Re: 12c pluggable database shared SGA question
- From: Debaditya Chatterjee <debaditya.chatterjee@xxxxxxxxx>
- To: Stojan Veselinovski <stojan.veselinovski@xxxxxxxxx>
- Date: Wed, 17 Sep 2014 22:20:51 -0700
Correction the issue was fixed in the mid-2014.
Debaditya Chatterjee
On Wed, Sep 17, 2014 at 10:17 PM, Debaditya Chatterjee <
debaditya.chatterjee@xxxxxxxxx> wrote:
> 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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