|Net8 Administrator's Guide
A unique network location used to identify a network object, such as a listener address, Oracle Connection Manager, or Oracle Names server. Addresses have a specific format and must be unique. See also well-known Oracle Names server.
An organizational entity for administering Net8 network components. Each administrative region includes:
An alternative name for an existing network object. Once an alias is created, it is resolved to the same name as the initial network object. An Oracle Names server stores aliases for any defined net service name, database server or database link.
Stands for American Standard Code for Information Interchange character set, a convention for representing alphanumeric information using digital data. The collation sequence used by most computers with the exception of IBM and IBM-compatible computers. Contrast with EBCDIC character set.
If the listener and server exist on the same node, the listener may create or spawn dedicated servers as connect requests are received. Dedicated servers are committed to one network session only and exist for the duration of that network session. The sequence of events that occur when the listener creates a dedicated server process and passes or "bequeaths" control of a network session to it.
Memory that stores recently-accessed data to so that subsequent requests to access the same data can be processed quickly.
Cell Directory Service
An Oracle Names network where network management consists of one administrative region for the entire network. With central administration, all Oracle Names servers know about one another and about all the services in the network. Contrast with delegated administration.
A utility included with Net8 to control various functions, such as to start, stop, and get the status of the Oracle Connection Manager.
A user, software application, or computer that requests the services, data, or processing of another application or computer. In a two-task environment, the client is the user process. In a network environment, the client is the local user process and the server may be local or remote.
Load balancing, whereby a client can randomly choose between the listeners for its connect requests if more than one listener services a single database. This randomization allows all listeners to share the burden of servicing incoming connect requests.
The properties of a client, which may include the preferred order of naming methodss, client and server logging and tracing, the domain from which to request names, and other client options for Oracle Names and Oracle Advanced Networking Option.
Software architecture based on a separation of processing between two CPUs, one acting as the client in the transaction, requesting and receiving services, and the other as the server that provides services in a transaction.
Files that are used to identify and characterize the components of a network. Configuration is largely a process of naming network components and identifying relationships among those components.
A portion of the connect descriptor, introduced by the keyword CONNECT DATA, that specifies the service to which the connection is to be made.
Clients and servers use this net service name when making a connection with an application.
A client connect request is forwarded to a another listener if first listener is not responding. Connect-time failover is enabled by database instance registration, because the listener knows if an instance is up prior to attempting a connection.
An interaction between two processes on a network. Connections are originated by an initiator (client), who requests a connection with a destination (server).
A feature of Oracle Connection Manager that consolidates multiple connection requests from clients to establish a single connection to a server in order to conserve server resources.
Load balancing, whereby the number of active connections among various instances and dispatchers for the same service are balanced. This enables listeners to make their routing decisions based on how many connections each dispatcher has and on how loaded the nodes that the instances run.
A resource utilization and user scalability feature that allows you to maximize the number of physical network connections to a multi-threaded server. A feature of Oracle Connection Manager that consolidates multiple connection requests from clients to establish a single connection to a server in order to conserve server resources.
A notification sent by an initiator and received by a listener that indicates that the initiator wants to start a connection.
(1) A person responsible for operating and maintaining an Oracle Server or a database application. (2) An Oracle username that has been given DBA privileges and can perform database administration functions. Usually the two meanings coincide. Many sites have multiple DBAs.
Database instances register themselves with the listener when started. Database instance registration is comprised of two elements:
A network object stored in the local database or in the network definition that identifies a remote database, a communication path to that database, and optionally, a username and password. Once defined, the database link is used to access the remote database.
A public or private database link from one database to another is created on the local database by a DBA or user.
A global database link is created automatically from each database to every other database in a network with Oracle Names. Global database links are stored in the network definition.
A server that requires its own dedicated server process for each user process. Contrast with multi-threaded server (MTS). Net8 sends the address of an existing server process back to the client. The client will then resend its connect request to the server address provided.
