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Saturday, December 5, 2009

Table Fragmentation

How to find table fragmentation?

SQL> select count(*) from big1;

1000000 rows selected.

SQL> delete from big1 where rownum <= 300000;

300000 rows deleted.

SQL> commit;

Commit complete.

SQL> update big1 set object_id = 0 where rownum <=350000;

342226 rows updated.

SQL> commit;

Commit complete.

SQL> exec dbms_stats.gather_table_stats('SCOTT','BIG1');

PL/SQL procedure successfully completed.
Table size (with fragmentation)

SQL> select table_name,round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 72952kb
Actual data in table:

SQL> select table_name,round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 30604.2kb
Note = 72952 - 30604 = 42348 Kb is wasted space in table

The difference between two values is 60% and Pctfree 10% (default) - so, the table has 50% extra space which is wasted because there is no data.

How to reset HWM / remove fragemenation?

For that we need to reorganize the fragmented table.

We have four options to reorganize fragmented tables:

1. alter table ... move + rebuild indexes
2. export / truncate / import
3. create table as select ( CTAS)
4. dbms_redefinition

Option: 1 "alter table ... move + rebuild indexes"

SQL> alter table BIG1 move;

Table altered.

SQL> select status,index_name from user_indexes
2 where table_name = 'BIG1';

STATUS INDEX_NAME
-------- ------------------------------
UNUSABLE BIGIDX

SQL> alter index bigidx rebuild;

Index altered.

SQL> select status,index_name from user_indexes
2 where table_name = 'BIG1';

STATUS INDEX_NAME
-------- ------------------------------
VALID BIGIDX


SQL> exec dbms_stats.gather_table_stats('SCOTT','BIG1');

PL/SQL procedure successfully completed.

SQL> select table_name,round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 38224kb

SQL> select table_name,round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 30727.37kb
Option: 2 “Create table as select”

SQL> create table big2 as select * from big1;

Table created.

SQL> drop table big1 purge;

Table dropped.

SQL> rename big2 to big1;

Table renamed.

SQL> exec dbms_stats.gather_table_stats('SCOTT','BIG1');

PL/SQL procedure successfully completed.

SQL> select table_name,round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 85536kb

SQL> select table_name,round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 68986.97kb

SQL> select status from user_indexes
2 where table_name = 'BIG1';

no rows selected

SQL> --Note we need to create all indexes.
Option: 3 "export / truncate / import"

SQL> select table_name, round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 85536kb

SQL> select table_name, round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 42535.54kb

SQL> select status from user_indexes where table_name = 'BIG1';

STATUS
--------
VALID

SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.1.0.5.0 - Pr
oduction
With the Partitioning, OLAP and Data Mining options

C:\>exp scott/tiger@Orcl file=c:\big1.dmp tables=big1

Export: Release 10.1.0.5.0 - Production on Sat Jul 28 16:30:44 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to: Oracle Database 10g Enterprise Edition Release 10.1.0.5.0 - Produc
tion
With the Partitioning, OLAP and Data Mining options
Export done in WE8MSWIN1252 character set and AL16UTF16 NCHAR character set

About to export specified tables via Conventional Path ...
. . exporting table BIG1 468904 rows exported
Export terminated successfully without warnings.

C:\>sqlplus scott/tiger@orcl

SQL*Plus: Release 10.1.0.5.0 - Production on Sat Jul 28 16:31:12 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.5.0 - Production
With the Partitioning, OLAP and Data Mining options

SQL> truncate table big1;

Table truncated.

SQL> exit
Disconnected from Oracle Database 10g Enterprise Edition Release 10.1.0.5.0 - Pr
oduction
With the Partitioning, OLAP and Data Mining options

C:\>imp scott/tiger@Orcl file=c:\big1.dmp ignore=y

Import: Release 10.1.0.5.0 - Production on Sat Jul 28 16:31:54 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to: Oracle Database 10g Enterprise Edition Release 10.1.0.5.0 - Produc
tion
With the Partitioning, OLAP and Data Mining options

Export file created by EXPORT:V10.01.00 via conventional path
import done in WE8MSWIN1252 character set and AL16UTF16 NCHAR character set
. importing SCOTT's objects into SCOTT
. . importing table "BIG1" 468904 rows imported
Import terminated successfully without warnings.

