Re: Managing Dynamic Allocation of Extents?

In article <6g20sb$kqq$2_at_news00.btx.dtag.de>, Matthias Gresz wrote:

Rick,

I fail to see why you would not want Oracle to keep things 'tidier' for you. I see no advantage (given your example) in having 40, 600K extents over 1, 32M extent.

regs

Neil Chandler

>Hi,
>
>maybe your 40 extent where stored in a consecutive manner so that oracle concatenated them togehter to get this 35MB extent?
>
>On Thu, 02 Apr 1998 13:44:29 -0500, Richard A Papaj <papaj_at_acsu.buffalo.edu> wrote:
>
>>I couldn't understand why the value I chose for a next extent was being
>>overridden until I
>>read that Oracle7 may dynamically modify size of extents based on
>>rounding criteria and
>>available storage space. I can see advantages with Oracle doing this
>>(e.g. maximizing
>>reuse of extents). On the other hand, wouldn't there be times when you
>>may want to
>>override these dynamic sizes?
>>
>>Note the following example: Within an empty tablespace of 100M (1
>>datafile), I created
>>an index with an initial extent size of 45M and next extent 600K. As a
>>result, I was
>>expecting an initial extent of 45M and about forty 600K extents (I
>>realize this may not be
>>optimum sizing). Instead, I got an initial of 45M and one next extent
>>of 32M! That's a
>>big jump in next extent size and one that I don't want. It's probably a
>>result of the
>>tablespace being empty at the time but I did plan on creating more
>>segments in there.
>>
>>Is there any way to override dynamic sizing? Or must I keep trying
>>different extent sizes
>>until I get acceptable dynamic sizes as a result? I'm a relatively new
>>DBA so maybe I'm
>>missing something here. It just seems that it would be nice to have
>>more control over this
>>sizing at times.
>>
>>Any feedback is much appreciated...
>>
>>Rick Papaj
>>papaj_at_acsu.buffalo.edu
>>State University of New York at Buffalo
>>
>
>--
>
>Regards
>
>Matthias Gresz :-)
>
>GreMa_at_T-online.de
>
Received on Fri Apr 03 1998 - 00:00:00 CST