Oracle Database Administration for Microsoft SQL Server DBAs part 11 pot

The parameter JOB_QUEUE_PROCESSESin Oracle Database 11g has a default of 1000, and the job coordinator starts only as many processes as requested.. Are the Oracle templates really like S

■ The flash recovery area is a valuable location for being able to flashback the database The sizing of this area may need to change based on the size of the transactions and database, but it is a dynamic change that can be made as needed The key to sizing this area is to have the disk space available This will be the area where the backup files can be stored, and based on retention, should be estimated appropriately

You can also remove databases with the DBCA The Delete a Database option (see Figure 4-2) takes care of removing the services and datafiles

CAUTION

Even though the DBCA will ask “Are you sure?”

when you choose to delete a database, without

a backup of the database, the only parts that

can be re-created are the structures

So what is created with the database? The redo logs and log groups, SYSTEMtablespace, SYSAUX tablespace, temporary tablespace, undo tablespace, and control files will be created The catalog.sql and catproc.sql construct the data dictionary with the views, tables, and stored procedures SYS, SYSTEM, and a couple more users are added as well

The job scheduler is set up with background processes, because it is the default setting for parameters to have job slave processes The parameter JOB_QUEUE_PROCESSESin Oracle Database 11g has a default of 1000, and the job coordinator starts only as many processes as requested

Database Templates = model Database?

Are the Oracle templates really like SQL Server’s model database? The templates are the basic building blocks for the database

creation They have defaults for the files, parameters, and some basic configuration In that respect, they have the same kind of information that is stored in the model database

However, only one database is created for an Oracle server; there is

no need for templates to be used over and over again to create the

databases, as the model database is used in SQL Server

Duplicating Databases

with Templates and Scripts

Oracle template files can be used to duplicate and rebuild databases You can use a template you saved to create another database in the same Oracle home

or copy the template file to another server for use This obviously makes it easy

to duplicate a database without having to go through the setup and configure all the options You can reuse previously defined values and make adjustments as needed The database can be created easily, similar to using a response file, but without having to go through all of the steps

Database scripts provide another way to duplicate or re-create databases Using a script is really the manual way to create the database It has the

advantage that you can take a database script from an older version, make

a couple of modifications if you want to use any new features, and then use

it to create the database in a new Oracle version

When you use a script, setting up the external operating system and

Oracle environment is more critical than with the DBCA This is because

nothing is set up to take the defaults All the environment variables are

empty, and you need to make sure they are set up properly before you

create the database

For scripts, a parameter file must be available with the parameters set for control files This parameter file can be copied from another database and

modified with the new database name and file directories Also, all of the

directories need to be created before running the script Otherwise, the

script will fail with the “ORA-27040: file create” error The following code shows the command-line steps for manual database creation in a Windows environment

set ORACLE_SID=dba01

set ORACLE_HOME=d:\oracle\app\product\11.2

## Create service

ORADIM –NEW –SID dba01 –STARTMODE auto

Instance created.

sqlplus /nolog

sqlplus> connect / as sysdba

Connected to an idle instance

sqlplus> startup nomount

sqlplus> create database dba01;

Database created.

## create tablespace for Temp, users

>sqlplus> create temporary tablespace TEMP1 TEMPFILE

'e:\oracle\oradata\dba01\temp01.dbf'

Tablespace created.

sqlplus> alter database default temporary tablespace TEMP1;

Database altered.

## Run scripts for dictionary views

sqlplus> %ORACLE_HOME%\rdbms\admin\catalog.sql

sqlplus> %ORACLE_HOME%\rdbms\admin\catproc.sql

sqlplus> %ORACLE_HOME%\sqlplus\admin\pupbld.sql

## Create server parameter file

sqlplus> create spfile from pfile;

## Shutdown and startup the database

sqlplus> shutdown immediate;

Database closed.

Database dismounted.

ORACLE instance shut down.

sqlplus> startup

ORACLE instance started.

Total System Global Area 535662592 bytes

Fixed Size 1334380 bytes

Variable Size 234881940 bytes

Database Buffers 293601280 bytes

Redo Buffers 5844992 bytes

Database mounted.

