RE: LOB Storage Characteristics

[Paul Drake]

uh - Stripe And Mirror Everything.
what's a tablespace?
add more NVRAM (cache).
 
he he he he ... its going to be another late one ...
 
sales critter.

-Original Message-
Sent: Monday, June 11, 2001 9:51 PM
To: Multiple recipients of list ORACLE-L


Greetings All, 

I am using Oracle 81630 on Solaris 7 and I have a table which contains a 
LOB (CLOB actually).  The DDL statement is as follows ... 


My question is one related to data access for the table, lobsegment and 
lobindex.  Would there be any I/O performance benefit in having the 
table, lobsegment and lobindex located in different tablespaces (which 
would be located on different physical drives)? 


As you can see I can split the table and lobsegment/lobindex into 
separate tablespaces.  I have tried to split the lobsegment and lobindex 
up into separate tablespaces but according to the 816 documentation this 
is no longer supported under 8i (depracation of the LOB_index_clause). 
According to Metalink the lobsegment and lobindex are co-located in 8i 
for a specific reason - but I cannot find what that is! 


Thanks 


Glen 

-- 

Glen Mitchell   NZ Phone: +64 9 3730400

Energy Research Lab URL:  http://www.peace.com
 

Peace Software  Email: [EMAIL PROTECTED]
  

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LOB Storage Characteristics

[Glen Mitchell]

Greetings All,
I am using Oracle 81630 on Solaris 7 and I have a table which contains
a
LOB (CLOB actually).  The DDL statement is as follows ...
CREATE TABLE B_STATEMENT_TEXT_ORA (stmtnum NUMBER(10) NOT NULL,
statement_content CLOB)
STORAGE (INITIAL 100M NEXT 100M PCTINCREASE 0)
TABLESPACE energy_proc_data_100M_02
LOB (statement_content) STORE AS b_statement_text_ora_lob
(TABLESPACE energy_proc_lob_100M
DISABLE STORAGE IN ROW
STORAGE (INITIAL 100M NEXT 100M PCTINCREASE 0)
CHUNK 8192
PCTVERSION 10
);
The details from user_lobs are ...
SEGMENT_NAME  
TABLESPACE_NAME
SEGMENT_TYPE   
BYTES    EXTENTS
-- -- --
-- --
B_STATEMENT_TEXT_ORA  
ENERGY_PROC_DATA_100M_02   TABLE  
104857600  1
SYS_IL046179C2$$   ENERGY_PROC_LOB_100M  
LOBINDEX   
104857600  1
B_STATEMENT_TEXT_ORA_LOB   ENERGY_PROC_LOB_100M  
LOBSEGMENT  104857600 
1
 
The DML operations on the table include SELECT, INSERT and DELETE.
There is no UPDATE activity.
Typically the data for each CLOB entry is larger than 4K so I am
specifying that it is stored in the lobsegment and not the table.
My question is one related to data access for the table, lobsegment
and
lobindex.  Would there be any I/O performance benefit in having
the
table, lobsegment and lobindex located in different tablespaces (which
would be located on different physical drives)?
As you can see I can split the table and lobsegment/lobindex into
separate tablespaces.  I have tried to split the lobsegment and
lobindex
up into separate tablespaces but according to the 816 documentation
this
is no longer supported under 8i (depracation of the LOB_index_clause).
According to Metalink the lobsegment and lobindex are co-located in
8i
for a specific reason - but I cannot find what that is!
Also, is there any way to specify a name for the lobindex, rather than
rely upon the system generated name?
Thanks
Glen
-- 
Glen Mitchell   NZ Phone: +64 9 3730400
Energy Research Lab URL: http://www.peace.com
Peace Software  Email: [EMAIL PROTECTED]