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Oracle partitioning :basis & new features in 12cR2


30.05.2017Oracle partitioning : basis & new features in 12cR2

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Oracle partitioning : basis & new features in 12cR2

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1. Introduction

2. Partitioning strategies

3. Partitioning features

4. What’s new in 12cR2 ?

5. Conclusion

Agenda


Few words about partitioningIntroduction


> Overview

> History

What is partitioning ?

> Functionality introduced in Oracle 8.0 (1997)

> Logical subdivision of tables (or indexes) into smaller pieces called “partitions”

> Each partition has its own name and its own storage characteristics

> Partition Key : composed of one or more column and used to determine the partition where each row will be stored

> Different strategies : list, range, hash, composite (subpartitions)

Overview

30.05.2017

Introduction


Why to use it ?

> Manageability

> Data management at partition level rather than on the entire table

> More flexibility from the DBA side

> Performance

> Faster access to the data (reduce unecessary I/O)

> Availability

> One partition is unavailable ? Others remain available

> Totally transparent for the application side

When to use it ?

> Big tables (> 2GB)

> Tables containing historical data

> Data need to be stored on different storage

Overview

30.05.2017

Introduction


History

30.05.2017

Introduction


Oracle version Partitioning features

8.0 Range partitioning

8iHash partitioningComposite Range-Hash partitioning

9iList partitioningComposite Range-List partitioning

10g Index partitioning – Range, Hash and List

11g

Interval partitioningReference partitioningSystem partitioningVirtual column-based partitioningPartition Advisor

12cR1

CASCADE option for exchange and truncate partition operationsMultiple partitions maintenanceONLINE move partition

12cR2 Be patient…

What can we do ?Partitioning strategies


> Range partitioning

> List partitioning

> Hash partitioning

> Composite partitioning

Characteristics

> Most popular method

> Often used with the partition key on a date column (historical data)

> Each partition has a VALUES LESS THAN clause (non-inclusive)

> Partition key column can be :

> Time based (date)

> Numerical

> String

Range partitioning

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Partitioning strategies


Simple business case

> “I want to store all the sales of the last years on a specific disk”

Range partitioning

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SQL> CREATE TABLE sales_range_partition (

product_id NUMBER(6),

customer_id NUMBER,

sale_date DATE

)

PARTITION BY RANGE (sale_date)

(

PARTITION sales_2014 VALUES LESS THAN (TO_DATE('01-JAN-2015','dd-MON-yyyy'))

TABLESPACE tbs_2014,




TABLESPACE tbs_2016);

Check partitions

Partitions must be defined before the data insertion

Or…

Range partitioning

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SQL> SELECT TABLE_NAME, PARTITION_NAME, PARTITION_POSITION FROM

DBA_TAB_PARTITIONS WHERE TABLE_NAME ='SALES_RANGE_PARTITION';

TABLE_NAME PARTITION_NAME PARTITION_POSITION

------------------------------ ------------------------------ ------------------

SALES_RANGE_PARTITION SALES_2014 1



SQL> INSERT INTO SALES_RANGE_PARTITION VALUES(1,1,'08-FEB-2017');

INSERT INTO SALES_RANGE_PARTITION VALUES(1,1,'08-FEB-2017')

*

ERROR at line 1:

ORA-14400: inserted partition key does not map to any partition

> Create a “MAXVALUE” partition

Catch-all for values that exceed all specified ranges.

> Configure interval partitioning

Range partitioning

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SQL> ALTER TABLE SALES_RANGE_PARTITION ADD PARTITION sales_other VALUES LESS THAN

(MAXVALUE);

SQL> CREATE TABLE sales_range_partition (


customer_id NUMBER,

sale_date DATE

)

PARTITION BY RANGE (sale_date) INTERVAL(NUMTOYMINTERVAL(1, 'YEAR'))

(






TABLESPACE tbs_2016);

Characteristics

> Use a list of values as partition key

> Can group and organize unordered and unrelated data

> DEFAULT partition for data that don’t correspond to any partition

List partitioning

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> “I want to group and store the sales by country”

List partitioning

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SQL> CREATE TABLE sales_list_partition (


quantity_sold INTEGER,

sales_city VARCHAR(100)

)

PARTITION BY LIST (sales_city)

(

PARTITION sales_CH VALUES ('DELEMONT','BASEL','ZURICH','NYON'),

PARTITION sales_DE VALUES ('BERLIN','MUNICH','NUREMBERG'),

PARTITION sales_FR VALUES ('PARIS','MULHOUSE','BORDEAUX'),

PARTITION sales_DEFAULT VALUES (DEFAULT));

