Re: Designing database tables for performance?
Date: 24 Feb 2007 05:30:20 -0800
> > In what RAM would be less physical than HD ? For any reason, an
Physical IO means that IO have some physical inmemory/hd counterpart
while logical IO mean *no media* at all as a prerequisite.
> > absurdity is an absurdity.
> Not an absurdity, you just aren't paying attention to how the I/O is
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?
Physical IO means that IO have some physical inmemory/hd counterpart while logical IO mean *no media* at all as a prerequisite.
> From Oracle's point of view, if the desired data exists in
> Oracle's buffers, that is a logical I/O.
As I said, I am well aware of ORACLE brainwashing over its troops. ORACLE succeded to convince the audience of practictionners that RAM (call it cache if you want) = logical. One of Larry Ellison *contribution* to the field of database technology. Reading and educating yourself in RM will help you see the absurdity in that. (See rule of indepedence netween logical and physical layer)
[Snipped Description of process - thanks for the pedagogic intent
> Now, you are welcome to think it is better to be more simple than that
> and just say RAM I/O is the same as HD, but that sounds patently
> absurd to me. Perhaps you have a better way of distinguishing the
It sounds absurd because Larry Ellison has brainwashed people like you (no disrespect meant) *not* to think otherwise to boost up his products sales and bank account. Read books written by knowledgeable audiences about RM and you will see what I am refering to.(was in your shoes once long ago;)) A few good books to read that may help... Received on Sat Feb 24 2007 - 14:30:20 CET