The domain within which most client requests take place. It could be the domain where the client resides, or it could be a domain from which the client requests network services often. Default domain is also the client configuration parameter that determines what domain should be appended to unqualified network name requests. A name request is unqualified if it does not have a "." character within it.
A Net8 network where network management is delegated to one or more administrative regions below the root administrative region. Also referred to as distributed or decentralized administration. Contrast with central administration.
The client that is the endpoint of a connection. The initiator of the connection requires some data or service of the destination.
A dispatcher enables many clients to connect to the same server without the need for a dedicated server for each client. A dispatcher handles and directs multiple incoming network session requests to the shared server.
Division of front-end and back-end processing to different computers. Net8 supports distributed processing by transparently connecting applications to remote databases.
A grouping of network objects, such as databases, that simplifies the naming of network services. Within a domain, all the names must be unique.
The set of domains that are managed within a given administrative region. Domains are only domestic relative to a region; they are never domestic in any absolute sense. Also referred to as local domains.
A message from a computer program informing you of a potential problem or condition preventing program or command execution.
Function or procedure written in a third-generation language (3GL) that can be called from PL/SQL code. Only C is supported for external procedures.
An Oracle Names infrastructure in which there is only one domain. All names must be unique within that domain.
The set of domains not managed within a given administrative region. Domains are only foreign relative to a region; they are not foreign in any absolute sense. A network administrator typically defines foreign domains relative to a particular region to optimize Names Server caching performance.
A database link that links each database in a network to all other databases. This enables any user of any database in the network to specify a global object name in a SQL statement or object definition. (The global object name for the Debunk must be the same as the database service name.)
The global database name is 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, .US.ORACLE.COM, specifies the database domain in which the database is located, making the global database name unique. When possible, Oracle Corporation recommends that your database domain mirror the network domain.
An integrated component that provides the generic technology for accessing non-Oracle systems from the Oracle server. Heterogeneous Services enables you to:
An Oracle Names infrastructure in which names are divided into multiple hierarchically-related domains. You can use the hierarchical naming model with either central or delegated administration.
A net service name resolution that enables users in a TCP/IP environment to resolve net service names via their existing name resolution service. This name resolution service might be Domain Name Services (DNS), NIS or simply a centrally-maintained set of /etc/hosts files. Host Naming allows users to connect to an Oracle server by simply providing the server computer's host name or host name alias. No client configuration is required to take advantage of this feature. This method is recommended for simple TCP/IP environments.
File that contains information to initialize the database and instance.
JDBC Drivers provide Java programmers access to an Oracle database.
Oracle's Level 2 JDBC driver is targeted to client-server Java application programmers and Java-based middle-tier developers. The JDBC/OCI driver converts JDBC invocations to calls to the Oracle Call Interface (OCI) which are then sent over Net8 to the Oracle database server.
Thin JDBC driver is Oracle's Type 4 driver designed for Java applet and Java application developers. The JDBC driver establishes a direct connection to the Oracle database server over Java sockets. Access to the database is assisted with a lightweight implementation of Net8 and Two-Task Common (TTC).
The combination of a keyword and a value, used as the standard unit of information in connect descriptors and many configuration files. Keyword-value pairs may be nested; that is, a keyword may have another keyword-value pair as its value.
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 that describes one or more listeners on a server. For a pre-release 8.1 database, the LISTENER.ORA.ORA file can also define the Oracle System Identifier (SID) of the database served by the listener. Release 8.1 databases do not require identification of the database because of database instance registration.
A utility included with Net8 to control various functions, such as to start, stop, and get the status of the listener.
A feature by which client connections are distributed evenly among multiple listeners, dispatchers, instances, and nodes so that no single component is overloaded.
Load balancing happens at the following levels:
A net service name resolution that locates network addresses by using information configured and stored on each individual client TNSNAMES.ORA file. Local naming is most appropriate for simple distributed networks with a small number of services that change infrequently.
