Starting Shared Server

Question: Does a DBA need to start "Oracle Shared Server" before beginning to use SQL *Plus?
A DBA needs to start Oracle Shared Server before beginning to use SQL*Plus. SQL*Plus is a client application that connects to the Oracle database server to perform SQL operations. In order to connect to the database server, SQL*Plus needs the database server to be running. Oracle Shared Server is a type of database server architecture that uses a pool of shared server processes to handle client requests. When a client application connects to the database, it is assigned to a shared server process. The shared server process then executes the SQL statements issued by the client application.
To start Oracle Shared Server, a DBA can use the following command:

$ORACLE_HOME/bin/oracle -shared_servers

This will start the database in shared server mode with the default number of shared server processes. The DBA can also specify a custom number of shared server processes using the `-shared_servers` parameter. Once Oracle Shared Server is running, a DBA can connect to the database using SQL*Plus or another client application.
Example:

$ sqlplus /nolog
SQL> SET SERVERNAME=localhost/ORCL;
SQL> CONNECT scott@localhost/ORCL SHARED_SERVERS;
Enter password: tiger

Connected to:
Oracle Database 19c Enterprise Edition Release 19.0.0.0.0 - Production
Version 19.3.0.0.0 - 64bit Production

SQL>

If Oracle Shared Server is not running, a DBA will not be able to connect to the database using SQL*Plus or another client application.

We have been through a lot of work just to figure out the command to start a program. You should now know the name for your Server Manager executable, so let us start it. If you are not running Oracle software, just make sure you know the executable name for the version that you will eventually be running. If you are running Oracle, go ahead and issue the command. If you are on Windows, you will need to open a command prompt window first.
The following example was done under NT using Oracle release 8.0.4:
The following commands have been deprecated since Oracle Server Manager has been retired since Oracle 9i.

C:\ORANT\BIN>svrmgr30
Oracle Server Manager Release 3.0.4.0.0 - Production
(c) Copyright 1998, Oracle Corporation.
All Rights Reserved.
Oracle8 Release 8.0.4.0.0 - Production
PL/SQL Release 8.0.4.0.0 - Production
SVRMGR>

After you start Server Manager, the next step is to connect to a database. You can do this by using the CONNECT command. The following example shows one way to connect to your default database. The internal keyword tells Server Manager that you want to connect as an administrative user.

There are two basic ways to connect to an Oracle database:

1. as an administrative user and
2. as a normal user.

For 90% of the tasks that you do, you will find that you can connect either way and it will not matter. Any priviledged user can connect normally to the database and still be able to

1. run queries,
2. create and alter schema objects.

However, to start up or shut down a database, recover a database, or create a new database, you must be connected as an administrator.
The keyword internal represents one way to tell Server Manager that you want to connect as an administrator. Two other keywords may also be used. These are

1. SYSDBA and
2. SYSOPER.

In order to use SYSDBA and SYSOPER, you must configure a database password file. We will do that in, Managing Users and Connectivity, the next course in this series.

SQL> connect internal

Depending on choices that you made when you installed Oracle, you might be prompted for a password.
This is a special password known as the internal password. The default for that password is “oracle,” but if you chose a different internal password when you installed Oracle, use that. If someone else created this database, and you do not know the internal password, then you should ask the person who created the database to help you connect to it.
Go ahead and try connecting to your default database. There exists a GUI version of Server Manager, but we will not address the GUI version in this course.

For UNIX users, Oracle supplies a GUI version of Server Manager. The command to start it is: svrmgrm.
The “m” at the end of the command stands for “Motif”.
Motif is an X-Windows-based windowing manager that you need in order to use the GUI version.
To start the GUI version of Server Manager from an X-windows client, you first open a Telnet session, then issue the svrmgrm command.
I do not emphasize learning the GUI version of Server Manager because it's not a strategic product for Oracle. Enterprise Manager is Oracle's flagship database administration tool, and it's GUI-based. If you want to learn a GUI administration tool, you are much better off focusing your efforts on learning Enterprise Manager, and in the next course of this series you will begin to do just that.

In 1996, Oracle made a first attempt at releasing a GUI tool to manage its databases. This was Oracle Server Manager, which featured a

1. command line and
2. GUI interface.

Grid Control