Re: Data Buffer Cache

"Michael J. Moore" <hicamel_x_the_spam_at_attbi.com> wrote in message news:cNli9.365405$_91.469820_at_rwcrnsc51.ops.asp.att.net...
> Hi Joel,
> I could easily forgive a few errors but at last count it was 21. Granted,
> some were trivial, but others were misinformation. Not only is this an
> unreasonable amount of slop, The book does NOT prepare one for the
> Fundamentals 1 test. The question on the real test were significantly more
> difficult than any of the practice exams on the book or the CD that came
> with the book. Based on doing very good on the practice exams I though I
> would have little problem with the actual test. I failed it on the first
> pass, and that was $125 down the crapper.
>
> Had I been able to find either of the authors of this book I may have
taken
> some pleasure at ramming their book up their buffer cache to see if it
would
> indeed cause a log jam.
> Mike

LOL! As a bit of a serious aside, I don't think any 'cramming' books are an appropriate way to prepare for the OCP exams. Partly because they all contain errors, as you've noted. But also, mainly because anyone who wants to go to the effort of getting OCP presumably wants to do it "right" -ie, actually understand all this stuff, and not take regurgitated stuff by "experts" at face-value.

The only way to get it "right" is to play with it for real. Insofar as cramming books might make you think of tests to perform, and experiments to conduct, they have a use.

But I personally find plenty of guidance for future research projects available for free: just visit this newsgroup for an afternoon, and pick three or four typical posts as an indicator of the sort of problems you should be able to fix as a "real" DBA. Work on your play database at home until you find a solution. Then repeat at regular intervals.

Regards
HJR
>
> "Joel Garry" <joel-garry_at_home.com> wrote in message
> news:91884734.0209181542.f760ed3_at_posting.google.com...
> > "Michael J. Moore" <hicamel_x_the_spam_at_attbi.com> wrote in message
> news:<P43h9.435668$me6.49737_at_sccrnsc01>...
> > > Howard,
> > > Since you teach this stuff, you might be interested in my students
come
> to
> > > you with
> > > crazy ideas like mine. I know that you have flat out stated that this
> > > information
> > > is WRONG, but for the record, I'd like to give you the entire quote.
> > >
> > > On page 129 of OCP Oracle 9i Database: Fundimentals 1 Exam Guide it
> says:
> > >
> > > "The events that occur at log switch are as follows. First, LGWR stops
> > > writing
> > > the redo log it filled. Second CKPT signals the DBWn to fluch the
dirty
> > > buffers into
> > > the data files and finally CKPT updates the control files and the data
> file
> > > headers
> > > with the checkpoint information. With the checkpointing tasks
complete,
> the
> > > LGWR will be allowed to start writing into the next redo log group
with
> a
> > > new
> > > sequence number."the checkpointing tasks complete
> > >
> > >
> > > It seems clear that the authors intend us to understand that
> > > 1) LGWR 'waits' until it is "allowed to start writing".
> > > 2) What does it wait for? It waits for "the checkpointing tasks
> complete".
> > >
> > > Granted there is nothing here that says anything waits for DBWn to
> finish,
> > > but it seems that the author at least intends us to believe that LGWR
> waits
> > > for CKPT!
> > >
> > > Since I don't have the source code in hand, I can only take the word
of
> > > people like you.
> > > Perhaps if you have some pull with Oracle, you can get them to proof
> read
> > > their own
> > > damn documentation.
> > >
> > > <RANT> -- skip this if you are in a hurry.
> > >
> > > I have found more than 20 errors in the OCP Oracle 9i Database:
> Fundamentals
> > > 1 Exam Guide Authorized by Oracle Press! These are blatant errors that
> > > anybody can check for themselves such as 'you can determine the
current
> > > sequence number from V$CONTROLFILE_RECORD_SECTION' or 'alter datafile
> > > resize' is a command that can be used to increase the size of a
> tablespace.
> > > It is clear that NOBODY proof read this book. Over the years I have
> > > witnessed an ever increasing decline in the quality of published
> materials
> > > especially in the technical field. I think we deserve better. I don't
> think
> > > that Osborne press and others should be allowed to toss together books
> of
> > > such poor quality and charge the public $50.00 for the privilege of
> proof
> > > reading them. For this, I give Osborne and Oracle Press the highest
> position
> > > in my personal Publisher's Hall of Shame.
> >
> > I have found errors like this in every book. Some are so funny I
> > consider
> > them fodder for .sig's. But I'm too lazy, and of course I don't think
> > it
> > is really fair to hold a few typos or errors against someone who's
> > taken
> > the time to write a whole book. On the other hand, anything published
> > is,
> > and should be, fair game. I've had authors ask me to proof their
> > books,
> > and turned them down because inevitably I'm too busy doing actual
> > non-bleeding-edge work to give it a fair go (or else doing no work at
> > all and not have access to resources to check things!). The last time
> > anyone offered to _pay_ me todo such things was in college, and at the
> > time it didn't seem as much fun
> > as being a scientist (man, I wish they had Dexter's Laboratory when I
> > was
> > a kid!). With that as a preamble, I'd like to say I agree with the
> > rant
> > insofar as there is an industry to crank crap out, but overall the
> > quality
> > of information available about Oracle is as high as it's ever been,
> > and I
> > don't mean that as a slam. Oracle docs in the "old days" (7 and
> > before)
> > were notoriously bad at times, and the commercially available books
> > were
> > often vague or useless before 7, with some notable exceptions. I
> > still
> > haven't seen anything as bad as the Oracle on Solaris install guide
> > with the
> > instructions for a different unix. Maybe the Velpuri backup scripts
> > that were exactly the same for 7 and 8 (completely ignoring RMAN,
> > which was perhaps a good thing contemporaneously).
> >
> > I think as we learn more, it is easier to spot the little mistakes.
> > And we
> > should all post them in this ng for all-time reference (ever try to
> > download a corrections list from a site that no longer exists?). I'd
> > like to see
> > a thread of "funniest typos," myself.
> >
> > >
> > > </RANT>
> > >
> > >
> > >
> > > Sorry if this is becomming tedious for you.
> > >
> > > regards,
> > > Mike> >
> > > > Not true at all.
> > > >
> > > > Really, this is DBA-101. There is no mystery about it -or at least,
> there
> > > > shouldn't be. I teach this on Day 1 of the introductory DBA course.
> It's
> > > > basic stuff.
> > > >
> >
> > On usenet, nobody knows it's your first day.
> >
> > jg
> > --
> > @home is bogus.
> > "Two Tuning Rules of Thumb...Add more. Make it bigger." OCP 8i
> > Performance Tuning and Network Administration Study Guide.
>
>
Received on Thu Sep 19 2002 - 18:53:26 CDT