RE: Coalescing tablespace

Bingo. I've included a few more details in a separate note sent just prior to my receiving this one.

Cary Millsap
Hotsos Enterprises, Ltd.
http://www.hotsos.com

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-----Original Message-----
Mladen Gogala
Sent: Monday, October 27, 2003 8:14 AM
To: Multiple recipients of list ORACLE-L

I wasn't feeling quite well when I was replying which made me confuse things. You, of course are right. SMON was locking fet$ table during those "coalesce" session, which was exceptionally dangerous in the OPS configurations. Coalescing doesn't buy much,the "coalesce" operation just combines two neighboring free extents into a single free extent, if those exist. This event was
much more rare then expected and if the database was properly configured (user data,temp, rbs, data dictionary separated from each other) it was highly unlikely that coalescing will be useful. Locally managed (bit mapped) tablespaces took care of the problem. Now, we can start defragmenting and stop living.

On 10/27/2003 01:34:25 AM, Cary Millsap wrote:
> You mean "make your PCTINCREASE 0 so that SMON will *not* coalesce
> them." Right? Some comments:
>
> - You don't want SMON coalescing your tablespaces. It is a complete
> waste of time. Oracle coalesces on demand during a CREATE statement.
> - The SMON coalesce feature was added under protest by the smart
> people
> in Server Technologies development, in response to pressure from
> Marketing and Support so that the Oracle RDBMS would look better in
> brochures.
> - Thank goodness the developers made SMON smart enough to *not*
> coalesce
> freespace in any tablespace with PCTINCREASE set to 0 (which is what
> it
> *should* be set to almost everywhere).
> - You can turn off SMON's ridiculous CPU-consuming, lock-holding
> behavior by setting event 10269.
>
>
> Cary Millsap
> Hotsos Enterprises, Ltd.
> http://www.hotsos.com
>
> Upcoming events:
> - Performance Diagnosis 101: 10/28 Phoenix, 11/19 Sydney
> - SQL Optimization 101: 12/8-12 Dallas
> - Hotsos Symposium 2004: March 7-10 Dallas
> - Visit www.hotsos.com for schedule details...
>
>
> -----Original Message-----
> Mladen Gogala
> Sent: Sunday, October 26, 2003 8:09 PM
> To: Multiple recipients of list ORACLE-L
>
> Well, having in mind that you're working on version 7 (chuckle) , you
> should
> make your tablespaces have PCTINCREASE 0 (alter tablespace default
> storage...)
> so SMON will coalesce them. You may also try (I'm not sure whether
> this
> has
> existed before 7.3) with alter tablespace coalesce, which should
> mark
> the
> tablespace to be coalesced by SMON at he first opportunity. I'm
> afraid
> that
> PCTINCREASE 0 is your best option.
>
> On 2003.10.26 20:04, Ross Collado wrote:
> > Hi,
> > For those like me still working on an Oracle 716 (hold the laughs),
> how do
> > we coalesce a tablespace?
> > Rgds,
> > Ross
> > --
> > Please see the official ORACLE-L FAQ: http://www.orafaq.net
> > --
> > Author: Ross Collado
> > INET: Ross.Collado_at_techpac.com
> >
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> --
> Mladen Gogala
> Oracle DBA
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.net
> --
> Author: Mladen Gogala
> INET: mgogala_at_adelphia.net
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> --
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> --
> Author: Cary Millsap
> INET: cary.millsap_at_hotsos.com
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Mladen Gogala
Oracle DBA

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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Mladen Gogala
  INET: mladen_at_wangtrading.com

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-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Cary Millsap
  INET: cary.millsap_at_hotsos.com

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
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