Oracle8i Parallel Server Setup and Configuration Guide
Release 2 (8.1.6)

Part Number A76934-01





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administrative context

A directory entry under which an Oracle Context (cn=OracleContext) resides. During directory access configuration, clients are configured with an administrative context in the directory configuration file,ldap.ora. The administrative context specifies the location of the Oracle Context in the directory whose entries a client expects to access

alert file

A file that contains important information about error messages and exceptions that occur during database operations.

BSP0 process

A process that manages out-going messages to requesting nodes for Cache Fusion.


A set of instances, each typically running on different nodes, that coordinate with one another when accessing the shared database residing on disk.

Cluster Manager (CM)

An Operating System Dependent component that discovers and tracks the membership state of nodes by providing a common view of cluster membership across the cluster.

CM monitors process health, specifically the health of the Oracle8i release 8.1 database instance. The LMON process, a background process that monitors the health of the Distributed Lock Manager (DLM), registers and de-registers from CM.

connect descriptor

A specially formatted description of the destination for a network connection. A connect descriptor contains destination service and network route information.

The destination service is indicated by using its service name for Oracle release 8.1 database or its Oracle System Identifier (SID) for Oracle release 8.0 or version 7 databases. The network route provides, at a minimum, the location of the listener through use of a network address.

connect identifier

A net service name or service name, that resolves to a connect descriptor. Users initiate a connect request by passing a user name and password along with a connect identifier in a connect string for the service to which they wish to connect, for example:

CONNECT username/password@connect_identifier

connection load balancing

A feature that balances the number of active connections among various instances and MTS dispatchers for the same service. Because of service registration's ability to register with remote listeners, a listener is always aware of all instances and dispatchers regardless. This way, a listener can sends an incoming client request for a specific service to the least loaded instance and least loaded dispatcher regardless of its location.

connect-time failover

A client connect request is forwarded to a another listener if first listener is not responding. Connect-time failover is enabled by service registration, because the listener knows if an instance is up prior to attempting a connection.


The Oracle Enterprise Manager Console gives you a central point of control for the Oracle environment through an intuitive graphical user interface (GUI) that provides powerful and robust system management.

control file

A file that records the physical structure of a database and contains the database name, the names and locations of associated databases and online redo log files, the timestamp of the database creation, the current log sequence number, and checkpoint information.

data file

File that contain the contents of logical database structures, such as tables and indexes. One or more data files form a logical unit of storage called a tablespace. A data file can be associated with only one tablespace, and only one database.

dedicated server

A server that requires a dedicated server process for each user process. There is one server process for each client. Net8 sends the address of an existing server process back to the client. The client then resends its connect request to the server address provided. Contrast with multi-threaded server (MTS).


A process that enables many clients to connect to the same server without the need for a dedicated server process for each client. A dispatcher handles and directs multiple incoming network session requests to shared server processes. See also multi-threaded server (MTS).

Distributed Lock Manager (DLM)

Oracle Parallel Server software that provides locking mechanisms to control allocation and modification of Oracle resources.

extended partition

A type of partition on Windows NT that points to raw space on the disk. An extended partition can be assigned multiple logical drives to accommodate data files, control files, and redo log files.

external procedures

Functions or procedures written in a third-generation language (3GL) that can be called from PL/SQL code. Only C is supported for external procedures.

global cache

Initialization parameters used to determine the size of the collection of global locks that protect the database buffers on all instances. These parameters should be set in the initdb_name.ora file.

global database name

The full name of the database which uniquely identifies it from any other database. The global database name is of the form "database_name.database_domain", for example,

The database name portion, sales, is a simple name you wish to call your database. The database domain portion,, specifies the database domain in which the database is located, making the global database name unique. When possible, Oracle recommends that your database domain mirror the network domain.

The global database name is the default service name of database, as specified by the SERVICE_NAMES parameter in the common database initialization file, initdb_name.ora.


The name of an Oracle home in an Oracle services on Windows NT.

initialization parameter file

Files that contains information to initialize the database (initdb_name.ora) and instances (initsid.ora).


An instance initialization file that contains parameters unique for an instance and points to initdb_name.ora for database parameters.


A common database initialization file shared among the instance that contains database parameters.

Input/Output (IO)

Input/Output is an Operating System Dependent component that provides I/O to access shared disks.


