Startup and Shutdown the database
As long as the parameter computer file (initialization parameter file) is in the standard place start-up control can be accomplished without the ‘pfile=’ parameter.
Platform-specific standard place is $ORACLE_HOME/dbs on UNIX, $ORACLE_HOMEdatabase on NT.
Using SPFILE is recommended by Oracle to start-up data source.
Doc Id of Metalink 166601.1 says on SPFILE and PFILE:
A server parameter computer file (SPFILE) can be thought of as a database for initialization factors that is managed on the machine where the Oracle data source server carries out. It is, by design, a server-side initialization parameter computer file. Initialization factors saved in a server parameter computer file are chronic, in that any changes made to the factors while an example is running can continue to persist across example shut down and start-up. This removes the need to personally upgrade initialization factors to make changes impacted by ALTER SYSTEM claims chronic.
It also provides a basis for self-tuning by the Oracle data source server.
1. Development of the Spfile from a Pfile First of all you have to produce a server parameter computer file (spfile).
2. The spfile must be created from a conventional written text initialization parameter computer file (pfile).
3. You must have the SYSDBA or the SYSOPER system benefit to produce a spfile.
The control can be accomplished either before or after example start-up.
CREATE SPFILE [= '<spfile_name>'] FROM PFILE [= '<pfile_name>'];
SQL> CREATE SPFILE FROM PFILE = ‘initV901.ora';
Creates a spfile called spfileV901.ora in the platform-specific default location
$ORACLE_HOME/dbs on UNIX, $ORACLE_HOME\database on NT
If you do not specify spfile_name, Oracle uses the platform-specific standard server parameter filename. If there is an existence of spfile_name already on the server, this statement will overwrite it. When using a standard server parameter pc data file, you begin up the data source without referring to the pc data file by name. If you do specify spfile_name, you are creating a non-default server parameter pc data file. In this case, to begin up the data source, you must first create a single-
line traditional parameter pc data file that points to the server parameter pc data file, and then name the single-line pc data file in your STARTUP command.
If the data source is using a spfile and you want to produce a new one in the same place you get an
ORA-32002: cannot make SPFILE already being used by the instance
Starting Up the Database
When you problem the STARTUP control with no PFILE stipulation, Oracle flows the initialization factors from a SPFILE in a platform-specific standard place.
For UNIX, the platform-specific standard place for the spfile or pfile is: $ORACLE_HOME/dbs For Ms windows NT and Ms windows 2000 the place is: $ORACLE_HOMEdatabase
In the platform-specific standard place, Oracle detects your initialization parameter computer file by analyzing filenames in the following order:
You can also specify the SPFILE in a PFILE. This is the only way to begin the example with an SPFILE in a non standard place. The access in the PFILE would look like:
Start an instance
– flows initialization parameter file
When Oracle starts an example, it flows the initialization parameter information file to determine the values of initialization factors. Then, it allocates an SGA, which is a shared area of storage used for information source information, and creates background procedures. At this stage, no information source is associated with these storage structures and procedures.
Mount the database
– flows management information file to identify the information files
Mounting of the information source means associating the started example with the specified information source by Oracle. The example installs the management declare a information source but does not start the information source.
In grouped and massively parallel systems (MPS), Actual Program Groups enable several circumstances to install a single information source.
The example installs a information source to associate the information source with that example. To install the information source, the example finds the information source management information files and reveals them. Control information files are specified in the CONTROL_FILES initialization parameter in the parameter information file used to begin with the example. Oracle then flows the management information files to get the names of the database’s datafiles and upgrade log information files.
At this aspect, the information source is still shut and is available only to the information source manager. The information source manager can keep the information source shut while completing specific maintenance functions. However, the information source is not yet available for regular functions.
In the situation of grouped database
When Oracle is to allow allows several circumstances to install the same information source concurrently, then the information source manager can use the initialization parameter CLUSTER_DATABASE to make the information source available to several circumstances. The standard value of the CLUSTER_DATABASE parameter is fake. Versions of Oracle that do not support Actual Program Groups only allow CLUSTER_DATABASE to be incorrect.
If CLUSTER_DATABASE is fake for the first example that installs a information source, thne only that example can install the information source. If CLUSTER_DATABASE is set to real on the first example, then other circumstances can install the information source if their CLUSTER_DATABASE factors are set to real. The number of circumstances that can install the information source is subject to a predetermined maximum, which you can specify when creating the information source.
In the situation of stand by database
The stand by information source is constantly in restoration method. To maintain your stand by information source, you must install it in stand by method using the ALTER DATABASE declaration and apply the stored upgrade records that your main information source generates.
You can begin a stand by information source in read-only method to use it as a temporary reporting information source. You cannot start a stand by information source in read/write method.
In the situation of a cloned database
When you execute tablespace point-in-time restoration, you install the replicated information source and recover the tablespaces to the desired time, then export metadata from the replicated to the main information source and copy the datafiles from the recovered tablespaces
This method of the information source helps execute following tasks
1. Renaming datafiles.
2. Adding, dropping, or renaming upgrade log files
3. Enabling and disabling upgrade log archiving options
4. Performing full information source recovery
Open the database
When you start the information source, Oracle reveals the internet datafiles and on the internet upgrade log information files. If a tablespace was off-line when the information source was previously shut down, the tablespace and its corresponding datafiles will still be off-line when you reopen the information source.
If any of the datafiles or upgrade log information files are not present when you attempt to begin with the information source, then Oracle returns an error. You must execute restoration on a backup of any damaged or missing information files before you can begin the information source.
The standard for start-up is to OPEN the information source in user mode
Oracle ends the information source.
Oracle Un-mounts the information source.
Then Oracle shuts down the example.
When you near a information source, Oracle writes all information source information and restoration information in the SGA to the datafiles and upgrade log information files, respectively. Next, Oracle ends all on the internet datafiles and on the internet upgrade log information files. (Any off-line datafiles of any off-line tablespaces have been shut already. If you subsequently reopen the information source, any tablespace that was off-line and its datafiles stay off-line and shut, respectively.) At this stage, the information source is shut and inaccessible for regular functions. The management information files stay start after a information source is shut but still installed.
After the information source is shut, Oracle un-mounts the information source to disassociate it from the example. At this stage, the example remains in the storage of your computer. After a information source is un-mounted, Oracle ends the management information files of the information source.
The start-up conditions let you install and start the information source so that it is available to customers.
Use the MOUNT stipulation to install the information source. Do not use this stipulation when the information source is installed.
MOUNT STANDBY DATABASE
Specify MOUNT STANDBY DATABASE to install a physical stand by information source. As soon as this declaration executes, the stand by example can receive stored upgrade records from the main example and can archive the records to the STANDBY_ARCHIVE_DEST location.
MOUNT CLONE DATABASE
Specify MOUNT CLONE DATABASE to install the replicated information source.
Use the OPEN stipulation to make the information source available for regular use. You must install the information source before you can begin it up.
If you specify only OPEN, without any other keywords, the standard is OPEN READ WRITE NORESETLOGS.
Specify READ WRITE to begin with the information source in read/write method, allowing customers to generate upgrade records. This is the standard. You can join the oracle dba training or the oracle training to make your profession in this field.