VIEWS WE QUERY IN DATABASE

1} V$CONTROLFILE > Lists the names and status of the control files.

2} V$DATABASE > Contains database information from the control files.

3} V$DATAFILE >Contains data file information from control file.

4} V$INSTANCE >Displays the state of the current instance.

5} V$PARAMETER > Lists parameters and values currently in effect for the Session also status and location of all parameters.

6} V$SESSION >Lists session information for each current session.

7} V$SGA >Contains summary information on SGA.

8} V$SPPARAMETER > Lists the contents of SPFILE.

9} V$TABLESPACE > Displays tablespace information from the control file.

10} V$THREAD >Contains thread information from control file.

11} V$VERSION > Version numbers of core library components in oracle server.

12} V$FIXED_TABLE >To find list of data dictionary views.

13} V$CONTROLFILE_RECORD_SECTION > Provides information about the Control file record section.

14}SHOW PARAMETER CONTROL_FILES > Lists the name, status and location of Control files.

15}V$THREAD >To display the current redo log group, the no. of online redo log groups and current sequence number.

16} V$LOGFILE >Displays each redo log group, member and status of each Member.

17} V$LOG > Same as above.

18} V$DATABASE_PROPERTIES >Name of default tablespaces.

19}V$DBA_TABLESPACES >Complete information about tablespaces.

20}V$DBA_DATA_FILES >Complete information of the files present in the Tablespaces.

21} V$DBA_TEMP_FILES >File’s information of temporary tablespace.

22} V$DBA_EXTENTS >To check the extents for a given segment.

23} V$DBA_SEGMENTS >View to get number of extents and blocks allocated to a Segment.

24} V$DBA_FREE_SPACE >Displays free extents in tablespace.

25} V$DBA_ROLLBACK_SEGS >To obtain information about all the undo segments In the database.

{IMP*:-Information about undo segments that are offline can be seen only in this view.}

26}V$ROLLSTAT & V$ROLLNAME >Views to obtain the statistics of the undo Segments currently used by the instance.

27} V$TRANSACTION & V$SESSION >To check the use of a undo segment by Currently active transactions.

28} V$DBA_TABLES à All the information about tables can be obtained here.

29} V$DBA_OBJECTS >All the information about objects in table can be Obtained here.

30} V$DBA_UNUSED_COL_TABS >To identify tables with unused columns.

31} V$DBA_PARTIAL_DROP_TABS >To identify tables that have partially Completed DROP columns operations.

32}V$DBA_INDEXES >Provides information on the indexes.

33}V$DBA_IND_COLUMNS >Provides information on the columns indexed.

34}V$OBJECT _USAGE >Provides information on the usage of an index.

35}V$DBA_CONSTRAINTS >To obtain name, type and status of all constraints.

36}V$DBA_CONS_COLUMNS >To obtain the columns in the constraints on table.

37}V$DBA_USERS >To obtain information about account status, default Tablespace for users.

38}V$DBA_PROPERTIES >View to display passwd profile information.

39}V$DBA_TS_QUOTAS >Amount of space a user can use in tablespaces.

40}V$DBA_SYS_PRIVS > Lists system privileges granted to users and roles.

41} V$SESSION_PRIVS > Lists the privileges that are currently available to user.

42} V$DBA_TAB_PRIVS > Lists all grants on all objects in the database.

43}V$DBA_COL_PRIVS >Describes all object grants in the database.

44}V$DBA_ROLES >All roles that exist in the database.

45}V$DBA_ROLES_PRIVS >Roles granted to users and roles.

46}V$ROLE_ROL_PRIVS > Roles that are granted to roles.

47}V$DBA_SYS_PRIVS >System privileges granted to users and roles.

48}V$ROLE_SYS_PRIVS > System privileges granted to roles.

49}V$ROLE_TAB_PRIVS >Object privileges granted to roles.

50}V$SESSION_ROLES >Roles that the user currently has enabled.

creating a synonym

Database links are notoriously slow, not an optimal solution for applications needing real-time response.
Expect the database link to cause a delay in accessing the remote data.

Here is an example of creating a synonym for scott's database link.

SQL> create synonym rem_emp for emp@remotedb;

Synonym created.

SQL> select count(*) from rem_emp;

COUNT(*)
----------
14

The other method is to create a view on your remote database's data.

SQL> create view v_emp as select * from emp@remotedb;

View created.

SQL> select count(*) from v_emp;

COUNT(*)
----------
14

How to drop a database link

Dropping a database link from your Oracle database is as easy as doing the following:
drop database link remotedb;
or
drop public database link remotedb;

You will need no other system privilege other than the 'create database link' privilege granted directly
to your username or granted via a role to drop your own database link.

It is not possible to drop a database link belonging to another user.

If you try to specify another schema's database link by qualifying it with a name,
Oracle will just look for a private database link in your schema with a name
which includes the other schema's name and will not find it.

To drop a public database link, you will need the system privilege 'drop public database link'.
For example:

SQL> connect / as sysdba
Connected.

SQL> drop database link scott.remotedb;
drop database link scott.remotedb
*
ERROR at line 1:
ORA-02024: database link not found

SQL> connect scott/tiger
Connected.
SQL> drop database link scott.remotedb;
drop database link scott.remotedb
*
ERROR at line 1:
ORA-02024: database link not found

SQL> drop database link remotedb;

Database link dropped.

******************************************************************************

Oracle Tablespace:-

create, add a file, remove a file, drop, rename

Tablespaces & Datafiles: Overview
Data for Oracle tables, indexes, etc is stored in data files, but never when an object is defined, the object is associated with a file directly. All the time the Oracle objects are “located” in the tablespaces. The “tablespaces” are logical concepts and each tablespace is in relation with one or more physical file. So, when an object is created in a tablespace, the data will be stored automatically in the file(s) associated with this tablespace.
Tablespace creation
=> Data tablespace (created for data objects like tables, materialized view, indexes)
          CREATE TABLESPACE DATA_1_TBS
          DATAFILE ‘C:\oradata\data_1.dbf’
          SIZE 20M AUTOEXTEND ON;

This tablespace named DATA_1_TBS has allocated 20M space on the file data_1.dbf and the size of the file will increase if the tablespace will need more space on the disk.

