RE: Dynamic re-mastering in RAC

  • From: "Hameed, Amir" <Amir.Hameed@xxxxxxxxx>
  • To: <racdba@xxxxxxxxxxxxx>
  • Date: Mon, 1 Aug 2005 22:25:19 -0400

Thanks KG!
Interesting. I just checked in my and databases and
parameter _lm_dynamic_remastering is set to FALSE (the default is TRUE).
Since this is a hidden parameter and therefore is not meant to be set
without Oracle's permission, I wonder why Oracle 9i manuals talk about
Dynamic Remastering if it is not  available out-of-the box in 9i2. Also,
is the reason that it is not available out-of-the-box is because the
algorithm in 9i2 is not that effective?
Any thoughts...

-----Original Message-----
From: racdba-bounce@xxxxxxxxxxxxx [mailto:racdba-bounce@xxxxxxxxxxxxx]
On Behalf Of K Gopalakrishnan
Sent: Monday, August 01, 2005 8:56 PM
To: racdba@xxxxxxxxxxxxx
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: Dynamic re-mastering in RAC


The right answer to your question is it depends. There is no dynamic
remastering in 9i RAC other than in 9204/9205 where the parameter
(only) _lm_dynamic_remastering is set to true.

In 10gR1 dynamic remastering is set at file level and starting from R2
the dynamic remastering is done at FILE+OBJECT Level. But conditions
are very stringent. For example one instance should touch the blocks
(of that object) 50 times more than the other instance in particular
period (say 10 mins). These touch ratio and time can be tuned by
_gc_affinity_limit and _gc_affinity_time parameters.


On 8/2/05, Hameed, Amir <Amir.Hameed@xxxxxxxxx> wrote:
> Folks, 
> Is dynamic re-mastering done at the file-level or at the block level?
> is, does an instance master the entire datafile or only those blocks
> were repeatedly accessed from its buffer cache in a certain file? Is
there a
> way to identify/tell which file/block is mastered by a certain
> Thanks 
> Amir 

Best Regards,
K Gopalakrishnan 
Co-Author: Oracle Wait Interface, Oracle Press 2004


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