Goals for This Week
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Brief SQL refresh
New SQL in Oracle 9i
Overview of Oracle Architecture
Basic Oracle Administration
Performance Tuning
Schema Design
Back-end Tools
Switch to SQL Intro
Role of Database Server
Results
SQL or
Procedure Call
SQL or
Procedure
Call
Results
Client
HTTP:
GET
HTML
Role of Database Server (4 tier)
Results
App.
Server
SQL or
Procedure Call
Proc./
Trans
Call
Results
HTML
Client
HTTP: GET
Web Server
Logical Objects
Logical Objects
Database
consists of
Schemas
own
Objects
Tables
Indexes
Sequences
Views
Procedures
Triggers
Etc
Schema Types
•Application Schemas
Database
Payroll
Student records
consists of
Schemas
own
Financial Reporting
Nascar
Hollywood
•User Schemas
Joe
Objects
(tables, indexes, etc)
Fred
Dave
Schema Attributes
•Application Schemas
Usually referred to as a “schema object”
Contains a set of closely related tables and associated objects
Typical Object Reference: Hollywood.Movies
•User Schemas
Often referred to as a “User” or “Account” object.
May or may not contain personal tables (Joe.Contacts).
May or may not have the right to even create objects.
Are generally granted privileges to objects in application schemas.
LAB
Create a user schema
And an application schema
Using dba studio
Note security weakness:
System (pw: manager)
Sys (pw: change_on_install)
Scott (pw: tiger)
Sysman (pw: oem_start)
Caution
Creating a user schema from SQL:
CREATE USER CALVIN IDENTIFIED by HOBBES
LAB
Creating a user schema from SQL:
CREATE USER CALVIN IDENTIFIED by HOBBES
DEFAULT TABLESPACE USERS
TEMPORARY TABLESPACE TEMP
QUOTA 100M on users
QUOTA 100M on temp
QUOTA 100M on rbs;
-- quota on RBS not necessary on 9i
GRANT CONNECT TO CALVIN; -- let him log in
GRANT RESOURCE TO CALVIN; -- let him create tables and other objects
Oracle
Database
consists of
Schemas
own
vs. SQL Server
SQL Server
Software Instance
defines
Users
own
Databases
contain
Objects
Objects
(tables, indexes, etc)
(tables, indexes, etc)
Oracle
Database
consists of
Schemas (users)
Granted
Privileges to
vs. SQL Server
SQL Server
Software Instance
defines
Users
own
Databases
contain
own
Objects
(tables, indexes, etc)
Granted
Privileges to
Objects
(tables, indexes, etc)
Controlling Application Access
•Each User is given an Oracle Account and control is
maintained by granting privileges to tables, procedures and
other objects. (e.g. DESIGN)
•All users connect ominously to a web site. The Web or
Application server connects to Oracle in the context of a
particular user.
•Although the Web or Application server connects to Oracle in
the context of a particular user, individuals connecting to the
web site must still authenticate for the interface to determine
what they should be allowed to do:
-Oracle Authentication
-Local “user” table in application
-Network authentication
Roles and Profiles
• Role
– Functions similar to NT Groups
– Specific Object and System Privileges are granted to the Role
– That Collection of Privs can be quickly granted to a USER by granting
them the Role (Example: GRANT DBA to HOMER)
• Profile
Provides default values for USER attributes such as
– Number of Concurrent Sessions
– Password complexity
LAB
Creating a role
Create ROLE trainee;
Grant connect to trainee; -- right to log on
Grant resource to trainee; -- right to create objects
Grant select_catalog_role to trainee; -- dictionary privs
LAB Creating user schemas from PL/SQL:
DECLARE
v_sqlstatement varchar2(200);
v_newclass newclass%rowtype;
CURSOR newclass_cursor IS SELECT * from newclass;
BEGIN
DBMS_OUTPUT.PUT_LINE ('****************** begin account creation');
OPEN newclass_cursor;
FETCH newclass_cursor into v_newclass;
WHILE newclass_cursor%found LOOP
DBMS_OUTPUT.PUT_LINE (v_newclass.userid);
v_sqlstatement := 'create user ' || UPPER(v_newclass.userid) || ' identified by oracle ';
v_sqlstatement := v_sqlstatement || 'DEFAULT TABLESPACE USERS ';
v_sqlstatement := v_sqlstatement || 'TEMPORARY TABLESPACE TEMP ';
v_sqlstatement := v_sqlstatement || 'QUOTA 100M on users ';
v_sqlstatement := v_sqlstatement || 'QUOTA 100M on temp ';
