Re: Can a segment span more than one datafiles

On Thu, 15 May 2003 23:00:45 +0100, "Paul Brewer" <paul_at_paul.brewers.org.uk> wrote:

Yes, a segment can span datafiles while an extent, which contains contiguous data blocks, cannot span datafiles.

>"Peter" <peter_at_nomorenewsspammin.ca> wrote in message
>news:cff6cvkedqaugm85sugg6mag2v47dv08rv_at_4ax.com...
>> A tablespace can span more than one datafiles, but can a segment span
>> more than one datafiles? I am just wondering what is the smallest
>> Oracle unit that can span different datafiles.
>> How about data block spanning datafiles? How about an extent?
>>
>
>We need to separate the physical from the logical here, I think.
>
>A tablespace is a logical entity which consists of one or more datafiles.
>A datafile is just a file in the file system (raw devices excluded here).
>A segment is also a logical entity (for example a table or an index) which
>physically consists of one or more extents. The various extents may exist in
>different datafiles, but each extent will reside in a single datafile.
>
>An extent is a collection of contiguous blocks in a datafile. The block is
>the lowest physical unit as far as Oracle is concerned.
>
>Does this help?
>
>Regards,
>Paul
>
>
Received on Fri May 16 2003 - 12:28:37 CDT