=> Temporary tablespace (keep temporary data for sort, join operations)

CREATE TEMPORARY TABLESPACE temp_1
TEMPFILE ‘c:\temp01.dbf’ SIZE 5M AUTOEXTEND ON;
This tablespace named “temp_1″ has allocated 5M space on the file temp01.dbf and the size of the file will increase if the tablespace will need more space on the disk. However, in general, the temporary tablespaces are not set to be “autoextend off”, but have enough room for the database needs.

=> UNDO tablespace (keep the old values for the transactions which are not commited)

      CREATE UNDO TABLESPACE undo1
       DATAFILE ‘c:\oradata\undo1.dbf’ SIZE 10M AUTOEXTEND ON
       RETENTION GUARANTEE;
If you use the “RETENTION GUARANTEE” clause Oracle guarantees that whatever retention period you have set will be honored.

NOTES:

EXTENT MANAGEMENT LOCAL UNIFORM SIZE 128K; –> creates a locally managed tablespace in which every extent is 128K
EXTENT MANAGEMENT LOCAL SEGMENT SPACE MANAGEMENT AUTO; –> creates a tablespace with automatic segment-space management (ASSM).

Add a file to the tablespace

ALTER TABLESPACE DATA_1_TBS
ADD DATAFILE ‘c:\oradata\data_file2.dbf’ SIZE 30M AUTOEXTEND OFF;

To get more information on the files which are associated with a tablespace the following query could be used:
SELECT TABLESPACE_NAME, FILE_NAME, FILE_ID, AUTOEXTENSIBLE, ONLINE_STATUS
FROM DBA_DATA_FILES ORDER BY 1;
Remove a file from a tablespace (Resizing a tablespace)
Removing a file from a tablespace cannot be done directly. First, the objects must be moved in another tablespace, the initial tablespace will be dropped and recreated. After that the objects could be moved again in the tablespace which was resized. If the reason you wanted to drop the file is because you mistakenly created the file of the wrong size, then consider using the RESIZE command.

Add more space to a tablespace without adding a new file
ALTER DATABASE DATAFILE ‘C:\oradata\data_1.dbf’ RESIZE 25M;

Dropping a tablespace
DROP TABLESPACE DATA_1_TBS; (if the tablespace is empty)
DROP TABLESPACE DATA_1_TBS INCLUDING CONTENTS; (if the objects in the tablespace are no longer needed)
However the files must be deleted from the OS level

Rename a tablespace
(in 10g)
ALTER TABLESPACE DATA_1_TBS RENAME TO DATA_10_TBS;
(in 9i)
1. Create a new tablespace NEW_TBLS.
2. Copy all objects from OLD_TBLS to NEW_TBLS.

3. Drop tablespace OLD_TBLS.

Moving the tablespace files

=> for Data files, Log files:

1) Shutdown the database.
2) Rename the physical file on the OS. ==> Win: SQL> HOST MOVE file1.dbf file2.dbf
3) Start the database in MOUNT mode.
ALTER DATABASE RENAME FILE ‘C:\OHOME_9I\ORADATA\DB9\REDO01.LOG’ TO ‘C:\ORACLE\data\REDO01.LOG’;

ALTER DATABASE RENAME FILE ‘C:\OHOME_9I\ORADATA\DB9\REDO02.LOG’ TO ‘C:\ORACLE\data\REDO02.LOG’;

ALTER DATABASE RENAME FILE ‘C:\OHOME_9I\ORADATA\DB9\REDO03.LOG’ TO ‘C:\ORACLE\data\REDO03.LOG’;

ALTER DATABASE OPEN;

=> for Control File (SPFILE is used)

1) Alter control_files initialisation parameter in SPFILE

ALTER SYSTEM SET control_files = ‘C:\NEW_PATH\RENAME_CONTROL01.CTL’,

   ‘C:\ORACLE\PRODUCT\10.1.0\ORADATA\DB10G\CONTROL02.CTL’,
   ‘C:\ORACLE\PRODUCT\10.1.0\ORADATA\DB10G\CONTROL03.CTL’
                  SCOPE = SPFILE;
  2) Shutdown the database.
  3) Rename the physical Controle file on the OS. ==> Win: SQL> HOST MOVE file1.ctl file2.ctl
  4) Start the database.

=> for TEMP files

1) CREATE TEMPORARY TABLESPACE TEMP1 TEMPFILE ‘…\temp_temp1.dbf’ SIZE 2M
EXTENT MANAGEMENT LOCAL UNIFORM SIZE 1M;
2) ALTER DATABASE DEFAULT TEMPORARY TABLESPACE TEMP1;
3) DROP TABLESPACE TEMP INCLUDING CONTENTS; – TEMP = 1st temporary tablespace
4) CREATE TEMPORARY TABLESPACE TEMP TEMPFILE ‘…\temp01.dbf’ SIZE 2G
EXTENT MANAGEMENT LOCAL UNIFORM SIZE 100M;
5) ALTER DATABASE DEFAULT TEMPORARY TABLESPACE TEMP;
6) DROP TABLESPACE TEMP1 INCLUDING CONTENTS;

Manage Oracle Database Jobs

What a database job is?
All the time we need some PL/SQL scripts to run at a specific period of time regularly. This is done by scheduling the database jobs to run following some rules. A job define what we have to run, when and at which interval. When a job is created (submitted), the job is put in a queue. The queue is monitored by a coordinator job queue (CJQ0) background process. The coordinator (CJQ0) periodically selects jobs that are ready to run from the jobs shown in the DBA_JOBS view. The time interval the coordinator looks for new jobs to start is establish by JOB_QUEUE_INTERVAL initialization parameter. JOB_QUEUE_INTERVAL set to 60 means that the CJQ0 will look at every minutes to see if is any job scheduled to run at this time. When CJQ0 find a job which must start, CJQ0 spawns a Jnnn processes to run the selected jobs. Each Jnnn process executes one of the selected jobs. The number of jobs which can run simultaneously is fixed by JOB_QUEUE_PROCESSES initialization parameter. If the JOB_QUEUE_PROCESSES parameter is equal to 10, only 10 Jnnn processes could run simultaneously, so only 10 jobs could run in the same time.
If JOB_QUEUE_PROCESSES = 0 no jobs could be scheduled for that database.

