Re: Seeking understanding of my "gc cr multi block request" waits

From: DA Morgan <damorgan_at_psoug.org>
Date: Thu, 19 Jul 2007 18:08:46 -0700
Message-ID: <1184893726.254157@bubbleator.drizzle.com>

sybrandb_at_hccnet.nl wrote:
> On Thu, 19 Jul 2007 09:36:32 -0700, DA Morgan <damorgan_at_psoug.org>
> wrote:
>

>> Would they let you go to 10g if you set optimizer_level to 1?

>
> I am afraid they don't know what 'optimizer_level 1' means. They
> already don't know what a database link is, and what it could do to
> merge 2 databases on 2 different sites.
> I am aware optimizer_level is already at 1 in the 9i database, I don't
> know whether it changes meaning in 10g.

The default in 10g is 2 and there is will be a 3 available in 11g. Though at least with the copy I have the default is still 2. I don't know if the released product will be 2 or 3.

> Frankly, this is the worst piece of Oracle software I ever saw. It
> fully qualifies to be included in Tom Kyte's upcoming 'Worst
> practices' web seminar.

That is going to be a tough competition to win there being so much horrendous garbage out there.

> They use ODBC as driver, and they always execute only 1 transaction
> per session. There currently only 42 transactions per minute.
> They use 31-byte varchar2 surrogate keys for everything, and as those
> key include the date and a sequence number those keys only increase
> (which is disastrous for index volume).

I know you are in a very small country ... but certainly there must be at least one job in the EU that would get you out of what seems like an exercise in extreme frustration.

> Right now, I've tested a few real statements, and it appears even
> without appropiate statistics CBO is providing better execution plans.
> Needless to say many columns are indexed which shouldn't have been
> indexed, and many columns which should have been indexed are not
> indexed. IOTs are not being used, and there are quite a few
> candidates.
> I seriously doubt whether they performed any statement tuning at all.
>
> I would like to avoid to disclose any more details in public, however
> I'm quite certain this is going to end up in disaster, and
> fingerpointing to an innocent DBA will start very soon.
>
> --
> Sybrand Bakker
> Senior Oracle DBA

Perhaps putting efforts into your CV would be a good use of your time. <g> Use me as a reference. <g>

-- 
Daniel A. Morgan
University of Washington
damorgan_at_x.washington.edu (replace x with u to respond)
Puget Sound Oracle Users Group
www.psoug.org

Received on Thu Jul 19 2007 - 20:08:46 CDT