Re: ASSM and tablespace fragmentation in a table that adds 140,140
- From: Randolf Geist <info@xxxxxxxxxxxxxxxxxxxxxxxxx>
- To: oracle-l@xxxxxxxxxxxxx
- Date: Sat, 04 May 2013 12:20:32 +0200
> Since ASSM uses different size extents, are there any issues with
> fragmentation? There was an Oracle-L thread dating from 2007 that discussed
> this.
You have to be very careful with all these acronyms - ASSM is about how the
blocks are managed within an extent
(MSSM freelist based vs. ASSM), so this is probably less relevant to what
you're actually looking for.
You seem to think more in terms of System Managed Extent sizes (also known as
AUTOALLOCATE) vs. UNIFORM extent size for Locally Managed Tablespaces.
You can have all kinds of combinations: AUTOALLOCATE with MSSM, UNIFORM with
ASSM, etc., however depending on the features you want to use (Bigfile
Tablespaces, Securefiles), in general the newer the features, they are no
longer supported with MSSM.
To address your question: System Managed Extents can be subject to
fragmentation - recently I got to know that the AU size adds another twist to
the allocation algorithm - I've posted about that here:
http://oracle-randolf.blogspot.de/2013/04/asm-au-size-and-lmt-autoallocate.html
Randolf
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Other related posts:
- » Re: ASSM and tablespace fragmentation in a table that adds 140,140 - Randolf Geist