How to create a job?
To create a job we have to use the DBMS_JOB.SUBMIT procedure.

declare
vnu_job NUMBER;
begin
DBMS_JOB.SUBMIT (vnu_job,’scott.Procedure_A;’, sysdate,’sysdate+3/(24*60)’);
end;

In this example, the procedure Procedure_A is scheduled to run at every 3 minutes starting from “sysdate”.

How to run a job?
begin
DBMS_JOB.RUN(vnu_job);
end;
/
This PL/SQL block run the previous job at this moment.

How to change the execution time for a job?
begin
DBMS_JOB.INTERVAL(vnu_job, ‘NULL’);
end;
/
In this example, the job will not run again after it successfully executes and it will be deleted from the job queue.

How to remove a job from the database ?
begin
DBMS_JOB.REMOVE(vnu_job);
end;
/

View the status of the running jobs
select * from DBA_JOBS_RUNNING;

View more information about the database jobs
select * from DBA_JOBS;

Managing Data Security in Oracle

How to change the password for an user?
SQL> ALTER USER scott identified by scott;

How to enforce strict password control?
By default, Oracle will allow users to choose single character passwords and passwords that match their names and userids. Also, by default the password will not expire. However, Oracle manage passwords through profiles. Some of the things that we can restrict:
FAILED_LOGIN_ATTEMPTS – failed login attempts before the account is locked
PASSWORD_LIFE_TIME – limits the number of days the same password can be used for authentication
PASSWORD_GRACE_TIME – number of days after the grace period begins during which a warning is issued and login is allowed
PASSWORD_LOCK_TIME – number of days an account will be locked after maximum failed login attempts
PASSWORD_REUSE_TIME – number of days before a password can be reused
PASSWORD_REUSE_MAX – number of password changes required before the current password can be reused
PASSWORD_VERIFY_FUNCTION – password complexity verification script

Example:
Create the Profile
SQL> CREATE PROFILE profile_A LIMIT FAILED_LOGIN_ATTEMPTS 3;
Associate the profile with an user:
SQL> ALTER USER scott PROFILE profile_A;

How to connect as sys without knowing his password?
If an administrative OS users belongs to the “dba” group on Unix or to the “ORA_DBA” (ORA_sid_DBA) group on NT, we can connect to oracle like this:
SQL> connect / as sysdba
SQL> show user

We can use show user command to verify that we are connected as SYS.
How to connect as a regular user without knowing his password

1) Select the encrypted password value
SQL> SELECT password FROM dba_users WHERE username=’SCOTT’;
PASSWORD
————————–
D794344J35502S67

2) Change Scott’s password (temporarily)
SQL> ALTER USER scott identified by new_pass;

3) Connect using this new password
SQL> connect scott/new_pass;

4) Connect as SYS (or SYSTEM)
SQL> connect / as sysdba

5) re-enable the first Scott’s password
SQL> ALTER USER scott identified by values ‘D794344J35502S67′;

Allowing/ Removing SELECT, DELETE, UPDATE, INSERT privileges on tables
SQL>   GRANT select, update, delete, insert on SCOTT.EMP to sonu ;
SQL>      REVOKE select, update, delete, insert on SCOTT.EMP FROM sonu ;
“ sonu ” could be a user (schema) or a role.
Allowing/ Removing EXECUTE privileges on procedures, functions, packages
grant EXECUTE on SCOTT.F1 to sonu ;               ( sonu  will be able to run (execute) scott.F1 function )
revoke EXECUTE on SCOTT.F1 from sonu ;

Using Roles

Sometimes, the same object, system privileges must be granted to many users. For this purpose we can create a ROLE, grant all the privileges we want to this role and after that we can grant the role to a user or many users.

1) Create the role (named “ROLE1″ in this example)
SQL> CREATE ROLE role1;

2) Grant privileges to this role
SQL> GRANT select, update, delete, insert on SCOTT.EMP to ROLE1;
grant EXECUTE on SCOTT.F1 to ROLE1;

3) Grant the Role to an user
SQL> GRANT role1 TO sonu;

REMOTE_LOGIN_PASSWORDFILE parameter

This parameter is used for managing the SYS authentication.
If REMOTE_LOGIN_PASSWORDFILE='NONE', Oracle will not check for a password file (we can input any user name, any password, we will be connected as SYS).
If REMOTE_LOGIN_PASSWORDFILE='SHARED' (or ‘EXCLUSIVE’ in 9i), Oracle will check for a password file and we can connect as SYS only if the password is the good one. (RECOMMENDED)

REMOTE_OS_AUTHENT parameter

The REMOTE_OS_AUTHENT parameter lets the Oracle database decide if the authentication can be performed by the remote operating system or if it must be performed by the database.

REMOTE_OS_AUTHENT = TRUE => Authentication just on the remote OS and no authentication on the database side.