Database opened.

sqlplus>

The creation of the instance starts with the service on the Windows platform When logging in to the database and doing a startup nomount, the background processes actually get started and services are running, so that the database can be created

You can use additional scripts to continue the configuration, including to create other tablespaces, set up the server parameter file, and then build the dictionary views, synonyms, and PL/SQL packages

Creating the Listener

A listener is needed on the database server in order for clients to connect to the database The listener can be created via another creation assistant: the Net Configuration Assistant (NETCA), as shown in Figure 4-5

The listener can retain the default name of LISTENER, or be renamed, perhaps to indicate the Oracle version or database service that it is listening for, as shown in the example in Figure 4-6

Shutdown Options

Several options are available for how the database is shut down:

■ Shutdownnormal will not allow any new connections, but will

wait until all current connections disconnect from the database

This is obviously the cleanest shutdown process, but can also

take a long time if users do not disconnect from the database,

and large transactions haven’t completed

■ Shutdownimmediate will not allow any new connections, but

will not wait for users to disconnect Any active transactions

will be rolled backed Long, uncommitted transactions still

might take a while to roll back with this option, but there is no

recovery needed on startup

■ Shutdowntransactional will wait for the currently running

transactions to complete There are no new connections allowed,

and connected users that are inactive are disconnected Current

transactions are not rolled backed because of shutdown, and

there is no recovery needed on startup

■ Shutdownabort is a last resort It will bring the database down

fast, but it will abort the current transactions, and uncommitted

transactions are not rolled back before shutting down A media

recovery on startup will be required to roll back the terminated

transactions and clean up these connections

FIGURE 4-5. Creating a listener with the Net Configuration Assistant

FIGURE 4-6. Naming the listener

One listener can listen for all of the databases on the server, so you do not need a listener for every database However, depending on your upgrade

plans or maintenance downtime considerations, it might be useful to have

more than one listener Each listener will need a different port number

The listener must be started before connections from other clients can be made On Windows, the listener is a service, which can be started and

stopped via the Administration panel On both Windows and Linux, the

lsnrctl utility can be used to script the startup and shutdown of the listener,

as in the following example

####TO START####

>lsnrctl start LISTENER

LSNRCTL for 32-bit Windows: Version 11.1.0.6.0 - Production

on 07-FEB-2010 13:49:33

Copyright (c) 1991, 2007, Oracle All rights reserved.

Starting tnslsnr: please wait

TNSLSNR for 32-bit Windows: Version 11.1.0.6.0 – Production

System parameter file is

d:\oracle\product\11.1.0\db_1\network\admin\listener.ora

Log messages written to

d:\oracle\tnslsnr\MMTEST\listener\alert\log.xml

Listening on: (DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)

(HOST=MMTEST.US.demo.com)(PORT=1521)))

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)

(HOST=MMTEST.US.demo.com)(PORT=1521)))

STATUS of the LISTENER

Version TNSLSNR for 32-bit Windows:

Version 11.1.0.6.0 – Production

Start Date 07-FEB-2010 13:49:35

Uptime 0 days 0 hr 0 min 3 sec

Trace Level off

Security ON: Local OS Authentication

Listener Parameter File

D:\oracle\product\11.1.0\db_1\network\admin\listener.ora

Listener Log File

D:\oracle\tnslsnr\MMTEST\listener\alert\log.xml

Listening Endpoints Summary (DESCRIPTION=(ADDRESS=

(PROTOCOL=tcp)(HOST=MMTEST.US.demo.com)(PORT=1521)))

The listener supports no services

The command completed successfully

####CHECK STATUS####

>lsnrctl status listener_name

LSNRCTL for 32-bit Windows: Version 11.1.0.6.0 – Production

on 07-FEB-2010 13:50:00

Copyright (c) 1991, 2007, Oracle All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)

(HOST=MMTEST.US.demo.com)(PORT=1521)))

STATUS of the LISTENER

Version TNSLSNR for 32-bit Windows:

Version 11.1.0.6.0 – Production

Start Date 07-FEB-2010 13:49:35

Uptime 0 days 0 hr 0 min 25 sec

Trace Level off

Security ON: Local OS Authentication

Listener Parameter File

D:\oracle\product\11.1.0\db_1\network\admin\listener.ora

Listener Log File

D:\oracle\tnslsnr\MMTEST\listener\alert\log.xml

Listening Endpoints Summary

(DESCRIPTION=(ADDRESS=(PROTOCOL=tcp)

(HOST=MMTEST.US.demo.com)(PORT=1521)))

Services Summary

Service "+ASM" has 1 instance(s).

Instance "+ASM", status READY, has 1 handler(s)

for this service

Service "MMDEV" has 1 instance(s).

Instance "MMDEV", status READY, has 1 handler(s)

for this service

The command completed successfully

####TO STOP####

>lsnrctl stop listener_name

LSNRCTL for 32-bit Windows: Version 11.1.0.6.0 – Production

on 07-FEB-2010 14:13:08

Copyright (c) 1991, 2007, Oracle All rights reserved.

