Chapter01 Oracle Architecture

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Exploring Oracle Database Administration Oracle Architectural Components and Database Creation

Oracle Architectural Components and

Database Creation

This chapter provides an overview of the Oracle architecture and talks about the various

components that make an Oracle Instance. It also talks about the creation of database andvarious modes of starting and shutting down a database.

SCOPE

1.1Oracle Architecture and its main components1.1.1System Global Area Overview1.1.2Program Global Area (PGA) Overview1.1.3Oracle Processes Overview

1.2Oracle Instance1.3Managing an Oracle Instance1.4Start up and shut down

1.4.1Starting up the database1.4.2Starting up an instance

1.4.3Shutting down a database1.5Alert Log File1.6Setup Password File Authentication1.7Oracle9i Installation Procedure1.8Configure OMF1.9 Prerequisites for database creation

1.9.1Planning for database creation1.9.2Meeting Prerequisites

1.10 Create and manage Initialization parameter files1.10.1Determine the global database name1.10.2Specify Control Files1.10.3Specify database block size1.10.4Setting Initialization parameters that affect the size of SGA1.10.5Specifying the Maximum Number of Processes1.10.6Specifying a method of Undo Space Management1.10.7Managing Initialization parameter files using a server parameter file

1.11 Creating a database manually1.12 Create a database using Oracle Database Configuration Assistant

1.12.1Advantages of using Oracle Database Configuration Assistant:1.12.2Creating a database1.12.3Global Database name and Parameters1.12.4Completing Database Creation1.12.5Deleting a database

1.13Monitor the use of Diagnostic Files

Copyright 2006, Tata Consultancy Services Limited (TCS). 1


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1.1Oracle Architecture and its main components

An Oracle Database is comprised of physical files, memory areas and processes. The

distribution of these components varies depending on the database architecture chosen.

The data in the database is stored in physical files (called data files) on a disk. As it isused that data is stored in the memory. Oracle uses memory areas to improveperformance and to manage the sharing of data between users. The main memory areain the database is called the System Global Area (SGA). To read and write data betweenSGA and data files, Oracle uses a set of background processes that are shared by allusers.

The basic memory structures of Oracle include:

System Global Area (SGA), which is shared by all server and background processes andholds the following:

Database buffer cache

Redo log buffer

Shared pool

Large pool (if configured)

Program Global Areas (PGA), which is private to each server and background process;there is one PGA for each process. The PGA holds the following:

Stack areas Data areas

Fig. 1.1 Oracle Memory Structure

1.1.1 System Global Area Overview



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A system global area (SGA) is a group of shared memory structures that contain dataand control information for one Oracle database instance. If multiple users areconcurrently connected to the same instance, then the data in the instances SGA isshared among the users. Consequently, the SGA is sometimes called the shared globalarea.

An SGA and Oracle processes constitute an Oracle instance. Oracle automaticallyallocates memory for an SGA when you start an instance, and the operating systemreclaims the memory when you shut down the instance. Each instance has its own SGA.

The SGA is read/write. All users connected to a multiple-process database instance canread information contained within the instances SGA, and several processes write to theSGA during execution of Oracle.

The SGA contains the following data structures:

Database buffer cache

Redo log buffer Shared pool

Java pool

Large pool (optional)

Data dictionary cache

Other miscellaneous information

Dynamic SGA

Beginning with Oracle9i, Release 1 (9.0.1), Oracle can change its SGA configurationwhile the instance is running. With the dynamic SGA infrastructure, the sizes of thebuffer cache, the shared pool, and the large pool can be changed without shutting downthe instance.

Dynamic SGA also allows Oracle to set, at run time, limits on how much virtual memoryOracle will use for the SGA. Oracle can start instances under configured and allow theinstance to use more memory by growing the SGA components, up to a maximum ofSGA_MAX_SIZE. If SGA_MAX_SIZE specified in INIT.ORA is less than the sum ofall components specified or defaulted at initialisation time, then the setting ofSGA_MAX_SIZE in INIT.ORA is ignored.

The size of the SGA is determined by several initialisation parameters. The parametersthat most affect SGA size are:

DB_CACHE_SIZE: The size of the cache of standard blocks.

LOG_BUFFER: The number of bytes allocated for the redo log buffer.SHARED_POOL_SIZE: The size in bytes of the area devoted to shared SQL and

PL/SQL statements.



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LARGE_POOL_SIZE: The size of the large pool; the default is 0.

1.1.1.1 Data Base Buffer Cache

The database buffer cache is the portion of the SGA that holds copies of data blocks readfrom data files. All user processes concurrently connected to the instance share access tothe database buffer cache.

The database buffer cache and the shared SQL cache are logically segmented intomultiple sets. This organization into multiple sets reduces contention on multiprocessorsystems.

Size of the Database Buffer Cache

Oracle9i, Release 1 (9.0.1), supports multiple block size in a database. This is the default

block sizethe block size used for the system table space. You specify the standardblock size by setting the initialisation parameter DB_BLOCK_SIZE.

Legitimate values are from 2K to 32K.

To specify the size of the standard block size cache, you set the initialisation parameterDB_CACHE_SIZE. Optionally, you can also set the size for two additional buffer pools,KEEP and RECYCLE, by setting DB_KEEP_CACHE_SIZE andDB_RECYCLE_CACHE_SIZE. These three parameters are independent of one anotherin Oracle9i, Release 1 (9.0.1).

The sizes and numbers of non-standard block size buffers are specified by thefollowing parameters:

DB_2K_CACHE_SIZEDB_4K_CACHE_SIZEDB_8K_CACHE_SIZEDB_16K_CACHE_SIZEDB_32K_CACHE_SIZE

Each parameter specifies the size of the cache for the corresponding block size.

1.1.1.2 Redo Log Buffer

The redo log buffer is a circular buffer in the SGA that holds information about changesmade to the database. This information is stored in redo entries. Redo entries contain theinformation necessary to reconstruct, or redo, changes made to the database by INSERT,UPDATE, DELETE, CREATE, ALTER, or DROP operations. Redo entries are used fordatabase recovery, if necessary.



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Redo entries are copied by Oracle server processes from the users memory space to theredo log buffer in the SGA. The redo entries take up continuous, sequential space in thebuffer. The background process LGWR writes the redo log buffer to the active onlineredo log file (or group of files) on disk.

The initialisation parameter LOG_BUFFER determines the size (in bytes) of the redo log

buffer. In general, larger values reduce log file I/O, particularly if transactions are long ornumerous. The default setting is four times the maximum data block size for the hostoperating system.

1.1.1.3 The Shared Pool

The shared pool portion of the SGA contains three major areas: library cache, dictionarycache, buffers for parallel execution messages, and control structures.

The total size of the shared pool is determined by the initialisation parameterSHARED_POOL_SIZE. The default value of this parameter is 8M on 32-bit platforms

and 64M on 64-bit platforms. Increasing the value of this parameter increases the amountof memory reserved for the shared pool.

Library Cache

The library cache includes the shared SQL areas, private SQL areas (in the case of amultiple transaction server), PL/SQL procedures and packages, and control structuressuch as locks and library cache handles.

