Re: LMT and DMT

> Hey Richard,
>
> DMT gives you more options when it comes to extent sizes in a single
> tablespace.

Come off it! WHY would you want 'more options' along these lines? give me one good reason why you think it desirable to be able to create 500 segments with 500 different extent sizes in the same tablespace.

There are *no* such good reasons. It all comes down to design, and if your particular business "needs" so many different extent sizes, then it's because someone doesn't know what they're talking about.

>
> What Oracle wants to do in the future is really besides the point.

No it's not, actually. The fact that they will abolish DMTs means that they recognise the inefficiencies associated with them, and wish to eliminate the inefficiencies. You'd be a fool not to want to eliminate them also.

>I am not
> even sure
> if we will use Oracle if it comes to 10i.

Fair enough. But that doesn't negate the fact that Oracle (in this particular case, just for once) isn't pushing LMTs because marketing thinks it sounds good, but because there are storage and performance benefits in making the switch. Not to mention less hassles for DBAs. Though I realise it makes it a bit tough for any DBA who is desperately searching for a justification for their job, and thinks 'space management' is a compelling argument.

>In the mean time we will continue
> to use DMT
> until we have to make a choice between uniform LMT - the one-size-fit-all
> approach

What on earth is 'one size fits all' about LMTs? Are you in any way prevented from creating a tablespace where the uniform size is 97K? Or 4302K? or 2636K? No you are not.

> or system LMT - the brain dead approach. :)

What's brain dead is claiming that auto-allocate is brain-dead. It is a very efficient, and rather elegant algorithm that has all the benefits of LMTs regarding no contention on the Data Dictionary, and yet manages to utterly minimise the possibility of fragmentation.

No one (apart from Oracle Corporation) will be forcing you to use LMTs in the near future, so I am not suggesting that you're not entitled to your opinion, or that others shouldn't feel free to share it. But please don't post bunkum about LMTs capabilites, or the 'advantages' of DMTs. Nothing you have posted stands up to technical scrutiny, and some of things you've posted just invite the response: you apparently don't know how to manage a database. Which I'm sure is not true: but there's a difference between a genuine business need and base prejudice.

HJR Received on Wed Feb 05 2003 - 06:23:09 CST