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【OH】Glossary Oracle词汇表(中)
Oracle? Database Net Services Administrator's Guide11g Release 2 (11.2) E41945-02 |
Glossary
The group of access directives that you define. The directives grant levels of access to specific data for specific clients or groups of clients.
A feature of Oracle Connection Manager that sets rules for denying or allowing certain clients to access designated servers.
See protocol address.
An alternative name for a network object in an Oracle Names server. An alias stores the name of the object it is referencing. When a client requests a lookup of an alias, Oracle completes the lookup as if it is the referenced object.
A host computer that runs the Oracle Net Firewall Proxy. An application gateway looks and acts like a real server from the client's point of view, and a real client from the server's point of view. An application gateway sits between the Internet and company's internal network and provides middleman services (or proxy services) to users on either side.
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.
A piece of information that describes some aspect of a directory entry. An entry comprises a set of attributes, each of which belongs to an object class. Moreover, each attribute has both a type—which describes the kind of information in the attribute—and a value—which contains the actual data.
A security method that enables you to have high confidence in the identity of users, clients, and servers in distributed environments. Network authentication methods can also provide the benefit of single sign-on for users. The following authentication methods are supported, depending on whether Oracle Advanced Security is installed:
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RADIUS
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Kerberos
● automatic diagnostic repository
The automatic diagnostic repository (ADR) is a systemwide tracing and logging central repository. The repository is a file-based hierarchical data store for depositing diagnostic information, including network tracing and logging information.
Memory that stores recently-accessed data so that subsequent requests to access the same data can be processed quickly.
Classless Inter-Domain Routing. In CIDR notation, an IPv6 subnet is denoted by the subnet prefix and the size in bits of the prefix (in decimal), separated by the slash (/) character. For example, 2001:0DB8:0000:0000::/64 denotes a subnet with addresses 2001:0DB8:000:0000:0000:0000:0000:0000 through 2001:0DB8:000:0000:FFFF:FFFF:FFFF:FFFF. The CIDR notation includes support for IPv4 addresses. For example, 192.168.2.1/24 denotes the subnet with addresses 192.168.2.1 through 192.168.2.255.
● Classless Inter-Domain Routing (CIDR)
See CIDR.
A user, software application, or computer that requests the services, data, or processing of another application or computer. 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 if more than one listener services a single database, a client can randomly choose between the listeners for its connect requests. This randomization enables all listeners to share the burden of servicing incoming connect requests.
The properties of a client, which may include the preferred order of naming methods, client and server logging and tracing, the domain from which to request names, and other client options for Oracle Advanced Security.
Software architecture based on a separation of processing between two CPUs. One CPU acts as the client in the transaction, requesting and receiving services. The other acts as the server that provides the requests.
A configuration file that specifies protocol addresses for incoming requests and administrative commands, as well as Oracle Connection Manager parameters and access control rules.
● CMADMIN (Oracle Connection Manager Administration)
An Oracle Connection Manager process that monitors the health of the listener and Oracle Connection Manager gateway processes, shutting down and starting processes as needed. CMADMIN registers information about gateway processes with the listener and processes commands run with the Oracle Connection Manager Control utility.
● CMGW (Oracle Connection Manager gateway)
An Oracle Connection Manager process that receives client connections screened and forwarded by the listener located at the Oracle Connection Manager instance. The gateway process forwards the requests to the database server. In addition, it can multiplex or funnel multiple client connections through a single protocol connection.
A portion of the connect descriptor that defines the destination database service name or Oracle system identifier (SID). In the following example, SERVICE_NAME defines a database service called sales.us.example.com:
(DESCRIPTION=
(ADDRESS=(PROTOCOL=tcp)(HOST=sales-server)(PORT=1521)
(CONNECT_DATA= (SERVICE_NAME=sales.us.example.com)))
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. The network route provides, at a minimum, the location of the listener through use of a network address.
A connect descriptor or a name that maps to a connect descriptor. A connect identifier can be a net service name, database service name, or net service alias. 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 want to connect:
CONNECT username@connect_identifier
Information the user passes to a service to connect, such as user name, password, and connect identifier:
CONNECT username@net_service_name
A client connect request is forwarded to a another listener if a listener is not responding. Connect-time failover is enabled by service registration, because the listener knows if an instance is running to attempt a connection.
An interaction between two processes on a network. Connections are originated by an initiator (client) that requests a connection with a destination (server).
The method for balancing the number of active connections for the same service across the instances and dispatchers. Connection load balancing enables listeners to make routing decisions based on how many connections for each dispatcher and the load on the nodes.
A resource utilization and user scalability feature that enables you to maximize the number of sessions over a limited number of protocol connections to a shared server.
A notification sent by an initiator and received by a listener that indicates that the initiator wants to start a connection.
See packet.
● database administrator (DBA)
(1) A person responsible for operating and maintaining an Oracle Server or a database application. (2) An Oracle user name that has been given DBA privileges and can perform database administration functions. Usually the two meanings coincide. Many sites have multiple DBAs.
● Database Configuration Assistant
A tool that enables you to create, delete, and modify a database.
A pointer that defines a one-way communication path from an Oracle database server to another database server. The link is a defined entry in a data dictionary table. To access the link, the user must be connected to the local database that contains the data dictionary entry.
A client connected to local database A can use a link stored in database A to access information in remote database B. However, users connected to database B cannot use the same link to access data in database A. If local users on database B want to access data on database A, then a link must be defined and stored in the data dictionary of database B.
The following database links are supported:
-
A private database link in a specific schema of a database. Only the owner of a private database link can use it.
-
A public database link for a database. All users in the database can use it.
A server process that is dedicated to one client connection. Contrast with shared server process.
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.
● directory information tree (DIT)
A hierarchical tree-like structure in a directory server of the distinguished names (DNs) of the entries.
A naming method that resolves a database service, net service name, or net service alias to a connect descriptor stored in a central directory server. A directory server provides central administration of directory naming objects, reducing the work effort associated with adding or relocating services.
A directory server that is accessed with the Lightweight Directory Access Protocol (LDAP). Support of LDAP-compliant directory servers provides a centralized vehicle for managing and configuring a distributed Oracle network. The directory server can replace client-side and server-side localized tnsnames.ora files.
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 shared server.
Name of entry in a directory server. The DN specifies where the entry resides in the LDAP directory hierarchy, much the way a directory path specifies the exact location of a file.
Division of front-end and back-end processing to different computers. Oracle Network Services support distributed processing by transparently connecting applications to remote databases.
Any tree or subtree within the Domain Name System (DNS) namespace. Domain most commonly refers to a group of computers whose host names share a common suffix, the domain name.
A system for naming computers and network services that is organized into a hierarchy of domains. DNS is used in TCP/IP networks to locate computers through user-friendly names. DNS resolves a friendly name into an IP address, which is understood by computers.
For Oracle Network Services, DNS translates the host name in a TCP/IP address into an IP address.
Domain Name System. See Domain Name System (DNS).
An enterprise role is analogous to a regular database role, except that it spans authorization on multiple databases. An enterprise role is a category of roles that define privileges on a particular database. An enterprise role is created by the database administrator of a particular database. An enterprise role can be granted to or revoked from one or more enterprise users. The information for granting and revoking these roles is stored in the directory server.
A user that has a unique identity across an enterprise. Enterprise users connect to individual databases through a schema. Enterprise users are assigned enterprise roles that determine their access privileges on databases.
The building block of a directory server, it contains information about an object of interest to directory users.
A naming method that uses a third-party naming service, such as NIS.
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.
See access control.
The set of domains not managed within a given administrative region. Domains are foreign only in relation 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 caching performance.
File Transfer Protocol. A client/server protocol which allows a user on one computer to transfer files to and from another computer over a TCP/IP network.
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, sales.us.example.com.
The database name portion, sales, is a simple name you want to call your database. The database domain portion, us.example.com, 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 the database, as specified by the SERVICE_NAMES parameter in the initialization parameter file.
An integrated component that provides the generic technology for accessing third-party systems from the Oracle database server. Heterogeneous Services enables you to:
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Use Oracle SQL to transparently access data stored in third-party systems as if the data resides within an Oracle server.
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Use Oracle procedure calls to transparently access third-party systems, services, or application programming interfaces (APIs), from your Oracle distributed environment.
An infrastructure in which names are divided into multiple hierarchically-related domains. For Oracle Names, hierarchical naming model can be used with either central or delegated administration.
A naming method resolution that enables users in a TCP/IP environment to resolve names through their existing name resolution service. This name resolution service might be Domain Name System (DNS), Network Information Service (NIS), or simply a centrally-maintained set of /etc/hosts files. Host Naming enables users to connect to an Oracle database 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.
Hypertext Transfer Protocol. A protocol that provides the language that enables Web browsers and application Web servers to communicate.
