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Tom Kyte

Thanks for the question, Ashish.

Asked: July 17, 2000 - 2:36 pm UTC

Last updated: March 02, 2005 - 9:27 am UTC

Version: 8.1.5

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You Asked

Hi Tom,

I wanted to know the max number of session the instance had without shutting down the database. Is it possible? if yes then how?
Is licence water mark in alert log corresponds to max session of the instance before it shut down?

Thanks,

rgds,
ashish

and Tom said...

A simple "select * from v$license" in sqlplus will give you this and other tidbits of information about the number of sessions in your database since its been started.

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v$license view - sessions_highwater

Pravesh karthik from chennai, December 30, 2004 - 1:41 am UTC

Tom,

I ran in to ORA-00020: maximum number of processes () exceeded.

To set the processes value, i checked v$license
</code> http://metalink.oracle.com/metalink/plsql/ml2_documents.showDocument?p_database_id=NOT&p_id=43722.1 <code>

SESSIONS_HIGHWATER
NUMBER
Highest number of concurrent user sessions since the instance started



SESSIONS_MAX SESSIONS_WARNING SESSIONS_CURRENT SESSIONS_HIGHWATER USERS_MAX
------------ ---------------- ---------------- ------------------ ----------
0 0 13 18 0

It shows me only 18. Though i could resolve the error with increasing the value to 350. I wanted to know, if we can relate the v$license view - sessions_highwater value to set this parameter ..if not, please let me know why?

Thanks for your consideration

Pravesh karthik

Tom Kyte
December 30, 2004 - 10:42 am UTC

did you happen to bounce the database when you hit the max processes.

v$ tables are "reset" during a restart.

but you don't mention what processes USED to be, so no clues.

v$license view - sessions_highwater

Pravesh Karthik from chennai, December 30, 2004 - 11:40 am UTC

Tom,

I am not sure, if some one in dba team restarted it. The processes value was 150 when it happened.

In case, if its not restarted, will this value SESSIONS_HIGHWATER can be used to set the processes value?
can i relate the v$license view -
sessions_highwater value to set processes parameter .


Thanks
Pravesh Karthik

Tom Kyte
December 30, 2004 - 11:45 am UTC

(v$instance will show you when the instance was started, as will the alert log, you can tell)



assuming you are using DEDICATED server

assuming you are using a PROCESS per SESSION (eg: you are not starting multiple sessions via a single process)


well, no -- not really. think about it -- if you make those assumptions, the session max will be bounded by processes so it would be a self fullfilling prophecy :) If you use this to SET processes, but this number is itself BOUNDED BY processes -- catch 22.


You as the DBA should have an idea of the number of concurrent sessions you need to support. From there, setting sessions/processes is possible.

A reader, March 02, 2005 - 9:27 am UTC