For an Oracle Parallel Server database, each node within the cluster has an instance of the running Oracle8i software referencing the database.

When a database is started on a database server (regardless of the type of computer), Oracle allocates a memory area called the System Global Area (SGA) and starts one or more Oracle processes. This combination of the SGA and the Oracle processes is called an instance. The memory and processes of an instance efficiently manage the associated database's data and serve the database users. You can connect to any instance to access information within a parallel server database.

Each instance has unique Oracle System Identifier (SID), instance name, instance number, rollback segments, and thread ID.

instance name

Represents the name of the instance and is used to uniquely identify a specific instance when multiple instances share common services names. The instance name is identified by the INSTANCE_NAME parameter in the instance initialization file, initsid.ora.

The instance name is the same as the Oracle System Identifier (SID).

instance number

A number that associates extents of data blocks with particular instances. The instance number allows you to start up an instance and ensure that it uses the extents allocated to it for inserts and updates. This will ensure that it does not use space allocated for other instances. The instance cannot use data blocks in another free list unless the instance is restarted with that instance number.

You can use various SQL options with the INSTANCE_NUMBER initialization parameter to associate extents of data blocks with instances.

The instance number is depicted by the INSTANCE_NUMBER parameter in the instance initialization file, initsid.ora.

Inter-Process Communication (IPC)

An Operating System Dependent component that transfers of messages and consistent-read versions of data blocks between instances on different nodes.

LCKN process

A process that manages the locks used by an instance and coordinates requests for those locks by other instances. Additional lock processes, LCK1 through LCK9, are available for systems requiring exceptionally high throughput of instance lock requests. The single lock process per instance, LCK0, is usually sufficient for most systems.


A separate process that resides on the server whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.

The listener brokers the client request, handing off the request to the server. Every time a client (or server acting as a client) requests a network session with a server, a listener receives the actual request. If the client's information matches the listener's information, the listener grants a connection to the server.


A configuration file for the listener that identifies the:

The listener.ora file typically resides in $ORACLE_HOME/network/admin on UNIX platforms and ORACLE_HOME\network\admin on Windows NT.

An Oracle release 8.1 databases does not require identification of the database service because of service registration. However, static service configuration is required for an Oracle release 8.1 databases if you plan to use Oracle Enterprise Manager.

LMDN process

A process that handles remote lock requests (those which originate from another instance).

LMON process

A process that manages instance and process deaths and associated recovery for the Distributed Lock Manager (DLM).

Management Server

The Oracle Enterprise Manager Management Server provides centralized intelligence and distributed control between the Console and the managed nodes. It also processes system management tasks sent by the Console and administers the distribution of these tasks across the enterprise. The Management Server stores all system data, application data, and information about the state of managed nodes in a repository, which is a set of tables stored in a database. High performance and scalability is ensured because the workload is automatically shared and balanced when there are multiple Management Servers.

multi-threaded server (MTS)

A server that is configured to allow many user processes to share very few server processes, so the number of users that can be supported is increased. With MTS configuration, many user processes connect to a dispatcher. The dispatcher directs multiple incoming network session requests to a common queue. An idle shared server process from a shared pool of server processes picks up a request from the queue. This means a small pool of server processes can server a large amount of clients. Contrast with dedicated server.


See multi-threaded server (MTS).

multiple Oracle homes

The capability of having more than one Oracle home directory on a machine.

naming method

The method used by a client application to resolve a net service name to a connect descriptor.

net service name

A simple name for a service that resolves to a connect descriptor. Users initiate a connect request by passing a user name and password along with a net service name in a connect string for the service to which they wish to connect:

CONNECT username/password@net_service_name

Depending on your needs, net service names can be stored in a variety of places, including:


The foundation of Oracle's family of networking products. It allows services and their applications to reside on different computers so they can communicate as peer applications. The main function of Net8 is to establish network sessions and transfer data between a client machine and a server or between two servers. Once a network session is established, Net8 acts as a data courier for the client and the server.

Net8 Assistant

Net8 Assistant is a graphical user interface tool that combines configuration abilities with component control to provide an integrated environment for configuring and managing Net8. It can be used on either the client or server.

You can use Net8 Assistant to configure the following network components:

Net8 Configuration Assistant

A post-installation tool that configure basic network components after installation, including:


A machine where an instance resides.