A collection of identities, all of which are governed by the same administrative policies. In an enterprise, all employees having access to the intranet may belong to one realm, while all external users who access the public applications of the enterprise may belong to another realm. An identity management realm is represented in the directory by a specific entry with a special object class associated with it.
The combination of the System Global Area (SGA) and the Oracle background processes. When a database is started on a database server (regardless of the type of computer), Oracle allocates a memory area called the SGA and starts one or more Oracle processes. 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 cluster database.
A name of an Oracle database instance. The instance name is identified by the INSTANCE_NAME parameter in the database initialization parameter file. INSTANCE_NAME corresponds to the Oracle system identifier (SID) of the instance. Clients can connect to a specific instance by specifying the INSTANCE_NAME parameter in the connect descriptor.
The instance name is included in the connect data part of the connect descriptor.
● Interprocess Communication (IPC)
A protocol used by client applications that resides on the same node as the listener to communicate with the database. IPC can provide a faster local connection than TCP/IP.
Used to identify a node on a network. Each computer on the network is assigned a unique Internet Protocol (IP) address, which is made up of the network ID and a unique host ID.
Internet Protocol Version 4. IPv4 is the current standard for the IP protocol. IPv4 uses 32-bit (four-byte) addresses, which are typically represented in dotted-decimal notation. The decimal value of each octet is separated by a period, as in 192.168.2.22.
Internet Protocol Version 6. The protocol designed to replace IPv4. In IPv6, an IP address is typically represented in eight fields of hexadecimal values separated by colons, as in 2001:0DB8:0000:0000:0000:0000:1428:57AB. In some cases, fields with 0 values can be compressed, as in 2001:DB8::1428:57AB.
See IPv4
See IPv6
● Java Database Connectivity (JDBC) Driver
A driver that provides Java applications and applets access to an Oracle database.
A Type II driver for use with client/server Java applications. This driver requires an Oracle client installation.
A Type IV driver for Oracle JDBC applets and applications. Because it is written entirely in Java, this driver is platform-independent. It does not require any additional Oracle software on the client side. The Thin driver communicates with the server using Two-Task Common (TTC), a protocol developed by Oracle to access the database server.
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.
● Lightweight Directory Access Protocol (LDAP)
A standard, extensible directory access protocol. It is a common language that LDAP clients and servers use to communicate. The framework of design conventions supporting industry-standard directory servers.
A file created by Oracle Internet Directory Configuration Assistant or Oracle Net Configuration Assistant that contains the following directory server access information:
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Type of directory server
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Location of the directory server
-
Default Oracle Context that the client or server use to look up or configure connect identifiers for connections to database services
When created with Oracle Internet Directory Configuration Assistant, ldap.ora is located in the ORACLE_HOME/ldap/admin directory. When created with Oracle Net Configuration Assistant, ldap.ora is located in the ORACLE_HOME/network/admin directory.
Lightweight Directory Interchange Format is the set of standards for formatting an input file for any of the LDAP command line utilities.
● Lightweight Directory Interchange Format (LDIF)
See LDIF.
A qualifier appended to a global database link to provide alternate settings for the database user name and password credentials. For example, a link qualifier of fieldrep can be appended to a global database link of sales.us.example.com.
SQL> SELECT * FROM emp@sales.us.example.com@fieldrep
See Oracle Net Listener.
A configuration file for Oracle Net Listener that identifies the following:
-
Unique name
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Protocol addresses that it is accepting connection requests on
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Services it is listening for
The listener.ora file typically resides in the ORACLE_HOME/network/admin directory.
Oracle Database does not require identification of the database service because of service registration. However, static service configuration is required if you plan to use Oracle Enterprise Manager.
A utility included with Oracle Network Services to control various listener functions, such as starting, stopping, and getting 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.
Oracle Network Services support client load balancing and connection load balancing.
A naming method that locates network addresses by using information configured and stored on each individual client's 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 enables 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, 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.
See also tracing.
A connection from the server back to itself. Performing a successful loopback verifies that Oracle Net is functioning on the database server.
Files used by the Network Information Service (NIS) ypserv program to handle name requests.
An LDAP-compliant directory server included with the Microsoft Windows 2000 Server. It stores information about objects on the network, and makes this information available to users and network administrators. Active Directory also provides access to resources on the network using a single logon process.
Active Directory can be configured as a directory naming method to store service information that clients can access.
● Microsoft Windows NT native authentication
An authentication method that enables a client to have single login access to a Microsoft Windows NT server and a database running on the server.
A high-level interface protocol providing interprocess communications between clients and servers using distributed applications.
A subtree that resides entirely on one directory server. It is a contiguous subtree, that is, it must begin at an entry that serves as the top of the subtree, and extend downward to either leaf entries or references to subordinate naming contexts. It can range in size from a single entry to the entire directory information tree (DIT).
Oracle Context can be created under a naming context.
The resolution method used by a client application to resolve a connect identifier to a connect descriptor when attempting to connect to a database service. Oracle Net provides four naming methods:
-
Easy Connect naming
An alternative name for a directory naming object in a directory server. A directory server stores net service aliases for any defined net service name or database service. A net service alias entry does not have connect descriptor information. Instead, it only references the location of the object for which it is an alias. When a client requests a directory lookup of a net service alias, the directory determines that the entry is a net service alias and completes the lookup as if the alias was actually the entry it is referencing.
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 want to connect:
CONNECT username@net_service_name
Depending on your needs, net service names can be stored in a variety of places, including:
-
Local configuration file, tnsnames.ora, on each client
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Directory server
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External naming service, such as NIS
A group of two or more computers linked together through hardware and software to allow the sharing of data and peripherals.
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.
● Network Information Service (NIS)
Sun Microsystems Yellow Pages (yp) client/server protocol for distributing system configuration data such as user and host names between computers on a network.
A network layer that provides a generic interface for Oracle clients, servers, or external processes to access Oracle Net functions. The NI layer handles the "break" and "reset" requests for a connection.
See listener.
● Network Program Interface (NPI)
An interface for server-to-server interactions that performs all of the functions that the OCI does for clients, allowing a coordinating server to construct SQL requests for additional servers.
A session layer that is used in typical Oracle Net connections to establish and maintain the connection between a client application and a database server.
Network Session. See Network Session (NS).
Network Transport. See transport.
In a directory server, a named group of attributes. When you want to assign attributes to an entry, you do so by assigning to that entry the object classes that hold those attributes.
All objects associated with the same object class share the attributes of that object class.
Oracle Call Interface. See Oracle Call Interface (OCI).
● Open Systems Interconnection (OSI)
A model of network architecture developed by International Organization for Standardization (ISO) as a framework for international standards in heterogeneous computer network architecture.
The OSI architecture is split between seven layers, from lowest to highest:
1. Physical layer
2. Data link layer
3. Network layer
4. Transport layer
5. Session layer
6. Presentation layer
7. Application layer
Each layer uses the layer immediately preceding it and provides a service to the layer following it.
A product that provides a comprehensive suite of security features to protect enterprise networks and securely extend corporate networks to the Internet. Oracle Advanced Security provides a single source of integration with network encryption and authentication solutions, single sign-on services, and security protocols. By integrating industry standards, it delivers unparalleled security to the network.
An application programming interface (API) that enables you to create applications that use the native procedures or function calls of a third-generation language to access an Oracle database server and control all phases of SQL statement execution. OCI supports the data types, calling conventions, syntax, and semantics of a number of third-generation languages including C, C++, COBOL and FORTRAN.
A router through which a client connection request may be sent either to its next hop or directly to the database server. Clients who route their connection requests through an Oracle Connection Manager can then take advantage of the session multiplexing, access control, or protocol conversion features configured on that Oracle Connection Manager.
● Oracle Connection Manager Control utility
A utility included with Oracle Network Services to control various functions, such as starting, stopping, and getting the status of the Oracle Connection Manager.
An entry in an LDAP-compliant Internet directory called cn=OracleContext, under which all Oracle software relevant information is kept, including entries for Oracle Net Services directory naming and checksumming security. There may be one or more than one Oracle Context in a directory. An Oracle Context can be associated with a directory naming context.
Oracle Internet Directory automatically creates an Oracle Context at the root of the DIT structure. This root Oracle Context has a DN of dn:cn=OracleContext.
A separate Oracle product that combines a graphical console, agents, common services, and tools to provide an integrated and comprehensive systems management platform for managing Oracle products.
An infrastructure enabling deployments to manage centrally and securely all enterprise identities and their access to various applications in the enterprise.
A directory server implemented as an application on the Oracle database. It enables retrieval of information about dispersed users and network resources. It combines Lightweight Directory Access Protocol (LDAP) Version 3, the open Internet standard directory server access protocol, with the high performance, scalability, robustness, and availability of the Oracle database.
