Leveraging partition enhancements

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© The Pythian Group Inc., 2018
Aishwarya Kala
Leveraging Partitioning
Enhancements

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© The Pythian Group Inc., 2018 2
ABOUT PYTHIAN
Pythian’s 400+ IT professionals help
companies adopt and manage
disruptive technologies to better
compete

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AGENDA
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● Introduction
● Partitioning 101
● Partition Extensions + New Features
● Partition Manageability + New Features
● ADO & Data Archival
● Some More New Features

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Partitioning 101

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● Divide and Conquer
● Divides Objects like tables, indexes, index-organized tables into smaller, more manageable
pieces, called partitions.
● Manage partitions individually as well as collectively.
● The decision to assign a row to a partition is taken based on a Partitioning Key ( one or more
columns of the table)
Partitioning

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Partitioning
01-Jan-19
02-Jan-19
03-Jan-19 03-Feb-19
02-Feb-19
01-Feb-19
03-Mar-19
02-Mar-19
01-Mar-19
01-Jan-19
02-Jan-19
03-Jan-19
01-Feb-19
02-Feb-19
03-Feb-19 03-Mar-19
02-Mar-19
01-Mar-19
Table : Orders
Jan19 Mar19
Feb19
Table : Orders
Data distributed by
order_date

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● Standard Data Distribution Methods
● Single-Level Partitioning [RANGE | LIST | HASH ]
● Composite Partitioning - subpartitions [RANGE | LIST | HASH ] || [RANGE | LIST | HASH ]
Partitioning Strategies
Jan19
Feb19
Mar19
RANGE
ASIA
EMEA
AFRICA
HASH
LIST
H1
H2
H3
H4

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Partition Extensions + New Features

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● Extension of Range Based Partitions (Introduced in 11g)
● Auto creates partitions when data exceeds all the existing ranges
● Subtle Differences
● Interval Based partitions do not have Max-value Partition
● Naming & Tablespace Constraints
Interval Partitioning

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● Interval Based partitions do not have Maxvalue Partition
MAXVAULE
Range Based Partitioning
Jan19 Feb19 Jan19
New Record with
order_date of
02-Mar-2019
Interval Based Partitioning

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● Range Based partitions do not have any Lower Bounds
MAXVAULE
Jan19 Feb19 Jan19
SYS_NAME
New Record with
order_date of
02-Mar-2019

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Partition Bounds
MAXVAULE
Values less than Feb 2019
Values less than Apr 2019
Values belonging to Jan 2019
Values belonging to Apr 2019
New Record with
order_date of
02-Mar-2019

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● Range Based partitions do not have any Lower Bounds
Be wary of jobs that do not query data dictionary views for partition names, when moving from
range to interval partitioning.

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● Automatic List Partitions
● Extension of List Based Partitions ( Introduced in 12.2 )
● Auto creates partitions when no corresponding partition key value found.
● The decision is to choose between
o List + Default
o Auto List
● Multi-Column List Partitioning ( Introduced in 12.2 )
Only one Default bucket
List Partitioning Enhancements
Not Suitable when too many distinct
values expected.

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● Automatic List Partitions
● Extension of List Based Partitions ( Introduced in 12.2 )
● Auto creates partitions when no corresponding partition key value found.
● Not Suitable when too many distinct values expected.
● The decision is to choose between
o List + Default
o Auto List
● Multi-Column List Partitioning ( Introduced in 12.2 )
Only one Default bucket
List Partitioning Enhancements
D
E
F
A
U
L
T
ASIA ASIA EMEA
INDIA NEPAL U.K.

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● Referential Partitioning
● Child table inherits the partitioning strategy of parent table through Referential Constraints
● Reduces Data Maintenance Overhead
■ A split operation on Parent will split the dependent child partitions.
■ Dropping a partition in parent table, will drop the dependent child partition – No need to disable the FK-PK
■ Applies to Truncate as well. (TRUNCATE CASCADE)
● Virtual Column Based Partitioning
● Partition based on the virtual columns of a table.
Other Extensions

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● What do you want to achieve ?
● Performance
 Partition Pruning
 Partition-wise join
 DML Speed up
 Data Load
● Data Management Benefits
● Do you know your data ?
● Type of Data - Records, transactions…
● Data Access Patterns
● Data Lifecycle Requirements.
Choosing a Partitioning- Strategy

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Partition Manageability +
New Features

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● Partition a Stand-Alone Table
1. Create a separate Partitioned Table + Transfer Data
2. Exchange Partitioning
■ Create Separate Tables with Filtered Data
■ Transfer the Filtered Data into a corresponding partition
3. DBMS_REDEFINITION
Online Conversion of a Non-Partitioned to a Partitioned Table
CREATE TABLE ORDERS_2018
where Order_DATE < 2018 ;
Alter table ORDERS_PART Exchange
partition ORDERS_PART2018 with table
orders_2018;

