Datapump

Datapump

Oracle Data Pump:- Oracle has introduced an enhanced version of "export" and "import" utility known as DATA PUMP. Data Pump is similar to "export" and "import" utility but it has many advantages.

Advantages of Datapump:-     1) Data Pump export and import operations occur on the Oracle database server. i.e. all the dump files are created in the server even if you run the Data Pump utility from client machine.
     This results in increased performance because data is not transferred through network.
     2) You can Stop and Re-Start export and import jobs. This is particularly useful if you have started an export or import job and after some time you want to do some other urgent work.The ability to detach from and reattach to long-running jobs without affecting the job itself. This allows DBAs and other operations personnel to monitor jobs from multiple locations.
    3) The ability to estimate how much space an export job would consume, without actually performing the export.
    4) Support for an interactive-command mode that allows monitoring of and interaction with ongoing jobs
    5) Encryption available in Datapump
    6) "include" and "exclude" feature available in datapump
    7) We can dump more than one place simulteneously

Using Data Pump Export Utility:-To Use Data Pump,  DBA has to create directory in Server Machine and create a Directory Object in the database mapping to the directory created in the file system.

Example:- For creating a directory in the filesystem, mapping directory object in the database and grants privileges on the Directory Object to the SCOTT user.

$mkdir my_dump_dir
$sqlplus / as sysdba
SQL>create directory data_pump_dir as ‘/u01/oracle/my_dump_dir’;

Now grant access on this directory object to SCOTT user

SQL> grant read,write on directory data_pump_dir to scott;

Example:- Full Database  export from datapump

expdp  scott/tiger FULL=y DIRECTORY=data_pump_dir DUMPFILE=full.dmp LOGFILE=myfullexp.log JOB_NAME=myfullJob

The above command will export the full database and it will create the dump file full.dmp in the directory on the server /u01/oracle/my_dump_dir

In some cases where the Database is in Terabytes the above command will not feasible since the dump file size will be larger than the operating system limit, and hence export will fail.
In this situation you can create multiple dump files by typing the following command

expdp  scott/tiger FULL=y DIRECTORY=data_pump_dir DUMPFILE=full%U.dmp FILESIZE=5G  LOGFILE=myfullexp.log JOB_NAME=myfullJob

This will create multiple dump files named full01.dmp, full02.dmp, full03.dmp and so on. The FILESIZE parameter specifies how much larger the dump file should be.
Example of Exporting a Schema

To export all the objects of SCOTT’S schema you can run the following export data pump command.

expdp scott/tiger DIRECTORY=data_pump_dir DUMPFILE=scott_schema.dmp SCHEMAS=SCOTT

You can omit SCHEMAS since the default mode of Data Pump export is SCHEMAS only.

If you want to export objects of multiple schemas you can specify the following command

expdp scott/tiger DIRECTORY=data_pump_dir DUMPFILE=scott_schema.dmp SCHEMAS=SCOTT,HR,ALI

Example :- Individual Tables export using Data Pump Export
We can use Data Pump Export utility to export individual tables. The following example shows the syntax to export tables

expdp hr/hr DIRECTORY=dpump_dir1 DUMPFILE=tables.dmp TABLES=employees,jobs,departments

Example:-Exporting Tablespace by datapump export
We can export complete tablespace by using datapump.

$expdp hr/hr DIRECTORY=dpump_dir1 DUMPFILE=tbs.dmp  TABLESPACES=example1, example2,example3

Excluding and Including Objects during Export

You can exclude objects while performing a export by using EXCLUDE option of Data Pump utility. For example you are exporting a schema and don’t want to export tables whose name  starts with “A” then you can type the following command

expdp scott/tiger DIRECTORY=data_pump_dir DUMPFILE=scott_schema.dmp SCHEMAS=SCOTT EXCLUDE=TABLE:”like ‘A%’”

Then all tables in Scott’s Schema whose name starts with “A “ will not be exported.

Similarly you can also INCLUDE option to only export certain objects like this

expdp scott/tiger DIRECTORY=data_pump_dir DUMPFILE=scott_schema.dmp SCHEMAS=SCOTT INCLUDE=TABLE:”like ‘A%’”

This is opposite of EXCLUDE option i.e. it will export only those tables of Scott’s schema whose name starts with “A”

Similarly you can also exclude INDEXES, CONSTRAINTS, GRANTS, USER, SCHEMA
Using Query to Filter Rows during Export

You can use QUERY option to export only required rows. For Example, the following will export only those rows of employees tables whose salary is above 10000 and whose dept id is 10.

expdp hr/hr QUERY=emp:'"WHERE dept_id > 10 AND sal > 10000"' NOLOGFILE=y DIRECTORY=dpump_dir1 DUMPFILE=exp1.dmp

Suspending and Resuming Export Jobs (Attaching and Re-Attaching to the Jobs)

You can suspend running export jobs and later on resume these jobs or kill these jobs using Data Pump Export. You can start a job in one client machine and then, if because of some work, you can suspend it. Afterwards when your work has been finished you can continue the job from the same client, where you stopped the job, or you can restart the job from another client machine.

For Example, suppose a DBA starts a full database export by typing the following command at one client machine CLNT1 by typing the following command

expdp scott/tiger@mydb FULL=y DIRECTORY=data_pump_dir DUMPFILE=full.dmp LOGFILE=myfullexp.log JOB_NAME=myfullJob

After some time, the DBA wants to stop this job temporarily. Then he presses CTRL+C to enter into interactive mode. Then he will get the Export> prompt where he can type interactive commands

Now he wants to stop this export job so he will type the following command

Export> STOP_JOB=IMMEDIATE
Are you sure you wish to stop this job ([y]/n): y

The job is placed in a stopped state and exits the client.

After finishing his other work, the DBA wants to resume the export job and the client machine from where he actually started the job is locked because, the user has locked his/her cabin. So now the DBA will go to another client machine and he reattach to the job by typing the following command

expdp hr/hr@mydb ATTACH=myfulljob

After the job status is displayed, he can issue the CONTINUE_CLIENT command to resume logging mode and restart the myfulljob job.

Export> CONTINUE_CLIENT

A message is displayed that the job has been reopened, and processing status is output to the client.

Note: After reattaching to the Job a DBA can also kill the job by typing KILL_JOB, if he doesn’t want to continue with the export job.