Comments below.
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"Md Irfan" <irfan_pk_at_hotmail.com> wrote in message
news:c42168e7.0204070242.702954ab_at_posting.google.com...
> Hi,
> I was trying to modify the RBS, but I got the following errors.
>
> The first one when trying to allocated minextents to 20 from 2.
>
> SVRMGR> alter rollback segment kse1_rbs5 storage (minextents 20);
> alter rollback segment kse1_rbs5 storage (minextents 20)
> *
> ORA-01570: MINEXTENTS must be no larger than the 2 extents currently
> allocated
>
And your question is....? I hope you're not surprised at this "error". If
your segment (whether it's a rollback segment or not is irrelevant: it
happens to them all) currently has (say) 5 extents, and you suddenly want to
change MINEXTENTS to 10, what you're really saying is that you want to
acquire an additional 5 extents on top of the ones you've already got. But
that's a low-down sneaky way of doing an 'alter ... allocate extent' 5
times, so it's not permitted. MINEXTENTS must therefore always be set lower
than or equal to the existing number of extents. But if it can only be set
to something lower (or equal) to what you;ve already got, what difference
does changing it make? Answer: none whatsoever. Not until you truncate the
segment. *Then* the new setting kicks in, and you'll be left with the
MINEXTENTS number of extents, not just the initial which you would otherwise
have got.
> This one, when I was modifying to initial 100K
>
> SVRMGR> alter rollback segment kse1_rbs5
> 2> storage (initial 100k);
> storage (initial 100k)
> *
> ORA-02203: INITIAL storage options not allowed
>
Oh dear. You are altering a segment (again, the fact that it's a rollbak is
irrelevant, it happens to all of them) which must therefore already exist.
If it already exists, it has already acquired its initial extent. If it's
already acquired an initial extent of, say, 500K, how on Earth is it
supposed to just relinquish 400K of that space in response to your SQL
command? It can't. If this was a table, those 400K might well be stuffed
full of records. You can never alter the size of any extent once it has
already been allocated. You can only alter the size of the NEXT setting, and
that only takes effect the next time the segment wants to extend.
> But when I dropped this RBS, and recreated with the new storage
> options for minextents and initial it went fine.
>
Naturally. When you dropped the segment, it ceased to exist. So when you
recreated it, settings for Initial are perfectly acceptable (it hasn't
acquired it's initial extent yet, so it's fine to say how big it should be
when it does). And since there are no extents allocated at all, it's
perfectly acceptable to demand that the segment should have a minimum number
of extents when it finally does get created.
These are not errors. And nothing to do with rollback segments. Try the
self-same tests on a table: the same thing will happen. This is just
standard Oracle behaviour.
Regards
HJR
> Thanks a lot...
> Irfan
Received on Sun Apr 07 2002 - 15:06:41 CDT