Check partitions

Data insertion

List partitioning

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SQL> SELECT TABLE_NAME, PARTITION_NAME, PARTITION_POSITION FROM

DBA_TAB_PARTITIONS WHERE TABLE_NAME ='SALES_LIST_PARTITION';

TABLE_NAME PARTITION_NAME PARTITION_POSITION

------------------------------ -------------------- ------------------

SALES_LIST_PARTITION SALES_CH 1

SALES_LIST_PARTITION SALES_DE 2

SALES_LIST_PARTITION SALES_FR 3

SALES_LIST_PARTITION SALES_DEFAULT 4

SQL> INSERT INTO SALES_LIST_PARTITION VALUES (1, 5, 'BASEL');

SQL> SELECT * FROM SALES_LIST_PARTITION PARTITION (SALES_CH);

PRODUCT_ID QUANTITY_SOLD SALES_CITY

---------- ------------- -----------

1 5 BASEL

SQL> INSERT INTO SALES_LIST_PARTITION VALUES (1, 5, 'MILAN');

SQL> SELECT * FROM SALES_LIST_PARTITION PARTITION (SALES_DEFAULT);

PRODUCT_ID QUANTITY_SOLD SALES_CITY

---------- ------------- -----------

1 5 MILAN

Characteristics

> Useful when other partitioning strategies are not appropriate

> Data distribution doesn’t need to respect a business constraint

> Hash function is applied to the partition key column

> Data distribution is balanced between all partitions (no control)

Hash partitioning

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> “The product table is too big. I want to partition it and I don't care about where the data goes.”

Hash partitioning

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SQL> CREATE TABLE product(


product_name VARCHAR2(50)

)

PARTITION BY HASH (product_id)

(PARTITION p1 TABLESPACE tbs1,

PARTITION p2 TABLESPACE tbs2,

PARTITION p3 TABLESPACE tbs3,

PARTITION p4 TABLESPACE tbs4);

SQL> CREATE TABLE product_hash_partition2(


product_name VARCHAR2(50))

PARTITION BY HASH (product_id) PARTITIONS 2;

SQL> SELECT partition_name, tablespace_name FROM dba_tab_partitions WHERE table_name

=('PRODUCT_HASH_PARTITION2');

PARTITION_NAME TABLESPACE_NAME

---------------------------------------- ------------------------------

SYS_P4547 SYSTEM

SYS_P4548 SYSTEM

What is it ?

> Combination of two partitioning methods (two levels)

> Each sub-partition is a separate segment

Existing strategies

> Range-Range

> Range-Hash

> Range-List

> List-Range

> List-Hash

> List-List

> Hash-Range

> Hash-Hash

> Hash-List

Composite partitioning

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Example

Composite partitioning

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CREATE TABLE sales_composite (


customer_id NUMBER,

sale_date DATE,

sale_city VARCHAR2(50))

PARTITION BY RANGE (sale_date)

SUBPARTITION BY LIST (sale_city)

(PARTITION sales_2014 VALUES LESS THAN (TO_DATE('01-JAN-2015','dd-MON-yyyy'))

(SUBPARTITION sales_2014_CH VALUES ('DELEMONT','BASEL','ZURICH','NYON'),

SUBPARTITION sales_2014_DE VALUES ('BERLIN','MUNICH','NUREMBERG'),

SUBPARTITION sales_2014_FR VALUES ('PARIS','MULHOUSE','BORDEAUX')),




SUBPARTITION sales_2015_FR VALUES ('PARIS','MULHOUSE','BORDEAUX')),




SUBPARTITION sales_2016_FR VALUES ('PARIS','MULHOUSE','BORDEAUX'))

);

Enhance partitioning strategiesPartitioning features


> Partition pruning

> Virtual column partitioning

What is it ?

> Simplest means to improve performances using partitioning

> Oracle performs operations only on partitions that are relevant to the statement

> Eliminate unneeded partitions

> Also available for composite partitioned tables

Partition pruning

30.05.2017

Partitioning features


P_SALES_2014

P_SALES_2015

P_SALES_2016

SELECT * FROM sales WHERE

sale_date = '02-MAY-2015';

SALES table

How does it work ?

