Hi All,
Take a look on the testcase below.
Couple of things seems strange to me in this testcase:
1. Step Nr. 5. Why Oracle can’t use already created copy of the block
during step Nr.4?
2. Step Nr. 4. Why there “52 redo size” during the CR?
Anybody have idea?
Jurijs
Test case
Tested on 9.2.0.4/5 Win32/Linux
- 1
- Make test
drop table testcr;
create table testcr (n number) tablespace users;
insert into testcr values (1);
commit;
- 2
- So far so good
DROPME:jozh> set autotrace on stat
DROPME:jozh> select * from testcr;
N
1
Statistics
…
7 consistent gets
0 redo size
…
- 3
- In parallel session run
begin for f in 1..10000 loop
update testcr set n=f;
end loop;
end;
/
- 4
-- “10008 consistent gets” understandable. Session create copy of the
block and apply UNDO 10000 times.
DROPME:jozh> select * from testcr;
N
1
Statistics
…
10008 consistent gets
52 redo size
…
- 5
-- “10008 consistent gets” Seams very strange for me. There copy of the
block already.
DROPME:jozh> select * from testcr;
N
1
Statistics
…
10008 consistent gets
52 redo size
…
- 6
- In parallel session run
commit;
- 7
- It’s OK.
DROPME:jozh> select * from testcr;
N
10000
Statistics
…
7 consistent gets
0 redo size
…
--
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Received on Sun Oct 10 2004 - 14:42:22 CDT