RE: 11g READ ONLY table
- From: "Ric Van Dyke" <ric.van.dyke@xxxxxxxxxx>
- To: <oralrnr@xxxxxxxxx>, "Mark W. Farnham" <mwf@xxxxxxxx>
- Date: Mon, 12 Jul 2010 17:08:10 -0500
What I was trying to say and show was that it's just an attribute of the table.
In the data dictionary there is likely a flag set in the table definition that
show this table is READ ONLY. There would be no need to do anything with the
individual extents.
I assume you are thinking of READ ONLY table spaces and trying to see a
connection between the two, I doubt there is any. Even READ ONLY table spaces
just have an attribute in the data dictionary that make the table space as READ
ONLY.
To work with any object in the database you have to go thru the data
dictionary. There is no need to set something like this at the individual
extent level. Oracle might set something at the extent level I suppose, I
haven't dumped blocks to check, but I see no need to do such a thing.
Why didn't oracle do this earlier? Likely it never boiled up high enough on
the priority list.
Can I ask why this is important? Just for academic understanding or is there
an issue you are trying to solve?
Ric (the ROCK) Van Dyke
Hotsos Enterprises Ltd
-----Original Message-----
From: oracle-l-bounce@xxxxxxxxxxxxx on behalf of Orlando L
Sent: Tue 13-Jul-10 5:31 AM
To: Mark W. Farnham
Cc: oracle-l@xxxxxxxxxxxxx
Subject: Re: 11g READ ONLY table
THanks Mark, Connor and Rock. I was not looking for the syntax.
I was looking for an explantion or maybe a paper on the internal details
on how a read write table gets converted to read only. If table has extents
all over a tablespace does Oracle mark the extent headers of the table as
READ ONLY which prevents future updates?
If it was a simple task I wonder why Oracle did not have this feature in
older versions.
I am also checking to see if people have used this feature in their
envorinments. If so i want to see how efficient it is or any lessons learned
type of things.
On Fri, Jul 9, 2010 at 12:38 PM, Mark W. Farnham <mwf@xxxxxxxx> wrote:
> . is what is confusing you. They are just different things.
>
>
> ------------------------------
>
> *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:
> oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Mark W. Farnham
> *Sent:* Friday, July 09, 2010 1:33 PM
> *To:* oralrnr@xxxxxxxxx; oracle-l@xxxxxxxxxxxxx
> *Subject:* RE: 11g READ ONLY table
>
>
>
> Ric and Connor gave you the mechanics of this. But I suspect from the way
> you phrased your question that the difference between a table that Oracle is
> protecting from changes (READ ONLY table) and a tablespace that you don't
> have to back up any more.
>
>
>
> mwf
>
>
> ------------------------------
>
> *From:* oracle-l-bounce@xxxxxxxxxxxxx [mailto:
> oracle-l-bounce@xxxxxxxxxxxxx] *On Behalf Of *Orlando L
> *Sent:* Wednesday, July 07, 2010 11:20 AM
> *To:* oracle-l@xxxxxxxxxxxxx
> *Subject:* 11g READ ONLY table
>
>
>
> List
>
>
>
> Does anyone know how 11g is able to convert read write tables to READ ONLY
> and back when the extents are all over mixed in with other tables in a
> tablespace?
>
>
>
> Orlando.
>
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