Communication software that enables a network session from a client application to an Oracle database server. After a network session is established, Oracle Net acts as a data courier for the client application and the database server. It is responsible for establishing and maintaining the connection between the client application and database server, as well as exchanging messages between them. Oracle Net is able to perform these jobs because it is located on each computer in the network.
● Oracle Net Configuration Assistant
A postinstallation tool that configures basic network components after installation, including:
-
Listener names and protocol addresses
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Naming methods the client uses to resolve connect identifiers
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Net service names in a tnsnames.ora file
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Directory server usage
Product offered by some firewall vendors that supplies Oracle Connection Manager functionality.
A networking communication layer that is responsible for establishing and maintaining the connection between the client application and server, as well as exchanging messages between them.
A process that resides on the server whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.
When a client requests a network session with a database server, a listener receives the actual request. If the client information matches the listener information, then the listener grants a connection to the database server.
A tool that combines configuration abilities with component control to provide an integrated environment for configuring and managing Oracle Net Services.
You can use Oracle Net Manager to configure the following network components:
-
Naming
Define connect identifiers and map them to connect descriptors to identify the network location and identification of a service. Oracle Net Manager supports configuration of connect descriptors in a local tnsnames.ora file or directory server.
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Naming Methods
Configure the different ways in which connect identifiers are resolved into connect descriptors.
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Listeners
Create and configure listeners to receive client connections.
A suite of networking components that provide enterprise-wide connectivity solutions in distributed, heterogeneous computing environments. Oracle Net Services is comprised of Oracle Net, listener, Oracle Connection Manager, Oracle Net Configuration Assistant, and Oracle Net Manager.
● Oracle Program Interface (OPI)
A networking layer responsible for responding to each of the possible messages sent by OCI. For example, an OCI request to fetch 25 rows would have an OPI response to return the 25 rows after they have been fetched.
A software layer responsible for mapping Transparent Network Substrate (TNS) functionality to industry-standard protocols used in the client/server connection.
A database for Digital 64-bit platforms. Because Oracle Rdb has its own listener, the client interacts with Rdb in the same manner as it does with an Oracle database.
A set of rules that determine what can be stored in a directory server. Oracle has its own schema that is applied to many types of Oracle entries, including Oracle Net Services entries. The Oracle schema for Oracle Net Services' entries includes the attributes the entries may contain.
● Oracle system identifier (SID)
A name that identifies a specific instance of a database. For any database, there is at least one instance referencing the database.
A high-performance XML storage and retrieval technology provided with Oracle database server. It is based on the W3C XML data model.
● Oracle Real Application Clusters (Oracle RAC)
An architecture that allows multiple instances to access a shared database of datafiles. Oracle Real Application Clusters is also a software component that provides the necessary cluster database scripts, initialization files, and datafiles needed for Oracle Enterprise Edition and Oracle Real Application Clusters.
An alternate name for the top directory in the Oracle directory hierarchy on some directory-based operating systems.
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, and so on. Packet information can be useful in troubleshooting.
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 and server processes and restarts them if they have failed. As a part of service registration, PMON registers instance information with the listener.
A networking communication layer that manages the representation of information that application layer entities either communicate or reference in their communication. Two-Task Common (TTC) is an example of presentation layer.
A database link created by one user for his or her exclusive use.
See also database link and public database link.
A collection of parameters that specifies preferences for enabling and configuring Oracle Net Services' features on the client or server. A profile is stored and implemented through the sqlnet.ora file.
An address that identifies the network address of a network object.
When a connection is made, the client and the receiver of the request, such as the listener or Oracle Connection Manager, are configured with identical protocol addresses. The client uses this address to send the connection request to a particular network object location, and the recipient "listens" for requests on this address. It is important to install the same protocols for the client and the connection recipient, and to configure the same addresses.
A feature of Oracle Connection Manager that enables a client and server with different networking protocols to communicate with each other.
Designates a particular presentation layer and session layer combination.
A server that substitutes for the real server, forwarding client connection requests to the real server or to other proxy servers. Proxy servers provide access control, data and system security, monitoring, and caching.
A database link created by a DBA on a local database that is accessible to all users on that database.
See also database link and private database link.
An Oracle Context contained in each identity management realm. It stores the following information:
-
User naming policy of the identity management realm—that is, how users are named and located
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Mandatory authentication attributes
-
Location of groups in the identity management realm
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Privilege assignments for the identity management realm—for example: who has privileges to add more users to the realm.
-
Application specific data for that realm including authorizations
● relative distinguished name (RDN)
The local, most granular level entry name. It has no other qualifying entry names that would serve to address the entry uniquely. In the example, cn=sales,dc=us,dc=example,dc=com, cn=sales is the RDN.
In the Oracle Identity Management infrastructure, the root Oracle Context is an entry in Oracle Net Services containing a pointer to the default identity management realm in the infrastructure. It also contains information about how to locate an identity management realm given a simple name of the realm.
An industry standard protocol designed by Netscape Communications Corporation for securing network connections. SSL provides authentication, encryption, and data integrity using public key infrastructure (PKI).
A binary file containing initialization parameter settings that is maintained on the Oracle Database host. You cannot manually edit this file with a text editor. A server parameter file is initially built from a text initialization parameter file by means of the CREATE SPFILE statement or created directly with the Database Configuration Assistant.
Work done for others. The database is a service that stores and retrieves data for clients.
A process that acts as a connection point from the listener to the database server. A service handler can be a dispatcher or dedicated server.
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, that is, 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, then you can obtain it from the value of the SERVICE_NAMES parameter in the initialization parameter file.
The service name is included in the connect data part of the connect descriptor.
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 information about:
-
Service names for each running instance of the database
-
Instance names of the database
-
Service handlers (dispatcher or dedicated server) available for each instance
These enable the listener to direct a client request appropriately.
-
Dispatcher, instance, and node load information
This load information enables the listener to determine which dispatcher can best handle a client connection request. If all dispatchers are blocked, then the listener can spawn a dedicated server for the connection.
A buffer that Oracle Net uses to place data before transmitting it across the network. Oracle Net sends the data in the buffer either when requested or when it is full.
A network layer that provides the services needed by the protocol address 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).
Combining multiple sessions for transmission over a single network connection to conserve the operating system's resources.
A database 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 shared server 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. Thus, a small pool of server processes can serve a large number of clients. Contrast with dedicated server.
A process type used with shared server configuration.
A section of the listener.ora file that defines the Oracle system identifier (SID) of the database served by the listener. This configuration is not required for an Oracle database because information for the instance is automatically registered with the listener. However, static configuration is required for other services, such as external procedure calls and Heterogeneous Services.
The ability of a user to log in to different servers using a single password. This permits the user to authenticate to all servers the user is authorized to access.
A configuration file for the client or server that specifies:
-
Client domain to append to unqualified service names or net service names
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Order of naming methods the client should use when resolving a name
-
Logging and tracing features to use
-
Route of connections
-
External naming parameters
-
Oracle Advanced Security parameters
The sqlnet.ora file typically resides in the ORACLE_HOME/network/admin directory.
A group of shared memory structures that contain data and control information for an Oracle instance.
Transmission Control Protocol/Internet Protocol. The standard communication protocol used for client/server conversation over a network.
A protocol that enables an Oracle application on a client to communicate with remote Oracle databases through the TCP/IP and Secure Sockets Layer (SSL).
The amount of time it takes for a message to be sent and processed from the client to the server or from the server to the client
A configuration file that contains maps net service names to connect descriptors. This file is used for the local naming method. The tnsnames.ora file typically resides in the ORACLE_HOME/network/admin directory.
A utility that writes detailed information about an operation to an output file. The trace utility produces a detailed sequence of statements that describe the events of an operation as they are run. Administrators use the trace utility for diagnosing an abnormal condition; it is not normally turned on.
See also logging.
● Transparent Application Failover (TAF)
A run-time failover for high-availability environments, such as Oracle Real Application Clusters and Oracle Fail Safe, that refers to the failover and re-establishment of application-to-service connections. It enables 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.
● Transparent Network Substrate (TNS)
A foundation technology, built into the Oracle Net foundation layer that works with any standard network transport protocol.
A networking layer that maintains end-to-end reliability through data flow control and error recovery methods. The Oracle Net foundation layer uses Oracle protocol support for the transport layer.
A presentation layer type that is used in a typical Oracle Net connection to provide character set and data type conversion between different character sets or formats on the client and server.
A piece of shared memory used by the dispatcher for client database connection requests and replies. The dispatcher places a virtual circuit on a common queue when a request arrives. An idle shared server picks up the virtual circuit from the common queue, services the request, and relinquishes the virtual circuit before attempting to retrieve another virtual circuit from the common queue.
World Wide Web Distributed Authoring and Versioning. A protocol with a set of extensions to the HTTP protocol which allows users to manage files on remote Web servers.
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GlossaryGlossary
An impact analysis that categorizes the business processes based on the severity of the impact of IT-related outages.