REMOTE_OS_AUTHEN = FALSE => Only database authentication is available from these remote systems. (RECOMMENDED)

Kill an Oracle process / jobs from OS (Linux, AIX,UNIX)

1. Find the job we what to kill and the session associated with the job
             SQL> select j.sid,
                       s.spid,
                       s.serial#,
                       j.log_user,
                       j.job,
                       j.broken,
                       j.failures,
                       j.last_date||’:'||j.last_sec last_date,
                       j.this_date||’:'||j.this_sec this_date,
                       j.next_date||’:'||j.next_sec next_date,
                       j.next_date – j.last_date interval,
                       j.what
              from ( select djr.SID, dj.LOG_USER, dj.JOB, dj.BROKEN, dj.FAILURES, dj.LAST_DATE, dj.LAST_SEC, dj.THIS_DATE, dj.THIS_SEC, dj.NEXT_DATE, dj.NEXT_SEC, dj.INTERVAL, dj.WHAT
              from dba_jobs dj, dba_jobs_running djr
              where dj.job = djr.job ) j,
              (select p.spid, s.sid, s.serial#
              from v$process p, v$session s
              where p.addr = s.paddr ) s
             where j.sid = s.sid;

2. Mark the job as Broken
                  SQL> begin
                     DBMS_JOB.BROKEN(job#,TRUE);
                     commit;
                  end;

3. Kill the Oracle Session

SQL> ALTER SYSTEM KILL SESSION ‘sid, serial#’;

NOTE: In many situations the session is marked ‘KILLED’ but is not killed.

4. Kill the O/S Process

For UNIX:
kill -9 spid

For Windows at the DOS Prompt:
orakill sid spid

Oracle Database ARCHIVELOG mode

Database ARCHIVELOG mode: Overview
An Oracle database could be in ARCHIVELOG or NON ARCHIVELOG mode. When the database is in ARCHIVELOG mode one or more ARC process(es) are taking backups of the redo log files when the redo logs are full or switched. That assures that all the database operations are kept in 2 places (in data files and in archive log files). Having the database in ARCHIVELOG mode assure us that the data will not be lost even if the original data (from datafiles) will become inaccessible or will be deleted accidentally.

Is my database in ARCHIVELOG mode ?

To see if the database is in archivelog mode the following command could be used:

SQL> select NAME, LOG_MODE, ARCHIVELOG_CHANGE# from v$database;

How could I enable the ARCHIVELOG mode ?

In Oracle 9i
3) assure that we have the following parameters in init.ora:
log_archive_dest_1=’location=C:\Ohome_9i\ARC’
log_archive_start=TRUE obsolete for 10g and higher.

2) startup mount
3) alter database archivelog; (enable automatic archiving)
alter database archivelog MANUAL; (ALTER SYSTEM ARCHIVE LOG ALL; must be run to archive the log files)
In Oracle 10g
SQL> shutdown immediate
SQL> startup mount
SQL> alter database archivelog;
SQL> alter database open;
SQL> select NAME, LOG_MODE, ARCHIVELOG_CHANGE# from v$database;

How could I disable the ARCHIVELOG mode ?
SQL> shutdown immediate
SQL> startup mount
SQL> alter database noarchivelog;
SQL> alter database open;
SQL> select NAME, LOG_MODE, ARCHIVELOG_CHANGE# from v$database;

Automatic/ Manual Archiving
ARCHIVE LOG LIST; -> Show the Status of Automatic Archiving.
ARCHIVE LOG START; -> Start Automatic Archiving.
ARCHIVE LOG STOP; -> Stop Automatic Archiving.

Views used in managing database ARCHIVELOG mode

V$ARCHIVE_DEST -> Show the places where the archive logs are shipped.
V$ARCHIVED_LOG -> Show the history of archived log files
V$ARCHIVE_PROCESSES -> Show information about the current archiving process.

Oracle Maintenance Task

1. What is the current version/ maintenance release of the database I use?
To check the Oracle database version from the SQL*Plus prompt, you can issue following sql:

SQL> SELECT banner FROM v$version WHERE banner LIKE ‘Oracle%’;
Or
SQL> SELECT version FROM product_component_version WHERE product LIKE ‘Oracle%’;

2. How could I interpret the Oracle version digits?
Example: Oracle version 10.2.0.5.0

1st Digit: “10” is a major version database number. This is a major new edition of the software, which usually contains significant new functionalities.

2nd Digit: “2” is the database maintenance release number. The maintenance release number increases when bug fixes or new features to existing programs become available.

3rd Digit: “0” is the patch set number. A patch release contains fixes for serious bugs that cannot wait until the next maintenance release.

4th/ 5th Digit: “5.0” identifies a release level specific to a component/OS. This is used to identify a particular emergency patch release of a software product on that operating system.

3. How could I know if my database is 32-bit or 64-bit version?

From the sqlplus prompt you can run :
SQL> SELECT banner FROM v$version;

One line will tell you if the database is 32-bit or 64-bit.
Example:
“TNS for 32-bit Windows: Version 10.2.0.5.0 – Production” means that the database is 32-bit.

On Unix/Solaris/Linux:
cd $ORACLE_HOME/bin
file oracl*

This will display the file type of your oracle binaries. If you are running 64-bit binaries, the output should look like this:
oracle: ELF 64-bit MSB executable SPARCV9 Version 1, dynamically linked, not stripped
oracleO: ELF 64-bit MSB executable SPARCV9 Version 1, dynamically linked, not stripped

If your binaries are 32-bit, the output will look like this:
oracle: ELF 32-bit MSB executable SPARC Version 1, dynamically linked, not stripped

4. How could I know if my OS is 32-bit or 64-bit version?
On Solaris:
From the command line (as root or not) run this command:

$ /usr/bin/isainfo -kv

If your OS is 64-bit, you will see output like:
64-bit sparcv9 kernel modules

If your OS is 32-bit, you will get this output:
32-bit sparc kernel modules

On Linux, use uname –a
$ uname -a
Linux linux2 2.6.9-22.ELsmp #1 SMP Sat Oct 8 19:11:43 CDT 2005 i686 i686 i386 GNU/Linux

That means 32-bit.

A 64-bit would be
Linux linux2 2.6.9-22.ELsmp #1 SMP Sat Oct 8 19:11:43 CDT 2005 x86_64 x86_64 x86_64 GNU/Linux

On HP-UX
$ getconf KERNEL_BITS
64

On Microsoft Windows Server 2003
1. Click Start, click Run, type sysdm.cpl, and then click OK.
2. Click the General tab. The operating system appears as follows:

For a 64-bit version operating system: Microsoft Windows Server 2003 Enterprise x64 Edition appears under System.
For a 32-bit version operating system: Microsoft Windows Server 2003 Enterprise Edition appears under System.

