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Home -> Community -> Mailing Lists -> Oracle-L -> RE: Locally managed tablespaces
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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
Hamilton
Sent: Wednesday, January 31, 2001 05:28
To: Multiple recipients of list ORACLE-L
Subject: 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:
When using locally managed tablespace, you should not have more extents than the number of extents that the segment header can hold in 1 block.
For a 8K block you should not have more than 505 extents.
The main drawback I see with lmt using uniform extent is if you want to change the extent size. You must drop/recreate the tablespace or migrate it to dictionnary managed ,make the change than migrate it back to locally managed.
Also, If all your tbs are locally managed you must have an online rollback segment in the system tablespace before putting all the other rbs offline (like in Oracle 7.1) .
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<DIV><FONT color=3D#0000ff face=3DArial size=3D2><SPAN =
class=3D615322918-31012001>I have=20
an 8k block size on 8.1.6 Win2K system, with LMT - UNIFORM extent =
size of=20
516k and a DEFAULT MAXEXTENTS of 2147483645 ! This I take it was the =
default, as=20
I didn't specify that on creation.. A little more than 505...=20
</SPAN></FONT></DIV>
<DIV><FONT color=3D#0000ff face=3DArial size=3D2><SPAN=20
class=3D615322918-31012001></SPAN></FONT> </DIV>
<DIV><FONT color=3D#0000ff face=3DArial size=3D2><SPAN=20
class=3D615322918-31012001>Regards</SPAN></FONT></DIV>
<DIV><FONT color=3D#0000ff face=3DArial size=3D2><SPAN=20
class=3D615322918-31012001></SPAN></FONT> </DIV>
<DIV><FONT color=3D#0000ff face=3DArial size=3D2><SPAN=20
class=3D615322918-31012001>Mark</SPAN></FONT></DIV>
<BLOCKQUOTE>
<DIV align=3Dleft class=3DOutlookMessageHeader dir=3Dltr><FONT =
face=3DTahoma=20
size=3D2>-----Original Message-----<BR><B>From:</B> root_at_fatcity.com=20
[mailto:root_at_fatcity.com]<B>On Behalf Of </B>Chuck =
Hamilton<BR><B>Sent:</B>=20
Wednesday, January 31, 2001 05:28<BR><B>To:</B> Multiple recipients of =
list=20
ORACLE-L<BR><B>Subject:</B> RE: Locally managed=20
tablespaces<BR><BR></DIV></FONT>
<P>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=20
approximately 256k bits for the bitmap per datafile. If each bit =
represents=20
one extent, I'd expect to be able to have a lot more than 505 extents. =
<P> <B><I>paquette stephane =
<stephane_paquette_at_yahoo.com></I></B>=20
wrote: <BR>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #1010ff 2px solid; MARGIN-LEFT: 5px; =
PADDING-LEFT: 5px">When=20
using locally managed tablespace, you should not<BR>have more =
extents than=20
the number of extents that the<BR>segment header can hold in 1=20
block.<BR><BR>For a 8K block you should not have more than=20
505<BR>extents.<BR><BR>The main drawback I see with lmt using =
uniform=20
extent<BR>is if you want to change the extent size. You=20
must<BR>drop/recreate the tablespace or migrate it to<BR>dictionnary =
managed=20
,make the change than migrate it<BR>back to locally =
managed.<BR><BR>Also, If=20
all your tbs are locally managed you must<BR>have an online rollback =
segment=20
in the system<BR>tablespace before putting all the other rbs=20
offline<BR>(like in Oracle 7.1) .<BR><BR><BR>--- "Malkuns, Skip"=20
<SMALKUNS_at_SYSTEMS.TEXTRON.COM>a<BR>icrit : > Is anyone using =
LMTSs?=20
What is the largest<BR>number of<BR>> extents that an =
object<BR>>=20
has?<BR>> Notice any performance difference between LMTS =
and<BR>>! ! ;=20
Locally managed<BR>> tablespaces??<BR>> Had any problems with=20
LMTS?<BR>> Skip<BR>> <BR>> > -----Original =
Message-----<BR>>=20
> From: The Oracle DBA [SMTP:theoracledba_at_lycos.com]<BR>> > =