Operating System Dependent layer

A software layer that consists of several software components developed by vendors. The OSD layer maps the key operating system/cluster-ware services required for proper operation of Oracle Parallel Server.

OPSCTL utility

A utility that manage instances. OPSCTL gathers information about all the instances for Oracle Enterprise Manager. OPSCTL serves as a single point of control between the Oracle Intelligent Agent and the nodes. Only one node's Oracle Intelligent Agent is used to communicate to OPSCTL. OPSCTL on that node then communicates to the other nodes through Net8.

OPS Communication Daemon (OPSD)

A process that receives requests from the OPSCTL utility to execute administrative job tasks, such as startup or shutdown. The command is executed locally on each node and the results are returned to OPSCTL. OPSD is installed on the nodes. OPSD is only implemented on UNIX platforms.

Optimal Flexible Architecture (OFA)

A set of file naming and placement guidelines for Oracle software and databases.

Oracle Context

An entry in a LDAP-compliant directory of cn=OracleContext, under which all Oracle software relevant information is kept.

Oracle Database Configuration Assistant

A tool that enables you to create, delete, and modify a database.

Oracle Data Gatherer

The Oracle Data Gatherer collects performance statistics for the Oracle Performance Manager. The Oracle Data Gatherer must be installed on a node somewhere on the network.

Oracle Enterprise Manager

A system management tool that provides an integrated solution for centrally managing your heterogeneous environment. Oracle Enterprise Manager combines a graphical Console, Management Server, Oracle Intelligent Agent, repository database, and tools to provide an integrated, comprehensive systems management platform for managing Oracle products.

A product family consists of system management tools designed to efficiently manage the complete Oracle environment.

Oracle Intelligent Agent

A process that runs on each of the nodes. It functions as the executor of jobs and events sent by the console via the Management Server. High availability is ensured since the agent can function regardless of the status of the Console or network connections.

Oracle Parallel Execution

Divides the work of processing certain types of SQL statements among multiple parallel execution server processes.

Oracle Parallel Server

An architecture that allows multiple instances to access a shared database of data files. Oracle Parallel Server is also a software component that provides the necessary Oracle Parallel Server scripts, initialization files, and data files to make the Oracle8i Enterprise Edition an Oracle Parallel Server database.

Oracle Parallel Server Management

A comprehensive and integrated system management solution for the Oracle Parallel Server. Oracle Parallel Server Management allows you to manage multi-instance databases running in heterogeneous environments through an open client-server architecture through Oracle Enterprise Manager.

In addition to managing parallel databases, Oracle Parallel Server Management allows you to schedule jobs, perform event management, monitor performance, and obtain statistics to tune parallel databases.

Oracle Performance Manager

An add-on application for Oracle Enterprise Manager that offers a variety of tabular and graphic performance statistics for parallel servers. The statistics represent the aggregate performance for all instances running on an Oracle Parallel Server.

Oracle services

Oracle services are created and associated with Oracle products, such as the database or listener.

Oracle System Identifier (SID)

A name that identifies a specific instance of a running pre-release 8.1 Oracle database. For an Oracle Parallel Server database, each node within the cluster has an instance referencing the database. The database name, specified by the DB_NAME parameter in the initdb_name.ora file, and unique thread ID make up each node's SID. The thread ID starts at 1 for the first instance in the cluster, and is incremented by 1 for the next instance, and so on.

For pre-release 8.1 databases, SID was used to identify the database. The SID was included in the part of the connect descriptor in a tnsnames.ora file, and in the definition of the network listener in the listener.ora file.

Oracle8i Enterprise Edition

Oracle8i Enterprise Edition is an Object-Relational Database Management System (ORDBMS). It provides the applications and files to manage a database. All other Oracle Parallel Server components are layered on top of Oracle8i Enterprise Edition.

PMON process

A process monitor database process that performs process recovery when a user process fails. PMON is responsible for cleaning up the cache and freeing resources that the process was using. PMON also checks on dispatcher (see below) and server processes and restarts them if they have failed. As a part of service registration, PMON registers instance information with the listener.

preferred credentials

Each Oracle Enterprise Manager administrator can set up specific user names, passwords, and roles for nodes, listeners, databases, and other services that you administer in the network.