C:\>sqlplus scott/tiger@orcl

SQL*Plus: Release 10.1.0.5.0 - Production on Sat Jul 28 16:32:21 2007

Copyright (c) 1982, 2005, Oracle. All rights reserved.

Connected to:
Oracle Database 10g Enterprise Edition Release 10.1.0.5.0 - Production
With the Partitioning, OLAP and Data Mining options

SQL> select table_name, round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 85536kb

SQL> select table_name, round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 42535.54kb

SQL> exec dbms_stats.gather_table_stats('SCOTT','BIG1');

PL/SQL procedure successfully completed.

SQL> select table_name, round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 51840kb

SQL> select table_name, round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'BIG1';

TABLE_NAME size
------------------------------ ------------------------------------------
BIG1 42542.27kb

SQL> select status from user_indexes where table_name = 'BIG1';

STATUS
--------
VALID

SQL> exec dbms_redefinition.can_redef_table('SCOTT','BIG1',-> dbms_redefinition.cons_use_pk);

PL/SQL procedure successfully completed.
Option: 4 "dbms_redefinition"

SQL> create table TABLE1 (
2 no number,
3 name varchar2(20) default 'NONE',
4 ddate date default SYSDATE);

Table created.

SQL> alter table table1 add constraint pk_no primary key(no);

Table altered.

SQL> begin
2 for x in 1..100000 loop
3 insert into table1 ( no , name, ddate)
4 values ( x , default, default);
5 end loop;
6 end;
7 /

PL/SQL procedure successfully completed.

SQL> create or replace trigger tri_table1
2 after insert on table1
3 begin
4 null;
5 end;
6 /

Trigger created.

SQL> select count(*) from table1;

COUNT(*)
----------
100000

SQL> delete table1 where rownum <= 50000;

50000 rows deleted.

SQL> commit;

Commit complete.

SQL> exec dbms_stats.gather_table_stats('SCOTT','TABLE1');

PL/SQL procedure successfully completed.

SQL> select table_name, round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'TABLE1';

TABLE_NAME size
------------------------------ ------------------------------------------
TABLE1 2960kb

SQL> select table_name, round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'TABLE1';

TABLE_NAME size
------------------------------ ------------------------------------------
TABLE1 822.69kb


SQL> --Minimum Privs required "DBA" role or "SELECT" on dbms_redefinition pkg
SQL> --First check table is condidate for redefinition.
SQL>
SQL> exec sys.dbms_redefinition.can_redef_table('SCOTT',-> 'TABLE1',-> sys.dbms_redefinition.cons_use_pk);

PL/SQL procedure successfully completed.

SQL> --After verifying that the table can be redefined online, you manually crea
te an empty interim table (in the same schema as the table to be redefined)
SQL>
SQL> create table TABLE2 as select * from table1 WHERE 1 = 2;

Table created.

SQL> exec sys.dbms_redefinition.start_redef_table ( 'SCOTT',-> 'TABLE1',-> 'TABLE2');

PL/SQL procedure successfully completed.

SQL> --This procedure keeps the interim table synchronized with the original tab
le.
SQL>
SQL> exec sys.dbms_redefinition.sync_interim_table ('SCOTT',-> 'TABLE1',-> 'TABLE2');

PL/SQL procedure successfully completed.

SQL> --Create PRIMARY KEY on interim table(TABLE2)
SQL> alter table TABLE2
2 add constraint pk_no1 primary key (no);

Table altered.

SQL> create trigger tri_table2
2 after insert on table2
3 begin
4 null;
5 end;
6 /

Trigger created.

SQL> --Disable foreign key on original table if exists before finish this proces
s.
SQL>
SQL> exec sys.dbms_redefinition.finish_redef_table ( 'SCOTT',-> 'TABLE1',-> 'TABLE2');

PL/SQL procedure successfully completed.

