Re: 12c pluggable database shared SGA question
- From: Debaditya Chatterjee <debaditya.chatterjee@xxxxxxxxx>
- To: Stojan Veselinovski <stojan.veselinovski@xxxxxxxxx>
- Date: Wed, 17 Sep 2014 22:17:52 -0700
Hi Stojan,
Do you remember when you ran your tests ? Was it in early 2013 ? I remember
filing a similar issue with a query on cdb_segments for calculating space
usage in a cdb. We are probably referring to the same cloud control issue
here.
But that issue has been fixed with the mid-2013 release of the DB plug-in.
I cannot remember the plug-in version of the top of my head though.
Thanks
Deba
Debaditya Chatterjee
On Wed, Sep 17, 2014 at 8:33 PM, Stojan Veselinovski <
stojan.veselinovski@xxxxxxxxx> wrote:
> I think we also need to factor the bloat in the data dictionary when you
> consolidate so many databases in this multitenant world. At a previous
> workplace we were trialling a 12c multitenant environment and I tried a few
> scalability tests.
>
> I documented some of my findings here :
> http://www.stojanveselinovski.com/blog/2014/03/03/too-many-pdbs-part-2/
> but unfortunately I wasn't able to finish it off as I moved to greener
> pastures.
>
> What I found interesting is managing these pdbs with DB control was
> chewing up to 50% of the available cpu at times with parallel queries over
> the CDB_ views. There was no load on the system other than db control.
> Again, there wasn't much science to these tests and time constraints
> prevented any further analysis.
>
> Once management were aware of the costs of this PDB thing it got shut down
> pretty quickly. Just can't see many use cases for multitenancy at this
> price point.
>
> Stojan
> www.stojanveselinovski.com/blog
> www.stojanveselinovski.com
>
> On Wed, Sep 17, 2014 at 2:57 PM, Connor McDonald <
> mcdonald.connor@xxxxxxxxx> wrote:
>
>> Regarding "I am, however, skeptical that there is any problem getting
>> enough DRAM bolted to modern CPUs"
>>
>> This is true, but there (sadly) is large difference between what the
>> hardware is capable of, what the incredible cheap cost is.... versus some
>> infrastructure manager stuck in the 90's quibbling over an extra 16G to
>> bring the server up to a "ridiculous" 48G....
>>
>> sigh....
>>
>> I know some clients who are "excited" at multitenant as a way of reducing
>> their total SGA and they remain excited no matter how many times you tell
>> them just to head down the local IT shop and ffs just buy more RAM.....
>>
>>
>>
>>>
>>
>> --
>> Connor McDonald
>> ===========================
>> blog: connormcdonald.wordpress.com
>> web: http://www.oracledba.co.uk
>>
>> "If you are not living on the edge, you are taking up too much room."
>> - Jayne Howard
>>
>>
>
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