More Table Blocks in 11g with same number of rows as in 9i

Question

I was using SQL performance analyzer to compare performance difference between 9i and 11g databases.
For this purpose I generated a trace file in 9i database and used it to build STS in 11g database.
After runing two trials and comparison the report showed performance regression (comparing "buffer gets") while using following SQL statement
*"SELECT * FROM EMP";*
There were total 14 rows in emp table in both databases( i.e 9i and 11g)
There was no plan change for above SQL statement in 11g database but still there was performance regression in 11g.
After querying dba_tables view for number of blocks in emp table on both sides i found that EMP table in 9i database had 1 block where as in 11g emp table had 5 blocks (Even after using alter table emp move;)
I am unable to understand why emp table has more number of blocks in 11g with same number of rows as in 9i emp table?

Answer 1

user8916506 wrote:
Below query was executed in 9i database.
SQL> select extent_management,initial_extent,allocation_type from dba_tablespaces where tablespace_name='SYSTEM';
EXTENT_MAN INITIAL_EXTENT ALLOCATIO
LOCAL 65536 SYSTEM
Results shows that SYSTEM tablespace in 9i database is locally managed.
Where as results of below query from 11g database is indicating that users tablespace in 11g is also locally managed.
SQL> select extent_management,initial_extent,allocation_type from dba_tablespaces where tablespace_name='USERS';
EXTENT_MAN INITIAL_EXTENT ALLOCATIO
LOCAL 65536 SYSTEMGood to see that you also picked up the allocation_type at the same time.
So you have shown that the discrepancy between 9i and 11g isn't down to the difference in extent management.
Are there any other differences between the tablespaces when you compare 9i system with non-system, and 9i system with 11g non-system ? (Hint - we have an anomaly with space allocation.)
Regards
Jonathan Lewis
http://jonathanlewis.wordpress.com
Author: <b><em>Oracle Core</em></b>