redolog?)

> 

> I might have added more on Tuning and Performance, but Gaja has already

> exploded all those myths!

> 

> 

> I am sure that others would add to this! (and I note that the 'lots of

> extents is bad' myth is already noted!)

> 

> John Kanagaraj

> Oracle Applications DBA

> DBSoft Inc

> (W): 408-970-7002

> 

> Grace - Getting something we don't deserve

> Mercy - NOT getting something we deserve

> 

> Click on 'http://www.needhim.org' for Grace and Mercy that is freely

> available!

> 

> ** The opinions and statements above are entirely my own and not those of my

> employer or clients **

> -- 

> Please see the official ORACLE-L FAQ: http://www.orafaq.com

> -- 

> Author: John Kanagaraj

>   INET: john.kanagaraj_at_hds.com

> 

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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.com
-- 
Author: Jeremiah Wilton
  INET: jwilton_at_speakeasy.net

Fat City Network Services    -- (858) 538-5051  FAX: (858) 538-5051
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