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Hybrid Partitioned Tables in Oracle Database 19c

This article shows how to combine internal and external partitions into a single Hybrid Partitioned Table in Oracle Database 19c.

Hybrid Partitioned Tables

Hybrid partitioned tables support the following external table types for external partitions.

In this article we'll focus on the ORACLE_LOADER and ORACLE_DATAPUMP examples.

Related articles.

Setup

Connect to a privileged user and create a new test user called TESTUSER1.

CONN sys/SysPassword1@//localhost:1521/pdb1 AS SYSDBA

--DROP USER testuser1 CASCADE;

CREATE USER testuser1 IDENTIFIED BY testuser1 QUOTA UNLIMITED ON users;
GRANT CREATE SESSION, CREATE TABLE TO testuser1;

Create two new directory objects, making sure TESTUSER1 has READ, WRITE and EXECUTE permissions on them.

CREATE OR REPLACE DIRECTORY TMP_DIR1 AS '/tmp/';
GRANT READ, WRITE, EXECUTE ON DIRECTORY TMP_DIR1 TO testuser1;

CREATE OR REPLACE DIRECTORY TMP_DIR2 AS '/tmp/';
GRANT READ, WRITE, EXECUTE ON DIRECTORY TMP_DIR2 TO testuser1;

All other actions will be performed from TESTUSER1.

CONN testuser1/testuser1@//localhost:1521/pdb1

Create Hybrid Partitioned Table (ORACLE_LOADER)

Generate some flat files with dummy data for use with external table partitions.

SET MARKUP CSV ON QUOTE ON
SET TRIMSPOOL ON LINESIZE 1000 FEEDBACK OFF PAGESIZE 0

SPOOL /tmp/gbr1.txt
SELECT 'GBR',
       object_id,
       owner,
       object_name
FROM   all_objects
WHERE  object_id <= 3999
AND    rownum <= 1000;
SPOOL OFF

SPOOL /tmp/gbr2.txt
SELECT 'GBR',
       object_id,
       owner,
       object_name
FROM   all_objects
WHERE  object_id BETWEEN 4000 AND 5999
AND    rownum <= 1000;
SPOOL OFF

SPOOL /tmp/ire1.txt
SELECT 'IRE',
       object_id,
       owner,
       object_name
FROM   all_objects
WHERE  object_id <= 3999
AND    rownum <= 1000;
SPOOL OFF

SPOOL /tmp/ire2.txt
SELECT 'IRE',
       object_id,
       owner,
       object_name
FROM   all_objects
WHERE  object_id BETWEEN 4000 AND 5999
AND    rownum <= 1000;
SPOOL OFF

SET MARKUP CSV OFF
SET TRIMSPOOL ON LINESIZE 1000 FEEDBACK ON PAGESIZE 14

The following example creates a hybrid partitioned table. It uses list partitioning, with a single internal partition for USA data, and two external partitions for GBR and IRE data respectively.

--DROP TABLE test_ol_hybrid_part_tab PURGE;

CREATE TABLE test_ol_hybrid_part_tab (
  country_code  VARCHAR2(3)   NOT NULL,
  object_id     NUMBER        NOT NULL,
  owner         VARCHAR2(128) NOT NULL,
  object_name   VARCHAR2(128) NOT NULL
)
  EXTERNAL PARTITION ATTRIBUTES (
    TYPE ORACLE_LOADER 
    DEFAULT DIRECTORY tmp_dir1
    ACCESS PARAMETERS (
      FIELDS CSV WITH EMBEDDED TERMINATED BY ',' OPTIONALLY ENCLOSED BY '"'
      MISSING FIELD VALUES ARE NULL
      (country_code, object_id, owner, object_name)
    ) 
    REJECT LIMIT UNLIMITED
  ) 
  PARTITION BY LIST (country_code) (
    PARTITION usa VALUES ('USA'),
    PARTITION gbr VALUES ('GBR') EXTERNAL
      LOCATION ('gbr1.txt', 'gbr2.txt'),
    PARTITION ire VALUES ('IRE') EXTERNAL
      DEFAULT DIRECTORY tmp_dir2 LOCATION ('ire1.txt', 'ire2.txt')
  );

The EXTERNAL PARTITION ATTRIBUTES clause defines the table-level external table parameters. For external partitions, the EXTERNAL clause is used to define partition-level attributes, such as file locations and non-default directory objects.

The HYBRID column in the CDB|DBA|ALL|USER}_TAABLES views show this is a hybrid table.

COLUMN table_name FORMAT A30
COLUMN hybrid FORMAT A6

SELECT table_name, hybrid FROM user_tables;

TABLE_NAME                     HYBRID
------------------------------ ------
TEST_OL_HYBRID_PART_TAB        YES

SQL>

We only have data in the external partitions at the moment.

COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_ol_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
GBR                2000
IRE                2000

SQL>

We can perform DML on the internal partition as normal.

INSERT INTO test_ol_hybrid_part_tab
SELECT 'USA',
       object_id,
       owner,
       object_name
FROM   all_objects
WHERE  rownum <= 2000;
COMMIT;


COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_ol_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
GBR                2000
IRE                2000
USA                2000

SQL>

As you might expect, trying to insert into the external partitions results in an error.