The whole cluster hosting the Oracle RAC database is unavailable or fails. This includes failures of nodes in the cluster, and any other components that result in the cluster being unavailable and the Oracle database and instances on the site being unavailable.
An outage that occurs when the system running the database becomes unavailable because it has crashed or is no longer accessible.
A complete business impact analysis provides the insight needed to quantify the cost of unplanned and planned downtime. Understanding this cost is essential because it helps prioritize your high availability investment and directly influences the high availability technologies that you choose to minimize the downtime risk.
A corrupt block is a block that has been changed so that it differs from what Oracle Database expects to find. Block corruptions fall under two categories: physical and logical block corruptions.
See also physical corruption and logical corruption.
Hang or slow down occurs when the database or the application is unable to process transactions because of a resource or lock contention. Perceived hang can be caused by lack of system resources.
An outage that occurs when unintentional or malicious actions are committed that cause data in the database to become logically corrupt or unusable. The service level impact of a human error outage can vary significantly depending on the amount and critical nature of the affected data.
The contents of the block are logically inconsistent. Examples of logical corruption include corruption of a row piece or index entry.
Three-bit identifiers used on a SCSI bus to distinguish between up to eight devices (logical units) with the same SCSI ID.
A lost write is another form of data corruption that can occur when an I/O subsystem acknowledges the completion of the block write, while in fact the write I/O did not occur in the persistent storage. No error is reported by the I/O subsystem back to Oracle Database.
An architecture that provides the most comprehensive set of solutions for both unplanned and because it inherits the capabilities and advantages of both Oracle Database 11g with Oracle RAC and Oracle Database 11g with Data Guard.
The MAA environment consists of a site containing an Oracle RAC primary database and a second site containing a cluster that hosts both logical and physical standby databases, or at least one physical or logical standby database.
More subjective than either the RPO or the RTO, the manageability goal results from an objective evaluation of the skill sets and management resources available in an organization, and the degree to which the organization can successfully manage all elements of a high availability architecture. Understanding manageability goals helps organizations differentiate between what is possible and what is practical to implement.
The Data Guard network server processes, also referred to as LNSn processes, on the primary database perform a network send to the RFS process on the standby database. There is one network server process for each destination.
● Oracle Active Data Guard option
A physical standby database can be open for read-only access while Redo Apply is active if a license for the Oracle Active Data Guard option has been purchased. This capability, known as Active Data Guard, also provides the ability to have block-change tracking on the standby database, thus allowing incremental backups to be performed on the standby.
Note: The Active Data Guard option may also be referred to as "real-time query" in other documentation.
The database does not recognize the block at all: the checksum is invalid, the block contains all zeros, or the header and footer of the block do not match. A physical corruption is also called a media corruption.
● recovery point objective (RPO)
The maximum amount of data an IT-based business process may lose before causing harm to the organization. RPO indicates the data-loss tolerance of a business process or an organization in general. This data loss is often measured in terms of time, for example, five hours or two days worth of data loss.
● recovery time objective (RTO)
The maximum amount of time that an IT-based business process can be down before the organization suffers significant material losses. RTO indicates the downtime tolerance of a business process or an organization in general.
Return on Investment (or Rate of return) is used to evaluate the efficiency of an investment in finance and economics.
An outage that occurs when an event causes all or a significant portion of an application to stop processing or slow to an unusable service level. A site failure may affect all processing at a data center, or a subset of applications supported by a data center.
An outage that occurs when the storage holding some or all of the database contents becomes unavailable because it has shut down or is no longer accessible.
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GlossaryGlossary
A script that defines the start, stop and check actions for a resource. The start action is invoked while starting the resource, the stop action for stopping the resource, and the check action while checking the running status of a resource.
Database administrators define on which servers a database resource should run, and place resources manually as needed. This is the management strategy used in previous releases.
Instructions to Oracle Clusterware to reconfigure the system when a server leaves or joins a cluster.
The number of servers on which a resource can run, simultaneously.
Multiple interconnected computers or servers that appear as if they are one server to end users and applications.
A resource that is aware of the cluster environment and subject to cross-node switchover and failover.
● Cluster Time Synchronization Service
A time synchronization mechanism that ensures that all internal clocks of all nodes in a cluster are synchronized.
● Cluster Verification Utility (CVU)
A tool that verifies a wide range of Oracle RAC components such as shared storage devices, networking configurations, system requirements, Oracle Clusterware, groups, and users.
A predefined Oracle Clusterware administrator role intended to control the creation of server pools. A permanent CRS Administrator is either the user (Grid user) that installed Oracle Clusterware in the Grid Infrastructure home or the system superuser (root in Linux and UNIX, and Administrator in Windows).
The relationship between two or more resources. and the interaction expressed between them.
An Oracle ASM disk group is a collection of disks that Oracle ASM manages as a unit. Within a disk group, Oracle ASM exposes a file system interface for Oracle Database files. The content of files that is stored in a disk group is evenly distributed, or striped, to eliminate hot spots and to provide uniform performance across the disks. Oracle ASM files may also be optionally mirrored within a disk group. The performance of disks in a disk group is comparable to the performance of raw devices.
The software that provides the infrastructure for an enterprise grid architecture. In a cluster this software includes Oracle Clusterware and Oracle ASM. For a standalone server, this software includes Oracle Restart and Oracle ASM. Oracle Database 11g release 2 (11.2) combines these infrastructure products into one software installation called the Grid Infrastructure home (Grid_home).
Oracle Universal Installer detects when minimum requirements for installation are not completed, and creates shell script programs, called fixup scripts, to resolve many incomplete system configuration requirements. If Oracle Universal Installer detects an incomplete task, it prompts you to create a fixup script and then to run the fixup script in a separate terminal session. You can also generate fixup scripts with certain CVU commands by using the -fixup flag.
A resource that runs on the nodes of a cluster but is unaware of anything outside of the scope of the node.
Each crsd process also acts as an OCR server. One of the crsd processes in the cluster is the OCR server that performs I/O to the disk group or file, or block or raw device.
● Oracle Automatic Storage Management (Oracle ASM)
Oracle ASM manages the storage disks used by Oracle Clusterware and Oracle RAC in disk groups. By default, Oracle Clusterware uses Oracle ASM to store OCR and voting disks.
● Oracle Cluster Registry (OCR)
The Oracle RAC configuration information repository that manages information about the cluster node list and instance-to-node mapping information. OCR also manages information about Oracle Clusterware resource profiles for customized applications.
Software that allows groups (clusters) of connected servers to operate or be controlled as a unit.
The Oracle Clusterware stack includes Oracle Clusterware, Event Manager, Cluster Synchronization Services, and Oracle ASM (if used).
Database administrators specify the server pool (excluding generic or free) in which the database resource runs. Oracle Clusterware places the database resource on a server.
The state of a particular resource at any given time that determines its availability to the cluster.
Defines whether a resource is either a cluster resource or a local resource.
A logical division of servers in a cluster into a group that hosts applications, databases, or both.
● Single Client Access Name (SCAN)
A single name that resolves to three IP addresses in the public network.
The process that Oracle Clusterware goes through when it starts a resource. During this process, Oracle Clusterware considers resource dependencies contained in the profile of the resource.
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GlossaryGlossary
Assembly is Microsoft's term for the module that is created when a DLL or .EXE is complied by a .NET compiler.
External binary files that exist outside the database tablespaces residing in the operating system. BFILES are referenced from the database semantics, and are also known as external LOBs.
A large object data type whose content consists of binary data. Additionally, this data is considered raw as its structure is not recognized by the database.
● Character Large Object (CLOB)
The LOB data type whose value is composed of character data corresponding to the database character set. A CLOB may be indexed and searched by the Oracle Text search engine.
As the term is used with Oracle Data Provider for .NET, a data provider is the connected component in the ADO.NET model and transfers data between a data source and the DataSet.
A DataSet is an in-memory copy of database data. The DataSet exists in memory without an active connection to the database.
DDL refers to data definition language, which includes statements defining or changing data structure.
Document Object Model (DOM) is an application program interface (API) for HTML and XML documents. It defines the logical structure of documents and the way that a document is accessed and manipulated.
● Extensible Stylesheet Language Transformation (XSLT)
The XSL W3C standard specification that defines a transformation language to convert one XML document into another.
Flush or flushing refers to recording changes (that is, sending modified data) to the database.
● implicit database connection
The connection that is implicitly available from the context of the .NET stored procedure execution.
A term used in object-based languages such as C# to refer to the creation of an object of a specific class.
The content of a change notification which indicates that the cache is now invalid
The class of SQL data type that is further divided into internal LOBs and external LOBs. Internal LOBs include BLOBs, CLOBs, and NCLOBs while external LOBs include BFILEs.
● Microsoft .NET Framework Class Library
The Microsoft .NET Framework Class Library provides the classes for the .NET framework model.