Sent:=20
Tuesday, January 30, 2001 2:11 PM<BR>> > To: Multiple =
recipients of=20
list ORACLE-L<BR>> > Subject: Re: Locally managed =
tablespaces<BR>>=20
> <BR>> > Has anyone taken a PROD DB and changed it to=20
using<BR>> LMTSs and then noticed<BR>> > a perf change + or =
-?<BR>> > <BR>> > ---<BR>> > <BR>> >=20
TheOracleDBA<BR>> > theoracledba_at_lycos.com<BR>> > =
<BR>> >=20
<BR>> > <BR>> > On Tue, 30 Jan 2001 10:30:29 <BR>> =
>=20
Bunyamin K.Karadeniz wrote:<BR>> > > But some had claimed =
that=20
Locally managed<BR>> tablespaces are slower. I<BR>> > =
do<BR>>=20
> >not know if it is correct but you must consider<BR>> it=20
.<BR>> > > And I wonder the performance results too.<BR>! ! =
>=20
> >----- Original Message -----<BR>> > >To: Multiple=20
recipients of list ORACLE-L<BR>> <ORACLE-L_at_FATCITY.COM><BR>> =
>=20
>Sent: Tuesday, January 30, 2001 3:35 PM<BR>> > =
><BR>> >=20
><BR>> > >> I have always been concerned with=20
fragmentation<BR>> of tablespaces, whether<BR>> > =
it<BR>> >=20
>> be lots of extents, honeycomb or<BR>> > >> =
bubble=20
fragmentation. Now I am reading that in<BR>> Oracle 8i with the=20
use<BR>> > of<BR>> > >> locally-managed table=20
spaces,<BR>> > >> these concerns are a thing of the past =
as<BR>> Oracle now uses bit maps<BR>> > within<BR>> > =
>> the tablespaces themselves to<BR>> > >> do =
space=20
management. This seems foreign to me<BR>> that even though =
Oracle<BR>>=20
> will<BR>> > >> use up all the space in<BR>> > =
>> the tablespaces with no coalescing, it is OK<BR>> that =
extents=20
will! ! go into<BR>> > >the<BR>> > >> thousands =
with no=20
performance degradation.<BR>> > >> Could folks who are =
currently=20
using locally<BR>> managed tablespaces please<BR>> > =
>>=20
comment on how well it<BR>> > >> is working for them and =
if they=20
have<BR>> experienced any problems in using<BR>> >=20
>them.<BR>> > >> Thanks<BR>> > >> =
Skip<BR>>=20
> >> Here is a good white paper on the subject.<BR>> =
>=20
>><BR>> =
http://www.embarcadero.com/news/white_papers.htm<BR>>=20
> >> --<BR>> > <BR>> -- <BR>> Please see the =
official=20
ORACLE-L FAQ:<BR>> http://www.orafaq.com<BR>> -- <BR>> =
Author:=20
Malkuns, Skip<BR>> INET: SMALKUNS_at_SYSTEMS.TEXTRON.com<BR>> =
<BR>>=20
Fat City Network Services -- (858) 538-5051 FAX:<BR>> (858)=20
538-5051<BR>> San Diego, California -- Public Internet<BR>> =
access /=20
Mailing Lists<BR>><BR>----------------------------------! !=20
----------------------------------<BR>> To REMOVE yourself from =
this=20
mailing list, send an<BR>> E-Mail message<BR>> to:=20
ListGuru_at_fatcity.com (note EXACT spelling of<BR>> 'ListGuru') and =
in<BR>> the message BODY, include a line containing: =
UNSUB<BR>>=20
ORACLE-L<BR>> (or the name of mailing list you want to be =
removed<BR>>=20
from). You may<BR>> also send the HELP command for other=20
information<BR>> (like =
subscribing).<BR><BR><BR>=3D=3D=3D=3D=3D<BR>Stephane=20
Paquette<BR>DBA=20
=
Oracle<BR>stephane_paquette_at_yahoo.com<BR><BR>____________________________=
______________________<BR>Get=20
personalized email addresses from Yahoo! Mail - only $35 <BR>a year! =
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FAQ: http://www.orafaq.com<BR>-- <BR>Author:=20
=3D?iso-8859-1?q?paquette=3D20stephane?=3D<BR>INET:=20
stephane_paquette_at_yahoo.com<BR><BR>Fat City Network Services -- =
(858)=20
538-5051 FAX: (858) 538-5051<BR>San Diego, California -- Public =
Internet=20
access / Mailing Lis! !=20
=
ts<BR>-------------------------------------------------------------------=
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REMOVE yourself from this mailing list, send an E-Mail =
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Received on Wed Jan 31 2001 - 12:35:25 CST
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