A distributed database characteristic that allows applications to access data tables without knowing where they reside. All data tables appear to be in a single database, and the system determines the actual data location based on the table name. The user can reference data on multiple nodes in a single statement, and the system automatically and transparently routes (parts of) SQL statements to remote nodes for execution if needed. The data can move among nodes with no impact on the user or application.
A feature in which errors, service activity, and statistics are written to a log file. The log file provides additional information for an administrator when the error message on the screen is inadequate to understand the failure. The log file, by way of the error stack, shows the state of the software at various layers.
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. Without MTS, each user process requires its own dedicated server. A new server process is created for each client requesting a connection. With MTS (also called shared server) configuration, many user processes connect to a dispatcher.
A feature of Oracle Connection Manager that enables a client and server with different networking protocols to communicate with each other. This feature replaces functionality previously provided by the Oracle Multi-Protocol Interchange with SQL*Net version 2.
The method used by a client application to resolve a net service name to a network address when attempting to connect to a database service. Net8 provides four naming methods:
The set and structure of domains within which names can be allocated.
In a flat naming model, there is a single domain.
In a hierarchical naming model, the highest level is the root domain, and all other domains are hierarchically related.
NetWare Directory Service
A name for a connect descriptor that is easy to use and remember. End users need only know the appropriate service name to make a connection. Each connect descriptor is assigned a service name in the network definition. It identifies a:
Oracle's remote data access software that enables both client-server and server-server communications across any network. Net8 supports distributed processing and distributed database capability. Net8 runs over and interconnects many communications protocols. Net8 is backward compatible with SQL*Net version 2.
A Java-based tool that helps you to configure and administer:
Profile -- The tool enables the user to create or edit the local configuration file (SQLNET.ORA) on the local machine.
Net Service Names-- The tool enables the user to create or edit the local naming file (TNSNAMES.ORA).
Listeners -- The tool enables the user to create or edit the local configuration file (LISTENER.ORA) on the local machine.
Oracle Names Servers -- The tool enables the user to configure and control an Oracle Names server from the local machine, and to control other Oracle Names servers on remote machines.
A Java-based tool that configures certain client and server Net8 components after an install.
The application program interface (API) to Net8 that enables programmers to develop both database and non-database applications that make use of the Net8 network already deployed in their environment. Net8 Open provides applications a single common interface to all industry standard network protocols.
A network operating system produced by Novell.
A group of two or more computers linked together through hardware and software to allow the sharing of data and/or peripherals.
A feature of Oracle Connection Manager that sets rules for denying or allowing certain clients to access designated servers. Also known as firewall support.
The person who performs network management tasks such as installing, configuring, and testing network components. The administrator typically maintains the configuration files, connect descriptors and service names, aliases, and public and global database links.
As defined by Oracle, the set of characters acceptable for use as values in keyword-value pairs (that is, in connect descriptors and configuration files). The set includes alphanumeric upper- and lowercase, and some special characters.
Any service that can be directly addressed on a network; for example, a listener or a Oracle Names server.
In an Oracle application network, a service performs tasks for its service consumers; for example, a Names Server provides name resolution services for clients.
A network descriptions of a service name. The network description specifies one or more network routes to the service, including any number of Net8 components such as listeners. Net service names also specify whether network connections should be load balanced among multiple listeners and/or fail over to an alternate listener if a network connection cannot be established.
Network Naming (Oracle Names)
A computer or terminal that is part of a network.
Network Program Interface
Open Program Interface
An alternate name for the top directory in the Oracle directory hierarchy on some directory-based operating systems.
A directory service made up of a system of Oracle Names servers that provide name-to-address resolution for each Net8 service on the network.
A server that uses Oracle Names to store a service's network address along with its simple name so that client applications can request connections with simple names, rather than lengthy addresses.
A set of rules that defines how data is transported across networks. There are several industry standard transport protocols, such as TCP/IP and SPX.
A database for Digital's 64-bit platforms. With Net8, Oracle Rdb servers appears the same way to clients as Oracle databases. Because Oracle Rdb has its own listener, the client interacts with Rdb in the same manner as it does with Oracle7.
