Re: Importing into a LMT?

tim.kearsley_at_milton-keynes.gov.uk (Tim Kearsley) wrote in message news:<725736ef.0304020716.3adff8f2_at_posting.google.com>...
> Hi all,
>
> Environment:
>
> Oracle 8.1.7 on AIX 4.3.3 on RS6000 SP node
>
> I've created a new, test database using LMTs exclusively. In all
> cases I've used a uniform extent size.
>
> I'm importing data into this new database from a database which uses
> DMTs. Additionally, the export used the COMPRESS=Y option to compress
> the extents.
>
> What will be the effect when I import into the new database? I
> assumed that the storage clause, at least in terms of INITIAL_EXTENT
> and NEXT_EXTENT, would be ignored, and the segment would be allocated
> however many extents would be required of the UNIFORM size.
>
> However, when I query DBA_SEGMENTS for the imported segments, I find
> the INITIAL extent is certainly NOT the UNIFORM size, whereas the
> NEXT_EXTENT always is.
>
> Am I interpreting this result correctly, and is this, in your opinion,
> sensible behaviour for this scenario?
>
> Many thanks,
>
> Tim Kearsley
> Database Manager
> Milton Keynes Council

Tim, Look at dba_extents to see the actual extent size used. Dba_segments and dba_tables will show the create statement initial extent. When Oracle allocates the table in an LMT it will allocate as many uniform extents as necessary to hold the initial extent storage request. It would be most efficient from a space usage point of view on import if the export file was made with the compress=n option set then ojbects will take only as many extent allocations as necessary to hold their data on import.

HTH -- Mark D Powell -- Received on Wed Apr 02 2003 - 14:09:01 CST