Re: PGA_AGGREGATE_TARGET, AUTO PGA TARGET and WORKAREA_SIZE_POLICY

I don't think that Ram needs oratap and mmap/munmap calls. That is a bit too much details.

Regards

On 10/09/2017 03:20 PM, Franky Weber Faust wrote:
> Hi Raman,
>
> Also take a look at some articles, written by Frits Hoogland, which he
> shows a deep dive into PGA allocation:
> https://fritshoogland.wordpress.com/?s=pga
>
>
> /Kind regards / Cordialmente / Saludos cordiales / Sincères amitiés
> / Mit freundlichen Grüßen / Cordiali saluti,/
>
> Franky Weber Faust
> Oracle DBA
> Skype: franky.faust
>
> 2017-10-09 16:06 GMT-03:00 Mladen Gogala <gogala.mladen_at_gmail.com
> <mailto:gogala.mladen_at_gmail.com>>:
>
> Hi Ram,
>
> SYS processes are exempt from almost any limitations. You should
> never, ever log into database as SYS, especially if the database
> is 12c. Previous releases could have not been backed up without
> logging in as SYS, but 12c has a special role called "SYSBACKUP"
> which allows the database to backed up without logging in as SYS.
> Logging in as SYS means that you are doing database maintenance.
> Period. In such context, it doesn't matter how much PGA is burned
> by the user SYS.
>
> As for the untunable memory, the expression refers to the segments
> over which the administrator has no control, like code, stack and
> bss. Overall memory parameters are controlled by the OS. For
> Linux, the page I usually recommend is the following:
>
> https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Performance_Tuning_Guide/s-memory-tunables.html
> <https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Performance_Tuning_Guide/s-memory-tunables.html>
>
> PS:
> ----
> Untunable memory is also defined by an undocumented parameter
> _ora_alzheimer_max_size.
>
>
>
> On 10/09/2017 02:30 PM, Ram Raman wrote:
>> Thanks, I did not realize that SYS' processes are exempted from
>> that limit. So, it is still possible for the usage to exceed PAL,
>> even in 12c.
>>
>> Can someone explain what is "most untunable memory" ?
>>
>>
>> On Fri, Oct 6, 2017 at 5:57 PM, Mladen Gogala
>> <gogala.mladen_at_gmail.com <mailto:gogala.mladen_at_gmail.com>> wrote:
>>
>> Hi Ravi,
>>
>> I know that this is unexpected, but Oracle actually puts the
>> documentation on the Internet for free. The first thing I
>> would try is this:
>>
>> https://docs.oracle.com/database/121/REFRN/GUID-E364D0E5-19F2-4081-B55E-131DF09CFDB3.htm#REFRN10328
>> <https://docs.oracle.com/database/121/REFRN/GUID-E364D0E5-19F2-4081-B55E-131DF09CFDB3.htm#REFRN10328>
>>
>> This document has a section with the title "What happens when
>> PGA_AGGREGATE_LIMIT is exceeded". I will not ruin you the
>> pleasure of reading the documentation by telling you the ending.
>>
>> Regards
>>
>>
>> On 10/06/2017 06:05 PM, Ravi Teja Bellamkonda wrote:
>>> It would be really helpful if someone can throw some light
>>> on this. I understand that workarea_size_policy parameter
>>> set to auto is related to this. But wanted to confirm that
>>> PGA used actually crosses the PGA_AGGREGATE_LIMIT. Is there
>>> any documentation which states that PGA_AGGREGATE_LIMIT is a
>>> soft limit.
>>>
>>> It would be very helpful, if someone can clarify.
>>>
>>> --
>>> Thanks & Regards,
>>> Ravi Teja
>>
>> --
>> Mladen Gogala
>> Oracle DBA
>> Tel:(347) 321-1217 <tel:%28347%29%20321-1217>
>>
>>
>>
>>
>> --
>>
>
> --
> Mladen Gogala
> Oracle DBA
> Tel: (347) 321-1217
>
>

-- 
Mladen Gogala
Oracle DBA
Tel: (347) 321-1217


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