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.NET:
A namespace is naming device for grouping related types. More than one namespace can be contained in an assembly.
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XML Documents:
A namespace describes a set of related element names or attributes within an XML document.
● National Character Large Object (NCLOB)
The LOB data type whose value is composed of character data corresponding to the database national character set.
The Oracle client/server communication software that offers transparent operation to Oracle tools or databases over any type of network protocol and operating system.
Oracle XML DB is the name for a distinct group of technologies related to high-performance XML storage and retrieval that are available within the Oracle database. Oracle XML DB is not a separate server.
Oracle XML DB is based on the W3C XML data model.
The column or set of columns included in the definition of a table's PRIMARY KEY constraint.
Reference semantics indicates that assignment is to a reference (an address such as a pointer) rather than to a value. See value semantics.
Safe Type Mapping allows the OracleDataAdapter to populate a DataSet with .NET type representations of Oracle data without any data or precision loss.
A stored procedure is a PL/SQL block that Oracle stores in the database and can be executed from an application.
● Transparent Application Failover (TAF)
Transparent Application Failover is a runtime failover for high-availability environments. It enables client applications to automatically reconnect to the database if the connection fails. This reconnect happens automatically from within the Oracle Call Interface (OCI) library.
Unicode is a universal encoded character set that enables information from any language to be stored using a single character set.
Value semantics indicates that assignment copies the value, not the reference or address (such as a pointer). See reference semantics.
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GlossaryGlossary
Descriptive information characterizing a geographical feature such as a point, line, or area.
Nondimensional data that provides additional descriptive information about multidimensional data, for example, a class or feature such as a bridge or a road.
An operation that simultaneously geocodes many records from one table. See also geocoding.
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The lower or upper extent of the range of a dimension, expressed by a numeric value.
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The line representing the outline of a polygon.
A coordinate system in which the location of a point in n-dimensional space is defined by distances from the point to the reference plane. Distances are measured parallel to the planes intersecting a given reference plane. See also coordinate system.
The presence of two or more spatial objects at the same location or at significantly close distances from each other.
A geometric relationship where one object encompasses another and the inner object does not touch any boundaries of the outer. The outer object contains the inner object. See also inside.
Synonymous with coordinate system in Oracle Spatial documentation. The term coordinate reference system is used extensively by the European Petroleum Survey Group (EPSG).
A reference system for the unique definition for the location of a point in n-dimensional space. Also called a spatial reference system. See also Cartesian coordinate system, geodetic coordinates, projected coordinates, and local coordinates.
A geometric relationship in which one object encompasses another and the inner object touches the boundary of the outer object in one or more places.
A repository of information about data. A data dictionary stores relational information on all objects in a database.
See transformation.
Data that has one or more dimensional components and is described by multiple values.
The direction of an LRS geometric segment is indicated from the start point of the geometric segment to the end point. Measures of points on a geometric segment always increase along the direction of the geometric segment.
A geometric relationship where two objects do not interact in any way. Two disjoint objects do not share any element or piece of their geometry.
A geometric relationship in which two objects are considered to represent the same geometric figure. The two objects must be composed of the same number of points; however, the ordering of the points defining geometries of the two objects may differ (clockwise or counterclockwise).
A rectangle bounding a map, the size of which is determined by the minimum and maximum map coordinates.
The process of converting tables of address data into standardized address, location, and possibly other data. See also batch geocoding.
Angular coordinates (longitude and latitude) closely related to spherical polar coordinates and defined relative to a particular Earth geodetic datum. Also referred to as geographic coordinates.
A means of representing the figure of the Earth, usually as an oblate ellipsoid of revolution, that approximates the surface of the Earth locally or globally, and is the reference for the system of geodetic coordinates.
See geodetic coordinates.
● geographic information system (GIS)
A computerized database management system used for the capture, conversion, storage, retrieval, analysis, and display of spatial data.
● geographically referenced data
See spatiotemporal data.
● geometric segment (LRS segment)
An LRS element that contains start and end measures for its start and end points, and that can contain measures for other points on the segment.
The geometric representation of the shape of a spatial feature in some coordinate space. A geometry is an ordered sequence of vertices that are connected by straight line segments or circular arcs.
See spatiotemporal data.
A data structure composed of points located at the nodes of an imaginary grid. The spacing of the nodes is constant in both the horizontal and vertical directions.
A subelement of a polygon that negates a section of its interior. For example, consider a polygon representing a map of buildable land with an inner polygon (a hole) representing where a lake is located.
In mathematics, any space having more than the three standard X, Y, and Z dimensions. Sometimes referred to as multidimensional data.
A geometric relationship where one object is surrounded by a larger object and the inner object does not touch the boundary of the outer. The smaller object is inside the larger. See also contain.
North/south position of a point on the Earth defined as the angle between the normal to the Earth's surface at that point and the plane of the equator.
A geometric object represented by a series of points, or inferred as existing between two coordinate points.
One or more pairs of points that define a line segment. See also multiline string.
East/west position of a point on the Earth defined as the angle between the plane of a reference meridian and the plane of a meridian passing through an arbitrary point.
A point with linear measure information along a geometric segment. See also geometric segment (LRS segment).
The linear distance (in the LRS measure dimension) to a point measured from the start point (for increasing values) or end point (for decreasing values) of the geometric segment.
● minimum bounding rectangle (MBR)
A single rectangle that minimally encloses a geometry or a collection of geometries.
See hyperspatial data.
A geometry object made up of nonconnected line string elements (for example, a street with a gap caused by a city park, such as Sixth Avenue in New York City with Central Park as the gap). See also line string.
A polygon collection geometry in which rings must be grouped by polygon, and the first ring of each polygon must be the exterior ring.
See spatial correlation.
The perpendicular distance between a point along a geometric segment and the geometric segment. Offsets are positive if the points are on the left side along the segment direction and are negative if they are on the right side. Points are on a geometric segment if their offsets to the segment are zero.
A special type of point geometry that includes coordinates representing the locations of the point and a virtual end point, to indicate an orientation vector that can be used for rotating a symbol at the point or extending a label from the point
A class of spatial objects having a nonzero area and perimeter, and representing a closed boundary region of uniform characteristics.
The operation that permits fast selection of candidate records to pass along to the secondary filter. The primary filter compares geometry approximations to reduce computation complexity and is considered a lower-cost filter. Because the primary filter compares geometric approximations, it returns a superset of the exact result set. See also secondary filter and two-tier query model.
Planar Cartesian coordinates that result from performing a mathematical mapping from a point on the Earth's surface to a plane. There are many such mathematical mappings, each used for a particular purpose.
The point on the LRS geometric segment with the minimum distance to the specified point.
A set of conditions or questions that form the basis for the retrieval of information from a database.
Area within which the retrieval of spatial information and related attributes is performed.
A process, function, or routine that executes continuously until a specified condition is met.
● Relational Database Management System (RDBMS)
A computer program designed to store and retrieve shared data. In a relational system, data is stored in tables consisting of one or more rows, each containing the same set of columns. Oracle Database is an object-relational database management system. Other types of database systems are called hierarchical or network database systems.
The ratio of the distance on a map, photograph, or image to the corresponding image on the ground, all expressed in the same units.
The operation that applies exact computations to geometries that result from the primary filter. The secondary filter yields an accurate answer to a spatial query. The secondary filter operation is computationally expensive, but it is only applied to the primary filter results, not the entire data set. See also primary filter and two-tier query model.
Points that are specified when an LRS segment is constructed, and that are assigned measure information.
The operation of arranging a set of items according to a key that determines the sequence and precedence of items.
The process of discretizing the location values into a small number of groups associated with geographical areas. Also referred to as spatial discretization.
The phenomenon of the location of a specific object in an area affecting some nonspatial attribute of the object. Also referred to as neighborhood influence.
Data that is referenced by its location in n-dimensional space. The position of spatial data is described by multiple values. See also hyperspatial data.
A class of data structures designed to store spatial information and facilitate its manipulation.
See spatial binning.
A query in which each of the geometries in one layer is compared with each of the geometries in the other layer. Comparable to a spatial cross product.
A query that includes criteria for which selected features must meet location conditions.
See coordinate system.
Data that contains time or location (or both) components as one of its dimensions, also referred to as geographically referenced data or georeferenced data.
The distance that two points can be apart and still be considered the same (for example, to accommodate rounding errors). The tolerance value must be a positive number greater than zero. The significance of the value depends on whether or not the spatial data is associated with a geodetic coordinate system.
A geometric relationship where two objects share a common point on their boundaries, but their interiors do not intersect.
The conversion of coordinates from one coordinate system to another coordinate system. If the coordinate system is georeferenced, transformation can involve datum transformation: the conversion of geodetic coordinates from one geodetic datum to another geodetic datum, usually involving changes in the shape, orientation, and center position of the reference ellipsoid.