Shared SQL Areas

A shared SQL area contains the parse tree and execution plan for a given SQL statement.Oracle saves memory by using one shared SQL area for SQL statements executedmultiple times, which often happens when many users execute the same application.

PL/SQL Program Units and the Shared Pool

Oracle processes PL/SQL program units (procedures, functions, packages, anonymousblocks, and database triggers) much the same way it processes individual SQLstatements. Oracle allocates a shared area to hold the parsed, compiled form of a programunit. Oracle allocates a private area to hold values specific to the session that executes theprogram unit, including local, global, and package variables (also known as packageinstantiation) and buffers for executing SQL. If more than one user executes the same

program unit, then a single, shared area is used by all users, while each user maintains aseparate copy of his or her private SQL area, holding values specific to his or her session.

Dictionary Cache

The data dictionary is a collection of database tables and views containing referenceinformation about the database, its structures, and its users. Oracle accesses the data



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dictionary frequently during SQL statement parsing. This access is essential to thecontinuing operation of Oracle.

The data dictionary is accessed so often by Oracle that two special locations in memoryare designated to hold dictionary data. One area is called the data dictionary cache, also

known as the row cache because it holds data as rows instead of buffers (which holdentire blocks of data). The other area in memory to hold dictionary data is the librarycache. All Oracle user processes share these two caches for access to data dictionaryinformation.

1.1.1.4 Large Pool

The database administrator can configure an optional memory area called the large poolto provide large memory allocations for:

Session memory for the shared server and the Oracle XA interface (used where

transactions interact with more than one database) I/O server processes

Oracle backup and restore operations

Parallel execution message buffers, if the initialisation parameter PARALLEL_AUTOMATIC_TUNING is set to TRUE (otherwise, these buffers are allocated tothe shared pool)

By allocating session memory from the large pool for shared server, Oracle XA, orparallel query buffers, Oracle can use the shared pool primarily for caching shared SQLand avoid the performance overhead caused by shrinking the shared SQL cache.

In addition, the memory for Oracle backup and restore operations, for I/O serverprocesses, and for parallel buffers is allocated in buffers of a few hundred kilobytes.

The large pool is better able to satisfy such large memory requests than the shared pool.The large pool does not have an LRU list. It is different from reserved space in the sharedpool, which uses the same LRU list as other memory allocated from the shared pool.

1.1.2 Program Global Area (PGA) Overview

A program global area (PGA) is a memory region, which contains data and controlinformation for a server process. It is a nonshared memory created by Oracle when a

server process is started. Access to it is exclusive to that server process and is read andwritten only by Oracle code acting on behalf of it. The total PGA memory allocated byeach server process attached to an Oracle instance is also referred to as the aggregatedPGA memory allocated by the instance.Contents of PGA:

Private SQL Area



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A private SQL area contains data such as bind information and runtime memorystructures. Each session that issues a SQL statement has a private SQL area. Each userthat submits the same SQL statement has his/ her own private SQL area that uses a singleshared SQL area. Thus, many private SQL areas can be associated with the same-sharedSQL area.

Cursors and SQL Areas

The application developer of an Oracle precompiler program or OCI program canexplicitly open cursors, or handles to specific private SQL areas, and use them as anamed resource throughout the execution of the program.

Recursive cursors that Oracle issues implicitly for some SQL statements also use sharedSQL areas. The management of private SQL areas is the responsibility of the userprocess. The allocation and deallocation of private SQL areas depends largely on whichapplication tool you are using, although the number of private SQL areas that a userprocess can allocate is always limited by the initialisation parameter OPEN_CURSORS.

The default value of this parameter is 50.

1.1.3 Oracle Processes Overview

This section describes the two types of processes that execute the Oracle server code(server processes and background processes). It also describes the trace files and alertfile, which record database events for the Oracle processes.

Server Processes

Oracle creates server processes to handle the requests of user processes connected to the

instance. In some situations when the application and Oracle operate on the samemachine, it is possible to combine the user process and corresponding server process intoa single process to reduce system overhead. However, when the application and Oracleoperate on different machines, a user process always communicates with Oracle througha separate server process.

Server processes (or the server portion of combined user/server processes) created onbehalf of each users application can perform one or more of the following:

Parse and execute SQL statements issued through the application

Read necessary data blocks from data files on disk into the shared database

buffers of the SGA, if the blocks are not already present in the SGA Return results in such a way that the application can process the information

Background Processes

To maximize performance and accommodate many users, a multiprocess Oracle systemuses some additional Oracle processes called background processes.



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An Oracle instance can have many background processes; not all are always present. Thebackground processes in an Oracle instance include the following:

Database Writer (DBW0 or DBWn)

Log Writer (LGWR)

Checkpoint (CKPT)

System Monitor (SMON) Process Monitor (PMON)

Archiver (ARCn)

Recoverer (RECO)

Lock Manager Server (LMS) - Real Application Clusters only

Queue Monitor (QMNn)

Dispatcher (Dnnn)

Server (Snnn)

On many operating systems, background processes are created automatically when aninstance is started.

Figure 1.2 show how each background process interacts with the different parts of anOracle database, and the rest of this section describes each process.



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Fig 1.2 Showing background process interacting with different parts of oracle database

1.1.3.1 Database Writer Process (DBWn)

The database writer process (DBWn) writes the contents of buffers to data files. TheDBWn processes are responsible for writing modified (dirty) buffers in the database

buffer cache to disk. Although one database writer process (DBW0) is adequate for mostsystems, you can configure additional processes (DBW1 through DBW9) to improvewrite performance if your system modifies data heavily. These additional DBWnprocesses are not useful on uniprocessor systems.

1.1.3.2 Log Writer Process (LGWR)



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The log writer process (LGWR) is responsible for redo log buffer managementwriting the redo log buffer to a redo log file on disk.LGWR writes all redo entries that have been copied into the buffer since the last time itwrote. The redo log buffer is a circular buffer. When LGWR writes redo entries from theredo log buffer to a redo log file, server processes can then copy new entries over the

entries in the redo log buffer that have been written to disk. LGWR normally writes fastenough to ensure that space is always available in the buffer for new entries, even whenaccess to the redo log is heavy.

LGWR writes one contiguous portion of the buffer to disk. LGWR writes:

A commit record when a user process commits a transaction

Redo log buffers1. Every three seconds2. When the redo log buffer is one-third full3. When a DBWn process writes modified buffers to disk, if necessary

1.1.3.3 Checkpoint Process (CKPT)

When a checkpoint occurs, Oracle must update the headers of all data files to record thedetails of the checkpoint. This is done by the CKPT process. The CKPT process does notwrite blocks to disk; DBWn always performs that work.

The statistic DBWR checkpoints displayed by the System_Statistics monitor inOracle Enterprise Manager indicates the number of checkpoint requests completed .

1.1.3.4 System Monitor Process (SMON)

The system monitor process (SMON) performs crash recovery, if necessary, at instancestartup. SMON is also responsible for cleaning up temporary segments that are no longerin use and for coalescing contiguous free extents within dictionary-managed table spaces.If any dead transactions were skipped during crash and instance recovery because of file-read or offline errors, SMON recovers them when the table space or file is brought backonline. SMON wakes up regularly to check whether it is needed. Other processes can callSMON if they detect a need for SMON to wake up.