After these credentials are set up, you log in once to start the Console and are then automatically logged in as needed to the nodes. All login credentials are encrypted in the repository database.

redo log file

A file that contains a record of all changes made to data in the database buffer cache. If an instance failure occurs, the redo log files are used to recover the modified data that was in memory.

repository database

A repository database is a set of tables in an Oracle database that stores data required by Oracle Enterprise Manager. This database is separate from the database on the nodes.

rollback segment

Contains transactions to undo changes to data blocks for uncommitted transactions. Rollback segments also provide read consistency to roll back transactions and to recover the database. Each node typically has two rollback segments that are identified with a naming convention of RBSthread_id_rollback_number by the ROLLBACK_SEGMENTS parameter in the instance initialization file, initsid.ora.

seed database

A preconfigured, ready-to-use database that requires minimal user input to create.

service discovery

When you execute the Discover Node command from the Console, the Management Server contacts the Oracle Intelligent Agent installed on that node to discover the Oracle services installed on the node. The Management Server then places the new information in the repository and updates the hierarchical tree in the Navigator window of the Console, displaying a big-picture view of all nodes and their respective services.

service name

A logical representation of a database, which is the way a database is presented to clients. A database can be presented as multiple services and a service can be implemented as multiple database instances. The service name is a string that is the global database name, a name comprised of the database name (DB_NAME) and domain name (DB_DOMAIN), entered during installation or database creation.

If you are not sure what the global database name is, you can obtain it from the combined values of the SERVICE_NAMES parameter in the common database initialization file, initdbname.ora.

The service name is included in the CONNECT_DATA part of the connect descriptor.

service registration

A feature by which the PMON process automatically registers information with a listener. Because this information is registered with the listener, the listener.ora file does not need to be configured with this static information.

Service registration provides the listener with the following information:


SID is an abbreviation for Oracle System Identifier (SID).

sqlnet.ora file

A configuration file for the client or server that specifies:

The sqlnet.ora file typically resides in $ORACLE_HOME/network/admin on UNIX platforms and ORACLE_HOME\network\admin on Windows platforms.

starter database

A preconfigured, ready-to-use database that requires minimal user input to create.

Startup (START)

Startup is an Operating System Dependent component that provides one-time configuration to startup functionality.

symbolic link name

A name for a Windows NT logical partition.


A database administration role that contains all system privileges with the ADMIN OPTION and the SYSOPER system privileges. SYSDBA also permits CREATE DATABASE and time-based recovery.


A database administration role that enables a database administrator to perform STARTUP, SHUTDOWN, ALTER DATABASE OPEN/MOUNT, ALTER DATABASE BACKUP, ARCHIVE LOG, and RECOVER, and includes the RESTRICTED SESSION privilege.

System Global Area (SGA)

A group of shared memory structures that contain data and control information for an Oracle instance.


A logical portion of an Oracle database used to allocate storage for table and index data. Each tablespace corresponds to one or more physical data files. Every Oracle database has a tablespace called SYSTEM and may have additional tablespaces. A tablespace is used to group related logical structures. For example, tablespaces commonly group all of an application's objects to simplify administrative operations.

thread ID

The number of the redo thread to be used by an instance. Any available redo thread number can be used, but an instance cannot use the same thread number as another instance. Also, an instance cannot start when its redo thread is disabled. An instance cannot mount a database if the thread is used by another instance or if the thread is disabled.

The thread starts at 1 node for the first instance in the cluster, and is incremented by 1 for the next instance, and so on.

Threads are depicted by the THREAD parameter in the instance initialization file, initsid.ora.

When redo log files are generated, they include the thread ID, allowing you to easily identify a particular node's log files.

tnsnames.ora file

A configuration file that contains net service names mapped to connect descriptors. The tnsnames.ora file typically resides in $ORACLE_HOME/network/admin on UNIX platforms and ORACLE_HOME\network\admin.

This file is needed on clients, nodes, the Console, and on the Oracle Performance Manager machine.

Transparent Application Failover (TAF)

A runtime failover for high-availability environments, such as Oracle Parallel Server and Oracle Fail Safe, that refers to the failover and re-establishment of application-to-service connections. It allows client applications to automatically reconnect to the database if the connection fails, and optionally resume a SELECT statement that was in progress. This reconnect happens automatically from within the Oracle Call Interface (OCI) library.

trace file

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

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