A name that identifies a specific instance of the running Oracle8i software. For any database, there is at least one instance referencing the database.
For pre-release 8.1, SID was used to identify the database. The SID is included in the CONNECT DATA part of the connect descriptor in a TNSNAMES.ORA file, and in the definition of the network listener in the LISTENER.ORA file. If you choose the default configuration, the SID defaults to "*".
A block of information sent over the network each time a connection or data transfer is requested. The information contained in packets depends on the type of packet: connect, accept, redirect, data, etc. Packet information can be useful in troubleshooting.
Information passed to a program, command, or function, such as a file specification, a keyword, or a constant value.
A string (word or phrase) used for data security and known only to its owner. Passwords are entered in conjunction with an operating system login ID, Oracle username, or account name, in order to connect to an operating system or software application (such as the Oracle database). Whereas the username or ID is public, the secret password ensures that only the owner of the username can use that name, or access that data.
The Oracle Names Server(s) preferred by a client for names resolution; usually the Oracle Names Server that is physically closest to the client, or available over the least expensive network link.
The presentation layer manages the representation of information that application layer entities either communicate or reference in their communication. Example of session layers are Two-Task Common (TTC) and General Inter-Orb Protocol (GIOP).
Prespawned dedicated server processes are prestarted by the Net8 listener before any incoming connection request. They improve the time it takes to establish a connection on servers where the multi-threaded server is not used or not supported on a given machine. They also use allocated memory and system resources better by recycling server processes for use by other connections with shutting down and recreating a server.
A database link created by one user for his or her exclusive use.
A database link created by a DBA on a local database which is accessible to all users on that database.
Relational Database Management System
Tables in an Oracle database that store Oracle Names information.
The highest level administrative region in a distributed installation. The root administrative region contains the root domain.
The highest level domain in a hierarchical naming model.
Remote Procedure Call
A process that fully replicates a directory system on the network. New services need to register with only one Names Server. The service replication process automatically distributes the new registration to all other active Names Servers on the network.
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 and domain name, 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 database initialization file, INITSID.ORA.
The session layer provides the services needed by the presentation layer entities that enable them to organize and synchronize their dialogue and manage their data exchange. This layer establishes, manages, and terminates network sessions between the client and server. An example of a session layer is Network Session (NS).
A section of the LISTENER.ORA file that defines the Oracle System Identifier (SID) of the database served by the listener. This section is only valid for version 7.x and version 8.0 Oracle databases, as release 8.1 instance information is now automatically registered with the listener. Static configuration is also required for other services, such as external procedures and heterogeneous services, and some management tools, including Oracle Enterprise Manager version 2.
Sequenced Packet Exchange, a network protocol known for high performance and acceptance among many major network management systems, in particular, Novell Advanced NetWare.
Net8's precursor. An Oracle product that works with the Oracle Server and enables two or more computers that run the Oracle RDBMS or Oracle tools such as SQL*Forms to exchange data through a network. SQL*Net supports distributed processing and distributed database capability. SQL*Net runs over and interconnects many communications protocols.
Data used by the Oracle Names server to control regular functioning or communicate with other Oracle Names servers. Includes interchanges, root region's Oracle Names servers, and any delegated regions' Oracle Names servers.
A file that contains connect descriptors mapped to service names. The file may be maintained centrally or locally, for use by all or individual clients.
A facility that writes detailed information about an operation to an output file. The trace facility produces a detailed sequence of statements that describe the events of an operation as they are executed. Administrators use the trace facility for diagnosing an abnormal condition; it is not normally turned on.
A foundation technology, built into Net8, Oracle Connection Manager and Oracle Names, that works with any standard network transport protocol.
The name by which a user is known to the Oracle Server and to other users. Every username is associated with a password, and both must be entered to connect to an Oracle database.
User Program Interface
Addresses for one or more Oracle Names servers are hardcoded into both the Oracle Names server and its clients. Oracle Names servers then become available at these well known addresses, so that clients do not need to be told, by way of configuration files, where to find the server.