> The optimizer analyzes FROM and WHERE clauses in SQL statements

> The optimizer use predicates for pruning

Limitations

> For Range and List partitioning

> Equality (WHERE… =, <[=], >[=] …)

> Range (WHERE…BETWEEN…AND…)

> IN-list (WHERE…IN…)

> LIKE (WHERE…LIKE…)

> For Hash partitioning

> Equality (WHERE… =, <[=], >[=] …)

> IN-list (WHERE…IN…)

Partition pruning

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Example without pruning

> Usage of a function on the partition key filter predicate

Partition pruning

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SQL> select plan_table_output from table(dbms_xplan.display_cursor);

PLAN_TABLE_OUTPUT

-------------------------------------

SQL_ID 572pnngc9xjbw, child number 1

-------------------------------------

SELECT customer_id FROM sales_range_partition WHERE to_char(sale_date,'yyyy')='2015'

Plan hash value: 2968405107

-------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |

-------------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | | | 854 (100)| | | |

PLAN_TABLE_OUTPUT

-------------------------------------------------------------------------------------------------------------

| 1 | PARTITION RANGE ALL| | 333K| 3581K| 854 (5)| 00:00:01 | 1 | 4 |

|* 2 | TABLE ACCESS FULL | SALES_RANGE_PARTITION | 333K| 3581K| 854 (5)| 00:00:01 | 1 | 4 |

-------------------------------------------------------------------------------------------------------------

Example with pruning

> Usage of BETWEEN…AND predicate

Partition pruning

30.05.2017



SQL> select plan_table_output from table(dbms_xplan.display_cursor);

PLAN_TABLE_OUTPUT

-------------------------------------

SQL_ID 3um6bnzk9r21q, child number 0

-------------------------------------

SELECT customer_id FROM sales_range_partition WHERE sale_date BETWEEN '01-JAN-2015' AND '31-DEC-2015'

Plan hash value: 2536827120

----------------------------------------------------------------------------------------------------------------

| Id | Operation | Name | Rows | Bytes | Cost (%CPU)| Time | Pstart| Pstop |

----------------------------------------------------------------------------------------------------------------

| 0 | SELECT STATEMENT | | | | 279 (100)| | | |

PLAN_TABLE_OUTPUT

----------------------------------------------------------------------------------------------------------------

| 1 | PARTITION RANGE SINGLE| | 333K| 3581K| 279 (2)| 00:00:01 | 2 | 2 |

|* 2 | TABLE ACCESS FULL | SALES_RANGE_PARTITION | 333K| 3581K| 279 (2)| 00:00:01 | 2 | 2 |

----------------------------------------------------------------------------------------------------------------

Virtual column

> Expression based on one (or more) existing columns in a table

> Stored as metadata -> don’t use physical space

> Can be used as a Partition Key

> Useful where existing columns are not relevant Partition Key

Example

Virtual column partitioning

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SQL> desc shop;

Name Null? Type

------------------ -------- ---------------------

SHOP_REF VARCHAR2(50)

SHOP_NAME VARCHAR2(50)

SQL> SELECT * FROM shop;

SHOP_REF SHOP_NAME

-------------------- --------------------

CH-123456 Sport shop

DE-654321 Shoes shop

FR-024680 IT shop

Business requirement

> “I want to partition this table by country”


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CREATE TABLE shop_part (

shop_ref VARCHAR2(50),

shop_name VARCHAR2(50),

country AS (case

when substr(shop_ref,1,2) = 'CH' then 'Switzerland'

when substr(shop_ref,1,2) = 'DE' then 'Deutschland'

when substr(shop_ref,1,2) = 'FR' then 'France'

end))

partition by list (country) (

partition p_CH values ('Switzerland'),

partition p_DE values ('Deutschland'),

partition p_FR values ('France'));

Check partitions

Check data


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SQL> SELECT * FROM shop_part PARTITION (P_CH);

SHOP_REF SHOP_NAME COUNTRY

-------------------- -------------------- -----------

CH-123456 Sport shop Switzerland

SQL> SELECT * FROM shop_part;

SHOP_REF SHOP_NAME COUNTRY

-------------------- -------------------- -----------

CH-123456 Sport shop Switzerland

DE-654321 Shoes shop Deutschland

FR-024680 IT shop France

SQL> SELECT TABLE_NAME, PARTITION_NAME, PARTITION_POSITION, HIGH_VALUE FROM

DBA_TAB_PARTITIONS WHERE TABLE_NAME ='SHOP_PART';

TABLE_NAME PARTITION_NAME PARTITION_POSITION HIGH_VALUE

-------------------- -------------------- ------------------ --------------------

SHOP_PART P_CH 1 'Switzerland'

SHOP_PART P_DE 2 'Deutschland'

SHOP_PART P_FR 3 'France'

Some new functionalitiesWhat’s new in 12cR2 ?


