pauline -- Thanks for the question regarding "Compress in export", version 8.1.7.2

You Asked

Tom,
As I know that compress=y in the export will consolidate table's extents into first 
extents. So you suggest that always use compress=N.

I have the impression that if use locally managered tablespace, the table being created 
in that tablespace will always use the initial extent from that tablespace even we 
specify some different initial extent in the table creation statement. 

I am just thinking about this question: If use compress=y in export 
for the table which was created in locally managered tablspace, after 
import ,the table will get the consolidated initial extent or still
use the initial extent size of that locally managered tablespace ?

Please clarify it.
Thanks.

Pauline 

and we said...

With an LMT -- ever extent will either be:

o uniformly sized (my preference)
o "auto" sized by the system using some undocumented method for sizing.

If you use a uniform size of 1m and you do an export with compress=y and the initial 
extent requested was 100m, we will allocate 100 1m extents to satisfy your "initial" 
request.  We will take the INITIAL, NEXT and MINEXTENTS -- decide what they would be in a 
DMT and preallocate at least that much space in an LMT for you.

 

Reviews

January 20, 2002 - 11am Central time zone Bookmark | Bottom | Top Reviewer: a reader from NY, U.S.A Tom, So if in the case of uniformly sized locally managed tablespace, if tablespace is uniform size of 1m and the table's extents reached to 100M,at this moment, we do export with compress=y or take the default from compress, oracle will allocate 100 1m extents to satisfy "initial" request--100M, right? Please confirm it. Thanks. Followup   January 20, 2002 - 11am Central time zone: yes. correct. EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO ;   November 11, 2005 - 3pm Central time zone Bookmark | Bottom | Top Reviewer: dost  I am on the way to export a schema ,drop Dictonary manage tablespace then creation of LMT and the import back Do you think following command is ok? CREATE TABLESPACE FPADATA DATAFILE '/REP/data03/fpadata01.dbf' size 2000m EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO ; after that I add 94 files of 2Gb size Thanks! Followup   November 12, 2005 - 10am Central time zone: I would not use export/import for this. Just use ALTER TABLE T move TABLESPACE lmt storage (initial 1k next 1k pctincrease 0 ); ALTER INDEX I rebuild tablespace lmt storage (initial 1k next 1k pctincrease 0 ); much less risky - faster - can be done without logging if you like and won't generate any undo. (180gb in a single tablespace, I'd be tempted to - during this move/reorg - segregate that out into something more manageable - but that is up to you)

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