Partitioning an existing table using datapump - a sample demo

First create a sample  table for testing purpose, 
SQL>CREATE TABLE big_table (
  id            NUMBER(10),
  created_date  DATE,
  lookup_id     NUMBER(10),
  data          VARCHAR2(50)
);

Execute the following procedure to insert large number of rows ,

DECLARE
  l_lookup_id    NUMBER(10);
  l_create_date  DATE;
BEGIN
  FOR i IN 1 .. 1000000 LOOP
    IF MOD(i, 3) = 0 THEN
      l_create_date := ADD_MONTHS(SYSDATE, -24);
      l_lookup_id   := 2;
    ELSIF MOD(i, 2) = 0 THEN
      l_create_date := ADD_MONTHS(SYSDATE, -12);
      l_lookup_id   := 1;
    ELSE
      l_create_date := SYSDATE;
      l_lookup_id   := 3;
    END IF;
    INSERT INTO big_table (id, created_date, lookup_id, data)
    VALUES (i, l_create_date, l_lookup_id, 'This is some data for ' || i);
  END LOOP;
  COMMIT;
END;
/
-- Apply some constraints and index to the table.

SQL> ALTER TABLE big_table ADD (CONSTRAINT big_table_pk PRIMARY KEY (id));

SQL>CREATE INDEX bita_created_date_i ON big_table(created_date);

Now big_table is created 

SQL>  select table_name, tablespace_name, partitioned
      from dba_tables where table_name like 'BIG_%';

TABLE_NAME                     TABLESPACE_NAME                PAR
------------------------------ ------------------------------ ---
BIG_TABLE                      EXAMPLE                        NO  ----->(No partition)

Export the table using datapump:
C:\Windows\system32>expdp admin/admin@oradb1 tables=sample.big_table directory=ar1 dumpfile=big_table.dmp parallel=4

Screen shot of my expdp:
--------------------------
Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
Starting "ADMIN"."SYS_EXPORT_TABLE_01":  admin/********@oradb1 tables=sample.big_table directory=ar1 dumpfile=big_table.dmp parallel=4
Estimate in progress using BLOCKS method...
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
Total estimation using BLOCKS method: 55 MB
. . exported "SAMPLE"."BIG_TABLE"                        46.61 MB 1000000 rows
Processing object type TABLE_EXPORT/TABLE/TABLE
Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS
Master table "ADMIN"."SYS_EXPORT_TABLE_01" successfully loaded/unloaded
******************************************************************************
Dump file set for ADMIN.SYS_EXPORT_TABLE_01 is:
  /u01/software/datapump/big_table.dmp
Job "ADMIN"."SYS_EXPORT_TABLE_01" successfully completed at 14:52:38

Now drop and recreate the table ,
SQL> drop table big_table;

Table dropped.

SQL> CREATE TABLE big_table (
    id            NUMBER(10),
    created_date  DATE,
    lookup_id     NUMBER(10),
    data          VARCHAR2(50)
)
PARTITION BY RANGE (created_date)
(PARTITION big_table_2003 VALUES LESS THAN (TO_DATE('01/01/2004', 'DD/MM/YYYY')),
 PARTITION big_table_2004 VALUES LESS THAN (TO_DATE('01/01/2005', 'DD/MM/YYYY')),
 PARTITION big_table_2005 VALUES LESS THAN (MAXVALUE));

SQL>  select table_name, tablespace_name, partitioned
      from dba_tables where table_name like 'BIG_%';

TABLE_NAME                     TABLESPACE_NAME                PAR
------------------------------ ------------------------------ ---
BIG_TABLE                      EXAMPLE                        YES ----> TABLE IS PARTITIONED

SQL> select count(*) from big_table;

  COUNT(*)
----------
         0  ----------> no data

Import the table using datapump
C:\Windows\system32> impdp admin/admin@oradb1 directory=ar1 dumpfile=big_table.dmp logfile=big_table.log table_exists_action=append parallel=4

note: job will be completed with one error because of "TABLE_EXISTS_ACTION=append" parameter.Use ignore=y if you are using old export utility.
Exclude Metadata and copy only data to avoid the error caused by the above parameter

screen shot:
-------------
Import: Release 11.2.0.1.0 - Production on Tue Jun 28 15:11:53 2011

Copyright (c) 1982, 2009, Oracle and/or its affiliates.  All rights reserved.

