Exporting and Importing Statistics for Schema objects.

Question

Hello All,
I am trying to gather stats for optimization using, gather_schema_stats for all objects under schema. The manual what i am reading says it covers both Tables and Indexes and we can also include the all partions too. For the safety reasons i was informed by a friend that we should take a back up of old stats into a table (user defined), so as in case of messing up with new stats for performance issue we can use it as an backup copy. So, i have created a user table and exported the stats from existing schema. My Question is, do i have to create one for the indexes too. Or its all in one table. I hope my question is clear.
Generally manuals don't teach all this kind of stuff until unless we learn it by ourselves by trial and error Or getting solutions from great resolvers like you people.
Hope to hear soon.
Thanks in Advance.

Answer 1

One table for table and indexes stats is enough, a little test for you :
SCOTT@demo102> exec DBMS_STATS.CREATE_STAT_TABLE('SCOTT','MYTBL');
PL/SQL procedure successfully completed.
SCOTT@demo102> desc mytbl
Name                                      Null?    Type
STATID                                             VARCHAR2(30)
TYPE                                               CHAR(1)
VERSION                                            NUMBER
FLAGS                                              NUMBER
C1                                                 VARCHAR2(30)
C2                                                 VARCHAR2(30)
C3                                                 VARCHAR2(30)
C4                                                 VARCHAR2(30)
C5                                                 VARCHAR2(30)
N1                                                 NUMBER
N2                                                 NUMBER
N3                                                 NUMBER
N4                                                 NUMBER
N5                                                 NUMBER
N6                                                 NUMBER
N7                                                 NUMBER
N8                                                 NUMBER
N9                                                 NUMBER
N10                                                NUMBER
N11                                                NUMBER
N12                                                NUMBER
D1                                                 DATE
R1                                                 RAW(32)
R2                                                 RAW(32)
CH1                                                VARCHAR2(1000)
SCOTT@demo102> create table mytable_obj as select * from all_objects;
Table created.
SCOTT@demo102> create index myindex on mytable_obj(object_id);
Index created.
SCOTT@demo102> exec dbms_stats.gather_table_stats(ownname=>'SCOTT',tabname=>'MYTABLE_OBJ',cascade=>true);
PL/SQL procedure successfully completed.
SCOTT@demo102> select last_analyzed from all_tables where table_name='MYTABLE_OBJ';
07/06/06
SCOTT@demo102> select last_analyzed from all_indexes where table_name='MYTABLE_OBJ';
07/06/06
SCOTT@demo102> exec dbms_stats.export_table_stats('SCOTT','MYTABLE_OBJ',stattab=>'MYTBL')
PL/SQL procedure successfully completed.
SCOTT@demo102> exec dbms_stats.delete_table_stats('SCOTT','MYTABLE_OBJ');
PL/SQL procedure successfully completed.
SCOTT@demo102> select last_analyzed from all_tables where table_name='MYTABLE_OBJ';
-->No value
SCOTT@demo102> select last_analyzed from all_indexes where table_name='MYTABLE_OBJ';
-->No value
SCOTT@demo102>  exec dbms_stats.import_table_stats('SCOTT','MYTABLE_OBJ',stattab=>'MYTBL');
PL/SQL procedure successfully completed.
SCOTT@demo102> select last_analyzed from all_tables where table_name='MYTABLE_OBJ';
07/06/06
SCOTT@demo102> select last_analyzed from all_indexes where table_name='MYTABLE_OBJ';
07/06/06
SCOTT@demo102> Nicolas.