v_sqlstatement := v_sqlstatement || 'QUOTA 100M on rbs '; -- rbs quota not needed in 9i
execute immediate v_sqlstatement; -- this is dynamic SQL needed because of early binding
v_sqlstatement := 'GRANT trainee TO ' || v_newclass.userid;
execute immediate v_sqlstatement;
FETCH newclass_cursor into v_newclass;
END LOOP;
DBMS_OUTPUT.PUT_LINE ('****************** end account creation');
CLOSE newclass_cursor;
END;
/
Oracle’s Architecture
Instance vs. Database
Instance
(memory structures)
Database
(disk structures)
Multiple Instances for 1 Database
Instance A
Instance B
(memory structures)
(memory structures)
Database 1
(disk structures)
Multiple Databases for 1 Instance
Instance A
(memory structures)
Database 1
Database 2
(disk structures)
(disk structures)
Instance to Instance Communication
Instance A
Instance B
(memory structures)
(memory structures)
Via client
Or replication
process
Database 1
Database 2
(disk structures)
(disk structures)
Key structures and Processes
CLIENT
CLIENT
CLIENT
ORACLE INSTANCE
Database Buffer Cache
Network
Redo Log Buffer
Shared Pool
Library
Cache
LSTNR
Data Dictionary
Cache
SERVER
SERVER
SERVER
DBWR
SMON
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
PMON
CKPT
Control
Files
Control
Files
LGWR
ARCH
On-line
Redo
On-line
Log Files
Redo
On-line
Log Files
Redo
Log Files
Background
Processes
Database Buffer Cache
Database Buffer Cache
Number of Buffers determined by
Initialization File Parameter:
DB_BLOCK_BUFFERS (8i)
DB_CACHE_SIZE (9i)
Block Size is a multiple of OS Block.
DBWR
Block Size if fixed in Oracle 8i.
Block Size is not fixed in 9i except for the system,
rollback, and temp tablespaces.
LRU algorithm used to determine buffered data.
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
Free block
Used block
Dirty block
Buffer Hit Ratio
Consistent Gets + DB Block Gets - Physical Reads
* 100
Consistent Gets + DB Block Gets
Generally, a hit ratio below 80% indicates too many
physical reads and suggests that DB_Block_Buffers
should be increased.
LAB
Hit Ratio Since Instance Startup
Select
sum(decode(NAME, 'consistent gets',VALUE, 0)) "Consistent Gets",
sum(decode(NAME, 'db block gets',VALUE, 0)) "DB Block Gets",
sum(decode(NAME, 'physical reads',VALUE, 0)) "Physical Reads",
round((sum(decode(name, 'consistent gets',value, 0)) +
sum(decode(name, 'db block gets',value, 0)) sum(decode(name, 'physical reads',value, 0))) /
(sum(decode(name, 'consistent gets',value, 0)) +
sum(decode(name, 'db block gets',value, 0))) * 100,2) "Hit Ratio"
from v$sysstat
Next: change number of buffers, bounce service, large query, check hits
Shared Pool
Shared Pool
Library
Cache
Data Dictionary
Cache
Library Cache
•Holds parsed SQL statements
•Interrogate via v$sqlarea & v$librarycache
•CURSOR_SHARING = FORCE
Data Dictionary Cache
•Holds table and column definitions
and privileges
LAB
Shared Pool Hit Ratios
Library Cache Hit Ratio
Select (sum(pins) / (sum(pins) + sum(reloads))) * 100 “Lib. Hit Ratio”
from v$librarycache
Dictionary Hit Ratio
Select (sum(gets) / (sum(getmisses) + sum(gets))) * 100 “Dict. Hit Ratio”
from v$rowcache
Also look at v$sqlarea
Oracle Processes
•Background Processes
run on server
-as separate processes on UNIX (ps –ef | grep
-As separate threads in single service on NT
<ORA_SID>)
•Listener Process
one or more per server
listens for connection requests
hands off to server process (on diff. Port)
•Server Processes
Run on server
Typically one process to support each connected user (unless MTS)
•Client (“User”) Process
runs on client machine
communicates with a server process on server
Oracle Background Processes
•DBWR
Writes dirty blocks from the buffer pool back to disk.
•SMON
Checks for consistency, initiates recovery
•PMON
Cleans up resources if process fails
•CKPT
Updates database status after commits and other key
events.
•LGWR
Writes before and after images of changed rows into the
on-line redo log files
•ARCH
Numbers and archives on-line redo log files
LAB
Start and stop the instance
And listener services using
Various methods
LAB
Who is logged in?