Connected to: Oracle Database 11g Enterprise Edition Release 11.2.0.1.0 - 64bit Production
With the Partitioning, Real Application Clusters, Automatic Storage Management, OLAP,
Data Mining and Real Application Testing options
Master table "ADMIN"."SYS_IMPORT_FULL_01" successfully loaded/unloaded
Starting "ADMIN"."SYS_IMPORT_FULL_01":  admin/********@oradb1 directory=ar1 dumpfile=big_table.dmp logfile=big_table.log table_exists_action=append parallel=4
Processing object type TABLE_EXPORT/TABLE/TABLE
ORA-39152: Table "SAMPLE"."BIG_TABLE" exists. Data will be appended to existing table but all dependent metadata will be skipped due to table_exists_action of append
Processing object type TABLE_EXPORT/TABLE/TABLE_DATA
. . imported "SAMPLE"."BIG_TABLE"                        46.61 MB 1000000 rows
Processing object type TABLE_EXPORT/TABLE/INDEX/INDEX
Processing object type TABLE_EXPORT/TABLE/CONSTRAINT/CONSTRAINT
Processing object type TABLE_EXPORT/TABLE/INDEX/STATISTICS/INDEX_STATISTICS
Job "ADMIN"."SYS_IMPORT_FULL_01" completed with 1 error(s) at 15:12:49

SQL> select count(*) from big_table;

  COUNT(*)
----------
   1000000


SQL> insert into big_table (id, created_date, lookup_id, data)
  2  values(1001,'27-jun-03',5,'This is some old data');

1 row created.


SQL> select * from big_table partition(big_table_2004);

no rows selected

SQL> select * from big_table partition(big_table_2003);

        ID CREATED_D  LOOKUP_ID DATA
---------- --------- ---------- -------------------------
      1001 27-JUN-03          5 This is some old data

TESTING PARTITION PRUNING

SQL>  SET AUTOTRACE TRACEONLY EXPLAIN
SQL> select * from big_table
  2  where created_date='27-JUN-03';

Execution Plan
----------------------------------------------------------
Plan hash value: 1710340555

----------------------------------------------------------------------------------------
| Id  | Operation              | Name      | Rows  | Bytes | Cost (%CPU)| Time     | Pstart| Pstop |
----------------------------------------------------------------------------------------
|   0 | SELECT STATEMENT       |           |     1 |    37 |     3   (0)| 00:00:01 |       |       |
|   1 |  PARTITION RANGE SINGLE|           |     1 |    37 |     3   (0)| 00:00:01 |   KEY |   KEY |
|*  2 |   TABLE ACCESS FULL    | BIG_TABLE |     1 |    37 |     3   (0)| 00:00:01 |   KEY |   KEY |
----------------------------------------------------------------------------------------

Predicate Information (identified by operation id):
---------------------------------------------------

   2 - filter("CREATED_DATE"='27-JUN-03')

Source:- http://arundaskalathil.blogspot.in/2011/06/partitioning-existing-table-using.html

Oracle Cluster tables - an efficient way to reduce the I/O

If you two are more tables are joined together on a single column and most of the time you issue join queries on them, then consider creating a cluster of these tables.
 A cluster is a group tables that share the same data blocks i.e. all the tables are physically stored together.

For example EMP and DEPT table are joined on DEPTNO column. If you cluster them, Oracle physically stores all rows for each department from both the emp and dept tables in the same data blocks.
Since cluster stores related rows of different tables in same data blocks, Disk I/O is reduced and access time improves for joins of clustered tables.
Each cluster key value is stored only once each in the cluster and the cluster index, no matter how many rows of different tables contain the value.
Therefore, less storage might be required to store related table and index data in a cluster than is necessary in non-clustered table format.

Creating a Clustered Table 
 To create clustered tables. First, create a cluster and create index on it. Then create tables in it.
For example to create a cluster of EMP and DEPT tables in which the DEPTNO will be cluster key, first create the cluster by typing the following command.

SQL>create cluster emp_dept (deptno number(2));

Then create index on it.

SQL>create index on cluster emp_dept;

Now create table in the cluster like this

SQL>create table dept (deptno number(2),
                    name varchar2(20),
                    loc varchar2(20))
                    cluster emp_dept (deptno);

SQL>create table emp (empno number(5),
            name varchar2(20),
            sal number(10,2),
            deptno number(2)) cluster emp_dept (deptno)      

Dropping Clusters
To drop a cluster use DROP CLUSTER statement. For example to drop the emp_dept cluster give the following command.

SQL>drop cluster emp_dept;

This will drop the cluster, if the cluster is empty i.e. no tables are existing it it. If tables are there in the cluster first drop the tables and then drop the cluster. If you want to drop the cluster even when tables are there then give the following command.

SQL>drop cluster emp_dept including tables;

Listing Information about Clusters
To see how many clusters are there in your schema give the following statement.

SQL>select * from user_clusters;

To see which tables are part of a cluster. Give the following command.

SQL>select * from tab

TABLE_NAME    TYPE            CLUSTER_ID
----------             ----              -----------
EMP                  TABLE         1
SALGRADE        TABLE        
CUSTOMER        TABLE        
DEPT                TABLE         1
In the above example notice the CLUSTER_ID column, for EMP and DEPT table the cluster_id is 1. That means these tables are in cluster whose cluster_id is 1. You can see the cluster_id’s name in USER_CLUSTERS table.
Source:- http://www.oracle-dba-online.com/