Comments on: Shared Servers and Automatic Workarea Management

By: Fran Zolick

Fran Zolick — Mon, 29 Oct 2007 19:05:26 +0000

Please ignore my previous email, I just found out that SID is part of the user system conext.

By: Fran Zolick

Fran Zolick — Mon, 29 Oct 2007 17:19:49 +0000

How can you find out the SID if one user can have multiple sessions

By: Hesham

Hesham — Mon, 20 Aug 2007 10:44:41 +0000

Thank you Alex

By: Alex Fatkulin

Alex Fatkulin — Thu, 16 Aug 2007 14:03:28 +0000

Hesham, logon trigger could be like this:

SQL> create trigger logon_trigger after logon on database
2 begin
3 for cur in (
4 select null
5 from v$session
6 where sid=sys_context(’userenv’, ’sid’)
7 and server=’SHARED’
8 ) loop
9 execute immediate ‘alter session set workarea_size_policy=manual’;
10 end loop;
11 end;
12 /

Trigger created.

Changing this at instance level will affect, well, instance instead of a session. This can be appropriate if you do not want Oracle instance to use auto pga memory management by “default”.

By: Hesham

Hesham — Thu, 16 Aug 2007 09:30:07 +0000

dear friends ,
first : can you explain how can i create this trigger to change workarea_size_policy to manual on session level ?

what will happen if i change all things on instance level ?

thank you

By: Alex Fatkulin

Alex Fatkulin — Fri, 29 Jun 2007 14:03:56 +0000

Hesham,

you would use alter session instead of alter system of course…

I mistyped.

By: Alex Fatkulin

Alex Fatkulin — Thu, 28 Jun 2007 23:54:09 +0000

Hesham,

just use a logon trigger. Recognize the shared server connection (by looking at v$session.server) and do an alter system set workarea_size_policy=manual if it’s a shared server session.

By: Hesham

Hesham — Thu, 28 Jun 2007 09:04:04 +0000

Dear friend ,

can you tell me Alex how you can do that

“set pga_aggregate_target on instance level and workarea_size_policy=manual for certain shared sessions ”

thank you

By: yumianfeilong

yumianfeilong — Thu, 21 Jun 2007 02:14:23 +0000

nice and good point.10g automatic managed pga enable SQL WORK AREA allocated in PGA under MTS mode.
We will also notice this issue when using workarea_size_policy=AUTO.

By: Alex Gorbachev

Alex Gorbachev — Wed, 20 Jun 2007 21:05:26 +0000

Hey, who is there! Welcome to the English blogosphere! ;-)

Good catch, by the way. So we can set pga_aggregate_target on instance level and workarea_size_policy=manual for certain shared sessions exhibiting thus buggy behavior.

By the way, you reminded me about a similar issue I hit with shared servers. But that is a good topic for another blog.