With Oracle9i Real Application Clusters, the SMON process of one instance can performinstance recovery for a failed CPU or instance.

1.1.3.5 Process Monitor Process (PMON)

The process monitor (PMON) performs process recovery when a user process fails.PMON is responsible for cleaning up the database buffer cache and freeing resources thatthe user process was using. For example, it resets the status of the active transaction table,releases locks, and removes the process ID from the list of active processes.

PMON periodically checks the status of dispatcher and server processes, and restarts anythat have died (but not any that Oracle has terminated intentionally).



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PMON also registers information about the instance and dispatcher processes with thenetwork listener. Like SMON, PMON wakes up regularly to check whether it is neededand can be called if another process detects the need for it.

1.1.3.6 Recoverer Process (RECO)

The recoverer process (RECO) is a background process used with the distributeddatabase configuration that automatically resolves failures involving distributedtransactions. The RECO process of a node automatically connects to other databasesinvolved in an in-doubt distributed transaction.

When the RECO process re-establishes a connection between involved database servers,it automatically resolves all in-doubt transactions, removing from each databasespending transaction table any rows that correspond to the resolved in-doubt transactions.

If the RECO process fails to connect with a remote server, RECO automatically tries to

connect again after a timed interval. However, RECO waits an increasing amount of time(growing exponentially) before it attempts another connection.

The RECO process is present only if the instance permits distributed transactions and ifthe DISTRIBUTED_TRANSACTIONS parameter is greater than zero. If thisinitialisation parameter is zero, RECO is not created during instance startup.

1.1.3.7 Job Queue Processes

Job queue processes are used for batch processing. They execute user jobs. They can beviewed as a scheduler service that can be used to schedule jobs as PLSQL statements or

procedures on an Oracle instance. Given a start date and an interval, the job queueprocesses try to execute the job at the next occurrence of the interval.

Beginning with Oracle9i, Release 1 (9.0.1), job queue processes are manageddynamically. This allows job queue clients to use more job queue processes whenrequired. The resources used by the new processes are released when they are idle.

Dynamic job queue processes can execute a large number of jobs concurrently at a giveninterval. The job queue processes execute user jobs as they are assigned by the CJQprocess. Heres what happens:

1. The coordinator process, named CJQ0, periodically selects jobs that needto be run from the system JOB$ table. New jobs selected are ordered by time.

2. The CJQ0 process dynamically spawns job queue slave processes (J000J999) to execute the jobs.

3. The job queue process executes one of the jobs that were selected by theCJ process for execution. The processes execute one job at a time.



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4. After the process finishes execution of a single job, it polls for more jobs.If there are no scheduled jobs for execution, it enters a sleep state, from which itwakes up at periodic intervals and polls for more jobs. If the process does not findany new jobs, it aborts after a preset interval.

The init.ora parameter JOB_QUEUE_PROCESSES represents the maximum number ofjob queue processes that can concurrently run on an instance. However, clients should notassume that all job queue processes are available for job execution.

1.1.3.8 Archiver Processes (ARCn)

The archiver process (ARCn) copies online redo log files to a designated storage deviceafter a log switch has occurred. ARCn processes are present only when the database is inARCHIVELOG mode, and automatic archiving is enabled.

An Oracle instance can have up to 10 ARCn processes (ARC0 to ARC9). The LGWRprocess starts a new ARCn process whenever the current number of ARCn processes isinsufficient to handle the workload. The ALERT file keeps a record of when LGWRstarts a new ARCn process.

1.1.3.9 Lock Manager Server Process (LMS)

In Oracle9i Real Application Clusters, a Lock Manager Server process (LMS) providesinter-instance resource management.



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Only the database administrator can start up an instance and open the database. If adatabase is open, the database administrator can shut down the database so that it isclosed. When a database is closed, users cannot access the information that it contains.Security for database startup and shutdown is controlled through connections to Oracle

with administrator privileges. Normal users do not have control over the current status ofan Oracle database.

1.3Managing an Oracle Instance

Initialization Parameter Files

To start an instance, Oracle must read an initialisation parameter filea file containinga list of configuration parameters for that instance and database. Set these parameters toparticular values to initialise many of the memory and process settings of an Oracleinstance. Most initialisation parameters belong to one of the

following groups: Parameters that name things (such as files) Parameters that set limits (such as maximums) Parameters that affect capacity (such as the size of the SGA), which are called

variable parameters

Among other things, the initialisation parameters tell Oracle:

The name of the database for which to start up an instance How much memory to use for memory structures in the SGA What to do with filled online redo log files

The names and locations of the databases control files The names of private rollback segments or undo table spaces in the database

The following is an example of a parameter file

DB_BLOCK_BUFFERS = 550DB_NAME = ORAESDDB_DOMAIN = US.ACME.COM#LICENSE_MAX_USERS = 64#CONTROL_FILES = filename1, filename2#

LOG_ARCHIVE_DEST = C:\DESTLOG_ARCHIVE_START = TRUELOG_BUFFER = 64512UNDO_MANAGEMENT = TRUE



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1.4Start up and shut down

1.4.1 Starting up the database

These are the preliminary steps to be performed before attempting to start an instance of

database using SQL*Plus.

1. Start SQL*Plus without connecting to the database:SQLPLUS /NOLOG

2. Connect to Oracle as SYSDBA:CONNECT username/password AS SYSDBA

Now you are connected to Oracle and ready to start up an instance of your database.

Using SQL*Plus to Start Up a Database

You use the STARTUP command to start up a database instance. To start an instance,Oracle must read instance configuration parameters (the initialisation parameters) fromeither a server parameter file or a traditional text initialisation parameter file.

When you issue the STARTUP command with no PFILE clause, Oracle reads theinitialisation parameters from a server parameter file (SPFILE) in a platform-specificdefault location.

Note: For UNIX, the platform-specific default location (directory) for the serverparameter file (or text initialisation parameter file) is:

$ORACLE_HOME/dbs

For Windows NT and Windows 2000 the location is:$ORACLE_HOME\database

In the platform-specific default location, Oracle locates your initialisation parameter fileby examining filenames in the following order:

1. spfile$ORACLE_SID.ora2. spfile.ora

3. init$ORACLE_SID.ora

You can direct Oracle to read initialisation parameters from a traditional text initialisationparameter file, by using the PFILE clause of the STARTUP command.



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For example:

STARTUP PFILE = /home/oracle/product/9.0.1/dbs/inittest1.ora

1.4.2 Starting up an instance

You can start up an instance in these modes:

Start the instance without mounting a database. This does not allow access to thedatabase and usually would be done only for database creation or the re-creation ofcontrol files

Start the instance and mount the database, but leave it closed. This state allows forcertain activities, but does not allow general access to the database.

Start the instance, and mount and open the database. This can be done inunrestricted mode, allowing access to all users, or in restricted mode, allowingaccess for database administrators only.

1.4.2.1 Starting an Instance, and Mounting and Opening a Database

Normal database operation means that an instance is started and the database is mountedand open. This mode allows any valid user to connect to the database and perform typicaldata access operations.

