RE: Locally managed tablespaces

From: Mark Leith <mark_at_cool-tools.co.uk>
Date: Wed, 31 Jan 2001 11:00:44 -0800
Message-ID: <F001.002A60AC.20010131103715@fatcity.com>

I have
an 8k block size on 8.1.6 Win2K system, with LMT - UNIFORM extent size of 516k and a DEFAULT MAXEXTENTS of 2147483645 ! This I take it was the default, as I didn't specify that on creation.. A little more than 505...

Regards

Mark

-----Original Message-----From: root_at_fatcity.com [mailto:root_at_fatcity.com]On Behalf Of Chuck HamiltonSent: Wednesday, January 31, 2001 05:28To: Multiple recipients of list ORACLE-LSubject: RE: Locally managed
 tablespaces
 Where did you get the number 505 from? I read somewhere that 64k is allocated at the beginning of each datafile in a LMT for a bitmap yielding approximately 256k bits for the bitmap per datafile. If each bit represents one extent, I'd expect to be able to have a lot more than 505 extents. paquette stephane <stephane_paquette_at_yahoo.com> wrote:
 <BLOCKQUOTE
 style="BORDER-LEFT: #1010ff 2px solid; MARGIN-LEFT: 5px; PADDING-LEFT: 5px">When using locally managed tablespace, you should nothave more extents than the number of extents that thesegment header can hold in 1 block.For a 8K block you should not have more than 505extents.The main drawback I see with lmt using uniform extentis if you want to change the extent size. You mustdrop/recreate the tablespace or migrate it todictionnary managed ,make the change than migrate itback to locally managed.Also, If all your tbs are locally managed you musthave an online rollback segment in the systemtablespace before putting all the other rbs offline(like in Oracle 7.1) .--- "Malkuns, Skip" aicrit : > Is anyone using LMTSs?
 What is the largestnumber of> extents that an object> has?> Notice any performance difference between LMTS and>! ! ; Locally managed> tablespaces??> Had any problems with LMTS?> Skip> > > -----Original Message----->
> From: The Oracle DBA [SMTP:theoracledba_at_lycos.com]> > Sent:
 Tuesday, January 30, 2001 2:11 PM> > To: Multiple recipients of list ORACLE-L> > Subject: Re: Locally managed tablespaces>
> > > Has anyone taken a PROD DB and changed it to
 using> LMTSs and then noticed> > a perf change + or -?> > > > ---> > > >
 TheOracleDBA> > theoracledba_at_lycos.com> > > >
> > > > On Tue, 30 Jan 2001 10:30:29 > >
 Bunyamin K.Karadeniz wrote:> > > But some had claimed that Locally managed> tablespaces are slower. I> > do>
> >not know if it is correct but you must consider> it
 .> > > And I wonder the performance results too.! ! >
> >----- Original Message -----> > >To: Multiple
 recipients of list ORACLE-L> > >
 >Sent: Tuesday, January 30, 2001 3:35 PM> > >> > >> > >> I have always been concerned with fragmentation> of tablespaces, whether> > it> > >> be lots of extents, honeycomb or> > >> bubble fragmentation. Now I am reading that in> Oracle 8i with the use> > of> > >> locally-managed table spaces,> > >> these concerns are a thing of the past as> Oracle now uses bit maps> > within> >

    >> the tablespaces themselves to> > >> do space 
    management. This seems foreign to me> that even though Oracle>

> will> > >> use up all the space in> >
>> the tablespaces with no coalescing, it is OK> that extents will! ! go into> > >the> > >> thousands with no performance degradation.> > >> Could folks who are currently using locally> managed tablespaces please> > >> comment on how well it> > >> is working for them and if they have> experienced any problems in using> >

    >them.> > >> Thanks> > >> Skip> 


    > >> Here is a good white paper on the subject.> > 

    >>> http://www.embarcadero.com/news/white_papers.htm>

> >> --> > > -- > Please see the official
ORACLE-L FAQ:> http://www.orafaq.com> -- > Author: Malkuns, Skip> INET: SMALKUNS_at_SYSTEMS.TEXTRON.com> > Fat City Network Services -- (858) 538-5051 FAX:> (858)

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