The query model used by Spatial to resolve spatial queries and spatial joins. Two distinct filtering operations (primary and secondary) are performed to resolve queries. The output of both operations yields the exact result set. See also primary filter and secondary filter.
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GlossaryGlossary
In an Oracle Real Application Clusters (Oracle RAC) databases environment, the apply instance is the one instance applying archived redo data to a standby database.
A distributed management framework that automates and simplifies most of the complex operations required to create, control, and monitor a Data Guard configuration.
A logical grouping of the primary and standby databases (including redo transport services and log apply services) of a Data Guard configuration.
See also Data Guard configuration.
A standby database that is not the target of, or directly involved in, a switchover or failover operation.
A named collection of database objects. It is an abstraction of a Data Guard configuration.
The database guard controls whether or not modifications can be made to the tables in a logical standby database.
A named object that corresponds to a primary or standby database in a Data Guard configuration. The broker uses this object to manage and control the state of a single database and to associate properties with the database.
● Data Guard command-line interface
The Data Guard command-line interface (DGMGRL) enables you to control and monitor a Data Guard configuration from the DGMGRL prompt or within scripts.
A distributed computing system that prevents or minimizes losses due to unplanned events (for example, human errors, environmental disasters, or data corruption) as well as to planned downtime (such as for routine maintenance tasks).
See also broker configuration.
The physical configuration of the primary and standby databases. The environment depends on many factors, including the:
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Number of standby databases associated with a primary database
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Number of host systems used by the databases
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Directory structures of the machines used by the databases
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Network configuration
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Redo transport services
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Log apply services
The Data Guard environment can be managed manually by a DBA, automatically using Enterprise Manager or the Data Guard command-line interface (DGMGRL) or a combination of all of these.
The initial runtime state in which the database object will run when you enable broker management of the configuration. The actual default state can vary depending on the role (primary or standby) in which the database is running.
See also intended state.
Failover changes a standby database into the role of a primary database and disables the old primary database.
See also fast-start failover and manual failover.
Enables a failover automatically when the primary database becomes unavailable. When fast-start failover is enabled, the broker determines if a failover is necessary and automatically, quickly, and reliably fails over to a designated standby without requiring that you perform any manual steps to invoke the failover.
See also manual failover.
A named object; a database object is a collection of one or more named instance objects. The broker uses this object to manage and control the state of the database with which the instance is associated, and to associate instance-specific properties with this instance of the database.
The runtime state of a database object while it is enabled for management by the broker.
See also default state.
Refers to computing equipment or software whose operations are automated, requiring little to no intervention by human administrators.
The term "lights out" originated from when computing centers were located in one room and contained a number of servers that were kept under lock and key and in the dark. Under normal operation, the room was not entered by human administrators, and all operations in the room were automated.
A logical standby database takes standard Oracle archived redo log files, transforms them back into SQL transactions, and then applies them to an open standby database. Although changes can be applied concurrently with end-user access, the tables being maintained through regenerated SQL transactions allow read-only access to users of the logical standby database. Because the database is open to allow application of reconstructed SQL transactions, it is physically different from the primary database. The database tables can have different indexes and physical characteristics from their primary database peers, but the tables must maintain logical consistency from an application access perspective, to fulfill their role as a standby data source.
A failover that is initiated by the DBA who first determines a failover is necessary and then invokes one by clicking FAILOVER in Enterprise Manager or by issuing the DGMGRL FAILOVER command. The word manual is used to contrast this type of failover with a fast-start failover.
See also fast-start failover.
A DGMGRL client that continuously monitors the primary and target standby databases, evaluates whether failover is necessary, and initiates a fast-start failover when conditions warrant.
A physical standby database is an exact copy of a primary database. While the primary database is open and active, a physical standby database uses Redo Apply to apply redo data received from the primary database. Redo Apply can run on a physical standby database instance that is mounted. If a license for the Oracle Active Data Guard option has been purchased, Redo Apply can also run on a physical standby database instance that is open. See Oracle Data Guard Concepts and Administration for more details.
A production database from which one or more standby databases is created and maintained. Every standby database is associated with one and only one primary database. A single primary database can, however, support multiple standby databases. The Data Guard broker monitor (DMON) maintains the master copy of the binary configuration file with the primary database, ensuring that each standby database's copy of the file is kept up to date as changes are made.
The broker refers to this database using the value in the DB_UNIQUE_NAME initialization parameter which is defined to be globally unique.
The description of a database object including its current state (on or off), properties, and current status (for example, its health). This description is maintained persistently by the broker in its binary configuration file.
A mode in which a database can be opened that allows queries, but disallows modifications.
A physical standby database can be opened read-only so that queries may be performed. If a license for the Oracle Active Data Guard option has been purchased, a physical standby database can be open while Redo Apply is active. This capability is known as real-time query. See Oracle Data Guard Concepts and Administration for more details.
A physical standby database is kept synchronized with the primary database through Redo Apply, which recovers the redo data received from the primary database and applies the redo to the physical standby database.
Reinstatement is the process of turning a database, including the old primary database, that had been disabled after a failover operation into a viable standby database for the new primary database. Flashback database must be enabled on a database in order to reinstate it.
A snapshot standby is a fully updatable standby database that is created from a physical standby database. On snapshot standby databases, redo data is received but not applied until the snapshot standby database is converted back to a physical standby database.
A logical standby database is kept synchronized with the primary database through SQL Apply, which transforms the data in the redo received from the primary database into SQL statements and then executes the SQL statements on the standby database.
A copy of a primary database created using a backup of your primary database. Standby databases are kept synchronized with the primary database by applying archived redo data over time from the primary database to each standby database. The standby database can take over processing from the primary database, providing nearly continuous database availability. A standby database has its own server parameter file, control file, and data files. It also has a copy of the broker's configuration file, kept up to date at the direction of the DMON process running in the primary database instance.
The broker refers to a standby database by its globally unique name that is stored in its DB_UNIQUE_NAME initialization parameter.
See also logical standby database and physical standby database.
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GlossaryGlossary
A feature of the Support Vector Machine algorithm that provides a way to deal with large training data sets.
The process of consolidating data values into a smaller number of values. For example, sales data could be collected on a daily basis and then be totalled to the week level.
A sequence of steps for solving a problem. See data mining algorithm. The Oracle Data Mining programmatic interfaces support the following algorithms: MDL, Apriori, Decision Tree, k-Means, Naive Bayes, GLM, O-Cluster, and Support Vector Machine.
The detection of outliers or atypical cases. To build an anomaly detection model using the Data Mining programmatic interfaces, specify classification as the mining function, SVM as the algorithm, and pass a NULL or empty string as the target column name.
The data mining operation that scores data, that is, uses the model with new data to predict results.
A mining function that captures co-occurrence of items among transactions. A typical rule is an implication of the form A -> B, which means that the presence of itemset A implies the presence of itemset B with certain support and confidence. The support of the rule is the ratio of the number of transactions where the itemsets A and B are present to the total number of transactions. The confidence of the rule is the ratio of the number of transactions where the itemsets A and B are present to the number of transactions where itemset A is present. Oracle Data Mining uses the Apriori algorithm for association models.
An attribute is a predictor in a predictive model or an item of descriptive information in a descriptive model. Data attributes are the columns used to build a model. Data attributes undergo transformations so that they can be used as categoricals or numericals by the model. Categoricals and numericals are model attributes. See also target.
A mining function providing a measure of the importance of an attribute in predicting a specified target. The measure of different attributes of a training data table enables users to select the attributes that are found to be most relevant to a mining model. A smaller set of attributes results in a faster model build; the resulting model could be more accurate. Oracle Data Mining uses the Minimum Description Length to discover important attributes. Sometimes referred to as feature selection or key fields.
● Automatic Data Transformation
Mining models can be created in Automatic Data Preparation (ADP) mode. ADP transforms the build data according to the requirements of the algorithm, embeds the transformation instructions in the model, and uses the instructions to transform the test or scoring data when the model is applied.
See discretization.
All the data collected about a specific transaction or related set of values. A data set is a collection of cases. Cases are also called records or examples. In the simplest situation, a case corresponds to a row in a table.
A table or view in single-record case format. All the data for each case is contained in a single row. The case table may include a case ID column that holds a unique identifier for each row. Mining data must be presented as a case table.
An attribute whose values correspond to discrete categories. For example, state is a categorical attribute with discrete values (CA, NY, MA). Categorical attributes are either non-ordered (nominal) like state or gender, or ordered (ordinal) such as high, medium, or low temperatures.
See cluster centroid.
A mining function for predicting categorical target values for new records using a model built from records with known target values. Oracle Data Mining supports the following algorithms for classification: Naive Bayes, Decision Tree, and Support Vector Machines.
See trimming.
The vector that encodes, for each attribute, either the mean (if the attribute is numerical) or the mode (if the attribute is categorical) of the cases in the training data assigned to a cluster. A cluster centroid is often referred to as "the centroid."