> Multi-column list partitioning

> Auto-list partitioning

> Read-only partitions

> Filtered partition maintenance operations

> Online operations

Until today

> Only available with RANGE partitioning

Characteristics

> Data is organized in lists of multiple values (up to 16 columns)

> Partition key contains more than 1 value

> Individual partitions can contain sets of multiple values

> Supported by partitions and subpartitions

> Each set of partitioning keys must be unique

Multi-column list partitioning

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What’s new in 12cR2 ?


Syntax

Check partitions

Multi-column list partitioning

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CREATE TABLE cars(

car_make VARCHAR2(30),

car_model VARCHAR2(30)

)

PARTITION BY LIST (car_make, car_model)

(PARTITION P1 VALUES ('Ford','Focus'),

PARTITION P_DEFAULT VALUES (DEFAULT));

SQL> SELECT partitioning_type, partition_count, partitioning_key_count FROM

dba_part_tables WHERE table_name = 'CARS';

PARTITION PARTITION_COUNT PARTITIONING_KEY_COUNT

--------- --------------- ----------------------

LIST 2 2

SQL> SELECT partition_name, high_value FROM dba_tab_partitions WHERE table_name = 'CARS';

PARTITION_NAME HIGH_VALUE

-------------------- ------------------------------

P1 ( 'Ford', 'Focus' )

P_DEFAULT DEFAULT

Auto-list ?

> Extension of LIST partitioning

> Automatic creation of partitions for new values

> Maintenance is simplified

> No notion of DEFAULT partition

> Also available with subpartitions (since 12.2.0.2)

> Using multiple partition keys is also possible

Auto-list partitioning

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Syntax

Check partitions


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SQL> CREATE TABLE city(

city_zip NUMBER(5),

city_name VARCHAR2(30)

)

PARTITION BY LIST (city_name) AUTOMATIC

(PARTITION p_delemont VALUES ('Delemont'));

SQL> SELECT partition_name, high_value, partition_position FROM

dba_tab_partitions WHERE table_name = 'CITY';

PARTITION_NAME HIGH_VALUE PARTITION_POSITION

-------------------- ------------------------------ ------------------

P_DELEMONT 'Delemont' 1

New keyword

Data insertion

Check partitions


30.05.2017



SQL> INSERT INTO city VALUES (2800, 'Delemont');

SQL> INSERT INTO city VALUES (4001, 'Basel');

SQL> INSERT INTO city VALUES (8001, 'Zurich');

SQL> INSERT INTO city VALUES (1000, null);

SQL> SELECT partition_name, high_value, partition_position FROM

dba_tab_partitions WHERE table_name = 'CITY';

PARTITION_NAME HIGH_VALUE PARTITION_POSITION

-------------------- -------------------- ------------------

P_DELEMONT 'Delemont' 1

SYS_P5004 'Basel' 2

SYS_P5005 'Zurich' 3

SYS_P5006 '' 4

SQL> SELECT partitioning_type, autolist, partition_count FROM dba_part_tables

WHERE table_name = 'CITY';

PARTITIONING_TYPE AUT PARTITION_COUNT

------------------------------ --- ---------------

LIST YES 4

Evolving to auto-list

Requirement

> No DEFAULT partition


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SQL> ALTER TABLE cars SET AUTOMATIC;

ALTER TABLE cars SET AUTOMATIC

*

ERROR at line 1:

ORA-14852: SET [SUB]PARTITIONING AUTOMATIC is not legal on this table.

SQL> ALTER TABLE cars DROP PARTITION (P_DEFAULT);

Table altered.

SQL> ALTER TABLE cars SET AUTOMATIC;

Table altered.

Until today

> Only available on tablespace and table level

Characteristics

> Expand read-only functionality from table level to partitions level

> Partitions and subpartitons can be set to read-only or read-write

> Structural DDL for a table still permitted

Read-only partitions

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Syntax

Data insertion

Read-only partitions

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CREATE TABLE sales(

sales_product VARCHAR2(30),

sales_date DATE

) READ WRITE

PARTITION BY RANGE (sales_date)

(

PARTITION P_2013 VALUES LESS THAN (TO_DATE('01-JAN-2014','dd-MON-yyyy')) READ ONLY,



PARTITION P_2016 VALUES LESS THAN (TO_DATE('01-JAN-2017','dd-MON-yyyy'))

);

SQL> INSERT INTO sales VALUES ('SHIRT', '02-MAY-2013');

INSERT INTO sales VALUES ('SHIRT', '02-MAY-2013')

*

ERROR at line 1:

ORA-14466: Data in a read-only partition or subpartition cannot be modified.