Start an instance, read the initialisation parameters from the default server parameter filelocation, and then mount and open the database by using the STARTUP command byitself.SQL> STARTUP

ORACLE instance started.

Total System Global Area 235693104 bytesFixed Size 279600 bytesVariable Size 167772160 bytesDatabase Buffers 67108864 bytesRedo Buffers 532480 bytesDatabase mounted.Database opened.SQL>



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1.4.2.2 Starting an Instance Without Mounting a Database

You can start an instance without mounting a database. Typically, you do so only duringdatabase creation. Use the STARTUP command with the NOMOUNT option:

SQL> startup nomountORACLE instance started.Total System Global Area 235693104 bytesFixed Size 279600 bytesVariable Size 167772160 bytesDatabase Buffers 67108864 bytesRedo Buffers 532480 bytesSQL>

1.4.2.3 Starting an Instance and Mounting a Database

Start an instance and mount the database, but leave it closed by using the STARTUP

command with the MOUNT option:

SQL> startup mountORACLE instance started.

Total System Global Area 235693104 bytesFixed Size 279600 bytesVariable Size 167772160 bytesDatabase Buffers 67108864 bytesRedo Buffers 532480 bytesDatabase mounted.

1.4.3 Shutting down a database

To shut down a database and instance, you must first connect as SYSOPER or SYSDBA.

There are various modes of shutting down a database.

Shutting down with Normal option Shutting down with Immediate option Shutting down with transactional option Shutting down with abort option



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1.4.3.1 Shutting Down with the NORMAL Option

To shut down a database in normal situations, use the SHUTDOWN command with theNORMAL option:

SQL> shutdown normal;Database closed.Database dismounted.ORACLE instance shut down.SQL>

Normal database shutdown proceeds with the following conditions:

No new connections are allowed after the statement is issued. Before the database is shut down, Oracle waits for all currently connected users

to disconnect from the database.

The next startup of the database will not require any instance recovery procedures.

1.4.3.2 Shutting Down with the IMMEDIATE Option

The immediate database shutdown can be used in the following situations:

To initiate an automated and unattended backup When a power shutdown is going to occur soon When the database or one of its applications is functioning irregularly and you

cannot contact users to ask them to log off or they are unable to log off

To shut down a database immediately, use the SHUTDOWN command with theIMMEDIATE option:

SHUTDOWN IMMEDIATE

Immediate database shutdown proceeds with the following conditions:

No new connections are allowed Any uncommitted transactions are rolled back. Oracle implicitly rolls back active transactions and disconnects all

connected users.

The next startup of the database will not require any instance recovery procedures.

1.4.3.3 Shutting down with Transactional option

To perform a planned shutdown of an instance while allowing active transactions tocomplete first, use the SHUTDOWN command with the TRANSACTIONAL option:

SHUTDOWN TRANSACTIONAL



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Transactional database shutdown proceeds with the following conditions:

No new connections are allowed After all transactions have completed, any client still connected to the instance

is disconnected. At this point, the instance shuts down just as it would when a SHUTDOWN

IMMEDIATE statement is submitted.

1.4.3.4 Shutting down with ABORT Option

When you must do a database shutdown by aborting transactions and user connections,issue the SHUTDOWN command with the ABORT option:

SHUTDOWN ABORT

An aborted database shutdown proceeds with the following conditions:

No new connections are allowed, nor are new transactions allowed to be started, afterthe statement is issued.

Current client SQL statements being processed by Oracle are immediatelyterminated.

Uncommitted transactions are not rolled back. Oracle does not wait for users currently connected to the database to disconnect.

Oracle implicitly disconnects all connected users.The next startup of the database willrequire instance recovery procedures.

1.5Alert Log File

Each server and background process can write to an associated trace file. When a processdetects an internal error, it dumps information about the error to its trace file. Some of theinformation written to a trace file is intended for the database administrator, while otherinformation is for Oracle Support Services. Trace file information is also used to tuneapplications and instances.

The alert file, or alert log, is a special trace file. The alert file of a database is achronological log of messages and errors, which includes the following:

All internal errors (ORA-600), block corruption errors (ORA-1578), anddeadlock errors (ORA-60) that occur

Administrative operations, such as CREATE, ALTER, and DROP statements andSTARTUP, SHUTDOWN, and ARCHIVELOG statements

Several messages and errors relating to the functions of shared server anddispatcher processes

Errors occurring during the automatic refresh of a materialized view The values of all initialisation parameters at the time the database and instance

StartInitialization parameters controlling the location and size of trace files are:



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BACKGROUND_DUMP_DEST USER_DUMP_DEST MAX_DUMP_FILE_SIZE

1.5.1 Specifying the location of Trace and Alert Files

All trace files for background processes and the alert file are written to the destinationdirectory specified by the initialisation parameter BACKGROUND_DUMP_DEST.

All trace files for server processes are written to the destination directory specified by theinitialisation parameter USER_DUMP_DEST. The names of trace files are operatingsystem specific, but each file usually includes the name of the process writing the file(such as LGWR and RECO).

1.6Setup Password File Authentication

Password file can be created by a utility called ORAPWD. This section covers thesetopics.

Using ORAPWD Setting REMOTE_LOGIN_PASSWORDFILE Adding users to Password file Maintaining a password file

1.6.1 Using ORAPWD: Syntax for ORAPWD

orapwdUsage: orapwd file= password= entries=wherefile - name of password file (mand),password - password for SYS (mand),entries - maximum number of distinct DBAs and OPERs (opt),There are no spaces around the equal-to (=) character.

For example, the following command creates a password file namedacct.pwd thatallows up to 30 privileged users with different passwords:ORAPWD FILE=acct.pwd PASSWORD=secret ENTRIES=30



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Following are the description of parameters in ORAPWD utility:

File:

This parameter sets the name of the password file being created. You must specifythe full path name for the file. The contents of this file are encrypted, and the filecannot be read directly. This parameter is mandatory.

Password:

This parameter sets the password for user SYS. If you issue the ALTER USER statementto change the password for SYS after connecting to the database, both the passwordstored in the data dictionary and the password stored in the password file are updated.This parameter is mandatory.

Entries:

This parameter specifies the number of entries that you require the password file toaccept. This number corresponds to the number of distinct users allowed to connect

to the database as SYSDBA or SYSOPER.

1.6.2 Setting Remote_Login_PasswordFile

Apart from creating the Password file , you must also set the initialisation parameterRemote_Login_Passwordfile to an appropriate value. The values are the following:

None:Setting this parameter to NONE causes Oracle to behave as if the password file does not

exist. NONE is the default value for this parameter.

Exclusive:An EXCLUSIVE password file can be used with only one database. Only anEXCLUSIVE file can contain the names of users other than SYS. Using an EXCLUSIVEpassword file allows you to grant SYSDBA and SYSOPER system privileges toindividual users and have them connect as themselves.

Shared:

A SHARED password file can be used by multiple databases. However, the only userrecognized by a SHARED password file is SYS. You cannot add users to a SHAREDpassword file. All users needing SYSDBA or SYSOPER system privileges must connectusing the same name, SYS, and password. This option is useful if you have a single DBA

administering multiple databases.



