RE: How to resize the data files

From: Herring Dave - dherri <Dave.Herring_at_acxiom.com>
Date: Wed, 18 Apr 2007 19:59:03 -0500
Message-ID: <7ED53A68952D3B4C9540B4EFA5C76E36031CDE5B@CWYMSX04.Corp.Acxiom.net>

It wasn't clear whether or not you've reclaimed space within the tablespaces by shrinking their objects. If you've done that and have pockets of free space within each tablespace, one option is to move all objects to another tablespace, then back again. This will remove the "fragmentation", lowering your HWM.

You can view each database's HWM by a query similar to the following:

DEFINE TABLESPACE_NAME='%'; COLUMN file_name FORMAT A50 HEADING 'File Name' JUSTIFY CENTER COLUMN segment_name FORMAT A30 HEADING 'Segment Name' JUSTIFY CENTER COLUMN hwm_mb FORMAT 999,999 HEADING 'File|HWM(MB)' JUSTIFY CENTER COLUMN alloc_mb FORMAT 999,999 HEADING 'File|Size(MB)' JUSTIFY CENTER COLUMN tablespace_name NOPRINT

SELECT ddf.tablespace_name,

       ddf.file_name,
       a.segment_name, 
       a.partition_name,
       CEIL((((a.block_id - 1) + a.blocks) * a.db_block_size) / 1048576)
hwm_mb, 
       CEIL((ddf.blocks * a.db_block_size) / 1048576) alloc_mb
  FROM (SELECT file_id
             , block_id
             , blocks
             , segment_name
             , owner
             , partition_name
             , RANK() OVER (PARTITION BY file_id ORDER BY block_id desc)
rank1
             , (SELECT value FROM v$parameter WHERE name =
'db_block_size') db_block_size
          FROM cdba_extents
         WHERE tablespace_name LIKE '&TABLESPACE_NAME') a
     , dba_data_files ddf

 WHERE a.rank1 = 1
   AND a.file_id = ddf.file_id
 ORDER BY ddf.tablespace_name, ddf.file_name;

COLUMN tablespace_name PRINT

"cdba_extents" is a custom version of DBA_EXTENTS that gets past performance issues under 9i with LMTs.

Dave     

---

David C. Herring, DBA | A c x i o m Delivery Center Organization

630-944-4762 office | 630-430-5988 wireless | 630-944-4989 fax

> -----Original Message-----
> From: oracle-l-bounce_at_freelists.org

[mailto:oracle-l-bounce_at_freelists.org]
> Sent: Wednesday, April 18, 2007 4:37 PM
> To: oracle-l
> Subject: How to resize the data files
>
> Hi,
>
> We had a 4 big table in tablespace ts1 and we range partition the
tables
> into 4 partitions and assigned tablespaces ts2-ts5 and now we want to
> reduce the size of the datafiles in ts1. Even though the data for the
> big tables does not exists on ts1 anymore but due to high water mark
it
> is now allowing me to shrink the datafiles.
>
> What is the best possible way to resize the files.
>
> Thanks
> --Harvinder
>
> --
> http://www.freelists.org/webpage/oracle-l

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Received on Wed Apr 18 2007 - 19:59:03 CDT