 | | | DATAFILE?? | DATAFILE?? 2005-10-20 - By Niall Litchfield
On 10/18/05, oracle-l-bounce@(protected) <oracle-l-bounce@(protected)>
wrote:
>
> The best way to find out is to try it. You will probably find that it
> depends. If you use a LMT and do uniform extents then it will do it by
> concatenation. (fill up the first file then move on to the 2nd etc.).
> If you create an LMT and do automatic extents then it is different. It
> does it by striping. The first extent goes in the first file, the 2nd
> in the 2nd file...
>
> You can see this by setting up a small test.
> Jim
Unfortunately, if you run the test you'll find that your assertion isn't
correct on 10gR1 :)
1 create tablespace demo
2 datafile 'c:\temp\demo01.dbf' size 10m,'c:\temp\demo02.dbf' size 10m
3* extent management local uniform size 128k
USER @ orcl>/
Tablespace created.
USER @ orcl>create table t1(c1 number);
create table t1(c1 number)
*
ERROR at line 1:
ORA-00955 (See ORA-00955.ora-code.com): name is already used by an existing object
USER @ orcl>create table demo(c1 number);
Table created.
USER @ orcl>drop table demo;
Table dropped.
USER @ orcl>create table demo(c1 number)
2 tablespace demo;
Table created.
USER @ orcl>alter table demo allocate extent;
Table altered.
USER @ orcl>alter table demo allocate extent;
Table altered.
USER @ orcl>alter table demo allocate extent;
Table altered.
USER @ orcl>alter table demo allocate extent;
Table altered.
USER @ orcl>alter table demo allocate extent;
Table altered.
USER@ orcl>alter table demo allocate extent;
Table altered.
USER @ orcl>select file_id,count(*)
2 from dba_extents
3 where segment_name='DEMO'
4 group by file_id;
FILE_ID COUNT(*)
-- ---- -- -- ---- --
9 4
10 3
2 rows selected.
--
Niall Litchfield
Oracle DBA
http://www.niall.litchfield.dial.pipex.com
<div><span class="gmail_quote">On 10/18/05, <b class="gmail_sendername"><a href
="mailto:oracle-l-bounce@(protected)">oracle-l-bounce@(protected)</a></b>
<<a href="mailto:oracle-l-bounce@(protected)">oracle-l-bounce@(protected)
</a>> wrote:</span>
<blockquote class="gmail_quote" style="PADDING-LEFT: 1ex; MARGIN: 0px 0px 0px 0
.8ex; BORDER-LEFT: #ccc 1px solid">The best way to find out is to try it.
You will probably find that it<br>depends. If you use a LMT and
do uniform extents then it will do it by
<br>concatenation. (fill up the first file then move on to the 2nd etc.).<br>If
you create an LMT and do automatic extents then it is different. It
<br>does it by striping. The first extent goes in the first file, the
2nd
<br>in the 2nd file...<br><br>You can see this by setting up a small test.<br
>Jim</blockquote>
<div> </div>
<div>Unfortunately, if you run the test you'll find that your assertion isn't
correct on 10gR1 :)</div>
<div> </div>
<div>
<p><br> 1 create tablespace demo<br> 2 datafile 'c:
\temp\demo01.dbf' size 10m,'c:\temp\demo02.dbf' size 10m<br> 3* extent
management local uniform size 128k<br>USER @ orcl>/</p>
<p>Tablespace created.</p>
<p>USER @ orcl>create table t1(c1 number);<br>create table t1(c1 number
)<br> *
<br>ERROR at line 1:<br>ORA-00955 (See ORA-00955.ora-code.com): name is already used by an existing object</p
>
<p><br>USER @ orcl>create table demo(c1 number);</p>
<p>Table created.</p>
<p>USER @ orcl>drop table demo;</p>
<p>Table dropped.</p>
<p>USER @ orcl>create table demo(c1 number)<br> 2
tablespace demo;</p>
<p>Table created.</p>
<p>USER @ orcl>alter table demo allocate extent;</p>
<p>Table altered.</p>
<p>USER @ orcl>alter table demo allocate extent;</p>
<p>Table altered.</p>
<p>USER @ orcl>alter table demo allocate extent;</p>
<p>Table altered.</p>
<p>USER @ orcl>alter table demo allocate extent;</p>
<p>Table altered.</p>
<p>USER @ orcl>alter table demo allocate extent;</p>
<p>Table altered.</p>
<p>USER@ orcl>alter table demo allocate extent;</p>
<p>Table altered.</p>
<p>USER @ orcl>select file_id,count(*)<br> 2 from dba
_extents<br> 3 where segment_name='DEMO'<br> 4 group by
file_id;</p>
<p> FILE_ID COUNT(*)<br>-- ---- -- -- ---- --<br>
9
4<br> 10  
; 3</p>
<p>2 rows selected.</p>
<p> </p></div>
<div> </div>
<div> </div>
<div>-- <br>Niall Litchfield<br>Oracle DBA<br><a href="http://www.niall
.litchfield.dial.pipex.com">http://www.niall.litchfield.dial.pipex.com</a> </div
></div>
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