oracle 8 database administration volume 1 instruction guide phần 4 ppsx

The following information is logged in the ALERT file: ORA-01578 Manager statements such as STARTUP, SHUTDOWN, ARCHIVE LOG, and RECOVER • The values of all nondefault initialization para

The following parameters control the location and size of the trace files:

are dynamic initialization parameters

• On UNIX, the alert file is named alert_<SID>.log and is located in the

3-24 Copyright  Oracle Corporation, 1998 All rights reserved.

Controlling the Trace File

User

process

Server process

USER_DUMP_DEST BACKGROUND_DUMP_DEST

ALERT file

Instance SGA Shared pool

It is important for the database administrator to check the ALERT file

regularly to detect problems before they become serious

The following information is logged in the ALERT file:

(ORA-01578)

Manager statements such as STARTUP, SHUTDOWN, ARCHIVE

LOG, and RECOVER

• The values of all nondefault initialization parameters at the time the

instance starts

Instructor Note

You may query the current setting for BACKGROUND_DUMP_DEST,

change to that directory, and show the alert and trace files in the directory

3-25 Copyright  Oracle Corporation, 1998 All rights reserved.

Guidelines

Check the ALERT file periodically to:

• Detect internal errors (ORA-600)

and block corruption errors

• Monitor database operations

• View the nondefault initialization

parameter

Quick Reference

Initialization parameters DB_NAME

CONTROL_FILES SHARED_POOL_SIZE BACKGROUND_DUMP_DEST DB_BLOCK_BUFFERS

COMPATIBLE IFILE

LOG_BUFFER PROCESSES SQL_TRACE Dynamic initialization

parameters

USER_DUMP_DEST MAX_DUMP_FILE_SIZE TIMED_STATISTICS Dynamic initialization

parameters (deferred)

SORT_AREA_SIZE

Dynamic performance views V$FIXED_TABLE

V$PARAMETER V$CONTROLFILE V$DATABASE V$DATAFILE V$DATAFILE_HEADER V$INSTANCE

V$LOGFILE V$OPTION V$PROCESS V$PWFILE_USERS V$SESSION

V$SGA

V$VERSION

Data dictionary views None

Commands CONNECT / AS SYSDBA

CONNECT / AS SYSOPER STARTUP

SHUTDOWN SHOW PARAMETER ALTER SYSTEM KILL SESSION ALTER SYSTEM DISCONNECT SESSION

POST_TRANSACTION ALTER SYSTEM ENABLE RESTRICTED SESSION ALTER SYSTEM DISABLE RESTRICTED SESSION ALTER SESSION SET

ALTER SYSTEM SET ALTER SYSTEM SET DEFERRED ALTER DATABASE MOUNT

ALTER DATABASE OPEN Packaged procedure and

functions

None

4

Creating a Database

4-2 Copyright  Oracle Corporation, 1998 All rights reserved.

Objectives

Creating the database is the first step in managing and organizing a database

system

Database creation is a task that prepares several operating system files and is

needed only once no matter how many data files the database has This is a

very important task because the database administrator must decide on

database settings, such as the size of the database block and the database

character set, which cannot be changed after the creation

Depending on the operating system, a database may have been created

automatically as part of the installation

You can use this initial database, or you can erase it and create a new one

manually

During migration from an older version of Oracle, database creation is

necessary only if an entirely new database is needed Otherwise you can use

version of the database

You can create a database with new data files or by erasing information in an

existing database that has the same physical structure

The CREATE DATABASE command initiates the creation of the control

files, redo log files, and the data dictionary structure that Oracle server

requires to access the database

4-3 Copyright  Oracle Corporation, 1998 All rights reserved.

Overview

Password file

Parameter file

User

process

Server process

PGA

Instance SGA Shared Pool

Database

Control files Datafiles Redo log

files

Preparing the Operating System

The database administrator should be fully privileged on the operating

system or should use the password file authentication (see the lesson

“Managing an Oracle Instance”)

Before you create the database, make sure that the memory for the SGA, the

Oracle executable, and the processes is sufficient Refer to your operating

system installation and administration guides

Calculate the necessary disk space for the database, including online redo

log files, control files, and the data files

4-4 Copyright  Oracle Corporation, 1998 All rights reserved.

Creation Prerequisites

one of the following ways:

- By the operating system

- Using a password file

database

Planning File Location

Plan how to protect the database, including the online redo log files, control

files, data files, and archived redo log files, and provide a backup strategy

Control Files

For the sake of safety, you should create at least two control files on two

different disks (see the lesson “Maintaining the Control File”) Because

control file copies must always be placed on different disks, they can have

identical names, such as control01.ctl on UNIX or control.ora on NT.

Online Redo Log Files

The online redo log files of a database should consist of multiplexed groups

of online redo log files A group of log files consists of identical copies,

which should be located on different disks (see the lesson “Maintaining

Redo Log Files”)

To distinguish between groups and their members, use a name like

log0101.rdo or log01a.rdo.