SQL> INSERT INTO sales VALUES ('SHOES', '29-MAR-2016');

1 row created.

Partition maintenance -> always to the whole partition

> Move a partition

> Split a partition

> …

For what ?

> Combine data maintenance and partition maintenance

Filtered partition maintenance operations

30.05.2017



Check partitions


> “I want to delete all orders dated of 2013, but keep the one that are still open and store them in an other tablespace”


30.05.2017



SQL> SELECT PARTITION_NAME, HIGH_VALUE, TABLESPACE_NAME FROM DBA_TAB_PARTITIONS WHERE

TABLE_NAME = 'ORDERS';

PARTITION_NAME HIGH_VALUE TABLESPACE_NAME

-------------------- ------------------------------ ------------------------

P_2013 2013 USERS

P_2014 2014 USERS

P_2015 2015 USERS

P_2016 2016 USERS

ALTER TABLE orders MOVE PARTITION p_2013 TABLESPACE archive INCLUDING ROWS WHERE

order_status = 'OPEN' ONLINE;

SQL> SELECT * FROM orders;

ORDER_ID ORDER_PRODUCT ORDER_STATUS ORDER_YEAR

---------- ------------------------------ ------------------------------ ----------

1 SHOES CLOSE 2013

4 SHOES OPEN 2013

2 SOCKS CLOSE 2015

3 TSHIRT OPEN 2016

What happened ?

> Partition p_2013 before the move

> Partition p_2013 after the move

The data excluded of the filter are deleted !


30.05.2017



SQL> SELECT * FROM orders PARTITION (p_2013);


---------- ----------------- ------------- ----------

1 SHOES CLOSE 2013

4 SHOES OPEN 2013

SQL> SELECT * FROM orders PARTITION (p_2013);


---------- ----------------- ------------- ----------

4 SHOES OPEN 2013

Limitations

> Maintenance operations

> MOVE

> SPLIT

> MERGE

> Filter conditions

> Limited to the partitioned table itself

> Any reference to other tables (JOIN) is not allowed


30.05.2017



Online partitioning DDL operations

> 12cR1

> Move partition

> 12cR2

> Split partition

> Convert non-partitioned table to partitioned table

Online operations

30.05.2017



Split partition

Online operationsWhat’s new in 12cR2 ?


Conversion of a non-partitioned table to a partitioned table

“Old” way -> DBMS_REDEFINITION (since 9i)

1. Verify that the table is a candidate for redefinition> DBMS_REDEFINITION.CAN_REDEF_TABLE

2. Create an interim partitioned table

3. Start the redefinition> DBMS_REDEFINITION.START_REDEF_TABLE

4. Copy dependent objects to the new table (grants, constraints, …)> DBMS_REDEFINITION.COPY_TABLE_DEPENDENTS

5. Synchronize the interim table (optional)> DBMS_REDEFINITION.SYNC_INTERIM_TABLE

6. Complete the redefinition> DBMS_REDEFINITION.FINISH_REDEF_TABLE

Online operations

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> One shot

> In-place conversion

> No business interruption

Online operations

30.05.2017




Online operationsWhat’s new in 12cR2 ?



> What about indexes ?

> By default> Prefixed* indexes local partitioned indexes

> Non-prefixed indexes global non-partitioned indexes

> With the UPDATE INDEX clause> You can change the partition state of an index (partitioned or not)

> You can change the storage properties (move it to another tablespace)

> You can NOT change the columns of an index

> You can NOT change the uniqueness of an index

* Prefixed means that the partition key column is in the index definition :

Ex. : Table partitioned on column1 -> prefixed-index contains [column1, columnX, …]

Online operations

30.05.2017



Conclusion


Partitioning can improve

> Manageability

> Performance

> Availability

Partitioning still evolving

> More and more business requirements are met

Partitioning is an option

> Available in Enterprise Edition

Conclusion


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30.05.2017

We look forward to working with you!


Joël CattinConsultant

+41 79 961 29 65

[email protected]

Any questions? Please do ask

oracle partitioning : basis & new features in 12cr2 · infrastructure at your service. oracle...

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