i guess my question wasnt clear. What Im getting at is do other databases have wait 
interfaces? Is there architecture such that Physical I/Os are a serious concern. Far 
more than other bottlenecks. Or is this book just garbage... 
> 
> From: Daniel Fink <[EMAIL PROTECTED]>
> Date: 2003/10/02 Thu PM 01:09:36 EDT
> To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]>
> Subject: Re: Physical I/O and databases other than oracle
> 
> This is not an issue of answering the question, but pointing out that the question 
> is not correct.
> 
> Why do databases exist (aside to make Larry money)? To 'permanently' store data. As 
> this storage must survive a system failure, we choose to place the data on a 
> non-volatile medium (disk, paper, stone tablets). In order to save and retrieve this 
> data, we need to perform some sort of physical action (write/read). Let's take the 
> telephone system as an example. If we need to look up a phone number, we open the 
> phone book and do a search for the right entry. This can be rather time consuming, 
> especially if we don't know the person's last name or business name. Let's assume we 
> do know the last name, we can get to the proper entry
> fairly quickly, but it still takes some time. Once we have retrieved the information 
> into our memory, we can dial the phone fairly quickly. In this case, the bottleneck 
> is indeed physical i/o. Of course, if we get a busy signal, we can access our memory 
> to redial, completely bypassing the phone book. However, if we are using an old 
> rotary dial phone and we have to make a long distance call, it may take longer to 
> dial the phone than look up the number.
> 
> The real question should be "What is the primary bottleneck in presenting data to 
> the user?"  In my recent projects, I have found that the database is rarely the 
> bottleneck. I have seen bad code, cpu-starvation, spooling to RAID-5 devices, 
> cartesian products.
> 
> Did I mention that I once got an A on an essay test because I argued that the 
> question asked was itself invalid?
> 
> Dan
> 
> Mladen Gogala wrote:
> 
> > On Thu, 2003-10-02 at 11:44, Garry Gillies wrote:
> > > > Im reading an academic book on databases and it states that Physical I/O
> >
> > > Eh?
> > > What IS the primary bottleneck in tuning Oracle?
> >
> > Cache hit ratio. You tune the buffer cache hit ratio (BCHR) and your job
> > is done. Database with 99.9% BCHR must be OK.
> >
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> > Author: Mladen Gogala
> >   INET: [EMAIL PROTECTED]
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