Anton Topurov IT-DB

23 April 2013 Introduction to Oracle 2

23 April 2013 Introduction to Oracle 3

23 April 2013 Introduction to Oracle 4

IT manager

23 April 2013 Introduction to Oracle 5

App Developer

23 April 2013 Introduction to Oracle 6

Database Administrator

23 April 2013 Introduction to Oracle 7

System Administrator

23 April 2013 Introduction to Oracle 8

IT manager

23 April 2013 Introduction to Oracle 9

23 April 2013 Introduction to Oracle 10

23 April 2013 Introduction to Oracle 11

Introduction to Oracle 12

23 April 2013 Introduction to Oracle 13

Oracle Database Internals

23 April 2013 Introduction to Oracle 14

23 April 2013 Introduction to Oracle 15

Real Application Clusters (RAC)

23 April 2013 Introduction to Oracle 16

23 April 2013 Introduction to Oracle 16

Oracle Database Server

23 April 2013 Introduction to Oracle 17

Simplified view

23 April 2013 Introduction to Oracle 18

System Global Area (SGA)

Background

Processes

Data Files Control Files Online Redo Logs

Server Processes

PGA

Database Physical Layout

23 April 2013 Introduction to Oracle 19

Data Files Control Files Online Redo Logs

Physical to Logical

23 April 2013 Introduction to Oracle 20

Data Files

Logical Layout

23 April 2013 Introduction to Oracle 21

Block

• The smallest

logical unit

of data storage

Extent

• Continios set of

blocks

Segment

• Type (table, index,..)

• Within a tablespace

Tablespace

• Maps to one or more

datafiles

23 April 2013 Introduction to Oracle 22

Real Application Clusters (RAC)

Oracle Instance

23 April 2013 Introduction to Oracle 23

System Global Area (SGA)

Background

Processes

Data Files Control Files Online Redo Logs

SGA contents

23 April 2013 Introduction to Oracle 24

Buffer cache

• holds copies of data blocks

• server processes manipulate

data from buffer cache (not

directly from data files)

• managed using LRU algorithm

(Least Recently Used)

Shared pool

• shared memory constructs

like shared SQL areas

• most recently executed SQL

statements

• most recently used data

definitions

Backup

Background Processes

23 April 2013 Introduction to Oracle 25

System Monitor

Process Monitor

Diagnosability Process

Data Files Control Files Online Redo Logs

Database Writer

Archived Redo Logs

Redo Log Archiver Redo Log Writer Checkpointer

Buffer Cache System Global Area (SGA)

Redo

Log

Buffer

23 April 2013 Introduction to Oracle 26

Real Application Clusters (RAC)

Real Application Clusters

23 April 2013 Introduction to Oracle 27

Data Files Control Files Online Redo Logs

SGA

PGA

SGA

PGA

Clusterware

SGA

PGA

Clusterware

23 April 2013 Introduction to Oracle 28

Real Application Clusters (RAC)

Database Account

• Database user

• username/password to connect to database

• Privileges

• System and object privileges / roles • CREATE SESSION, CREATE TABLE, CREATE PROCEDURE, CREATE JOB,…

• EXECUTE ON DBMS_LOCK, SELECT ON HR.EMPLOYEES, …

• Profiles • CERN_DEV_PROFILE: 10 concurrent sessions

• CERN_APP_PROFILE: 400 concurrent sessions

• Space quota on tablespaces

23 April 2013 Introduction to Oracle 29

Database vs Schema

A Schema?

• Collection of objects

• Owned by a database user and has the

same name as that user

• Each user owns a single schema.

• Good programming practice is to prefix

objects by schema name

23 April 2013 Introduction to Oracle 30

select name from hr.employees where id=7;

Connecting to Oracle Database

23 April 2013 Introduction to Oracle 31

Listener

port 10121

sqlplus username@

’( DESCRIPTION=

(ADDRESS= (PROTOCOL=TCP)

(HOST=node1.cern.ch) (PORT=10121))

(CONNECT_DATA= (SID=DEVDB11)))’

SGA

Instance SID: DEVDB11

PGA

node1

Data Files Control Files Online Redo Logs

node2-v

Connecting to RAC Database

23 April 2013 Introduction to Oracle 32

Data Files Control Files Online Redo Logs

SGA

PGA

sqlplus username@ ( DESCRIPTION=

(ADDRESS= (PROTOCOL=TCP) (HOST=node2-v.cern.ch) (PORT=10121))

(ADDRESS= (PROTOCOL=TCP) (HOST=node1-v.cern.ch) (PORT=10121))

(LOAD_BALANCE=off) (CONNECT_DATA= (SERVER=DEDICATED)

(SERVICE_NAME=CERN_SRV1.cern.ch) ))’

Listener

SGA

PGA

Listener

CERN_SRV1 CERN_SRV3 CERN_SRV2

node1.cern.ch node2.cern.ch

node1-v Clusterware Clusterware

Local naming method

Based on tnsnames.ora

/afs/cern.ch/project/oracle/admin

\\cern.ch\dfs\Applications\Oracle\ADMIN

23 April 2013 Introduction to Oracle 33

( DESCRIPTION=

(ADDRESS= (PROTOCOL=TCP) (HOST=node2-v.cern.ch) (PORT=10121))

(ADDRESS= (PROTOCOL=TCP) (HOST=node1-v.cern.ch) (PORT=10121))

(LOAD_BALANCE=off) (CONNECT_DATA= (SERVER=DEDICATED)

(SERVICE_NAME=CERN_SRV1.cern.ch) ))’

cerndb1 =

sqlplus username@

23 April 2013 Introduction to Oracle 34

Real Application Clusters (RAC)

SQL Statements Processing

23 April 2013 Introduction to Oracle 35

SQL Statement

Syntax Check

Semantic Check

Shared Pool

Check

Optimization

Row Source

Generation

Execution

Parsing

Soft

Parse

Hard Parse

select * from hr.employees;

select * from hr.employees; sql_id = 8k3hpjw6yjup5

select name from hr.employees where id=:id_val;

Summary

23 April 2013 Introduction to Oracle 36

Documentation

• Oracle Database Concepts http://docs.oracle.com/cd/E11882_01/server.112/e25789/toc.htm

• Oracle 11g documentation • http://www.oracle.com/pls/db112/portal.all_books

• Architecture poster

23 April 2013 Introduction to Oracle 37

23 April 2013 Introduction to Oracle 38