A mining function for finding naturally occurring groupings in data. More precisely, given a set of data points, each having a set of attributes, and a similarity measure among them, clustering is the process of grouping the data points into different clusters such that data points in the same cluster are more similar to one another and data points in different clusters are less similar to one another. Oracle Data Mining supports two algorithms for clustering, k-Means and Orthogonal Partitioning Clustering.
Measures the correctness of predictions made by a model from a test task. The row indexes of a confusion matrix correspond to actual values observed and provided in the test data. The column indexes correspond to predicted values produced by applying the model to the test data. For any pair of actual/predicted indexes, the value indicates the number of records classified in that pairing.
When predicted value equals actual value, the model produces correct predictions. All other entries indicate errors.
An n by n table that defines the cost associated with a prediction versus the actual value. A cost matrix is typically used in classification models, where n is the number of distinct values in the target, and the columns and rows are labeled with target values. The rows are the actual values; the columns are the predicted values.
Negative instance of a target. Counterexamples are required for classification models, except for one-class Support Vector Machines.
Data mining is the practice of automatically searching large stores of data to discover patterns and trends that go beyond simple analysis. Data mining uses sophisticated mathematical algorithms to segment the data and evaluate the probability of future events. Data mining is also known as Knowledge Discovery in Data (KDD).
A data mining model implements a data mining algorithm to solve a given type of problem for a given set of data.
A specific technique or procedure for producing a data mining model. An algorithm uses a specific data representation and a specific mining function.
The algorithms in the Oracle Data Mining programming interfaces are Naive Bayes, Support Vector Machine, Generalized Linear Model, and Decision Tree for classification; Support Vector Machine and Generalized Linear Model for regression; k-Means and O-Cluster for clustering; Minimum Description Length for attribute importance; Non-Negative Matrix Factorization for feature extraction; Apriori for associations, and one-class Support Vector Machine for anomaly detection.
The component of the Oracle database that implements the data mining engine and persistent metadata repository. You must connect to a data mining server before performing data mining tasks.
In general, a collection of data. A data set is a collection of cases.
A descriptive model helps in understanding underlying processes or behavior. For example, an association model describes consumer behavior. See also mining model.
Discretization groups related values together under a single value (or bin). This reduces the number of distinct values in a column. Fewer bins result in models that build faster. Many Oracle Data Mining algorithms (for example NB) may benefit from input data that is discretized prior to model building, testing, computing lift, and applying (scoring). Different algorithms may require different types of binning. Oracle Data Mining includes transformations that perform top N frequency binning for categorical attributes and equi-width binning and quantile binning for numerical attributes.
● distance-based (clustering algorithm)
Distance-based algorithms rely on a distance metric (function) to measure the similarity between data points. Data points are assigned to the nearest cluster according to the distance metric used.
A decision tree is a representation of a classification system or supervised model. The tree is structured as a sequence of questions; the answers to the questions trace a path down the tree to a leaf, which yields the prediction.
Decision trees are a way of representing a series of questions that lead to a class or value. The top node of a decision tree is called the root node; terminal nodes are called leaf nodes. Decision trees are grown through an iterative splitting of data into discrete groups, where the goal is to maximize the distance between groups at each split.
An important characteristic of the decision tree models is that they are transparent; that is, there are rules that explain the classification.
See also rule.
See data mining server.
Equi-width binning determines bins for numerical attributes by dividing the range of values into a specified number of bins of equal size.
For a categorical attribute, replace a multi-value categorical column with several binary categorical columns. To explode the attribute, create a new binary column for each distinct value that the attribute takes on. In the new columns, 1 indicates that the value of the attribute takes on the value of the column; 0, that it does not. For example, suppose that a categorical attribute takes on the values {1, 2, 3}. To explode this attribute, create three new columns, col_1, col_2, and col_3. If the attribute takes on the value 1, the value in col_1 is 1; the values in the other two columns is 0.
A combination of attributes in the data that is of special interest and that captures important characteristics of the data. See feature extraction.
See also text feature.
Creates a new set of features by decomposing the original data. Feature extraction lets you describe the data with a number of features that is usually far smaller than the number of original attributes. See also Non-Negative Matrix Factorization.
A statistical technique for linear modeling. Generalized linear models (GLM) include and extend the class of simple linear models. Oracle Data Mining supports logistic regression for GLM classification and linear regression for GLM regression.
A distance-based clustering algorithm that partitions the data into a predetermined number of clusters (provided there are enough distinct cases). Distance-based algorithms rely on a distance metric (function) to measure the similarity between data points. Data points are assigned to the nearest cluster according to the distance metric used. Oracle Data Mining provides an enhanced version of k-Means.
A measure of how much better prediction results are using a model than could be obtained by chance. For example, suppose that 2% of the customers mailed a catalog make a purchase; suppose also that when you use a model to select catalog recipients, 10% make a purchase. Then the lift for the model is 10/2 or 5. Lift may also be used as a measure to compare different data mining models. Since lift is computed using a data table with actual outcomes, lift compares how well a model performs with respect to this data on predicted outcomes. Lift indicates how well the model improved the predictions over a random selection given actual results. Lift allows a user to infer how a model will perform on new data.
The sequence of transformations performed on a data set during the data preparation phase of the model build process.
The GLM regression algorithm supported by Oracle Data Mining.
The GLM classification algorithm supported by Oracle Data Mining.
Normalize numerical attributes using this transformation:
x_new = (x_old-min) / (max-min)
Given a sample of data and an effective enumeration of the appropriate alternative theories to explain the data, the best theory is the one that minimizes the sum of
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The length, in bits, of the description of the theory
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The length, in bits, of the data when encoded with the help of the theory
This principle is used to select the attributes that most influence target value discrimination in attribute importance.
A major subdomain of data mining that shares common high level characteristics. The Oracle Data Mining programming interfaces support the following mining functions: classification, regression, attribute importance, feature extraction, and clustering. In both programming interfaces, anomaly detection is supported as classification.
An important function of data mining is the production of a model. A model can be a supervised model or an unsupervised model. Technically, a mining model is the result of building a model from mining settings. The representation of the model is specific to the algorithm specified by the user or selected by the DMS. A model can be used for direct inspection, for example, to examine the rules produced from an association model, or to score data.
The end product(s) of a mining task. For example, a build task produces a mining model; a test task produces a test result.
A data value that is missing at random. It could be missing because it is unavailable, unknown, or because it was lost. Oracle Data Mining interprets missing values in columns with simple data types (not nested) as missing at random. Oracle Data Mining interprets missing values in nested columns as sparse.
Data mining algorithms vary in the way they treat missing values. There are several typical ways to treat them: ignore them, omit any records containing missing values, replace missing values with the mode or mean, or infer missing values from existing values. See also sparse data.
See mining model.
Each case in the data table is stored in multiple rows. Also known as transactional data. See also single-record case.
An algorithm for classification that is based on Bayes's theorem. Naive Bayes makes the assumption that each attribute is conditionally independent of the others: given a particular value of the target, the distribution of each predictor is independent of the other predictors.
Oracle Data Mining supports transactional data in nested columns of name/value pairs. Multidimensional data that expresses a one-to-many relationship can be loaded into a nested column and mined along with single-record case data in a case table.
● Non-Negative Matrix Factorization
A feature extraction algorithm that decomposes multivariate data by creating a user-defined number of features, which results in a reduced representation of the original data.
Normalization consists of transforming numerical values into a specific range, such as [–1.0,1.0] or [0.0,1.0] such that x_new = (x_old-shift)/scale. Normalization applies only to numerical attributes. Oracle Data Mining provides transformations that perform min-max normalization, scale normalization, and z-score normalization.
An attribute whose values are numbers. The numeric value can be either an integer or a real number. Numerical attribute values can be manipulated as continuous values. See also categorical attribute.
● one-class Support Vector Machine
The version of the Support Vector Machine model used to solve anomaly detection problems. The Oracle Data Mining programmatic interfaces implement the one-class algorithm as classification.
● Orthogonal Partitioning Clustering
An Oracle proprietary clustering algorithm that creates a hierarchical grid-based clustering model, that is, it creates axis-parallel (orthogonal) partitions in the input attribute space. The algorithm operates recursively. The resulting hierarchical structure represents an irregular grid that tessellates the attribute space into clusters.
A data value that does not come from the typical population of data; in other words, extreme values. In a normal distribution, outliers are typically at least 3 standard deviations from the mean.
In binary classification problems, you may designate one of the two classes (target values) as positive, the other as negative. When Oracle Data Mining computes a model's lift, it calculates the density of positive target values among a set of test instances for which the model predicts positive values with a given degree of confidence.
A predictive model is an equation or set of rules that makes it possible to predict an unseen or unmeasured value (the dependent variable or output) from other, known values (independent variables or input). The form of the equation or rules is suggested by mining data collected from the process under study. Some training or estimation technique is used to estimate the parameters of the equation or rules. A predictive model is a supervised model.