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1.6.3 Adding Users to Password File:

1. Create a password file using ORAPWD utility following the syntax2. Set the Remote_Login_Passwordfile parameter to EXCLUSIVE

3. Connect with SYSDBA privilege as shown in example

Connect sys/password as sysdba

4. Start up the instance and create the database if necessary, or mount and open anexisting database.

5. Create users as necessary. Grant SYSDBA or SYSOPER privileges.1.6.4 Maintaining a Password file:

This section describes how to:

Expand the number of password file users if the password file becomes full Remove the password file Avoid changing the state of the password file

1.6.4.1 Expanding the number of Password file users:

If you receive the file full error (ORA-1996) when you try to grant SYSDBA orSYSOPER system privileges to a user, you must create a larger password file and re-grant the privileges to the users.

To replace a password file:

Shutdown the database Delete the existing password file Create a new password file using ORAPWD utility with sufficient ENTRIESparameter which u think might be used.

1.6.4.2 Remove the password file

If you determine that you no longer require a password file to authenticate users, you candelete the password file and reset the REMOTE_LOGIN_PASSWORDFILE initialisation

parameter to NONE. After you remove this file, only those users who can be authenticated

by the operating system can perform database administration operations.

1.6.4.3 Changing the state of password file:

The password file state is stored in the password file. When you first create a passwordfile, its default state is SHARED. You can change the state of the password file by settingthe initialisation parameter REMOTE_LOGIN_PASSWORDFILE. When you start up aninstance, Oracle retrieves the value of this parameter from the parameter file stored onyour client machine. When you mount the database, Oracle compares the value of this



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parameter to the value stored in the password file. If the values do not match, Oracleoverwrites the value stored in the file.

1.7Oracle9i Installation Procedure

Oracle Universal Installer Overview

Oracle Universal Installer is a Java-based graphical user interface (GUI) tool that enablesyou to install Oracle components from your CD-ROM. Oracle Universal Installerprovides the following capabilities:

Component and suite installations Web-based installations National language and globalisation support Distributed installation support Unattended "silent" installations using response files Uninstallation of installed components

Multiple Oracle homes support

1.7.1 Oracle9i products for Installation:

Oracle9i has these components.

Oracle9i Database Oracle9i Client Oracle9i Management and Integration

1.7.1.1 Oracle9i database:

The Oracle9i Database is an object-oriented relational database management system,which consists of an Oracle database and an Oracle instance. There are four installationtypes: Enterprise Edition, Standard Edition, Personal Edition, or Custom.

Enterprise Edition: If you select this type, Oracle Universal Installer installs apreconfigured seed database, networking services, licensable Oracle Options, databaseenvironment tools, the Oracle Enterprise Manager framework of management tools,including Console, Management Server, and Intelligent Agent, Oracle utilities, and onlinedocumentation. It also installs those products most commonly used in data warehousingand transaction processing environments.



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Standard Edition: If you select this type, Oracle Universal Installer installs apreconfigured seed database, networking services, Oracle Enterprise Manager frameworkof management tools, including Console, Management Server, and Intelligent Agent, andOracle utilities.

Personal Edition: If you select this type, Oracle Universal Installer installs the samesoftware as the Enterprise Edition installation type, but supports only a single userdevelopment and deployment environment that requires full compatibility with EnterpriseEdition and Standard Edition.

Personal Edition is the only Oracle9i Database installation type that is supported onWindows 98. Note that Oracle Management Server and Intelligent Agent are notsupported on Windows 98.

Custom: If you select this type, Oracle Universal Installer prompts you to selectindividual components to install from the components available with Enterprise Edition,Standard Edition, and Personal Edition installations.

1.7.1.2 Oracle9iClient

The Oracle9i Client is a front-end database application that connects to the databasethrough one or more application servers. There are three Client installation types:

Administrator, Runtime, and Custom.

Administrator: If you select this type, Oracle Universal Installer installs the OracleEnterprise Manager Console, including enterprise management tools, networkingservices, utilities, and basic client software.

Runtime: If you select this type, Oracle Universal Installer installs networking servicesand support files.

Custom: If you select this type, Oracle Universal Installer prompts you to selectindividual components to install from the components available with Administrator andRuntime.

1.7.1.3 Oracle9i Management and Integration

Oracle Management Server is a central processing and distribution system formanagement tasks. It enables distributed control between clients and managed nodes.Oracle Internet Directory is an database-based LDAP v3 directory server. OracleIntegration Server is a suite of software that provides Internet and intranet tools tointegrate applications within and across organizations.

There are four Management and Integration installation types: Oracle ManagementServer, Oracle Internet Directory, Oracle Integration Server, and Custom.



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Oracle Management Server: If you select this type, Oracle Universal Installerinstalls the Oracle Management Server, which processes all system management tasksfrom the Enterprise Manager console and administers the distribution of these tasks toIntelligent Agents on managed nodes across the enterprise. In addition, Oracle UniversalInstaller installs basic client software.

Oracle Internet Directory: If you select this type, Oracle Universal Installer installsa Lightweight Directory Access Protocol (LDAP)-enabled Oracle Internet DirectoryServer, LDAP-enabled client tools, and the Oracle Internet Directory database schema.

Oracle Integration Server: If you select this type, Oracle Universal Installer installsXML-enabled components that integrate enterprise applications. Components includeOracle9i JVM, a workflow engine, and advanced queuing.

Custom: If you select this type, Oracle Universal Installer prompts you to selectindividual components to install from the components available with Oracle Management

Server, Oracle Internet Directory, and Oracle Integration Server.

1.8Configure OMF

Oracle managed files simplifies the administration of an Oracle Database.The following initialisation parameters allow the database server to use the Oraclemanaged files feature:

DB_CREATE_FILE_DEST: Defines the location of the default file system directorywhere Oracle creates data files or tempfiles when no file specification is given in thecreation operation. Also used as the default file system directory for online redo log and

control files if DB_ CREATE_ONLINE_LOG_DEST_ n is not specified.

DB_CREATE_ONLINE_LOG_DEST_n: Defines the location of the default file systemdirectory for online redo log files and control file creation when no file specification isgiven in the creation operation. You can use this initialisation parameter multiple times,where n specifies a multiplexed copy of the online redo log or control file. You canspecify up to five multiplexed copies.

Include the DB_CREATE_FILE_DEST initialisation parameter in your initialisationparameter file to identify the default location for the database server to create:

Data files Tempfiles Online redo log files Control files

The following example sets /u01/oradata/payroll as the defaultdirectory to use when creating Oracle-managed files.



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DB_CREATE_FILE_DEST = '/u01/oradata/payroll'

Setting the DB_CREATE_ONLINE_LOG_DEST_n initialisation parameter in theinitialisation parameter file to identify the default location for the database server tocreate:

Online Redo log files Control Files

DB_CREATE_ONLINE_LOG_DEST_1 = /u02/oradata/payrollDB_CREATE_ONLINE_LOG_DEST_2 = /u02/oradata/payroll

1.9 Prerequisites for database creation

The following topics are to be looked into for database creation

Planning for data base creation Meeting certain prerequisites

1.9.1 Planning for database creation

Plan the database tables and indexes and estimate the amount of space they willrequire.

