Partitioning allows tables and indexes to be subdivided into smaller pieces called partitions. Tables can be partitioned using a partition key which determines which partition each row belongs to. Partitioning provides benefits like improved query performance for large tables, easier management of historical data, and increased high availability. Some disadvantages include additional licensing costs, storage space usage, and administrative overhead to manage partitions. Common partitioning strategies include range, list, hash and interval which divide tables in different ways based on column values.

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Partitioning
Presented By :
Reema Gajjar

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What is partitioning?
When to partition a table?
Partitioning stratergies
Partitioning operations
Advantages of partitioning
Disadvantages of partitioning
What We'll Cover ...

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What Is Partitioning ??
Partitioning allows tables, indexes to be subdivided into
smaller pieces.
Each piece of database object is called PARTITIONS.
Tables are partitioned using a 'PARTITION KEY', a set of
column/columns which determine in which partition a given row will
reside.
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What Is Partitioning ??
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When to Partition a table???
“Slow” queries ??
Tables containing historical data, in which new data is
added into newest partition.
When the contents of a table need to be distributed across
different types of storage devices.
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Partitioning Strategies
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1. Range partitioning
2. Interval partitioning
3. List partitioning
4. Hash partitioning
5. Composite partitioning

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1. Range Partitioning
It maps data into partition based on ranges of partition key
values.
Partitioning done based on consecutive range of values.
Ex : Partition sales data into monthly partitions.
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1. Range Partitioning
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January to August data

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Range Partitioning Example
sal_3
sal_more
sal_4
sal_3
sal_2
sal_more
sal_1
sal_1
Inserting A Records Into Range Partitioned Table :

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2. Interval Partitioning
Extension of range partitioning.
Automatically create new partition when data inserted into
a table exceeds transition point.
TRANSITION POINT – highest range partition.
You must specify atleast one range partition.
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Interval Partitioning Example
Inserting A Records Into Interval Partitioned Table :
sal_3
SYS_P14160
SYS_P14159
30000
40000
55000
High_value

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Interval Partitioning Example
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3. List Partitioning
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Partitioning done based on list of discrete values for the
partition key .
Enables to group and organize unordered and unrelated
sets of data.
Ex : States into a Region

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3. List Partitioning
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Sales Data

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List Partitioning Example
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p1
p2
p3
p4
p3
p5
Inserting A Records Into List Partitioned Table :

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4. Hash Partitioning
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Hash partitioning stores data to partitions based on a
hashing algorithm that oracle applies to the partitioning
key.
Distribution is handled by oracle.
Ex : order table → partitioned by cust_id
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4. Hash Partitioning
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Order Table

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Hash Partitioning Example
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Hash Partitioning Example
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View All Partitions Of Table
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SELECTING RECORDS
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Syntax :
select * from TABLE_NAME partition
(PARTITION_NAME);

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Adding a Partition
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1. ADDING PARTITIONS :
Syntax :
ALTER TABLE table_name ADD PARTITION
partition_name VALUES LESS THAN (VALUE);
Partitioning Operations

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Adding a Partition
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1. ADDING PARTITIONS :
Range :
We can't add partition when maxvalue specified in range
partition.
We can't add partition for the lower ranges.
List :
We can't add partition when default specified in list partition
method.
Interval :
We can't add partitions.
Partitioning Operations

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Dropping a Partition
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2. DROPING PARTITIONS :
Syntax :
ALTER TABLE table_name DROP PARTITION
partition_name ;
Hash :
We can't drop partitions created by hash method.
Partitioning Operations

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Renaming a Partition
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3. RENAMING PARTITIONS :
Syntax :
ALTER TABLE table_name RENAME PARTITION
old_partition_name TO new_partition_name;
Partitioning Operations

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Splitting a Partition
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4. SPLITTING PARTITIONS :
Syntax :
ALTER TABLE table_name SPLIT PARTITION
partition_name AT (value) INTO ( PARTITION
partition_name1 , PARTITION partition_name2);
Partitioning Operations

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Splitting a Partition
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4. SPLITTING PARTITIONS :
Hash :
We can't split partitions.
Partitioning Operations

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Merging a Partition
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5. MERGING PARTITIONS :
Syntax :
ALTER TABLE table_name MERGE PARTITION
partition_name1,partition_name2 INTO PARTITION
partition_name3;
Partitioning Operations

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Merging a Partition
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5. MERGING PARTITIONS :
Hash :
We can't merge partitions.
Partitioning Operations

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Advantages Of Partitioning
Performance
Manageability
Availability
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Disadvantage Of Partitioning
You need to buy licenses before you can use it.
It take up a space.
additional administration tasks to manage partitions.
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Thank You...
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