SQL> exec dbms_stats.gather_table_stats('SCOTT','TABLE1');

PL/SQL procedure successfully completed.

SQL> select table_name, round((blocks*8),2)||'kb' "size"
2 from user_tables
3 where table_name = 'TABLE1';

TABLE_NAME size
------------------------------ ------------------------------------------
TABLE1 1376kb

SQL> select table_name, round((num_rows*avg_row_len/1024),2)||'kb' "size"
2 from user_tables
3 where table_name = 'TABLE1';

TABLE_NAME size
------------------------------ ------------------------------------------
TABLE1 841.4kb

SQL> select status,constraint_name
2 from user_constraints
3 where table_name = 'TABLE1';

STATUS CONSTRAINT_NAME
-------- ------------------------------
ENABLED PK_NO1

SQL> select status ,trigger_name
2 from user_triggers
3 where table_name = 'TABLE1';

STATUS TRIGGER_NAME
-------- ------------------------------
ENABLED TRI_TABLE2

SQL> drop table TABLE2 PURGE;

Table dropped.

Wednesday, September 9, 2009

Select Any Table

Select Any Table

•If you have O7_DICTIONARY_ACCESSIBILITY=TRUE then SELECT ANY TABLE privilege provides access to all SYS and non-SYS objects.

•If you have O7_DICTIONARY_ACCESSIBILITY=FALSE then SELECT ANY TABLE privilege provides access only to non-SYS objects.

•If only SELECT_CATALOG_ROLE is enabled then it provides access to all SYS views only.

•If only SELECT ANY DICTIONARY privilege is enabled then it provides access to SYS schema objects only.

•If both SELECT ANY TABLE and SELECT any DICTIONARY privilege is enabled then it allow access to all SYS and non-SYS objects.

•SELECT ANY DICTIONARY privilege and SELECT_CATALOG_ROLE has no affect over O7_DICTIONARY_ACCESSIBILITY settings.

Saturday, January 3, 2009

ROLE MANAGEMENT

1) How to create a role

Create role  role_name

            Create role satish_role

2) Create Password Protected Role

             Create role role name identified by  password

3) How to Assign Privilege To A Role

             GRANT privilege_name TO role_name;

             GRANT create session TO role_name

     You can give grant role to role

            Grant  to  

4) How to Assigning Roles To Users

            GRANT  roles_name  TO  user_name;

5) How to Revoking Privileges From Roles

REVOKE FROM ;

6) How to Revoke a role from a user

REVOKE  role_name  FROM  user_name;

7) How Activating A Role

SET ROLE  role_name;

8) How Activating A Password Protected Role

SET  ROLE  role_name  IDENTIFIED BY role_password;

9) How to Activating All Roles

SET ROLE all;

10) How to Activating All Roles Except One

SET ROLE all EXCEPT  role_name;

11) How to Deactivating A Role

Can not be done on an individual basis

12) How Deactivating All Roles

SET ROLE none;

13) How to Dropping A Role

DROP ROLE  role_name;

14) How to Creating And Assigning The PLUSTRACE Role Used By AUTOTRACE

            This role must be created by SYS and grants SELECT on the following v_$ views:

·         V$SESSTAT

·         V$STATNAME

·         V$MYSTAT

SQL> @c:\oracle\product\ora10\sqlplus\admin\plustrce.sql
GRANT plustrace TO uwclass;

15) User$

In this user$ table we can see all roles in our database

16) role_sys_privs

In this role_sys_privs table we can see which Privileges Granted To A Role

17) dba_role_privs

In this dba_role_privs  we can see which Roles Granted To Schemas

18) session_roles

In this session_roles we can see the present session have which roles

19) session_prives

In this session_prives table we can see the present session have which privelags

20) dba_roles

            In this dba_roles table we can see the dba user contain which roles

21) dba_sys_privs

In this dba_sys_privs table we can see all the system privileges

ORA-01045) this error will be come due to insufficient privs

 

all_tab_privs_made  in this table you can see all tables privs

user_tab_privs_made