Database Tuning Chap 8 : IOT Architecture Chap 9 : Cluster Factor Optimization Center for E-Business...

Database TuningDatabase TuningChap 8 : IOT ArchitectureChap 8 : IOT ArchitectureChap 9 : Cluster Factor OptimizationChap 9 : Cluster Factor Optimization

Center for E-Business TechnologySeoul National University

Seoul, Korea

Nam, Kwang Hyun

Intelligent Database Systems LabSchool of Computer Science & EngineeringSeoul National University, Seoul, Korea

Copyright 2008 by CEBT

Chap 8 : IOT ArchitectureChap 8 : IOT Architecture

Contents

IOT?

IOT Performance Analysis

Database Tuning - 2


IOT?IOT?

Definition

Acronym of ‘Index Organized Table’

Table which is organized like index structure (B*Tree indexes).

Property

Limited fast access

– Enable to complete all jobs with only Primary Key Index Scan

Storage saving

– Because IOT is mixed architecture with Primary Key Index and Table

Database Tuning - 3


IOT Performance AnalysisIOT Performance Analysis

IOT architecture

All column values are saved in Index Leaf Block

IOT creation

PCTTHRESHOLD should be set as big number.

Database Tuning - 4

Index Leaf Block

If the size of row is more than 20% of block except block

header, columns except key column are saved in Overflow

Tablespace



Comparison between general table and IOT

Data access

Case Study

Table access via Primary Key Index Scan, and extract 1 row

General Table IOT Table

Database Tuning - 5

Only Index ScanBut, Index depth is

deeper

Index Scan & Table Random Access



Comparison between general table and IOT

Storage

– IOT doesn’t need to have extra storage for Primary Key Index.

– Because it is sorted by Primary Key column and other columns are saved with it.

Considered case to convert into IOT table

– Most columns are used as Primary Key

– DML(Data Manipulation Language) ratio is low in table.

– Mass history table

– Only Primary Key Index exists in table.

Database Tuning - 6



IOT related data dictionary view

DBA_TABLES inquiry

DBA_INDEXES inquiry

Database Tuning - 7

Index name follows Primary Key Name

사원 Table’s type is Index



IOT related data dictionary view

DBA_SEGMENTS inquiry

Database Tuning - 8

IOTOverflow


ReferencesReferences

http://www.orafaq.com/wiki/IOT

http://wiki.oracleclub.com/pages/viewpage.action?pageId=1180842

http://www.psoug.org/reference/iot.html

http://www.filibeto.org/sun/lib/nonsun/oracle/11.1.0.6.0/B28359_01/server.111/b28310/tables012.htm

Database Tuning - 9


Chap 9 : Cluster Factor Chap 9 : Cluster Factor OptimizationOptimization

Contents

Cluster Factor?

Cluster Factor Optimization

Cluster Factor Optimization Method Application Examples

Database Tuning - 10


Cluster Factor?Cluster Factor?

Definition

Relationship between the number of row accessed by index scan and the number of accessed table block to extract concerned rows.

Calculate with only table block access except index block access.



Cluster Factor OptimizationCluster Factor Optimization

Definition

Cluster factor value comes close to the number of rows accessed by index scan (minimize the number of accessed block)

If cluster factor is optimized, the quantity of random access by index scan is decreased. Therefore, performance is improved.




Methods

Table reorganization

– If few business are in a day, It is hard to save data in same block.

Partition table




Cluster table

– No more used due to low performance in DML

Index-Organized Table (IOT)

– Saving with index order, cluster factor is optimized on first column of concerned primary key.


Database Tuning Chap 8 : IOT Architecture Chap 9 : Cluster Factor Optimization Center for E-Business...

Documents

Transcript of Database Tuning Chap 8 : IOT Architecture Chap 9 : Cluster Factor Optimization Center for E-Business...