4-5 Copyright  Oracle Corporation, 1998 All rights reserved.

Planning Database File Locations

• Keep at least two active copies of a database

control file on at least two different devices.

• Multiplex the redo log files and put group

members on different disks.

• Separate data files whose data:

– Will participate in disk resource contention

across different physical disk resources

– Have different life-spans

– Have different administrative characteristics

Data Files

Name data files by relating to the contents as the root of the name—for

example, data files such as system01.dbf, temp01.dbf, users01.dbf on UNIX

and system01.ora, temp01.ora on NT.

Consider the characteristics of the data to be stored before determining the

structure appropriate for your database in order to:

To minimize fragmentation of the database, you should separate database

objects with different life spans, such as application data and temporary

data, into different tablespaces

To ensure well-balanced I/O loads, you should separate objects with

competing I/O requirements, such as tables and indexes into different

tablespaces

Note

These subjects are covered in detail in the lessons “Maintaining Tablespaces

and Data Files” and “Storage Structure and Relationships.”

4-6 Copyright  Oracle Corporation, 1998 All rights reserved.

Oracle Software Locations /u01/app/oracle

/u02/app/applmgr

/product

/admin /local

4-7 Copyright  Oracle Corporation, 1998 All rights reserved.

Oracle Database Files /u02/

oradata/

db01/

system01.dbf control01.ctl redo0101.rdo

db02/

system01.dbf control01.ctl redo0101.rdo

/u03/

oradata/

db01/

tools01.dbf control02.ctl redo0102.rdo

db02/

users01.dbf control02.ctl redo0102.rdo

Optimal Flexible Architecture

Another important issue during installation and creation of a database is

organizing the file system so that it is easy to administer growth by adding

data into an existing database, adding users, creating new databases, and

adding hardware and distributing I/O load across sufficiently many drives

The Optimal Flexible Architecture (OFA) standard, which provides one

solution to these issues was written by an Oracle team responsible for

installing, tuning, and upgrading UNIX Systems OFA facilitates

configuration of complex Oracle systems with low maintenance During an

Oracle installation on several UNIX platforms, Oracle automatically uses

this standard configuration

The following steps explain the OFA structure:

into a unit, called a mount point (A mount point is a directory on UNIX

denoting where the file subsystem for a single disk slice will be linked

into an existing file system The selection of mount points makes it

possible to hide device details) In the example, u01 and u02 are

different mount points

2 Name all devices that might contain Oracle server data so that a wildcard

can be used to refer to the collection of devices as a unit

In the example, /u01/app/oracle is the Oracle software owner home

directory and /u02/app/applmgr is the Oracle Financial Applications

owner

software and tools, administrative files like database creation scripts,

initialization scripts, and local software which is used with Oracle

In the example, the directories product, admin, and local satisfy this

requirement

4 Store each version of Oracle server distribution software in a directory

matching the software such as /u01/app/oracle/product/7.3.3 or /u01/

app/oracle/product/8.0.3

5 Make a directory explicitly for storing Oracle server data at the same

level of each of the devices, such as /u02/oradata

on the system In the example, the databases are named dba01 and db01

are used to identify the directory structure

because of the naming conventions and the lack of symbolic links To

circumvent this problem, the creation of hard directories instead of

symbolic links like u01 and u02 is necessary

For example, instead of the creation /u01/oradata/db01/, where u01

represents a mount point on UNIX, you would create a directory

DISK_3:\ORADATA\DB01\ on NT

Instructor Note

For information about OFA architecture, see The OFA Standard— Oracle7

for Open Systems, by Cary V Millsap, Oracle Corporation Oracle part

number A19308-1

or http://guts.us.oracle.com:80/sgrepo/papers/cmillsap

For information about OFA and NT see

http://scalable.us.oracle.com/nt/collateral/coll_list.html

Oracle Software Directory Structure

After the Oracle installation, the ORACLE_HOME directory is

/mount_point/app/oracle/product

On UNIX the ORACLE_HOME directory contains the following

subdirectories, as well as subdirectories for each Oracle product, depending

on the Oracle products available on the platform:

Some examples of the contents of the product subdirectories are:

Note

Subdirectory Description

orainst Installation files and programs

log Log files

Creating a Database

If you use the installer to create a database, the installer prompts you to enter

the number and the location of the mount points, the character set, the

national character set, passwords for user SYS and SYSTEM, and the UNIX

group password to enable operating system authentications

On NT, during the installation you are prompted to create a database with a

wizard, the Oracle Database Assistant This utility can also be used after

installation to create or to delete a database

4-8 Copyright  Oracle Corporation, 1998 All rights reserved.

Creating a Database: Considerations

This lesson covers the first six steps in detail The last step,generating the

data dictionary, is discussed in the lesson “Data Dictionary Views and

Standard Packages.”

