RE: automatic segment space management

Rich - Good point. Yes, I create all the tables here, at least in production, and I probably wouldn't use autoextend if the situation were otherwise. The other thing to consider is if you are using uniform extents, by definition you have bought into the philosophy that you can have many extents and your database will not do a Linda Blair Exorcist imitation on you. If we use the guideline that the number of extents should be not many more than 1,000, then the 128K extent will get you 128M, which is good for most tables.

   While we are on the subject, anyone considering switching to LMTs should carefully read "How to Stop Defragmenting and Start Living" by Juan Loaiza, Rosanne Toohey, Bhaskar Himatsingka. You can find a copy on http://www.hotsos.com. Trying to implement a philosophy without fully understanding it is a recipe for failure.

Dennis Williams
DBA
Lifetouch, Inc.
dwilliams_at_lifetouch.com

-----Original Message-----
Sent: Tuesday, September 03, 2002 12:58 PM To: Multiple recipients of list ORACLE-L

Dennis, who creates tables in your DB? If devs do, don't you worry that one could accidentally create a 512MB table in your 128K TS, instead of a 512KB one?

I really would like to implement LMTs here, and am doing so in certain restricted instances where I'm the only one who creates the objects for that TS, but I'm a little leery of letting it go to the developers, even though I don't use AUTOEXTEND.

Thx!

Rich Jesse                           System/Database Administrator
Rich.Jesse_at_qtiworld.com              Quad/Tech International, Sussex, WI USA

> -----Original Message-----
> From: DENNIS WILLIAMS [mailto:DWILLIAMS_at_LIFETOUCH.COM]
> Sent: Tuesday, September 03, 2002 12:42 PM
> To: Multiple recipients of list ORACLE-L
> Subject: RE: automatic segment space management
>
>
> Rachel - I have been using LMTs with uniform extents
> (Oracle-recommended
> variation) for a couple of years now with Oracle 8.1.6, and
> now 9.2. The
> Oracle-recommended extent sizes are 128k, 4m, and 128m. As
> far as PCTFREE,
> et. al., these are at the table level, so my opinion would be that the
> guidelines for these are unchanged from the pre-LMT days. The
> key issue with
> the highly updated customer table would be whether the size
> of the row is
> changing. If you can keep the row size constant, then you
> won't wind up with
> chained rows. The biggest issue facing you is whether you
> turn AUTOEXTEND
> on. I did that and have encountered relatively few problems. Well, one
> problem. I had tables set with large NEXT extents to minimize
> extents, and
> when one extended boy did my sys admin get excited. I changed that.
> A bigger issue in building your data warehouse is whether
> you can use the
> partitioning option. Most of our queries were taking more
> than 2 minutes and
> I was able to partition and bring that down below 10 seconds.
> The users were
> pretty excited.
>
> Dennis Williams
> DBA
> Lifetouch, Inc.
> dwilliams_at_lifetouch.com
>

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