Re: calculating next extent

In article <7r05so$mn$1_at_oceanite.cybercable.fr>,   "Michel Cadot" <micadot_at_netcourrier.com> wrote:
> corky711_at_my-deja.com a écrit dans le message
<7r00ps$bro$1_at_nnrp1.deja.com>...
> >dear sirs 'n ma'ams,
> >
> >1. How exactly does oracle calculate the size of the next extent it
> >will allocate in a segment? formula?
>
> When Oracle allocates a new extent it calculates the "next next":
> new NEXT = old NEXT * (1+PCTINCREASE/100)
> this value is rounded up to the next multiple of 5 blocks.
>
> >2. I also see segments not following the next_extents value set for
> >that segment...instead it follows the next_extent value specified for
> >the tablespace's default...why's that happen?
> >
>
> May be the parameters NEXT and PCTINCREASE were not given at the
> creation of the table and the table have been altered after with
> the parameters NEXT and/or PCTINCREASE you see now.
>

I would just like to add: remember also that the the value of the next_extent column in dba_tables is recalculated each time an extent allocation takes place (after the first) to show the new next extent value and does not reflect the size of the extent just allocated whenever pctincrease is not set to zero.

--
Mark D. Powell -- The only advice that counts is the advice that  you follow so follow your own advice --

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Share what you know. Learn what you don't. Received on Tue Sep 07 1999 - 09:43:55 CDT