5. What UNIX-type Operating System I use ?
$ uname -a
SunOS hostname 5.8 Generic_117350-41 sun4u sparc SUNW,Sun-Fire

In this case is the OS is Sun Solaris SPARC version 8.

6. Which is the last Oracle database patch set available for a particular major version ?
a) Login to Metalink: https://support.oracle.com/CSP/ui/flash.html

b) Find the Document ID 730365.1 : Oracle Database Upgrade Path Reference List

* ACMS (atomic control file to memory service) per-instance process is an agent that contributes to ensuring a distributed SGA memory update is either globally committed on success or globally aborted in the event of a failure in an Oracle RAC environment.

* DBRM (database resource manager) process is responsible for setting resource plans and other resource manager related tasks.

* DIA0 (diagnosability process 0) (only 0 is currently being used) is responsible for hang detection and deadlock resolution.

* DIAG (diagnosability) process performs diagnostic dumps and executes global oradebug commands.

* EMNC (event monitor coordinator) is the background server process used for database event management and notifications.

* FBDA (flashback data archiver process) archives the historical rows of tracked tables into flashback data archives. Tracked tables are tables which are enabled for flashback archive. When a transaction containing DML on a tracked table commits, this process stores the pre-image of the rows into the flashback archive. It also keeps metadata on the current rows.

FBDA is also responsible for automatically managing the flashback data archive for space, organization, and retention and keeps track of how far the archiving of tracked transactions has occurred.

* GTX0-j (global transaction) processes provide transparent support for XA global transactions in an Oracle RAC environment. The database autotunes the number of these processes based on the workload of XA global transactions. Global transaction processes are only seen in an Oracle RAC environment.

* KATE performs proxy I/O to an ASM metafile when a disk goes offline.

* MARK marks ASM allocation units as stale following a missed write to an offline disk.

* SMCO (space management coordinator) process coordinates the execution of various space management related tasks, such as proactive space allocation and space reclamation. It dynamically spawns slave processes (Wnnn) to implement the task.

* VKTM (virtual keeper of time) is responsible for providing a wall-clock time (updated every second) and reference-time counter (updated every 20 ms and available only when running at elevated priority).

*******************************************************************************

Oracle Data Pump Exports/Imports

Oracle Data Pump is a newer, faster and more flexible alternative to the "exp" and "imp" utilities used in previous Oracle versions. In addition to basic import and export functionality data pump provides a PL/SQL API and support for external tables.

Getting Started

For the examples to work we must first unlock the SCOTT account and create a directory object it can access. The directory object is only a pointer to a physical directory, creating it does not actually create the physical directory on the file system.

CONN / AS SYSDBA
ALTER USER scott IDENTIFIED BY tiger ACCOUNT UNLOCK;

CREATE OR REPLACE DIRECTORY test_dir AS '/u01/app/oracle/oradata/';
GRANT READ, WRITE ON DIRECTORY test_dir TO scott;

Existing directories can be queried using the ALL_DIRECTORIES view.

Table Exports/Imports

The TABLES parameter is used to specify the tables that are to be exported. The following is an example of the table export and import syntax.

expdp scott/tiger@db10g tables=EMP,DEPT directory=TEST_DIR

dumpfile=EMP_DEPT.dmp logfile=expdpEMP_DEPT.log

impdp scott/tiger@db10g tables=EMP,DEPT directory=TEST_DIR

dumpfile=EMP_DEPT.dmp logfile=impdpEMP_DEPT.log

For example output files see expdpEMP_DEPT.log and impdpEMP_DEPT.log.

The TABLE_EXISTS_ACTION=APPEND parameter allows data to be imported into existing tables.

Schema Exports/Imports

The OWNER parameter of exp has been replaced by the SCHEMAS parameter which is used to specify the schemas to be exported. The following is an example of the schema export and import syntax.

expdp scott/tiger@db10g schemas=SCOTT directory=TEST_DIR dumpfile=SCOTT.dmp logfile=expdpSCOTT.log

impdp scott/tiger@db10g schemas=SCOTT directory=TEST_DIR dumpfile=SCOTT.dmp logfile=impdpSCOTT.log

For example output files see expdpSCOTT.log and impdpSCOTT.log.

Database Exports/Imports

The FULL parameter indicates that a complete database export is required. The following is an example of the full database export and import syntax.

expdp system/password@db10g full=Y directory=TEST_DIR

 dumpfile=DB10G.dmp logfile=expdpDB10G.log

impdp system/password@db10g full=Y directory=TEST_DIR

 dumpfile=DB10G.dmp logfile=impdpDB10G.log

For an example output file see expdpDB10G.log.

INCLUDE and EXCLUDE

The INCLUDE and EXCLUDE parameters can be used to limit the export/import to specific objects. When the INCLUDE parameter is used, only those objects specified by it will be included in the export/import. When the EXCLUDE parameter is used, all objects except those specified by it will be included in the export/import. The two parameters are mutually exclusive, so use the parameter that requires the least entries to give you the result you require. The basic syntax for both parameters is the same.

INCLUDE=object_type[:name_clause] [, ...]
EXCLUDE=object_type[:name_clause] [, ...]

The following code shows how they can be used as command line parameters.

expdp scott/tiger@db10g schemas=SCOTT include=TABLE:"IN

 ('EMP', 'DEPT')" directory=TEST_DIR dumpfile=SCOTT.dmp

logfile=expdpSCOTT.log

expdp scott/tiger@db10g schemas=SCOTT exclude=TABLE:"= 'BONUS'"

directory=TEST_DIR dumpfile=SCOTT.dmp logfile=expdpSCOTT.log

If the parameter is used from the command line, depending on your OS, the special characters in the clause may need to be escaped, as follows. Because of this, it is easier to use a parameter file.

include=TABLE:\"IN (\'EMP\', \'DEPT\')\"

A single import/export can include multiple references to the parameters, so to export tables, views and some packages we could use either of the following approaches.

