Re: MINIMUM EXTENT option

MINEXTENTS and MINIMUM EXTENT are two different things. MINIMUM EXTENT controls free space fragmentation in an Oracle8 database because in addition to specifying the size of the smallest extent allocated in the tablespace, it also forces each extent in the tablespace to be a multiple of that minimum value. That way if you drop any segment in the tablespace, the chances are you will be able to reclaim all of the released space.

Jurij Modic wrote:

> On 14 Oct 1998 22:19:34 GMT, pch_at_pinnacle. (Paul Chang) wrote:
>
> >Hi,
> >
> >Looks like MINIMUM EXTENT option is the new option in Oracle 8
> >to create tablespace.
>
> MINEXTENTS is actually a very old parameter, used to define *default*
> storage options for tables/indexes/clusters created in the tablespace.
> It was present at least back in Oracle6, i don't know about releases
> prior to 6.0
>
> >in manual it says
> >"with the setting of the MINIMUM EXTENT option, the database administrator
> >controls the fragmentation in the tablespace."
> >
> >What does the above indicate? and why?
> >
> >Can somebody share a real-world experience using this option?
>
> This parameter simply define the number of extents allocated to an
> object immediately after its creation in this particular tablespace,
> if the object creation command itself doesn't explicitely specify this
> storage parameter.
>
> I don't realy think you can actually control the tablespace
> fragmentation with this parameter (you can control it with the
> INITIAL, NEXT and PCTINCREASE). With MINEXTENTS you only preallocate
> the space at object creation, so that oracle doesn't waste time with
> new extent allocation when initial extent is filled.
>
> In a real world, you can take advantage of this parameter (on
> table/index creation level) when performing manual striping -
> allocating a number of extents of the same table/index on different OS
> files residing in different physical disks for better I/O distribution
> on large tables.
>
> >thanks,
> >
> >Paul.
>
> HTH
> Jurij Modic <jmodic_at_src.si>
> Certified Oracle7 DBA (OCP)
> ================================================
> The above opinions are mine and do not represent
> any official standpoints of my employer
Received on Thu Oct 15 1998 - 22:38:51 CDT