Home » RDBMS Server » Server Administration » Quick LMT Question (10.2.0.4)
Quick LMT Question [message #329020] Mon, 23 June 2008 13:57 Go to next message
coleing
Messages: 213
Registered: February 2008
Senior Member
Hi All,

Quick question hopefully.

I have converted some tablespaces from DICTIONARY managed to LOCALLY managed.

The ALLOCATION_TYPE in DBA_TABLESPACES is now showing as USER.

Although the Oracle documentation states that this is expected, does it mean that it is now allocating space incrementally, or uniformly? (since I could usually tell this from the ALLOCATION_TYPE).

Or is it just doing the same as it was before the conversion to LMT (ie, using initial and next extent and pct_increase?).
Re: Quick LMT Question [message #329052 is a reply to message #329020] Mon, 23 June 2008 23:22 Go to previous messageGo to next message
Michel Cadot
Messages: 63802
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
It is NOT a good idea to convert a tablespace from DMT to LMT, you should create a new LMT one and mobe the objects then you have a pure LMT tablespace.
Converting a tablespace result into a "mixed" tablespace that can't take benefit of all LMT properties.

Regards
Michel
Re: Quick LMT Question [message #329266 is a reply to message #329020] Tue, 24 June 2008 15:43 Go to previous messageGo to next message
coleing
Messages: 213
Registered: February 2008
Senior Member
Ok thanks.

Thats good enough for me.
Re: Quick LMT Question [message #329427 is a reply to message #329020] Wed, 25 June 2008 07:16 Go to previous messageGo to next message
varu123
Messages: 754
Registered: October 2007
Senior Member
Quote:
Converting a tablespace result into a "mixed" tablespace that can't take benefit of all LMT properties.


For example...?
Re: Quick LMT Question [message #329438 is a reply to message #329427] Wed, 25 June 2008 07:38 Go to previous messageGo to next message
Michel Cadot
Messages: 63802
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
No fragmentation that is no free hole that can't be reused.

Regards
Michel
Re: Quick LMT Question [message #329562 is a reply to message #329020] Wed, 25 June 2008 18:01 Go to previous messageGo to next message
coleing
Messages: 213
Registered: February 2008
Senior Member
I think he means that there are many benefits to LMT (like the auto allocation, re-use of space etc), however doing a conversion only gives you better performance on the issue of block header contention, as its held as a bitmap file, instead of serially updated in the dictionary. (FET$)

Thats if my understanding is correct?
Re: Quick LMT Question [message #329580 is a reply to message #329562] Wed, 25 June 2008 23:01 Go to previous messageGo to next message
Michel Cadot
Messages: 63802
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
This is correct.

Regards
Michel
Re: Quick LMT Question [message #422661 is a reply to message #329580] Fri, 18 September 2009 03:21 Go to previous messageGo to next message
QuickGun
Messages: 8
Registered: September 2009
Location: SG
Junior Member
Hi Michel,

One question!
How do you rate the performance between DMT and LMT?

How to decide if my tablespace should be DMT or LMT?

oh.. ya.. 2 questions Smile
Re: Quick LMT Question [message #422664 is a reply to message #422661] Fri, 18 September 2009 03:30 Go to previous messageGo to next message
Michel Cadot
Messages: 63802
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
No more use DMT, it is an obsolete feature.

Regards
Michel
Re: Quick LMT Question [message #422665 is a reply to message #422664] Fri, 18 September 2009 03:35 Go to previous messageGo to next message
QuickGun
Messages: 8
Registered: September 2009
Location: SG
Junior Member
oh... ok.
But I am on oracle 8i. Sad

From the above discussion, i understand LMT is better then DMT...
Is my understanding correct?

Re: Quick LMT Question [message #422668 is a reply to message #422665] Fri, 18 September 2009 04:00 Go to previous messageGo to next message
Michel Cadot
Messages: 63802
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
Maybe not on 8i.

Regards
Michel
Re: Quick LMT Question [message #422669 is a reply to message #422668] Fri, 18 September 2009 04:11 Go to previous messageGo to next message
QuickGun
Messages: 8
Registered: September 2009
Location: SG
Junior Member
hmmm... in that case,
i would leave the system tablespaces to be DMT and the rest to LMT?

Will that benefit me? atleast NOT srew up the system?
Re: Quick LMT Question [message #422670 is a reply to message #422669] Fri, 18 September 2009 04:28 Go to previous message
Michel Cadot
Messages: 63802
Registered: March 2007
Location: Nanterre, France, http://...
Senior Member
Account Moderator
You have no choice in 8i, SYSTEM tablespace must be in DMT.

Regards
Michel
Previous Topic: ORA-00600
Next Topic: Oracle database 10g critical patches
Goto Forum:
  


Current Time: Mon Sep 26 04:20:04 CDT 2016

Total time taken to generate the page: 0.12433 seconds