INCLUDE=TABLE,VIEW,PACKAGE:"LIKE '%API'"

or

INCLUDE=TABLE
INCLUDE=VIEW
INCLUDE=PACKAGE:"LIKE '%API'"

The valid object type paths that can be included or excluded can be displayed using the DATABASE_EXPORT_OBJECTS, SCHEMA_EXPORT_OBJECTS, and TABLE_EXPORT_OBJECTS views.

Network Exports/Imports (NETWORK_LINK)

The NETWORK_LINK parameter identifies a database link to be used as the source for a network export/import. The following database link will be used to demonstrate its use.

CONN / AS SYSDBA
GRANT CREATE DATABASE LINK TO test;

CONN test/test
CREATE DATABASE LINK remote_scott CONNECT TO scott IDENTIFIED BY tiger

 USING 'DEV';

In the case of exports, the NETWORK_LINK parameter identifies the database link pointing to the source server. The objects are exported from the source server in the normal manner, but written to a directory object on the local server, rather than one on the source server. Both the local and remote users require the EXP_FULL_DATABASE role granted to them.

expdp test/test@db10g tables=SCOTT.EMP network_link=REMOTE_SCOTT

directory=TEST_DIR dumpfile=EMP.dmp logfile=expdpEMP.log

For imports, the NETWORK_LINK parameter also identifies the database link pointing to the source server. The difference here is the objects are imported directly from the source into the local server without being written to a dump file. Although there is no need for a DUMPFILE parameter, a directory object is still required for the logs associated with the operation. Both the local and remote users require the IMP_FULL_DATABASE role granted to them.

impdp test/test@db10g tables=SCOTT.EMP network_link=REMOTE_SCOTT

 directory=TEST_DIR logfile=impdpSCOTT.log remap_schema=SCOTT:TEST

Miscellaneous Information

Unlike the original exp and imp utilities all data pump ".dmp" and ".log" files are created on the Oracle server, not the client machine.

All data pump actions are performed by multiple jobs (server processes not DBMS_JOB jobs). These jobs are controlled by a master control process which uses Advanced Queuing. At runtime an advanced queue table, named after the job name, is created and used by the master control process. The table is dropped on completion of the data pump job. The job and the advanced queue can be named using the JOB_NAME parameter. Cancelling the client process does not stop the associated data pump job. Issuing "ctrl+c" on the client during a job stops the client output and presents a command prompt. Typing "status" at this prompt allows you to monitor the current job.

Export> status

Job: SYS_EXPORT_FULL_01
  Operation: EXPORT
  Mode: FULL
  State: EXECUTING
  Bytes Processed: 0
  Current Parallelism: 1
  Job Error Count: 0
  Dump File: D:\TEMP\DB10G.DMP
    bytes written: 4,096

Worker 1 Status:
  State: EXECUTING
  Object Schema: SYSMAN
  Object Name: MGMT_CONTAINER_CRED_ARRAY
  Object Type: DATABASE_EXPORT/SCHEMA/TYPE/TYPE_SPEC
  Completed Objects: 261
  Total Objects: 261

Data pump performance can be improved by using the PARALLEL parameter. This should be used in conjunction with the "%U" wildcard in the DUMPFILE parameter to allow multiple dumpfiles to be created or read.

expdp scott/tiger@db10g schemas=SCOTT directory=TEST_DIR parallel=4

 dumpfile=SCOTT_%U.dmp logfile=expdpSCOTT.log

The DBA_DATAPUMP_JOBS view can be used to monitor the current jobs.

system@db10g> select * from dba_datapump_jobs;

OWNER_NAME                     JOB_NAME                  OPERATION
------------------------------ -------------------------------------
JOB_MODE                       STATE                    DEGREE ATTACHED_SESSIONS
------------------------------ ------------------------- -----------------
SYSTEM                         SYS_EXPORT_FULL_01         EXPORT
FULL                           EXECUTING                                                1

Data Pump API

Along with the data pump utilities Oracle provide an PL/SQL API. The following is an example of how this API can be used to perform a schema export.

SET SERVEROUTPUT ON SIZE 1000000
DECLARE
  l_dp_handle       NUMBER;
  l_last_job_state  VARCHAR2(30) := 'UNDEFINED';
  l_job_state       VARCHAR2(30) := 'UNDEFINED';
  l_sts             KU$_STATUS;
BEGIN
  l_dp_handle := DBMS_DATAPUMP.open(
    operation   => 'EXPORT',
    job_mode    => 'SCHEMA',
    remote_link => NULL,
    job_name    => 'EMP_EXPORT',
    version     => 'LATEST');

  DBMS_DATAPUMP.add_file(
    handle    => l_dp_handle,
    filename  => 'SCOTT.dmp',
    directory => 'TEST_DIR');

  DBMS_DATAPUMP.add_file(
    handle    => l_dp_handle,
    filename  => 'SCOTT.log',
    directory => 'TEST_DIR',
    filetype  => DBMS_DATAPUMP.KU$_FILE_TYPE_LOG_FILE);

  DBMS_DATAPUMP.metadata_filter(
    handle => l_dp_handle,
    name   => 'SCHEMA_EXPR',
    value  => '= ''SCOTT''');

  DBMS_DATAPUMP.start_job(l_dp_handle);

  DBMS_DATAPUMP.detach(l_dp_handle);
END;
/

Once the job has started the status can be checked using.

system@db10g> select * from dba_datapump_jobs;

External Tables

Oracle have incorporated support for data pump technology into external tables. The ORACLE_DATAPUMP access driver can be used to unload data to data pump export files and subsequently reload it. The unload of data occurs when the external table is created using the "AS" clause.