Look at v$session
Alter system kill session ‘sid, serial’;
Oracle Commit Processing
Database Buffer Cache
Redo Log Buffer
DB-7F3 FRED 30000
DB-7F4 JANE 36000
Data requested might or
Might not be in the buffer.
DBWR
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
Update Emp
Set Sal = 40000
Where name=‘FRED’
On-line
Redo
On-line
Log File C
Redo
On-line
Log File B
Redo
Log File A
Oracle Commit Processing
Database Buffer Cache
Redo Log Buffer
DB-7F3 FRED 30000
DB-7F4 JANE 36000
BEGIN SCN 412
LGWR
DBWR
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
Update Emp
Set Sal = 40000
Where name=‘FRED’
May or may not
Have written at this point.
On-line
Redo
On-line
Log File C
Redo
On-line
Log File B
Redo
Log File A
Oracle Commit Processing
Database Buffer Cache
Redo Log Buffer
DB-7F3 FRED 30000
DB-7F4 JANE 36000
RB-65B
BEGIN SCN 412
LGWR
DBWR
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
Update Emp
Set Sal = 40000
Where name=‘FRED’
May or may not
Have written at this point.
On-line
Redo
On-line
Log File C
Redo
On-line
Log File B
Redo
Log File A
Oracle Commit Processing
Database Buffer Cache
Redo Log Buffer
DB-7F3 FRED 30000
DB-7F4 JANE 36000
OLD:7F3 FRED 30000
RB-65B NULL
OLD:RB-65B
BEGIN SCN 412
LGWR
DBWR
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
Update Emp
Set Sal = 40000
Where name=‘FRED’
May or may not
Have written at this point.
On-line
Redo
On-line
Log File C
Redo
On-line
Log File B
Redo
Log File A
Oracle Commit Processing
Database Buffer Cache
Redo Log Buffer
DB-7F3 FRED 30000
DB-7F4 JANE 36000
NEW:RB-65B FRED 30000
OLD:DB-7F3 FRED 30000
RB-65B FRED 30000
OLD:RB-65B
BEGIN SCN 412
DBWR
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
May or may not
Have written at this point.
(rollback segs. First)
Update Emp
Set Sal = 40000
Where name=‘FRED’
LGWR
May or may not
Have written at this point.
On-line
Redo
On-line
Log File C
Redo
On-line
Log File B
Redo
Log File A
Oracle Commit Processing
Database Buffer Cache
Redo Log Buffer
DB-7F3 FRED 40000
NEW:7F3 FRED 40000
DB-7F4 JANE 36000
NEW:RB-65B FRED 30000
OLD:DB-7F3 FRED 30000
RB-65B FRED 30000
OLD:RB-65B
BEGIN SCN 412
DBWR
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
May or may not
Have written at this point.
(rollback segs. First)
Update Emp
Set Sal = 40000
Where name=‘FRED’
LGWR
May or may not
Have written at this point.
On-line
Redo
On-line
Log File C
Redo
On-line
Log File B
Redo
Log File A
Oracle Commit Processing
Database Buffer Cache
Redo Log Buffer
COMMIT SCN 412
DB-7F3 FRED 40000
NEW:7F3 FRED 40000
DB-7F4 JANE 36000
NEW:RB-65B FRED 30000
OLD:DB-7F3 FRED 30000
RB-65B FRED 30000
OLD:RB-65B
BEGIN SCN 412
DBWR
Data
Files
Data
(Inc. RB
Files
Segments)
(Inc. RB
Segments)
May or may not
Have written at this point.
(rollback segs. First)
Update Emp
Set Sal = 40000
Where name=‘FRED’
LGWR
Definitive write
through commit
record
On-line
Redo
On-line
Log File C
Redo
On-line
Log File B
Redo
Log File A
LAB
Simulate Server
Failure after update
But before commit
GO
BACK
Go Back 2 slides
And discuss
“consistent gets”
Logical to Physical Mapping
(controlling where objects are stored)
Database
Oracle
Tablespace is
similar to
SQL Server
File Group.
Stores objects in
Tablespaces
Made Persistent via
DataFiles
Why multiple Tablespaces?
• Reduce Disk Contention by spreading disk I/O
over multiple spindles.
– We control which TS objects are stored on
– We control physical location of TS datafiles
– Even if all disks are in use currently, the best practice is to keep major
apps on different tablespaces to more easily allow for future movement.
• Reduce performance degradation during on-line
physical backups.
