Oracle 11g FBDA

Question

Hi All,
We are currently using Oracle 11.1.0.7
FBDA is enabled in the Database and facing some peculiar behaviour in FBDA
Please find the error we are facing in FBDA
CREATE TABLE TEST
(A NUMBER(1)
B VARCHAR2(10)
CREATE_DT DATE
LAST_UPDATE_DT DATE);
ENABLing FLASHBACK FOR TEST
INSERT INTO TEST VALUES ( 1, 'TEST1');
COMMIT;
UPDATE TEST SET B='TEST2' WHERE A=1;
COMMIT;
SELECT * FROM TEST VERSIONS BETWEEN SCN MINVALUE AND MAXVALUE;
A B CREATE_DT LAST_UPDATE_DT
== === =========== ==============
1 TEST1 14-APR-11 NULL
1 TEST2 14-APR-11 14-APR-11
AFTER 1 HOUR
SELECT * FROM TEST VERSIONS BETWEEN SCN MINVALUE AND MAXVALUE;
A B CREATE_DT LAST_UPDATE_DT
== === ========== =============
1 TEST2 14-APR-11 14-APR-11
Create record is vanished, I tried this scenario for many records and this issue is consistent
Regards,
Mohanarangan K

Answer 1

Hi Gary,
Because the only real advantage of 64bit over 32bit is the more memory it can address.That's not strictly true (saying that that is the only real advantage). One of the other significant advantages of 64bit over 32bit is the extended register size, allowing manipulation and calculations of large numbers (i.e. numbers that's are larger than would fit into a 32bit register) much easier and faster.
A while ago I helped out on a (non Oracle related) scientific 'number-crunching' project where we basically gave some calculations to a cluster of AMD Opteron servers to churn through. We found that simply by recompiling the program as a 64bit executable rather than a 32bit executable led to around a 20% increase in speed (there were no other changes to the program, no other special GCC compiler options other than compiling as 64bit).
This was a very 'edge case', since the program was a pure calculation engine (it typically ran for around 4 weeks over 24 CPU's, i.e. around 672 CPU days of calculation), so the 20% increase in speed resulted in a very good gain in terms of the number of days saved.
So, in the case of the Oracle DB code you might not see anything noticibly faster about running in 64bit, I'm sure it probably helps out a few of those math calculations churning away inside to run a bit faster.
I agree with you that the memory is probably the key advantage for the 64bit move, however it's not the only advantage.
John.
http://jes.blogs.shellprompt.net