Connecting to (DESCRIPTION=(ADDRESS=(PROTOCOL=TCP)

(HOST=MMTEST.US.demo.com)(PORT=1521)))

The command completed successfully

There is also a client piece for the listener, which we will look at in the next chapter

The database is now ready to use, but it might still need some user tablespaces User objects should not be in the SYSTEM tablespaces or

owned be the SYSTEM schema You might develop scripts to add some

regular users, schemas, and tablespaces

Next, we’ll look at choosing a character set for your Oracle database

Choosing a Character Set

An important consideration for your Oracle database is the character set it

uses Before just accepting the default character set, you should do some

research about globalization and the options available, as well as the

application requirements for the character set of the database

For SQL Server, collations are available at the server level and can be

configured down to the column level of a table The SQL Server collations are not only for international characters, but also affect whether the

database is case-sensitive and the sort order

NLS Parameters

In Oracle, the character set choice is governed by which languages the

database needs to support, and separate parameters deal with sort order and case sensitivity: NLS_SORT and NLS_COMP As of Oracle Database 10g, the

CIvalue appended to the NLS_SORT parameter setting will determine if the sort is case-sensitive The NLS_SORT default value is BINARY, and with a

case-insensitive sort setting, it is BINARY_CI Here is a quick sort example using NLS_SORT, which shows the default behavior:

sqlplus> select first_name, last_name from cust1

order by last_name;

first_name last_name

-RANDY EASTWOOD

Laura Eastwood

danimal Johnson

henry johnson

sqlplus> select first_name, last_name from cust1

order by nlssort(last_name,'NLS_SORT=BINARY_CI');

first_name last_name

-Laura Eastwood

RANDY EASTWOOD

henry johnson

danimal Johnson

NLS_SORTcan also be set at the server or session level, instead of including it in the sort of the query

The client and the database can even have different character set settings based on the NLS_LANGUAGE (NLS_LANG) parameter, which has three parts: the language, territory, and character set Here are a few examples: NLS_LANG=AMERICAN_AMERICA.AL32UTF8

NLS_LANG=GERMAN_GERMANY.WE8ISO8859P1

NLS_LANG=FRENCH_CANADA.WE8ISO8859P1

The NLS (National Language Support) parameters are also modifiable at

a session level, so that the sorting and language can be changed by altering the session Here is a quick look at the NLS parameter list:

SQL> select parameter from v$nls_parameters;

PARAMETER

-NLS_CALENDAR

NLS_CHARACTERSET

NLS_COMP

NLS_CURRENCY

NLS_DATE_FORMAT

NLS_DATE_LANGUAGE

NLS_DUAL_CURRENCY

NLS_ISO_CURRENCY

NLS_LANGUAGE

NLS_LENGTH_SEMANTICS

NLS_NCHAR_CHARACTERSET

NLS_NCHAR_CONV_EXCP

NLS_NUMERIC_CHARACTERS

NLS_SORT

NLS_TERRITORY

NLS_TIME_FORMAT

NLS_TIMESTAMP_FORMAT

NLS_TIMESTAMP_TZ_FORMAT

NLS_TIME_TZ_FORMAT

These parameters are useful for globalization and allow you to adjust sorting and languages This is similar to collations on columns and

databases with SQL Server However, the Oracle database is created with the chosen character set It is possible to change a database character set, but it isn’t always an easy process

If different languages need to be supported in the database, the character set needs to be able to handle storing and retrieving the characters for the

language That is also why a Unicode character set, AL32UTF8, is normally selected for databases that must support international languages There is

also a national character setting for NCHAR, NVARCHAR2, and NCLOB This recommended value is AL16UTF16

At this point, you might be thinking, “NLS this and that, sorting,

case-sensitive with Unicode character sets—does this all really mean SQL_

Latin1_General_CPI_CI_AS?” An example might make things clearer First, to handle international characters and support other client character

sets, such as WE8ISO8859P1, the AL32UTF8 character set is recommended Using AL32UTF8, the database will hold multibyte characters Let’s look at the type definition of two columns:

last_name varchar2(20 BYTE),

last_name2 varchar2(20 CHAR)

The last_name column will hold international characters, but it will

hold only 20 bytes So, if any characters are 2 or more bytes, the column

will hold fewer than 20 characters The last_name2 column will hold

20 characters, no matter how many bytes are involved The NLS_LENGTH_ SEMANTICSparameter can be set to BYTE or CHAR for the database level,

or the datatypes can be defined on the column level

For an example for sorting and case sensitivity, consider the following

table, which has some columns for first name, last name, and an updated

date The character set for the database was created as AL32UTF8, and the NLS_LANGparameter was set to AMERICAN_AMERICA.UTF8 on the server side

SQL> select first_name, last_name, entered_date

from mmalcher.example_sort;

FIRST_NAME LAST_NAME ENTERED_D

- -

SQL> select customer_id,last_name,entered_date

from example_sort where last_name='JOHNSON';