Re: Designing database tables for performance?

From: Cimode <>
Date: 7 Mar 2007 01:16:45 -0800
Message-ID: <>

On Mar 7, 12:21 am, "joel garry" <> wrote:
> On Mar 6, 12:52 pm, "Cimode" <> wrote:
> > On 6 mar, 05:59, "" <> wrote:
> > > On 24 Feb, 13:30, "Cimode" <> wrote:
> > > > On 23 fév, 22:33, "jgar the jorrible" <> wrote:
> > > > > > In what RAM would be less physical than HD ? For any reason, an
> > > > > > absurdity is an absurdity.
> > > > > Not an absurdity, you just aren't paying attention to how the I/O is
> > > > > counted.
> > > > So you say there are *ways* to count IO's. Fair enough. Question is:
> > > > what has the way of counting IO's has any bearing on the media that
> > > > supports them and therefore qualifies their nature as physical or
> > > > logical? What is the difference: speed?
> > > Yes. A logical I/O does not go down an I/O channel but comes via the
> > > memory bus.
> > And in what a memory bus is less *physical* than an IO channel? How
> > do you think such bus is filled with data at some point in time
> > otherwise than by a pull on the IO channel.
> ??? The whole point is that it might have been updated only in memory
> and may have nothing to do with I/O until some time in the future, or
> maybe never if it is rolled back.
You are talking about transactional aspects now and how such trasactional aspect may impact the definition of how is defined a logical IO vs a physical IO. Does not that sound strange to you. Besides, you have not answered the question I have asked you so I rephrase it: in what do you think a memory bus is less physical than an IO channel and how do you think such bu is filled in time otherwise than by an IO channel pull....Answer this question please.

> You _really_ should read the Oracle concepts manual, as well as come
> into this century to see how modern databases deal with multiversion
> consistency. Thinking there is a one-to-one relationship between what
> is in memory and what is on disk is just stupid.
For your information, not only I know *exactly* how ORACLE works on transactional handling but also equally DB2 and SQL Server...

According to your definition, because there is a difference in time and speed such difference determines the nature of how an operation is considered as being logical or physical. You are calling any other definition plain stupid. Why do you think this would be stupid?

> > > The time to complete is therefore far less and the "cost" in terms of
> > > time is much less.
> > So because time is the difference that makes less physical. Don't you
> > see anything wrong in that?
> Not at all. One defines the terms from a viewpoint. In this case,
> the viewpoint is "stuff that the Database has control over versus
> stuff the Operating System has control over."
I am sorry but I am trying to understand by phrasing out exactly what you have stated previously.

So you consider that they may be different viewpoints on what's logical and what's physical. What you will probably discover some day if you get a chance to put your hands on DB2 or SQL Server is that they also have different viewpoints than one another. According to the approach you are preaching, each editor has its own definition of the difference between logical and physical: In other words, this is an example of proprietary definition. What I am telling you is basically that there is a precise fundamental nonproprietary definition of the difference between a logical and physical IO and such definition is certainly neither ORACLE's nor, MS nor DB2 definition but something that has been defined to be technology independent. Do you understand what I am getting at?

> If your theory can't deal with those concepts, it must not be a good
> theory. I'm sure we'll all readily concede the terminology won't make
> everyone happy, but that is no excuse for rejecting the terminology.
> That just anti-semanticism.
What terminology do you think we are rejecting ORACLE's, DB2's, SQL's server...And what theory do you think I am promoting? What I am presenting to you is simply the theory of RM that gave birth to the entire db industry. Its creator is Tedd Codd. Do you think that Codd himself did not know how to make the difference between logical and physical IO's?

I don't know what you mean by *anti semantiscism*. My point is not to discuss the words but what's behind the words.
> jg
> --
> is bogus.
> "They stand the whole game, and they scream at everything." -
Received on Wed Mar 07 2007 - 10:16:45 CET

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