Plan the layout of the underlying operating system files. Proper distribution of filescan improve database performance dramatically by distributing the I/O for accessingthe files.

Consider using Oracle Managed Files feature to create and manage operating systemsfiles.

Select the global database name, which is the name and location of the databasewithin the network structure. Create the global database name by setting both theDB_ NAME and DB_DOMAIN initialisation parameters.

Select the data base character set

Select the standard database block size. This is specified at database creation by the

DB_BLOCK_SIZE initialisation parameter and cannot be changed after the databaseis created.

Use an undo table space to manage your undo records. Develop a backup and recovery strategy to protect the database from failure. It is

important to protect the control, file by multiplexing, to choose the appropriatebackup mode, and to manage the online and archived redo logs.



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Get Familiar with the options of starting and shutting down an instance and mountingand opening a database.

1.9.2 Meeting Prerequisites

The desired Oracle Software has to be installed.

There should be sufficient memory available to start up the Oracle Instance There should be sufficient disk storage space available on the computer that executes

Oracle.

1.10 Create and manage Initialization parameter files

The following are the initialisation parameters one has to look into before creating adatabase:

Determine the global database name Specify control files

Specify database block sizes Setting Initialization Parameters that affect the size of SGA Specify the maximum number of processes Specify the method of undo space management Setting License Parameters

1.10.1 Determine the global database name

DB_DOMAIN parameter indicates the domain (logical location) within a networkstructure. The combination of the settings for these two parameters must form a databasename that is unique within a network.

For example, to create a database with a global database name of test.us.acme.com, editthe parameters of the new parameter file as follows:

DB_NAME = testDB_DOMAIN = us.acme.com

DB_NAME must be set to a text string of no more than eight characters. During databasecreation, the name provided for DB_NAME is recorded in the data files, redo log files,and control file of the database. If during database instance startup the value of theDB_NAME parameter (in the parameter file) and the database name in the control file are

not the same, the database does not start.

DB_DOMAIN is a text string that specifies the network domain where the database iscreated. This is typically the name of the organization that owns the database.

1.10.2 Specify Control Files



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CONTROL_FILES initialisation parameter has to be included in your new parameter fileand set its value to a list of control filenames to use for the new database. When youexecute the CREATE DATABASE statement, the control files listed in the CONTROL_FILES parameter will be created.



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1.10.3 Specify database block size

The DB_BLOCK_SIZE initialisation parameter specifies the standard block size for thedatabase. This block size is used in creation of SYSTEM table space and by default inother table spaces.

Typically DB_BLOCK_SIZE is set to either 4K or 8K

The block size cannot be changed after database creation, except by re-creating thedatabase. If a databases block size is different from the operating system block size,make the database block size a multiple of the operating systems block size.

For example, if your operating systems block size is 2K (2048 bytes), the followingsetting for the DB_BLOCK_SIZE initialisation parameter is valid:

DB_BLOCK_SIZE=4096

1.10.4 Setting Initialization parameters that affect the size of SGA

DB_CACHE_SIZE Initialization Parameter The DB_CACHE_SIZE initialisationparameter replaces the DB_BLOCK_BUFFERS initialisation parameter that was used inprevious releases. The DB_CACHE_SIZE parameter specifies the size of the cache ofstandard block size buffers, where DB_ BLOCK_SIZE specifies the standard block size.

DB_ nK_CACHE_SIZE Initialization Parameters

The sizes and numbers of non-standard block size buffers are specified by the followinginitialisation parameters:

DB_2K_CACHE_SIZE DB_4K_CACHE_SIZE DB_8K_CACHE_SIZE DB_16K_CACHE_SIZE

Adjusting the Size of the Shared Pool

The SHARED_POOL_SIZE initialisation parameter is a dynamic parameter (in previousreleases it was not dynamic) that allows you to specify or adjust the size of the sharedpool component of the SGA. Oracle selects an appropriate default value.

Adjusting the Size of the Large Pool

The LARGE_POOL_SIZE initialisation parameter is a dynamic parameter (in previousreleases it was not dynamic) that allows you to specify or adjust the size of the large poolcomponent of the SGA. Oracle selects an appropriate default value.

Limiting the size of the SGA:



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The SGA_MAX_SIZE initialisation parameter specifies the maximum size of the SystemGlobal Area for the lifetime of the instance. You can dynamically alter the initialisationparameters affecting the size of the buffer caches, shared pool, and large pool, but only tothe extent that the sum of these sizes and the sizes of the other components of the SGA

(fixed SGA, variable SGA, and redo log buffers) does not exceed the value specified bySGA_MAX_SIZE.

SGA_MAX_SIZE >= DB_CACHE_SIZE + SHARED_POOL_SIZE + LARGE_POOL_SIZE +FIXED SGA + VARIABLE SGA + SIZE OF REDO LOG BUFFERS

1.10.5 Specifying the Maximum Number of Processes

The PROCESSES initialisation parameter determines the maximum number of operatingsystem processes that can be connected to Oracle concurrently. The value of thisparameter must be 6 or greater (5 for the background processes plus 1 for each userprocess). For example, if you plan to have 50 concurrent users, set this parameter to atleast 55.

1.10.6 Specifying a method of Undo Space Management

Undo Management Initialization parameter determines whether an instance will startup in automatic undo management mode where undo is stored in an undo table space, orrollback segment undo mode, where undo is stored in rollback segments. A value ofAUTO enables automatic undo management mode, MANUAL enables rollback segmentundo mode.

UNDO_TABLESPACE Initialization Parameter

When the instance starts up in automatic undo management mode, it selects the firstavailable undo table space in the instance for storing undo. A default undo table spacenamed SYS_UNDOTBS is automatically created when you execute a CREATEDATABASE statement and the UNDO_MANAGEMENT initialisation parameter is setto AUTO. This is the undo table space that Oracle will normally select whenever youstart up the database.

Setting License parameters:

To set the maximum number of concurrent sessions for an instance set the initialisationparameter LICENSE_MAX_SESSIONS in the initialisation parameter file that starts the

instance:



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LICENSE_MAX_SESSIONS = 80

To limit the number of users created in a database, set the LICENSE_MAX_USERSinitialisation parameter in the databases initialisation parameter file, as shown in thefollowing example:

LICENSE_MAX_USERS = 200

1.10.7 Managing Initialization parameter files using a server parameter file

Creating a server parameter file:

CREATE SPFILE='/u01/oracle/dbs/test_spfile.ora'FROM PFILE='/u01/oracle/dbs/test_init.ora';

If a server parameter file of the same name already exists on the server, it isOverwritten with the new information.

Exporting the server parameter file:

The following example creates a text initialisation parameter file from a server parameterfile where the names of the files are specified:

CREATE PFILE='/u01/oracle/dbs/test_init.ora'FROM SPFILE='/u01/oracle/dbs/test_spfile.ora';

1.11 Creating a database manually

Step 1:Decide on the instance identifier

Decide on a unique Oracle System Identifier and set the ORACLE_SID environmentvariable accordingly.

