Re: Specifying "RETENTION" in 9iR2 LOB segment still uses PCTVERSION?

From: fairlie rego <fairlie_r_at_yahoo.com>
Date: Sat, 10 Jun 2006 03:59:33 -0700 (PDT)
Message-ID: <20060610105933.69382.qmail@web31909.mail.mud.yahoo.com>

Hi Rich,

I am no LOB expert but I believe there is a related bug 4231990 which hasn't been updated since Mar 2005.

Regards,
Fairlie

"Jesse, Rich" <Rich.Jesse_at_qg.com> wrote: Hey all,

According to a LOB perftuning paper from Oracle, specifying RETENTION is preferred over PCTVERSION for creating LOBs when using automatic UNDO. In 9.2.0.5.0, a dev here has created a table whose subset of columns is this:

CREATE TABLE CALL_INFORMATION
(

S_CALL_ID VARCHAR2(20) NULL,
S_CUSTOMERNO VARCHAR2(6) NULL,
S_MACHINE_NO VARCHAR2(20) NULL,
S_CALL_DESCRIPTION CLOB NULL

)

TABLESPACE QT_SMALL
LOB (S_CALL_DESCRIPTION) STORE AS
( TABLESPACE QT_SMALL
ENABLE STORAGE IN ROW
CHUNK 8192
RETENTION
CACHE
)

/

Notice the "RETENTION" keyword in there? But when the DDL is grabbed:

SELECT dbms_metadata.get_ddl('TABLE', 'CALL_INFORMATION') FROM dual;

The RETENTION is ignored and PCTVERSION is used:

...LOB ("S_CALL_DESCRIPTION") STORE AS ( TABLESPACE "QT_SMALL" ENABLE STORAGE IN ROW CHUNK 8192 PCTVERSION 10 CACHE... Huh? DBA_LOBS shows both PCTVERSION of 10 and a RETENTION equal to the current value of the UNDO_RETENTION parameter. I even tested:

ALTER TABLE CALL_INFORMATION modify lob(S_CALL_DESCRIPTION) (retention);

...to no avail. Is this a bug? I altered the running system's UNDO_RETENTION and noticed that DBMS_LOB's PCTVERSION still remained at 10 while the RETENTION correctly adjusted to the new value.

I couldn't find anything about this on MetaLink and Google searches were too generic to be of use.

Thoughts?

Rich

--
http://www.freelists.org/webpage/oracle-l





          Fairlie Rego
Senior Oracle Consultant
  
  http://el-caro.blogspot.com/
   






 __________________________________________________
Do You Yahoo!?
Tired of spam?  Yahoo! Mail has the best spam protection around 
http://mail.yahoo.com 
--
http://www.freelists.org/webpage/oracle-l

Received on Sat Jun 10 2006 - 05:59:33 CDT