• Allows different applications to have different
physical parameters
– block size
– Fragmentation level
– etc
Typical Tablespaces:
•
•
•
•
•
•
•
•
SYSTEM
RBS
USERS
TEMP
TOOLS
INDX
DRSYS
OEM_REPOSITORY
32464
265600
89440
10560
1280
2560
2560
3841
E:\ORACLE\ORADATA\INSY\SYSTEM01.DBF
E:\ORACLE\ORADATA\INSY\RBS01.DBF
E:\ORACLE\ORADATA\INSY\USERS01.DBF
E:\ORACLE\ORADATA\INSY\TEMP01.DBF
E:\ORACLE\ORADATA\INSY\TOOLS01.DBF
E:\ORACLE\ORADATA\INSY\INDX01.DBF
E:\ORACLE\ORADATA\INSY\DR01.DBF
E:\ORACLE\ORADATA\INSY\OEM_REPOSITORY.ORA
Typical OFA segregation
1. Oracle software
12.Control file 1
2. System tablespace
13.Control file 2
3. System indexes
14.Control file 3
4. RBS tablespace
15.Application software
5. Data tablespace
16.User Tablespace inc.
indexes
6. Data Indexes TS
17.Archive log dest
7. Temp tablespace
8. Tools tablespace inc. index
9. Online redo log 1
10. Online redo log 2
11. Online redo log 3
RAID: Redundant Array of Inexpensive Disks
Volume Set:
C:
123
456
789
10 11
12 13
14 15
Stripe Set (Raid Level 0)
123
10 11
16 17
456
12 13
18 19
789
14 15
20 21
RAID: Redundant Array of Inexpensive Disks
Mirror set (Raid level 1):
1 3 2
4 3 5
=
Drive
Controller
1 3 2
4 3 5
RAID: Redundant Array of Inexpensive Disks
Stripe Set with Parity (Raid Level 5)
1
0
0
0
0
0
1
1
1
0
0
0
+
1
0
1
1
1
0
0
1
+
0
1
0
0
=
=
0
1
1
1
parity
data
0
0
0
1
1
0
0
1
=
0
1
0
0
1
0
1
1
0
1
0
1
RAID: Redundant Array of Inexpensive Disks
Stripe Set with Parity (Raid Level 5)
1
0
0
0
0
0
1
1
1
0
0
0
+
+
=
=
0
1
1
1
parity
data
0
0
0
1
1
0
0
1
=
0
1
0
0
1
0
1
1
0
1
0
1
RAID: Redundant Array of Inexpensive Disks
Mirrored Stripe Set (Raid Level 0 + 1)
Data container
123
10 11
16 17
456
12 13
18 19
789
14 15
20 21
456
12 13
18 19
789
14 15
20 21
Mirror container
123
10 11
16 17
RAID: Redundant Array of Inexpensive Disks
Stripe Set of Mirrors (Raid Level 1 + 0)
Stripe Set
Mirror Set
Mirror Set
Mirror Set
123
10 11
16 17
456
12 13
18 19
789
14 15
20 21
123
10 11
16 17
456
12 13
18 19
789
14 15
20 21
Large Scale RAID dependent Oracle Installation
Cabinet 1 (9 Containers, 42 drives)
Log 1
Ndx 3
c1
Log 2
Ndx 4
Intf 1
c3
c2
Data 1, Cntrl 1
Log 3
Data 2, Cntrl 2
Sys, Rbs, Temp
Cabinet 2 (9 containers, 42 drives)
Log 4
Ndx 1
c4
Log 5
Ndx 2
Data 4, Cntrl 4
RAID 1 (Log 1)
Controller 1
(c1) Details:
RAID 0 + 1 (Ndx 3)
RAID 0 + 1 (Data 1, Cntrl 1)
Source: Oracle Performance Tuning 101, Oracle Press
Intf 2
c6
c5
Data 3, Cntrl 3
Log 6
Archived Logs
Small Scale RAID dependent Oracle
Installation optimized for read/write operations.
Datafiles, INIT, and Control Files
RAID 1 + 0
Redo
Log Files
Arch
Log Files
Raid 1
Raid 1
LAB
Directly Examine:
dba_tables
dba_tablespaces
V$datafile
Or indirectly:
@\\neelix\oracle\scripts\admin\datafiles
@\\neelix\oracle\scripts\admin\usertabs
Look at Same using DBA studio
Create a new tablespace
And related datafile(s).
Creating Indexes and Tables in specific
tablespaces.
• Each user is assigned a default tablespace.
•Don’t create tables when logged in as system or sys
unless instructed to do so when installing Oracle tools.
•Override defaults when necessary through extended
DDL syntax.
CREATE TABLE GLACCOUNTS
( AccountNum
char(6)
Name
varchar2(30),
Balance
number(12,2))
TABLESPACE FINANCIALS;