Starting Up a Database

Starting Up a Database Using SQL*Plus

You can start a SQL*Plus session, connect to Oracle Database with administrator privileges, and then issue the STARTUP command. Using SQL*Plus in this way is the only method described in detail in this book.

Starting Up a Database Using Recovery Manager

You can also use Recovery Manager (RMAN) to execute STARTUP and SHUTDOWN commands. You may prefer to do this if your are within the RMAN environment and do not want to invoke SQL*Plus.

Starting Up a Database Using Oracle Enterprise Manager

You can use Oracle Enterprise Manager (EM) to administer your database, including starting it up and shutting it down. EM combines a GUI console, agents, common services, and tools to provide an integrated and comprehensive systems management platform for managing Oracle products. EM Database Control, which is the portion of EM that is dedicated to administering an Oracle database, enables you to perform the functions discussed in this book using a GUI interface, rather than command line operations.

The remainder of this section describes using SQL*Plus to start up a database instance.

Starting Up a Database Using SRVCTL

When Oracle Restart is installed and configured for your database, Oracle recommends that you use SRVCTL to start the database. This ensures that:

• Any components on which the database depends (such as Oracle Automatic Storage Management and the Oracle Net listener) are automatically started first, and in the proper order.

• The database is started according to the settings in its Oracle Restart configuration. An example of such a setting is the server parameter file location.

• Environment variables stored in the Oracle Restart configuration for the database are set before starting the instance.

See "srvctl start database" and "Starting and Stopping Components Managed by Oracle Restart" for details.

About Initialization Parameter Files and Startup

When you start the database instance, it attempts to read the initialization parameters from an SPFILE in a platform-specific default location. If it finds no SPFILE, it searches for a text initialization parameter file.

Table 2-4 lists PFILE and SPFILE default names and locations.

In the platform-specific default location, Oracle Database locates your initialization parameter file by examining file names in the following order:

1. spfileORACLE_SID.ora

2. spfile.ora

3. initORACLE_SID.ora

The first two files are SPFILEs and the third is a text initialization parameter file. If DBCA created the SPFILE in an Oracle Automatic Storage Management disk group, the database searches for the SPFILE in the disk group.

If you (or the Database Configuration Assistant) created a server parameter file, but you want to override it with a text initialization parameter file, you can do so with SQL*Plus, specifying the PFILE clause of the STARTUP command to identify the initialization parameter file:

STARTUP PFILE = /u01/oracle/dbs/init.ora

Non-Default Server Parameter Files A non-default server parameter file (SPFILE) is an SPFILE that is in a location other than the default location. It is not usually necessary to start an instance with a non-default SPFILE. However, should such a need arise, both SRVCTL (with Oracle Restart) and SQL*Plus provide ways to do so. These are described later in this section.

Initialization Files and Oracle Automatic Storage Management A database that uses Oracle Automatic Storage Management (Oracle ASM) usually has a non-default SPFILE. If you use the Database Configuration Assistant (DBCA) to configure a database to use Oracle ASM, DBCA creates an SPFILE for the database instance in an Oracle ASM disk group, and then causes a text initialization parameter file (PFILE) to be created in the default location in the local file system to point to the SPFILE, as explained in the next section.

Starting Up with SQL*Plus with a Non-Default Server Parameter File

With SQL*Plus you can use the PFILE clause to start an instance with a non-default server parameter file.

To start up with SQL*Plus with a non-default server parameter file:

1. Create a one-line text initialization parameter file that contains only the SPFILE parameter. The value of the parameter is the non-default server parameter file location.

   For example, create a text initialization parameter file /u01/oracle/dbs/spf_init.ora that contains only the following parameter:

   SPFILE = /u01/oracle/dbs/test_spfile.ora
   

   Note:

   You cannot use the IFILE initialization parameter within a text initialization parameter file to point to a server parameter file. In this context, you must use the SPFILE initialization parameter.

2. Start up the instance pointing to this initialization parameter file.

   STARTUP PFILE = /u01/oracle/dbs/spf_init.ora
   

The SPFILE must reside on the database host computer. Therefore, the preceding method also provides a means for a client machine to start a database that uses an SPFILE. It also eliminates the need for a client machine to maintain a client-side initialization parameter file. When the client machine reads the initialization parameter file containing the SPFILE parameter, it passes the value to the server where the specified SPFILE is read.

Starting Up with SRVCTL with a Non-Default Server Parameter File

If your database is being managed by Oracle Restart, you can specify the location of a non-default SPFILE by setting or modifying the SPFILE location option in the Oracle Restart configuration for the database.