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● Global partitioned
● Non-prefixed indexes
● Prefixed indexes
● Bitmap indexes
No Effect
Global Non-partitioned Indexes
Local Partitioned Indexes
Local Partitioned Indexes
Index that contains the
leading column of the
partitioning key
Partitioning_key =>
order_date
Index => (order_Date,
region)

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Online Split & Move Operations

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Online Split & Move Operations
• Indexes always remain ONLINE
• Concurrent Query & DML Operations allowed – not preferred => Impacts compression ratio

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Create Table For Exchange
TAB
ORA-14097: column
type or size
mismatch …
CREATE TABLE TAB
FOR EXCHANGE WITH TABLE PART_TAB;
PART_TAB

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Data Management
Jan19
Feb19
Mar19
Table Size 300 GB
Table Details Monthly Range-based Partitions
Requirements
• Compress All Data older than 3 months (~25 GB/Month)
• Move data older than a year from SSD To HDD

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Data Management
Jan19
Feb19
Mar19
Requirements
• Compress All Data older than
3 months (~25 GB/Month)
• Move data older than a year
from SSD To HDD
• ALTER TABLE ORDER_HISTORY MOVE PARTITION OH_MAY2019 COMPRESS ;
• ALTER TABLE ORDER_HISTORY MODIFY PARTITION OH_MAY2019 REBUILD
UNUSABLE LOCAL INDEXES;
Compression Steps
• ALTER TABLE ORDER_HISTORY MOVE PARTITION OH_JUN2018 TABLESPACE ORDER_HISTORY_SLOW ;
• ALTER TABLE ORDER_HISTORY MODIFY PARTITION OH_JUN2018 REBUILD UNUSABLE LOCAL INDEXES
TABLESPACE ORDER_HISTORY_SLOW ;
Data Archiving Steps

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Data Management
Manual Operation Involved
Repetitive - Every Month
Multiple Partitioned Tables

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Automatic Data
Optimization (ADO)

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Heat Maps

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Heat Maps
● Track Data Access
● Reads vs Writes
● Types of Reads – FTS vs Index Lookups
● Row, Segment, Tablespace Level
● Access the information via Data Dictionary Views
● Database-aware
● Maintenance jobs, stats gathering, backups, don’t affect heat map.
● Doesn’t track objects in SYSTEM and SYSAUX tablespaces
HEAT_MAP = ON
Advanced Compression
License

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Heat Maps

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Heat Maps

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Heat Maps

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Heat Maps

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Heat Maps

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Automatic Data Optimization (ADO)
● Policies that Manage Data Automatically
Compression
Data
Movement
HOW ??

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Compression
Data
Movement
HOW ??
Moving to tablespaces on
separate storage tiers.

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Compression
Data
Movement
HOW ??
Data can be compressed at
Row storage level
Segment level
Group (multiple objects) level

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● Policies can be
● Space Based
 E.g. When tablespace utilization reaches 85%, then move to another tablespace
● Time And Access method Based
 E.g. Compress any row that has not been updated for 90
 E.g. Move a segment that has not been updated for 180 to another tablespace
TRIGGERS

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Automatic Data Optimization (ADO) – Time & Access Method
Condition of the Policy

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Goal of the Policy

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Scope of the Policy

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Automatic Data Optimization (ADO) – Space
Goal of the Policy
Scope of the Policy
Condition of the Policy???

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Automatic Data Optimization (ADO) – Space
Condition of the Policy???
• Global Defaults
• Can be controlled
dbms_ilm_admin.customize_ilm

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Automatic Data Optimization (ADO) - Execution
● Row Level
● Remaining Policies
● Supports Manual Evaluation & Execution
Setup custom jobs for larger tables that evaluate the policy periodically
MMON (15 mins)
Maintenance Window

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Manual Execution

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Some More New Features

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● Protect Data from accidental modifications
● Columns can be added /modified
● RO Partitions Cannot be Dropped
● Benefits of RO Partitions vs RO Tablespaces
● No Need for separate tablespaces
● Benefits smaller partitions
Read Only Partitions
ALTER TABLE ORDERS MODIFY PARTITION
ORDERS_2018 READ ONLY;

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● Applicable to Partition Move, Split, Merge
● Only rows matching the filter condition are retained
Filtered Partition Maintenance Operations

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● Partition External Tables
● Combines of Regular Tables + External Partitioned Tables
Hybrid Partitioned Tables

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● Change the partitioning strategy
● Avoids Manual Rebuild
● Uses the MODIFY Clause
Modifying Partitioning Strategy

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Modifying Partitioning Strategy

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THANK YOU
You can reach me :
@aishwaryakala13

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