Re: PGA_AGGREGATE_TARGET, AUTO PGA TARGET and WORKAREA_SIZE_POLICY

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>:

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

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