Re: To estimate maximum active sessions on my oracle database is reasonable to the approach?

Yes, Jonathan! I searched IMHO on Google which is "in my humble option", initially I thought IMHO is In-Memory and xxxxxx.

It's the same as *ASAP (as soon as possible)* - the abbreviation English words, I am very happy to learn something new from you.

Best Regards
Quanwen Zhao

Quanwen Zhao <quanwenzhao_at_gmail.com> 于2021年11月7日周日 下午6:28写道：

> Thanks for your reply, Jonathan 😊.
>
> Yes, AAS can be equivalent to *sessions* from v$parameter. At this moment
> I think the value of AAS is probably equal to *CPU_COUNT* from
> v$parameter because sessions are the affordable value for oracle database
> currently. In your case I guess that AAS is *8* (CPUs) and background
> processes are *3* according to your description because your query
> count(*) is *11*.
>
> In other words I should go to estimate maximum concurrent connections
> (processes from v$parameter), here I assume that my oracle database server
> is *DEDICATED* server thus one session represents one foreground process.
> Concurrent conections should include ACTIVE and INACTIVE sessions by
> session status (or FOREGROUND and BACKGROUND processes by session type).
> Active sessions should only contain those who are running *ON CPU* by
> session_tate from v$active_session_history. Hence it makes no sense that we
> are discussing active sessions, am I right to the prior understanding?
>
> Another kind of thought if I am able to estimate one CPU is allowed to run
> the maximum processes then I'll know all cores of CPUs' maximum processes
> (maximum concurrent connections on my oracle database server).
>
> Best Regards
> Quanwen Zhao
>
> Jonathan Lewis <jlewisoracle_at_gmail.com> 于2021年11月6日周六 下午5:48写道：
>
>>
>> AAS can be as large as the sessions parameter (minus some value for the
>> background processes). Here's a query and result from an instance running
>> on a machine with 8 CPUs.
>>
>> SQL> select sample_time, count(*) from V$active_session_history where
>> sample_time > sysdate - 10/(24*60*60) group by sample_time order by 1;
>>
>> SAMPLE_TIME COUNT(*)
>> -------------------------------- ----------
>> 06-NOV-21 09.42.23.785 AM 11
>> 06-NOV-21 09.42.24.809 AM 11
>> 06-NOV-21 09.42.25.814 AM 11
>> 06-NOV-21 09.42.26.817 AM 11
>> 06-NOV-21 09.42.27.819 AM 11
>> 06-NOV-21 09.42.28.827 AM 11
>> 06-NOV-21 09.42.29.830 AM 11
>> 06-NOV-21 09.42.30.847 AM 11
>> 06-NOV-21 09.42.31.860 AM 11
>> 06-NOV-21 09.42.32.869 AM 11
>>
>> 10 rows selected.
>>
>>
>> A session doesn't have to be "doing" anything to be active, it only has
>> to be in the middle of a database call. In this case all the sessions are
>> waiting on an attempt to "lock table X in exclusive mode" when the table is
>> already locked.
>>
>> Regards
>> Jonathan Lewis.
>>
>>
>> P.S. In case no-one answered: "IMHO" means "in my humble opinion".
>>
>>
>>
>>
>> On Mon, 1 Nov 2021 at 01:30, Quanwen Zhao <quanwenzhao_at_gmail.com> wrote:
>>
>>> Concurrent is not matter ACTIVE?
>>>
>>> The logic cpus is 192 on my oracle database server, so AAS is allowed to
>>> increase to 192 because an AAS of 1 is equivalent to 100% of a CPU core.
>>> Since AAS has a maximum value I am also able to estimate the maximum
>>> concurrent connections using the current concurrent connections by the
>>> proportion with current AAS and logic cpus.
>>>
>>> By the way what's IMHO?
>>>
>>> Best Regards
>>> Quanwen Zhao
>>>
>>>
>>>

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