Re: Do triggers cause a context switch between SQL & PL/SQL

I have always been puzzled by the expression "context switch" when talking about sql and pl/sql.

To me, a context switch is something that happens at the O/S level when a process is suspended by the scheduler and a different process is resumed. If a trigger fires on an insert/update/delete, this is obviously not happening - the only process executing is your Oracle server (dedicated or MTS) - so what activity is being given the name "context switch" ? Surely the Oracle process is 'simply' calling a sub-routine somewhere else in its code path (and building a stack and acquiring sub-heaps and ...).

Regards

Jonathan Lewis
http://www.jlcomp.demon.co.uk

  The educated person is not the person
  who can answer the questions, but the
  person who can question the answers -- T. Schick Jr

One-day tutorials:
http://www.jlcomp.demon.co.uk/tutorial.html

____UK_______April 8th
____UK_______April 22nd
____Denmark__May 21-23rd
____USA_(FL)_May 2nd

Three-day seminar:
see http://www.jlcomp.demon.co.uk/seminar.html

____UK_(Manchester)_May
____Estonia___June (provisional)
____USA_(CA, TX)_August

The Co-operative Oracle Users' FAQ
http://www.jlcomp.demon.co.uk/faq/ind_faq.html

• Original Message ----- To: "Multiple recipients of list ORACLE-L" <ORACLE-L_at_fatcity.com> Sent: 01 April 2003 19:19

> Since you the action switches from SQL to PL/SQL to enforce the
trigger,
> it sounds like a context switch to me.
>
> FYI: This can be improved somewhat by adding "and rownum < 2 " into
the
> WHERE clauses of these. There will be noticable improvement when
there
> are many child rows.
>
> Jared
>
>
>

-- 
Please see the official ORACLE-L FAQ: http://www.orafaq.net
-- 
Author: Jonathan Lewis
  INET: jonathan_at_jlcomp.demon.co.uk

Fat City Network Services    -- 858-538-5051 http://www.fatcity.com
San Diego, California        -- Mailing list and web hosting services
---------------------------------------------------------------------
To REMOVE yourself from this mailing list, send an E-Mail message
to: ListGuru_at_fatcity.com (note EXACT spelling of 'ListGuru') and in
the message BODY, include a line containing: UNSUB ORACLE-L
(or the name of mailing list you want to be removed from).  You may
also send the HELP command for other information (like subscribing).