To start up with SRVCTL with a non-default server parameter file:

1. Prepare to run SRVCTL as described in "Preparing to Run SRVCTL".

2. Enter the following command:

   srvctl modify database -d db_unique_name -p spfile_path
   

   where db_unique_name must match the DB_UNIQUE_NAME initialization parameter setting for the database.

3. Enter the following command:

   srvctl start database -d db_unique_name [options]
   

See "SRVCTL Command Reference" for more information.

Starting an Instance, and Mounting and Opening a Database

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

The following command starts an instance, reads the initialization parameters from the default location, and then mounts and opens the database.

STARTUP

srvctl start database -d db_unique_name

where db_unique_name matches the DB_UNIQUE_NAME initialization parameter.

Starting an Instance Without Mounting a Database

You can start an instance without mounting a database. Typically, you do so only during database creation. Use one of the following commands:

STARTUP NOMOUNT

srvctl start database -d db_unique_name -o nomount

Starting an Instance and Mounting a Database

You can start an instance and mount a database without opening it, allowing you to perform specific maintenance operations. For example, the database must be mounted but not open during the following tasks:

• Enabling and disabling redo log archiving options. For more information, please refer to Chapter 12, "Managing Archived Redo Logs".

• Performing full database recovery. For more information, please refer to Oracle Database Backup and Recovery User's Guide

The following command starts an instance and mounts the database, but leaves the database closed:

STARTUP MOUNT

srvctl start database -d db_unique_name -o mount

Restricting Access to an Instance at Startup

You can start an instance, and optionally mount and open a database, in restricted mode so that the instance is available only to administrative personnel (not general database users). Use this mode of instance startup when you need to accomplish one of the following tasks:

• Perform an export or import of data

• Perform a data load (with SQL*Loader)

• Temporarily prevent typical users from using data

• Perform certain migration or upgrade operations

Typically, all users with the CREATE SESSION system privilege can connect to an open database. Opening a database in restricted mode allows database access only to users with both the CREATE SESSION and RESTRICTED SESSION system privilege. Only database administrators should have the RESTRICTED SESSION system privilege. Further, when the instance is in restricted mode, a database administrator cannot access the instance remotely through an Oracle Net listener, but can only access the instance locally from the machine that the instance is running on.

The following command starts an instance (and mounts and opens the database) in restricted mode:

STARTUP RESTRICT

srvctl start database -d db_unique_name -o restrict

You can use the restrict mode in combination with the mount, nomount, and open modes.

Later, use the ALTER SYSTEM statement to disable the RESTRICTED SESSION feature:

ALTER SYSTEM DISABLE RESTRICTED SESSION;

If you open the database in nonrestricted mode and later find that you need to restrict access, you can use the ALTER SYSTEM statement to do so, as described in "Restricting Access to an Open Database".

Forcing an Instance to Start

In unusual circumstances, you might experience problems when attempting to start a database instance. You should not force a database to start unless you are faced with the following:

• You cannot shut down the current instance with the SHUTDOWN NORMAL, SHUTDOWN IMMEDIATE, or SHUTDOWN TRANSACTIONAL commands.

• You experience problems when starting an instance.

If one of these situations arises, you can usually solve the problem by starting a new instance (and optionally mounting and opening the database) using one of these commands:

STARTUP FORCE

srvctl start database -d db_unique_name -o force

If an instance is running, the force mode shuts it down with mode ABORT before restarting it. In this case, the alert log shows the message "Shutting down instance (abort)" followed by "Starting ORACLE instance (normal)."

Starting an Instance, Mounting a Database, and Starting Complete Media Recovery

If you know that media recovery is required, you can start an instance, mount a database to the instance, and have the recovery process automatically start by using one of these commands:

STARTUP OPEN RECOVER

srvctl start database -d db_unique_name -o "open,recover"

If you attempt to perform recovery when no recovery is required, Oracle Database issues an error message.

Automatic Database Startup at Operating System Start

Many sites use procedures to enable automatic startup of one or more Oracle Database instances and databases immediately following a system start. The procedures for performing this task are specific to each operating system. For information about automatic startup, see your operating system specific Oracle documentation.

Beginning with Oracle Database 11g Release 2, the preferred (and platform-independent) method of configuring automatic startup of a database is Oracle Restart. See Chapter 4, "Configuring Automatic Restart of an Oracle Database" for details.

Starting Remote Instances

If your local Oracle Database server is part of a distributed database, you might want to start a remote instance and database. Procedures for starting and stopping remote instances vary widely depending on communication protocol and operating system.