% export ORACLE_SID=mynewdb

The value of DB_NAME initialisation parameter should match the SID setting.

Step 2: Establish the database administrator authentication method

To create a database one should have appropriate system privileges

Step 3: Create the initialisation parameter file

Have a look at the sample initialisation parameter file and edit it accordingly.Store the initialisation parameter file in the Oracles default location.



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Table 1.1 Default parameter file locations

Platform Default Name Default Location

Unix Init$ORACLE_SID.ora $ORACLE_HOME/dbs

NT Init$ORACLE_SID.ora $ORACLE_HOME/database

The initialisation parameter file initmynewdb.ora is stored in the following location:/home/oracle/product/9.0.1/dbs/initmynewdb.ora

Step3.1: Sample Initialization parameter file

#Cache and I/ODB_BLOCK_SIZE =4096DB_CACHE_SIZE=20971520

# Cursors and Library CacheCURSOR_SHARING=SIMILAROPEN_CURSORS=300

# Diagnostics and StatisticsBACKGROUND_DUMP_DEST=/home1/oracle9i/mynewdb/ bdumpCORE_DUMP_DEST=/home1/oracle9i /mynewdb/cdumpTIMED_STATISTICS=TRUEUSER_DUMP_DEST=/home1/oracle9i/mynewdb/udump

# Control File configuration

CONTROL_FILES=("/home1/oracle9i/mynewdb/control/control01.ctl","/home1/oracle9i/mynewdb/control/control02.ctl","/home1/oracle9i/mynewdb/control/control03.ctl")

# Archive

LOG_ARCHIVE_DEST_1='LOCATION=/home1/oracle9i/mynewdb/archive'LOG_ARCHIVE_FORMAT=%t_%s.dbfLOG_ARCHIVE_START=TRUE

# Shared Server# Uncomment and use first DISPATCHES parameter below when your listener is# configured for SSL# (listener.ora and sqlnet.ora)# DISPATCHERS = "(PROTOCOL=TCPS)(SER=MODOSE)",# "(PROTOCOL=TCPS)(PRE=oracle.aurora.server.SGiopServer)"

DISPATCHERS="(PROTOCOL=TCP)(SER=MODOSE)","(PROTOCOL=TCP)(PRE=oracle.aurora.server.SGiopServer)",(PROTOCOL=TCP)



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# Miscellaneous

COMPATIBLE=9.0.0DB_NAME=mynewdb

# Distributed, Replication and Snapshot

DB_DOMAIN=til.comREMOTE_LOGIN_PASSWORDFILE=EXCLUSIVE

# Network RegistrationINSTANCE_NAME=mynewdb

# PoolsJAVA_POOL_SIZE=31457280LARGE_POOL_SIZE=1048576

SHARED_POOL_SIZE=52428800

# Processes and SessionsPROCESSES=150

# Redo Log and RecoveryFAST_START_MTTR_TARGET=300

# Resource ManagerRESOURCE_MANAGER_PLAN=SYSTEM_PLAN

# Sort, Hash Joins, Bitmap IndexesSORT_AREA_SIZE=524288

# System Managed Undo and Rollback SegmentsUNDO_MANAGEMENT=AUTOUNDO_TABLESPACE=undotbs

Step4: Connect to the instance

Start SQL*Plus and connect to your Oracle instance AS SYSDBA.

$ SQLPLUS /nologCONNECT SYS /MANAGER AS SYSDBA

[oracle9i@esdlnx dbs]$ sqlplus /nolog

SQL*Plus: Release 9.0.1.0.0 - Production on Tue Oct 16 16:13:26 2001

(c) Copyright 2001 Oracle Corporation. All rights reserved.



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SQL> connect sys/manage as sysdbaConnected.SQL>

Step5: Start the Instance

Start the instance without mounting the database. This is done only during database

creation or while performing maintenance operations.

Use the Startup command without NOMOUNT option

STARTUP NOMOUNT

At this point, only instance is created and there is no database. Only SGA is created andbackground processes are started in preparation for the creation of new database.

Step6: Issue the Create database statement

To create new database use CREATE DATABASE statement. This statement does thefollowing: Creates the data files for the database Creates the control files for the database Creates the redo log files for the database and establishes the ARCHIVELOG

mode. Creates the SYSTEM table space and the SYSTEM rollback segment Creates the data dictionary Sets the character set that stores data in the database Sets the database time zone Mounts and opens the database for use

The following statement creates database mynewdb:CREATE DATABASE mynewdbMAXINSTANCES 1MAXLOGHISTORY 1MAXLOGFILES 5MAXLOGMEMBERS 5MAXDATAFILES 100DATAFILE '/home1/oracle9i/mynewdb/system01.dbf' SIZE 325M REUSEUNDO TABLESPACE undotbs DATAFILE '/home1/oracle9i/mynewdb/undotbs01.dbf'SIZE 200M REUSE AUTOEXTEND ON NEXT 5120K MAXSIZE UNLIMITEDDEFAULT TEMPORARY TABLESPACE tempts1TEMPFILE '/home1/oracle9i/mynewdb/temps1.dbf'SIZE 50M REUSE AUTOEXTEND ON NEXT 100K MAXSIZE UNLIMITED

CHARACTER SET US7ASCIINATIONAL CHARACTER SET AL16UTF16LOGFILE GROUP 1 ('/home1/oracle9i/mynewdb/redo01.log') SIZE 100M,GROUP 2 ('/home1/oracle9i/mynewdb/redo02.log') SIZE 100M,GROUP 3 ('/home1/oracle9i/mynewdb/redo03.log') SIZE 100M;A database is created with the following characteristics:

The database is named mynewdb



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Three control files are created as specified by CONTROL_FILES initialisationparameter

MAXINSTANCES specified that only one instance can have this database mountedand open.

MAXDATAFILES specifies the maximum number of data files that can be open inthe database.

The SYSTEM table space, consisting of the operating system file/home1/oracle9i/mynewdb/system01.dbf is created as specified by the DATAFILEclause. If the file already exists, it is overwritten.

The UNDO TABLE SPACE clause creates and names an undo table space to be usedfor undo records for this database.

The DEFAULT_TEMPORARY_TABLESPACE clause creates a temporary tablespace.

The US7ASCII character set is used to store data in this database. The AL16UTF16 character set is specified as the NATIONAL CHARACRTER SET

used to store data in columns of specifically defined as NCHAR, NCLOB, orNVARCHAR2.

The new database has three online redo log files as specified in the LOGFILE clause.MAXLOGHISTORY, MAXLOGFILES, and MAXLOGMEMBERS define limits forthe redo log.

As ARCHIVELOG clause is not specified in this CREATE DATABASE statement,redo log files will not initially be archived.

The default database time zone is the same as the operating systems time zone. You set the databases default time zone by specifying the SET TIME_ZONE clause

of the CREATE DATABASE statement. If omitted (as it is in this case), the defaultdatabase time zone is the operating system time zone.

