Re: data file compact

Firstly the RBS will not be fixed by an import/export. This tablespace is a special case used by your Roll back segments. Check that only rollback segments are being created in this tablespace. If your not sure about rollbacks read
http://otn.oracle.com/docs/products/oracle8i/doc_library/817_doc/server.817/ a76956/archredo.htm#5860, you may have to subscribe to OTN to get this but its worth it as OTN is a good resource and has all the Oracle docs online! This is a section 7 of the Administrators Guide which you should also have on a documentation CD if you it and the rest of the Oracle documentation is up on OTN at http://otn.oracle.com/docs/products/oracle8i/content.html.

In the info you read it said "Extents in locally managed tablespaces are not represented in the data dictionary at all. Free space is represented in a bitmap that is stored in the tablespace itself, and used extents are only recorded in the extent map in the segment header block of each segment, and if necessary, in additional extent map blocks within the segments.".... that's the main difference, the information on how to find your extents is stored inside the locally managed tablespace not in the dictionary. The major advantage of this is that when you need to allocate or de-allocate an extent you don't have to compete in a queue for the data dictionary with all the other tablespaces. In his Q&A bit,
http://www.ixora.com.au/q+a/0104/11095147.htm, Steve gives a good when to, when not to description of use of locally managed tablespaces.

Kind Regards

Fraser McCallum
MVP Oracle Administration
www.brainbench.com

"ed zappulla" <zappullae_at_rcn.com> wrote in message news:9sr7et$fgm$1_at_bob.news.rcn.net...
> Hi Fraser,
>
> I read the info about extents and understand. But What is ment by "localy
> managed"?
>
> We only have 2 table spaces that need work, RBS and USERS.
>
>
> "ed zappulla" <zappullae_at_rcn.com> wrote in message
> news:9sm2pj$bq1$1_at_bob.news.rcn.net...
> > Thanks for the help. Same for the help from Sybrand.
> >
> > We do a nightly export so I can kill the table space and recreate to
> reclaim
> > space.
> >
> > i'm not sure what you mean by, uniform extent size?
> >
> > I will defiitly check out the link.
> >
> >
> > "Fraser McCallum" <fmcc_at_NOSPAModbaguru.com> wrote in message
> > news:%HeH7.4648$ax1.49253_at_NewsReader...
> > > Ed,
> > >
> > > Try Alter tablespace xxxx coalesce;
> > >
> > > This will do the defragmentation of free space, what this means is
that
> if
> > > there are two segments of free space next to each other it will make
> them
> > > one larger segment. However it does not shrink datafile nor does it
> > > rearrange the contents of the tablespace to compact the data.
> > >
> > > You can shrink a datafile (look up alter datafile) if and only if
there
> is
> > > no data at the tail end of it.
> > >
> > > I suspect your real problem is a lack of uniform extent size. The best
> > space
> > > allocation comes when you choose table and index sizes using uniform
> > extent
> > > sizes. Rather than re hashing what's been said well else where suggest
> you
> > > look at http://www.ixora.com.au/tips/creation/extents.htm for a good
> > > explanation of what I'm talking about.
> > >
> > > Ultimately I would suggest, and this is my personal preference, a
> > > reorganisation of your database into locally managed tablespaces with
> > > uniformed extent sizes.
> > >
> > > Kind Regards
> > >
> > > Fraser McCallum
> > > MVP Oracle Administration
> > > www.brainbench.com
> > >
> > > "ed zappulla" <zappullae_at_rcn.com> wrote in message
> > > news:9sjqj3$oks$1_at_bob.news.rcn.net...
> > > > Compacting refers to the process where by holes in data files are
> > > > deframented and the data file shrunk to release unused space.
> > > >
> > > > We do have the table spaces on auto extend. purposfully. our
thought
> > was
> > > > that it was needed to allow for growth.
> > > >
> > > > Dose Oracle not reuse table space if auto extend is on, extend
before
> > > > reusing freed space?
> > > >
> > > >
> > > > "Sybrand Bakker" <postbus_at_sybrandb.demon.nl> wrote in message
> > > > news:tuqhjc537ah764_at_corp.supernews.com...
> > > > >
> > > > > "ed zappulla" <zappullae_at_rcn.com> wrote in message
> > > > > news:9sjedu$c8j$1_at_bob.news.rcn.net...
> > > > > > Is there a way to compact the data files that oracle 8.1.6 uses?
> > They
> > > > > seem
> > > > > > to be growing very large while the amount of data an indexs held
> > > remains
> > > > > the
> > > > > > same.
> > > > > >
> > > > > >
> > > > > >
> > > > >
> > > > > There is no mechanism to 'compact' the datafiles, whatever you may
> > mean
> > > by
> > > > > compacting.
> > > > > Please check whether you have any tablespace(s) on autoextend.
This
> > must
> > > > be
> > > > > the case otherwise datafiles wouldn't grow. Please also check how
> much
> > > of
> > > > > the allocated space is actually occupied.
> > > > > If you don't know how to do that please read the Oracle Server
> > > > > Administrators Manual.
> > > > >
> > > > > Hth
> > > > > --
> > > > > Sybrand Bakker
> > > > > Senior Oracle DBA
> > > > >
> > > > > to reply remove '-verwijderdit' from my e-mail address
> > > > >
> > > > >
> > > > >
> > > > >
> > > >
> > > >
> > >
> > >
> >
> >
>
>
Received on Tue Nov 13 2001 - 08:58:29 CST