Is there any performance value to making a tablespace READ ONLY?

Question

In 9i, if I were to set a tablespace which only contains data to be reported over - is there any value in making it READ ONLY other than "safety" of the data? I am particularly interested to know if it can increase performance.
Thanks

Answer 1

When you say safety, you are partly correct, because data cannot be deleted, but it can be dropped, check the below SQL statements.
With regard to performance, yes you will gain some. For better performance while accessing data in a read-only tablespace, you can issue a query that accesses all of the blocks of the tables in the tablespace just before making it read-only. A simple query, such as SELECT COUNT (*), executed against each table ensures that the data blocks in the tablespace can be subsequently accessed most efficiently. This eliminates the need for Oracle to check the status of the transactions that most recently modified the blocks.
http://download-east.oracle.com/docs/cd/B10501_01/server.920/a96521/tspaces.htm#922
SYS@BABU> create tablespace test_ts datafile 'D:\ORACLE\ORADATA\TEST_TS1.DAT' SIZE 15M
  2  EXTENT MANAGEMENT LOCAL UNIFORM SIZE 1M;
Tablespace created.
SYS@BABU> CREATE TABLE TAB1 (A NUMBER) tablespace test_ts ;
Table created.
SYS@BABU> BEGIN
  2  FOR A IN 1..10 LOOP
  3  INSERT INTO TAB1 VALUES (A);
  4  END LOOP;
  5  COMMIT;
  6  END;
  7  /
PL/SQL procedure successfully completed.
SYS@BABU> ALTER TABLESPACE test_ts READ ONLY;
Tablespace altered.
SYS@BABU> DELETE FROM TAB1;
DELETE FROM TAB1
ERROR at line 1:
ORA-00372: file 6 cannot be modified at this time
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\TEST_TS1.DAT'
SYS@BABU> truncate table TAB1;
truncate table TAB1
ERROR at line 1:
ORA-00372: file 6 cannot be modified at this time
ORA-01110: data file 6: 'D:\ORACLE\ORADATA\TEST_TS1.DAT'
SYS@BABU> DROP TABLE TAB1 ;
Table dropped.