Step7: Create Additional table spaces

To make the database functional, you need to create additional files and table spaces forusers. The following sample script creates some additional table spaces:

CONNECT SYS/ password AS SYSDBA

-- create a user table space to be assigned as the default table space for users

CREATE TABLESPACE users LOGGINGDATAFILE '/home1/oracle9i/mynewdb/users01.dbf'SIZE 25M REUSE AUTOEXTEND ON NEXT 1280K MAXSIZE UNLIMITED

EXTENT MANAGEMENT LOCAL;

-- Create a table space for indexes, separate from user table space

CREATE TABLESPACE indx LOGGINGDATAFILE '/home1/oracle9i/mynewdb/indx01.dbf'SIZE 25M REUSE AUTOEXTEND ON NEXT 1280K MAXSIZE UNLIMITEDEXTENT MANAGEMENT LOCAL;



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Step8: Run scripts to create Data Dictionary Views:

Run the scripts necessary to build views, synonyms, and PL/SQL packages:CONNECT SYS/ password AS SYSDBA

@/home/oracle/product/9.0.1/rdbms/admin/catalog.sql;@/home/oracle/product/9.0.1/rdbms/admin/catproc.sql;

EXIT

CATALOG.SQL Creates the views of the data dictionary tables, the dynamic

Performance views, and public synonyms for many of the views.Grants PUBLIC access to the synonyms.

CATPROC.SQL Runs all scripts required for or used with PL/SQL.

Step9: Create Server parameter file:

CONNECT SYS/ password AS SYSDBA-- Create the server parameter file

CREATE SPFILE=' /home/oracle/product/9.0.1/spfilemynewdb.ora' FROMPFILE='/home/oracle/product/9.0.1/initmynewdb.ora';

SHUTDOWN

This time you will start up using the server parameter file

CONNECT SYS/ password AS SYSDBASTARTUP

Step10: Back up the database

Take the back up of the database.



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1.12.3 Global Database name and Parameters

You are guided thorough a series of pages that allow you to further define your databaseor to accept default parameter values and file locations as recommended by Oracle. You

provide a global database name, specify database options to include, determine mode(dedicated server of shared server), and ultimately you can specify initialisationparameter.

Typical: This creates a database with minimal user input. You do not specify specificinitialisation parameter values; instead, you specify the maximum number of concurrentusers, the percentage of physical memory reserved for Oracle, and a database type(OLTP, Multipurpose or Data Warehousing).

Custom: Custom allows you to specify initialisation parameter values that affect the sizeof the System Global Area (SGA). Very experienced database administrators who havespecific tuning needs can use it

1.12.4 Completing Database Creation

After you have completed the specification of the parameters that define your databaseyou can:

Create the database Save the description as database template Generate database creation scripts.

1.12.5 Deleting a database

The Oracle Database Configuration Assistant enables you to delete a database.When you do so, you delete the database instance and its control file(s), redo log files,and data files. The initialisation parameter file is not deleted.

1.13 Monitor the use of Diagnostic Files

Trace Files: Background processes always write to a trace file when appropriate. In thecase of the ARCn background process, it is possible, through an initialisation parameter,to control the amount and type of trace information that is produced.

Trace files are written on behalf of server processes whenever internal errors occur.Additionally, setting the initialisation parameter SQL_TRACE = TRUE causes the SQLtrace facility to generate performance statistics for the processing of all SQL statementsfor an instance and write them to the USER_DUMP_DEST directory.

Optionally, trace files can be generated for server processes at user request. Regardless ofthe current value of the SQL_TRACE initialisation parameter, each session can enable or



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disable trace logging on behalf of the associated server process by using the SQLstatement ALTER SESSION SET SQL_TRACE. This example enables the SQL tracefacility for a specific session:

ALTER SESSION SET SQL_TRACE TRUE;

The DBMS_SESSION and DBMS_SYSTEM packages can also be used to control SQLtracing for a session.



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SUMMARY

An Oracle Data base is comprised of physical files, memory andprocesses.

A system global area (SGA) is a group of shared memory structures thatcontain data and control information for one Oracle database instance.

The database buffer cache is the portion of the SGA that holds copies ofdata blocks read from data files.

The redo log buffer is a circular buffer in the SGA that holds informationabout changes made to the database.

The total size of the shared pool is determined by the initialisationparameter SHARED_POOL_SIZE.

A shared SQL area contains the parse tree and execution plan for a givenSQL statement.

A program global area (PGA) is a memory region, which contains dataand control information for a server process.

The database writer process (DBWn) writes the contents of buffers todata files. The DBWn processes are responsible for writing modified (dirty) buffers inthe database buffer cache to disk

The log writer process (LGWR) is responsible for redo log buffermanagementwriting the redo log buffer to a redo log file on disk.

The system monitor process (SMON) performs crash recovery, ifnecessary, at instance startup.

The process monitor (PMON) performs process recovery when a userprocess fails.

The recoverer process (RECO) is a background process used with thedistributed database configuration that automatically resolves failures involving

distributed transactions. The archiver process (ARCn) copies online redo log files to a designatedstorage device after a log switch has occurred. ARCn processes are present only whenthe database is in ARCHIVELOG mode, and automatic archiving is enabled.

The queue monitor process is an optional background process for OracleAdvanced Queuing, which monitors the message queues.

Oracle allocates a memory area called the System Global Area (SGA) andstarts one or more Oracle processes. This combination of the SGA and the Oracleprocesses is called an Oracle instance.

The command for starting an instance without mounting the database isSTARTUP NOMOUNT.

The command for starting an instance and mounting the database isSTARTUP MOUNT.

To shut down the database in normal conditions the command used isSHUTDOWN NORMAL.

To shutdown the database immediately use SHUTDOWN IMMEDIATEcommand.

The parameters which control the location and size of trace files are:



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BACKGROUND_DUMP_DEST USER_DUMP_DEST MAX_DUMP_FILE_SIZE

Password file can be created by a utility called ORAPWD.

Oracle Universal Installer is a Java-based graphical user interface (GUI)tool that enables you to install Oracle components from your CD-ROM.

The DB_BLOCK_SIZE initialisation parameter specifies the standardblock size for the database. This block size is used in creation of SYSTEM tablespace and by default in other table spaces.

The PROCESSES initialisation parameter determines the maximumnumber of operating system processes that can be connected to Oracle concurrently.



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LABEXERCISES

1. Write a script for creation of database with the following configuration:i. Database name and Instance name: TESTDBii. One control file named control01.con located in the directory

"/home1/oracle9i/testdb/control/control01.ctl"

iii. Two redo log file groups each one 150K member named log1a.rdo andlog2a.rdo located in the directory '/home1/oracle9i/testdb/redo01.log'The maximum number of five logs files groups and five log file Members foreach groupiv. A 20M data file named system01.dbf and located in/home1/oracle9i/testdb/system01.dbf' directoryv. Maximum of 30 data files that can be created for the databasevi. A maximum number of 100 archived redo logs for automatic mediarecoveryvii. The Character set WE8ISO8859P1viii. The Trace file location should be in the BDUMP and CDUMP

directory.

2. Create additional table spaces called users and indx3. Create the data dictionary views.4. Where is the existing control file and what is its name5. Try to start the database without the control file. What happens?

Documents

Chapter01 Oracle Architecture