CREATE TABLE emp_xt
  ORGANIZATION EXTERNAL
   (
     TYPE ORACLE_DATAPUMP
     DEFAULT DIRECTORY test_dir
     LOCATION ('emp_xt.dmp')
   )
   AS SELECT * FROM emp;

The data can then be queried using the following.

SELECT * FROM emp_xt;

The syntax to create the external table pointing to an existing file is similar, but without the "AS" clause.

DROP TABLE emp_xt;

CREATE TABLE emp_xt (
  EMPNO     NUMBER(4),
  ENAME     VARCHAR2(10),
  JOB       VARCHAR2(9),
  MGR       NUMBER(4),
  HIREDATE  DATE,
  SAL       NUMBER(7,2),
  COMM      NUMBER(7,2),
  DEPTNO    NUMBER(2))
  ORGANIZATION EXTERNAL (
     TYPE ORACLE_DATAPUMP
     DEFAULT DIRECTORY test_dir
     LOCATION ('emp_xt.dmp')
  );

SELECT * FROM emp_xt;

Help

The HELP=Y option displays the available parameters.

expdp

expdp help=y

Export: Release 10.1.0.2.0 - Production on Tuesday, 23 March, 2004 8:33

Copyright (c) 2003, Oracle.  All rights reserved.


The Data Pump export utility provides a mechanism for transferring data objects
between Oracle databases. The utility is invoked with the following command:

   Example: expdp scott/tiger DIRECTORY=dmpdir DUMPFILE=scott.dmp

You can control how Export runs by entering the 'expdp' command followed
by various parameters. To specify parameters, you use keywords:

   Format:  expdp KEYWORD=value or KEYWORD=(value1,value2,...,valueN)
   Example: expdp scott/tiger DUMPFILE=scott.dmp DIRECTORY=dmpdir SCHEMAS=scott
               or TABLES=(T1:P1,T1:P2), if T1 is partitioned table

USERID must be the first parameter on the command line.

Keyword               Description (Default)
------------------------------------------------------------------------------
ATTACH                Attach to existing job, e.g. ATTACH [=job name].
CONTENT               Specifies data to unload where the valid keywords are:
                      (ALL), DATA_ONLY, and METADATA_ONLY.
DIRECTORY             Directory object to be used for dumpfiles and logfiles.
DUMPFILE              List of destination dump files (expdat.dmp),
                      e.g. DUMPFILE=scott1.dmp, scott2.dmp, dmpdir:scott3.dmp.
ESTIMATE              Calculate job estimates where the valid keywords are:
                      (BLOCKS) and STATISTICS.
ESTIMATE_ONLY         Calculate job estimates without performing the export.
EXCLUDE               Exclude specific object types, e.g. EXCLUDE=TABLE:EMP.
FILESIZE              Specify the size of each dumpfile in units of bytes.
FLASHBACK_SCN         SCN used to set session snapshot back to.
FLASHBACK_TIME        Time used to get the SCN closest to the specified time.
FULL                  Export entire database (N).
HELP                  Display Help messages (N).
INCLUDE               Include specific object types, e.g. INCLUDE=TABLE_DATA.
JOB_NAME              Name of export job to create.
LOGFILE               Log file name (export.log).
NETWORK_LINK          Name of remote database link to the source system.
NOLOGFILE             Do not write logfile (N).
PARALLEL              Change the number of active workers for current job.
PARFILE               Specify parameter file.
QUERY                 Predicate clause used to export a subset of a table.
SCHEMAS               List of schemas to export (login schema).
STATUS                Frequency (secs) job status is to be monitored where
                      the default (0) will show new status when available.
TABLES                Identifies a list of tables to export - one schema only.
TABLESPACES           Identifies a list of tablespaces to export.
TRANSPORT_FULL_CHECK  Verify storage segments of all tables (N).
TRANSPORT_TABLESPACES List of tablespaces from which metadata will be unloaded.
VERSION               Version of objects to export where valid keywords are:
                      (COMPATIBLE), LATEST, or any valid database version.

The following commands are valid while in interactive mode.
Note: abbreviations are allowed

Command               Description
------------------------------------------------------------------------------
ADD_FILE              Add dumpfile to dumpfile set.
                      ADD_FILE=dumpfile-name
CONTINUE_CLIENT       Return to logging mode. Job will be re-started if idle.
EXIT_CLIENT           Quit client session and leave job running.
HELP                  Summarize interactive commands.
KILL_JOB              Detach and delete job.
PARALLEL              Change the number of active workers for current job.
                      PARALLEL=.
START_JOB             Start/resume current job.
STATUS                Frequency (secs) job status is to be monitored where
                      the default (0) will show new status when available.
                      STATUS=[interval]
STOP_JOB              Orderly shutdown of job execution and exits the client.
                      STOP_JOB=IMMEDIATE performs an immediate shutdown of the
                      Data Pump job.

Oracle 10g Release 2 (10.2) added the following parameters.

Keyword               Description (Default)
------------------------------------------------------------------------------
COMPRESSION           Reduce size of dumpfile contents where valid
                      keyword values are: (METADATA_ONLY) and NONE.
ENCRYPTION_PASSWORD   Password key for creating encrypted column data.
SAMPLE                Percentage of data to be exported;

The following commands are valid while in interactive mode.
Note: abbreviations are allowed

Command               Description
------------------------------------------------------------------------------
FILESIZE              Default filesize (bytes) for subsequent ADD_FILE commands.

Oracle 11g Release 1 (11.1) added the following parameters.

