Re: Oracle's Myth: keep tables and indexes in separate tablespaces

Joel Garry wrote:

A good catch, Joel. Trouble is....

> "Howard J. Rogers" <hjr_at_dizwell.com> wrote in message
>> Though I will go one step further, though it's only a logical conclusion
>> from what's already been discussed: one should be very careful about
>> making statements about what Oracle recommends or what its 'position' on
>> something is. Because the right hand quite frequently doesn't agree with
>> what the left hand has been writing.
>
> At least one hand is getting it right. From 9.2 performance manual
>

http://download-west.oracle.com/docs/cd/B10501_01/server.920/a96533/iodesign.htm#23329
> :
>
> -------------- Begin Inclusion -------------------
> One popular approach to manual I/O distribution suggests

....this is what is commonly called being "economical with the actualite"! Why do they state "a popular approach suggests", as though it has nothing to do with them? When it is in fact their own bloomin' courseware that suggests it in the first place!!

But seriously: there is indeed better and better stuff coming out of Oracle on these sorts of things these days. Their courseware on the buffer cache hit ratio has improved out of all recognition since the dark days of 'make it 95% or else'. I think it might have something to do with James Morle's involvement, but that's just a guess.

It is therefore excellent seeing this quote you found in black and white... hopefully, it will mean the same old question doesn't keep getting re-hashed in the future.

Now, I can't wait for this nugget actually to filter into their classrooms (without my having to abandon the courseware to get it there).

Regards
HJR
>separating a
> frequently used table from its index. This is not correct. During the
> course of a transaction, the index is read first, and then the table
> is read. Because these I/Os occur sequentially, the table and index
> can be stored on the same disk without contention. It is not
> sufficient to separate a datafile simply because the datafile contains
> indexes or table data. The decision to segregate a file should be made
> only when the I/O rate for that file affects database performance.
> -------------- End Inclusion ---------------------
>
> jg
> --
> @home.com doesn't know what cox.net is doing.
> "I've got one hand in my pocket, and the other is flashing a peace
> sign." - whatshername
Received on Thu Oct 09 2003 - 17:52:37 CDT