anton topurov it-db · 23 april 2013 introduction to oracle 18 system global area (sga) background...
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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
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