INSERT INTO test_ol_hybrid_part_tab VALUES ('GBR', 9999, 'X', 'X');
            *
ERROR at line 1:
ORA-14466: Data in a read-only partition or subpartition cannot be modified.


SQL>

The full list of supported operations can be found in the Hybrid Partitioned Tables document.

Create Hybrid Partitioned Table (ORACLE_DATAPUMP)

We create a dump file called "bgr_xt.dmp" containing BGR data. Creating the external table generates the Data Pump dump file. When we drop the table the dump file remains on the database file system, so we can use it for our test.

CREATE TABLE bgr_xt
  ORGANIZATION EXTERNAL
    (
      TYPE ORACLE_DATAPUMP
      DEFAULT DIRECTORY tmp_dir1
      LOCATION ('bgr_xt.dmp')
    ) AS
    SELECT 'BGR' AS country_code,
           object_id,
           owner,
           object_name
    FROM   all_objects
    WHERE  rownum <= 2000;
   
DROP TABLE bgr_xt;

The following example creates a hybrid partitioned table. It uses list partitioning, with a single internal partition for USA data, and a data pump external partitions for BGR data.

--DROP TABLE test_dp_hybrid_part_tab PURGE;

CREATE TABLE test_dp_hybrid_part_tab (
  country_code  VARCHAR2(3)   NOT NULL,
  object_id     NUMBER        NOT NULL,
  owner         VARCHAR2(128) NOT NULL,
  object_name   VARCHAR2(128) NOT NULL
)
  EXTERNAL PARTITION ATTRIBUTES (
    TYPE ORACLE_DATAPUMP 
    DEFAULT DIRECTORY tmp_dir1
  ) 
  PARTITION BY LIST (country_code) (
    PARTITION usa VALUES ('USA'),
    PARTITION bgr VALUES ('BGR') EXTERNAL
      LOCATION ('bgr_xt.dmp')
  );

The EXTERNAL PARTITION ATTRIBUTES clause defines the table-level Data Pump external table parameters. For external partitions, the EXTERNAL clause is used to define partition-level attributes, such as file locations and non-default directory objects.

The HYBRID column in the CDB|DBA|ALL|USER}_TAABLES views show this is a hybrid table.

COLUMN table_name FORMAT A30
COLUMN hybrid FORMAT A6

SELECT table_name, hybrid FROM user_tables;

TEST_OL_HYBRID_PART_TAB        YES
TEST_DP_HYBRID_PART_TAB        YES

SQL>

We only have data in the external partitions at the moment.

COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_dp_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
BGR                2000

SQL>

We can perform DML on the internal partition as normal.

INSERT INTO test_dp_hybrid_part_tab
SELECT 'USA',
       object_id,
       owner,
       object_name
FROM   all_objects
WHERE  rownum <= 2000;
COMMIT;


COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_dp_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
BGR                2000
USA                2000

SQL>

As you might expect, trying to insert into the external partitions results in an error.

INSERT INTO test_dp_hybrid_part_tab VALUES ('GBR', 9999, 'X', 'X');
            *
ERROR at line 1:
ORA-14466: Data in a read-only partition or subpartition cannot be modified.


SQL>

The full list of supported operations can be found in the Hybrid Partitioned Tables document.

Add/Drop Partitions

We can add and drop partitions in a normal manner.

We drop the partition for the IRE data from the TEST_OL_HYBRID_PART_TAB table.

ALTER TABLE test_ol_hybrid_part_tab DROP PARTITION ire;


COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_ol_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
GBR                2000
USA                2000

SQL>

We add back the partition for the IRE data.

ALTER TABLE test_ol_hybrid_part_tab ADD PARTITION ire VALUES ('IRE') EXTERNAL
      DEFAULT DIRECTORY tmp_dir2 LOCATION ('ire1.txt', 'ire2.txt');


COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_ol_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
GBR                2000
IRE                2000
USA                2000

SQL>

We drop the partition for the BGR data from the TEST_DP_HYBRID_PART_TAB table.

ALTER TABLE test_dp_hybrid_part_tab DROP PARTITION bgr;


COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_dp_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
USA                2000

SQL>

We add back the partition for the BGR data.

ALTER TABLE test_dp_hybrid_part_tab ADD PARTITION bgr VALUES ('BGR') EXTERNAL
      DEFAULT DIRECTORY tmp_dir2 LOCATION ('bgr_xt.dmp');


COLUMN country_code FORMAT A12

SELECT country_code, COUNT(*) as amount
FROM   test_dp_hybrid_part_tab
GROUP BY country_code
ORDER BY country_code;

COUNTRY_CODE     AMOUNT
------------ ----------
BGR                2000
USA                2000

SQL>

The operations on the internal partitions are as you would expect to regular partitioned tables. The full list of supported operations can be found in the Hybrid Partitioned Tables document.

Restrictions

The standout restrictions are as follows.

Most of the other restrictions are what you would expect for the various types of partitions.

The full list of restrictions can be found in the Hybrid Partitioned Tables document.

For more information see:

Hope this helps. Regards Tim...

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