4-9 Copyright  Oracle Corporation, 1998 All rights reserved.

Creating a Database Manually

1 Decide on a unique instance and

database name and database character

set.

2 Set the operating system variables.

3 Prepare the parameter file.

4 Create a password file (recommended).

5 Start the instance.

6 Create the database.

7 Run scripts to generate the data dictionary

and accomplish postcreation steps.

Decide on a unique name for the instance and set the following environment

variables:

Variable Description

ORACLE_HOME Set to the directory where the Oracle software will be installed

(Example: /u01/app/oracle/product/8.0.3)

instances running on the same machine

installation (Example: /u01/app/oracle)

than US7ASCII (Example: $ORACLE_HOME/ocommon/nls/admin/data)

4-10 Copyright  Oracle Corporation, 1998 All rights reserved.

Operating System Environment

On UNIX set the following environment

For example, set the environment variables in a Korn Shell with the

following command:

$ORACLE_SID=U16; export ORACLE_SID

In a C-shell, execute the following command:

$setenv ORACLE_SID U16

Note

and character sets than the database default, they will not be recognized

operating system

Oracle on NT uses variables in the NT registry similar to the way Oracle on

UNIX uses shell environment variables

The Oracle Installer, the ORADIM80, and the Oracle Database Assistant

utilities define variables in the registry as well as registering the Oracle

instance as a service You can edit the registry manually via the regedit.exe

utility

For example, parameters such as ORACLE_HOME, ORA_NLS33, and

ORACLE_SID (the default is ORCL for the starter database), are stored in

the folder HKEY_LOCAL_MACHINE\ SOFTWARE \ORACLE folder

Therefore the creation of a new database requires ORACLE_SID to be set

with the following command:

C:\> set ORACLE_SID=U16

Now you create a new service and the new password file, if required, to run

the database with the ORADIM80 utility:

C:\>ORADIM80 -NEW -SID sid [-INTPWD internal_pwd][SRVC svrcname] [MAXUSERS number][STARTMODE auto,manual][-PFILE filename]

4-11 Copyright  Oracle Corporation, 1998 All rights reserved.

Operating System Environment

On NT

• Set the variable ORACLE_SID to use

SVRMGR30.

• Create the service and the password

file with ORADIM80.

C:\> ORADIM80 -NEW -SID u16

-INTPWD password -STARTMODE auto

-PFILE ORACLE_HOME\DATABASE\initU16.ora

The Oracle server records all operations that are executed with the

ORADIM80 utility in the ORACLE_HOME\RDBMS80\ORADIM80.LOG

file

Instructor Note

The students can review the description of the ORADIM80 utility in

the lesson “Managing an Oracle Instance.”

4-12 Copyright  Oracle Corporation, 1998 All rights reserved.

Preparing the Parameter File

Preparing the Parameter File

When preparing the new database, copy the default init.ora file with the new

name init<SID>.ora.

Change the settings for some parameters; others can be left to default

You should specify at least the following parameters before starting the

instance:

Note

The database name is associated with a database at create database time and

is stored in the control files To change the name of an existing database, use

the CREATE CONTROLFILE command to re-create the control file (see the

course Oracle8: Backup and Recovery Workshop).

This is the only parameter that is required whencreating a new database.This parameter does notneed to match the ORACLE_SID, but must matchthe name used in the CREATE DATABASEstatement

least two control filenames, placed on separatedisks if possible The control files do not need toexist at this point The Oracle server can createnew operating system files when creating thedatabase.)

size cannot be changed after database creation.)

Connect as SYSDBA using operating system authentication or the password

file method and start the instance using the STARTUP command

The password is the one that was previously used to create the service with

the ORDIM80 utility on NT or that was previously created by using the

orapwd utility on UNIX.

If the parameter file is not in the default location, you may need to

specify the PFILE clause in the STARTUP command For this course,

the parameter file is located in the current directory

4-14 Copyright  Oracle Corporation, 1998 All rights reserved.

Starting the Instance

To create a database, use the following SQL command:

CREATE DATABASE [database]

[CONTROLFILE REUSE]

[LOGFILE [GROUP integer] filespec

[, [GROUP integer] filespec] ]

[CHARACTER SET charset]

[NATIONAL CHARACTER SET charset]

[DATAFILE filespec [autoextend_clause]

4-15 Copyright  Oracle Corporation, 1998 All rights reserved.

SPOOL creU16.log

STARTUP NOMOUNT PFILE=initU16.ora

CREATE DATABASE U16

GROUP 1 ('/DISK3/log1a.rdo',/DISK4/log1b.rdo’) SIZE 1 M,

GROUP 2 ('/DISK3/log2a.rdo',/DISK4/log2b.rdo’) SIZE 1 M

DATAFILE

'/DISK1/system01.dbf' size 50M autoextend on

CHARACTER SET WE8ISO8859P1;

Creating the Database