Jared,
So, that means that to remedy a case of data block
fragmentation we just need to increase the pctused for
the fragmented tables.
Of course, things won't change as fast as an
export/import but it's certainly less work to do.
- Jared.Still_at_radisys.com a écrit : > John,
>
> Someone asked a question a month or so ago about
> changing
> PCTUSED and PCTFREE: When do the blocks go back on
> the
> free list, when the 'ALTER TABLE ... PCTFREE N'
> command was
> issued, or did the blocks go back on the free list
> when the next
> insert was issued.
>
> I don't remember what my conclusion was, and IIRC,
> it wasn't
> definite. But, testing shows that blocks do go back
> on the free list
> when PCTUSED is increased to a a value greater than
> the amount
> of data in the block.
>
> This was on 8.1.7 on Linux.
>
> It's in the archives if you care to look for it.
>
> Jared
>
>
>
>
>
>
> John.Hallas_at_vodafone.co.uk
> Sent by: root_at_fatcity.com
> 09/24/2002 09:08 AM
> Please respond to ORACLE-L
>
>
> To: Multiple recipients of list ORACLE-L
> <ORACLE-L_at_fatcity.com>
> cc:
> Subject: RE: Is the effect of
> modifying PCTFREE/PCTUSED immediate ?
>
>
> Well I was sure about it until you had the temerity
> to question me :)
> I think we agree on extents sizes not being changed
> after the event so it
> is
> now a discussion on whether changes to a
> pctfree/pctused are
> retrospective.
>
> I contend that if a table is fully loaded upto its
> pctfree/pctused limits
> and there are no available blocks on the freelist
> then by changing the
> pctfree/pctused values no additional blocks will
> suddenly appear on the
> freelist.
> I do agree however that if a block is amended by
> having a row deleted or a
> row updated then the new values come into play and
> the blockcould then be
> available on the freelist.
>
> I think I am correct on this but as with anything I
> am always ready to be
> proved wrong - it has happened before and wil
> lhappen may times in the
> future
>
> John
>
>
> -----Original Message-----
> Sent: 24 September 2002 15:47
> To: ORACLE-L_at_fatcity.com; John.Hallas_at_vodafone.co.uk
>
>
>
> Are you sure about that John?
>
> On Tuesday 24 September 2002 04:28,
> John.Hallas_at_vodafone.co.uk wrote:
> > No, it is not retrospective.
> > You are setting parameters to be used when the
> next extent is created.
> > A better example is when setting next extent size
> to be different than
> the
> > existing extent size (dictionary managed
> tablespaces only).
> > It does not alter all the existing extents it only
> works on the next one
> > that is created.
> >
> > HTH
> >
> > John
> >
> > -----Original Message-----
> > Sent: 24 September 2002 10:58
> > To: Multiple recipients of list ORACLE-L
> >
> >
> >
> > Is the effect of modifying PCTFREE/PCTUSED
> immediate ?
> >
> >
> > If I do an "ALTER TABLE <tablename> PCTFREE 99
> PCTUSED1",
> > does this take effect immediately, even for
> existing blocks.
> > [If so, existing blocks would not get new rows
> inserted].
> > Or is it effective only in new Extents ? In that
> case,
> > existing blocks in existing Extents still use the
> old
> > PCTFREE/PCTUSED parameters and keep re-entering
> the
> > FreeList.
> >
> > Hemant K Chitale
> > http://hkchital.tripod.com
> --
> Please see the official ORACLE-L FAQ:
> http://www.orafaq.com
> --
> Author:
> INET: John.Hallas_at_vodafone.co.uk
>
> Fat City Network Services -- 858-538-5051
> http://www.fatcity.com
> San Diego, California -- Mailing list and web
> hosting services
>
> To REMOVE yourself from this mailing list, send an
> E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of
> 'ListGuru') and in
> the message BODY, include a line containing: UNSUB
> ORACLE-L
> (or the name of mailing list you want to be removed
> from). You may
> also send the HELP command for other information
> (like subscribing).
>
>
>
> --
> Please see the official ORACLE-L FAQ:
> http://www.orafaq.com
> --
> Author:
> INET: Jared.Still_at_radisys.com
>
> Fat City Network Services -- 858-538-5051
> http://www.fatcity.com
> San Diego, California -- Mailing list and web
> hosting services
>
> To REMOVE yourself from this mailing list, send an
> E-Mail message
> to: ListGuru_at_fatcity.com (note EXACT spelling of
> 'ListGuru') and in
> the message BODY, include a line containing: UNSUB
> ORACLE-L
> (or the name of mailing list you want to be removed
> from). You may
> also send the HELP command for other information
> (like subscribing).
>
>
Stéphane Paquette
DBA Oracle, consultant entrepôt de données
Oracle DBA, datawarehouse consultant
stephane_paquette_at_yahoo.com
Do You Yahoo!? -- Une adresse @yahoo.fr gratuite et en français !
Yahoo! Mail :
http://fr.mail.yahoo.com
--
Please see the official ORACLE-L FAQ: http://www.orafaq.com
--
Author: =?iso-8859-1?q?paquette=20stephane?=
INET: stephane_paquette_at_yahoo.com
Fat City Network Services -- 858-538-5051 http://www.fatcity.com
San Diego, California -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from). You may
also send the HELP command for other information (like subscribing).
Received on Tue Sep 24 2002 - 13:53:27 CDT