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@xxxxxxxxx> 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@xxxxxxxxx> 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
