Data Pump in Oracle Database 10g

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:

CONN sys/password@db10g AS SYSDBA

ALTER USER scott IDENTIFIED BY tiger ACCOUNT UNLOCK;

GRANT CREATE ANY DIRECTORY TO scott;

CREATE OR REPLACE DIRECTORY test_dir AS '/u01/app/oracle/oradata/';

GRANT READ, WRITE ON DIRECTORY test_dir TO scott;

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The OWNER parameter of exp has been replaced by the SCHEMAS parameter which is used to specify the schemas to be exported.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.

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:TEMPDB10G.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                 1

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. When the EXCLUDE parameter is used all objects except those specified by it will be included in the export:

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

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: 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 help=y

impdp help=y