Keyword               Description (Default)
------------------------------------------------------------------------------
DATA_OPTIONS          Data layer flags where the only valid value is:
                      XML_CLOBS-write XML datatype in CLOB format
ENCRYPTION            Encrypt part or all of the dump file where valid keyword
                      values are: ALL, DATA_ONLY, METADATA_ONLY,
                      ENCRYPTED_COLUMNS_ONLY, or NONE.
ENCRYPTION_ALGORITHM  Specify how encryption should be done where valid
                      keyword values are: (AES128), AES192, and AES256.
ENCRYPTION_MODE       Method of generating encryption key where valid keyword
                      values are: DUAL, PASSWORD, and (TRANSPARENT).
REMAP_DATA            Specify a data conversion function,
                      e.g. REMAP_DATA=EMP.EMPNO:REMAPPKG.EMPNO.
REUSE_DUMPFILES       Overwrite destination dump file if it exists (N).
TRANSPORTABLE         Specify whether transportable method can be used where
                      valid keyword values are: ALWAYS, (NEVER).

The following commands are valid while in interactive mode.
Note: abbreviations are allowed

Command               Description
------------------------------------------------------------------------------
REUSE_DUMPFILES       Overwrite destination dump file if it exists (N).

Oracle 11g Release 1 (11.2) altered the format of the help output as well as adding the following parameters.

CLUSTER
Utilize cluster resources and distribute workers across the Oracle RAC.
Valid keyword values are: [Y] and N.

SERVICE_NAME
Name of an active Service and associated resource group to constrain Oracle RAC resources.

SOURCE_EDITION
Edition to be used for extracting metadata.

impdp

impdp help=y

Import: Release 10.1.0.2.0 - Production on Saturday, 11 September, 2004 17:22

The Data Pump Import utility provides a mechanism for transferring data objects
between Oracle databases. The utility is invoked with the following command:

     Example: impdp scott/tiger DIRECTORY=dmpdir DUMPFILE=scott.dmp

You can control how Import runs by entering the 'impdp' command followed
by various parameters. To specify parameters, you use keywords:

     Format:  impdp KEYWORD=value or KEYWORD=(value1,value2,...,valueN)
     Example: impdp scott/tiger DIRECTORY=dmpdir DUMPFILE=scott.dmp

USERID must be the first parameter on the command line.

Keyword               Description (Default)
------------------------------------------------------------------------------
ATTACH                Attach to existing job, e.g. ATTACH [=job name].
CONTENT               Specifies data to load where the valid keywords are:
                      (ALL), DATA_ONLY, and METADATA_ONLY.
DIRECTORY             Directory object to be used for dump, log, and sql files.
DUMPFILE              List of dumpfiles to import from (expdat.dmp),
                      e.g. DUMPFILE=scott1.dmp, scott2.dmp, dmpdir:scott3.dmp.
ESTIMATE              Calculate job estimates where the valid keywords are:
                      (BLOCKS) and STATISTICS.
EXCLUDE               Exclude specific object types, e.g. EXCLUDE=TABLE:EMP.
FLASHBACK_SCN         SCN used to set session snapshot back to.
FLASHBACK_TIME        Time used to get the SCN closest to the specified time.
FULL                  Import everything from source (Y).
HELP                  Display help messages (N).
INCLUDE               Include specific object types, e.g. INCLUDE=TABLE_DATA.
JOB_NAME              Name of import job to create.
LOGFILE               Log file name (import.log).
NETWORK_LINK          Name of remote database link to the source system.
NOLOGFILE             Do not write logfile.
PARALLEL              Change the number of active workers for current job.
PARFILE               Specify parameter file.
QUERY                 Predicate clause used to import a subset of a table.
REMAP_DATAFILE        Redefine datafile references in all DDL statements.
REMAP_SCHEMA          Objects from one schema are loaded into another schema.
REMAP_TABLESPACE      Tablespace object are remapped to another tablespace.
REUSE_DATAFILES       Tablespace will be initialized if it already exists (N).
SCHEMAS               List of schemas to import.
SKIP_UNUSABLE_INDEXES Skip indexes that were set to the Index Unusable state.
SQLFILE               Write all the SQL DDL to a specified file.
STATUS                Frequency (secs) job status is to be monitored where
                      the default (0) will show new status when available.
STREAMS_CONFIGURATION Enable the loading of Streams metadata
TABLE_EXISTS_ACTION   Action to take if imported object already exists.
                      Valid keywords: (SKIP), APPEND, REPLACE and TRUNCATE.
TABLES                Identifies a list of tables to import.
TABLESPACES           Identifies a list of tablespaces to import.
TRANSFORM             Metadata transform to apply (Y/N) to specific objects.
                      Valid transform keywords: SEGMENT_ATTRIBUTES and STORAGE.
                      ex. TRANSFORM=SEGMENT_ATTRIBUTES:N:TABLE.
TRANSPORT_DATAFILES   List of datafiles to be imported by transportable mode.
TRANSPORT_FULL_CHECK  Verify storage segments of all tables (N).
TRANSPORT_TABLESPACES List of tablespaces from which metadata will be loaded.
                      Only valid in NETWORK_LINK mode import operations.
VERSION               Version of objects to export where valid keywords are:
                      (COMPATIBLE), LATEST, or any valid database version.
                      Only valid for NETWORK_LINK and SQLFILE.

The following commands are valid while in interactive mode.
Note: abbreviations are allowed

Command               Description (Default)11g
------------------------------------------------------------------------------
CONTINUE_CLIENT       Return to logging mode. Job will be re-started if idle.
EXIT_CLIENT           Quit client session and leave job running.
HELP                  Summarize interactive commands.
KILL_JOB              Detach and delete job.
PARALLEL              Change the number of active workers for current job.
                      PARALLEL=.
START_JOB             Start/resume current job.
                      START_JOB=SKIP_CURRENT will start the job after skipping
                      any action which was in progress when job was stopped.
STATUS                Frequency (secs) job status is to be monitored where
                      the default (0) will show new status when available.
                      STATUS=[interval]
STOP_JOB              Orderly shutdown of job execution and exits the client.
                      STOP_JOB=IMMEDIATE performs an immediate shutdown of the
                      Data Pump job.

Oracle 10g Release 2 (10.2) added the following parameter.

Keyword               Description (Default)
------------------------------------------------------------------------------
ENCRYPTION_PASSWORD   Password key for accessing encrypted column data.
                      This parameter is not valid for network import jobs.