Data that is suitable for model building using a specified algorithm. Data preparation often accounts for much of the time spent in a data mining project. Oracle Data Mining supports transformations binning, normalization, and missing value treatment. Oracle Data Mining can automatically perform algorithm-appropriate transformations when Automatic Data Transformation is enabled.
The set of prior probabilities specifies the distribution of examples of the various classes in the original source data. Also referred to as priors, these could be different from the distribution observed in the data set provided for model build.
See prior probabilities.
A numerical attribute is divided into bins such that each bin contains approximately the same number of cases.
A sample in which every element of the data set has an equal chance of being selected.
Literally "change or rearrange the code." Recoding can be useful in many instances in data mining. Here are some examples:
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Missing values treatment: Missing values may be indicated by something other than NULL, such as "0000" or "9999" or "NA" or some other string. One way to treat the missing value is to recode, for example, "0000" to NULL. Then the Oracle Data Mining algorithms and the database recognize the value as missing.
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Change data type of variable: For example, change "Y" or "Yes" to 1 and "N" or "No" to 0.
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Establish a cutoff value: For example, recode all incomes less than $20,000 to the same value.
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Group items: For example, group individual US states into regions. The "New England region" might consist of ME, VT, NH, MA, CT, and RI; to implement this, recode the five states to, say, NE (for New England).
See case.
A data mining function for predicting continuous target values for new records using a model built from records with known target values. Oracle Data Mining supports linear regression (GLM) and Support Vector Machine algorithms for regression.
An expression of the general form if X, then Y. An output of certain algorithms, such as clustering, association, and decision tree. The predicate X may be a compound predicate.
See random sample.
Normalize numerical attributes using this transformation:
x_new = (x_old - 0) / (max(abs(max),abs(min)))
A collection of objects in an Oracle database, including logical structures such as tables, views, sequences, stored procedures, synonyms, indexes, clusters, and database links. A schema is associated with a specific database user.
See algorithm settings.
Each case in the data table is stored in one row. Contrast with multi-record case.
Data for which only a small fraction of the attributes are non-zero or non-null in any given case. Market basket data and text mining data are typically sparse. Oracle Data Mining interprets nested data as sparse. See also missing value.
Divide a data set into several disjoint subsets. For example, in a classification problem, a data set is often divided in to a training data set and a test data set.
Divide the data set into disjoint subsets (strata) and then take a random sample from each of the subsets. This technique is used when the distribution of target values is skewed greatly. For example, response to a marketing campaign may have a positive target value 1% of the time or less. A stratified sample provides the data mining algorithms with enough positive examples to learn the factors that differentiate positive from negative target values. See also random sample.
Mining models that contain instructions for their own data preparation. Oracle Data Mining provides Automatic Data Transformation and embedded data transformation, which together provide support for supermodels.
See supervised model.
A data mining model that is built using a known dependent variable, also referred to as the target. Classification and regression techniques are examples of supervised mining. See unsupervised model. Also referred to as predictive model.
An algorithm that uses machine learning theory to maximize predictive accuracy while automatically avoiding over-fit to the data. Support vector machines can make predictions with sparse data, that is, in domains that have a large number of predictor columns and relatively few rows, as is the case with bioinformatics data. Support vector machine can be used for classification, regression, and anomaly detection.
The basic unit of data storage in an Oracle database. Table data is stored in rows and columns.
In supervised learning, the identified attribute that is to be predicted. Sometimes called target value or target attribute. See also attribute.
A combination of words that captures important attributes of a document or class of documents. Text features are usually keywords, frequencies of words, or other document-derived features. A document typically contains a large number of words and a much smaller number of features.
Conventional data mining done using text features. Text features are usually keywords, frequencies of words, or other document-derived features. Once you derive text features, you mine them just as you would any other data. Both Oracle Data Mining and Oracle Text support text mining.
This type of binning bins categorical attributes. The bin definition for each attribute is computed based on the occurrence frequency of values that are computed from the data. The user specifies a particular number of bins, say N. Each of the bins bin_1,..., bin_N corresponds to the values with top frequencies. The bin bin_N+1 corresponds to all remaining values.
See build data.
The data for one case is contained in several rows. An example is market basket data, in which a case represents one basket that contains multiple items. Oracle Data Mining supports transactional data in nested columns of attribute name/value pairs. See also nested data, multi-record case, and single-record case.
A function applied to data resulting in a new representation of the data. For example, discretization and normalization are transformations on data.
A technique used for dealing with outliers. Trimming removes values in the tails of a distribution in the sense that trimmed values are ignored in further computations. This is achieved by setting the tails to NULL.
Images, audio, video, geospatial mapping data, and documents or text data are collectively known as unstructured data. Oracle Data Mining supports the mining of unstructured text data.
See unsupervised model.
A data mining model built without the guidance (supervision) of a known, correct result. In supervised learning, this correct result is provided in the target attribute. Unsupervised learning has no such target attribute. Clustering and association are examples of unsupervised mining functions. See supervised model.
A view takes the output of a query and treats it as a table. Therefore, a view can be thought of as a stored query or a virtual table. You can use views in most places where a table can be used.
A way of dealing with outliers. Winsorizing involves setting the tail values of an particular attribute to some specified value. For example, for a 90% Winsorization, the bottom 5% of values are set equal to the minimum value in the 6th percentile, while the upper 5% are set equal to the maximum value in the 95th percentile.
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GlossaryGlossary
A duplicate database that is created over a network without restoring backups of the target database. This technique is an alternative to backup-based duplication.
The parent incarnation is the database incarnation from which the current incarnation branched following an OPEN RESETLOGS operation. The parent of the parent incarnation is an ancestor incarnation. Any parent of an ancestor incarnation is also an ancestor incarnation.
A database backup that is exempted from the normal backup and recovery strategy. Typically, these backups are archived onto separate storage media and retained for long periods.
A copy of a filled member of an online redo log group made when the database is in ARCHIVELOG mode. After the LGWR process fills each online redo log with redo records, the archiver process copies the log to one or more redo log archiving destinations. This copy is the archived redo log. RMAN does not distinguish between an original archived redo log and an image copy of an archived redo log; both are considered image copies.
● archived redo log deletion policy
A configurable, persistent RMAN policy that governs when archived redo logs can be deleted. You can configure the policy with the CONFIGURE ARCHIVELOG DELETION POLICY command.
An RMAN feature that enables RMAN to complete a backup even when some archived log destinations are missing logs or have logs with corrupt blocks. For example, if you back up logs in the fast recovery area that RMAN determines are corrupt, RMAN can search for logs in other archiving locations and back them up instead if they are intact.
The mode of the database in which Oracle Database copies filled online redo logs to disk. Specify the mode at database creation or with the ALTER DATABASE ARCHIVELOG statement.
See Also: archived redo log, NOARCHIVELOG mode
The operation in which a filled online redo log file is copied to an offline log archiving destination. An offline copy of an online redo logs is called an archived redo log. You must run the database in ARCHIVELOG mode to archive redo logs.
A server process can begin an I/O and then perform other work while waiting for the I/O to complete while RMAN is either reading or writing data. RMAN can also begin multiple I/O operations before waiting for the first I/O to complete.
● automatic channel allocation
The ability of RMAN to perform backup and restore tasks without requiring the use of the ALLOCATE CHANNNEL command. You can use the CONFIGURE command to specify disk and tape channels. Then, you can issue commands such as BACKUP and RESTORE at the RMAN command prompt without manually allocating channels. RMAN uses whatever configured channels that it needs to execute the commands.
● Automatic Diagnostic Repository (ADR)
A system-managed repository for storing and organizing database trace files and other diagnostic data. ADR provides a comprehensive view of all the serious errors encountered by the database and maintains all relevant data needed for problem diagnostic and their eventual resolution. The repository contains data describing incidents, traces, dumps, alert messages, data repair records, data integrity check records, SQL trace information, core dumps, and so on.
The initialization parameter DIAGNOSTIC_DEST specifies the location of the ADR base, which is the directory that contains one or more ADR homes. Each ADR home is used by a product or a product instance to store diagnostic data in well-defined subdirectories. For example, diagnostic data for an Oracle database instance is stored in its ADR home, which includes an alert subdirectory for alert messages, a trace subdirectory for trace files, and so on. The easiest way to locate trace files and the alert log is to run the following SQL query: SELECT NAME, VALUE FROM V$DIAG_INFO.
● Automatic Storage Management (ASM)
A vertical integration of both the file system and the volume manager built specifically for Oracle database files. ASM consolidates storage devices into easily managed disk groups and provides benefits such as mirroring and striping without requiring a third-party logical volume manager.
● automatic undo management mode
A mode of the database in which undo data is stored in a dedicated undo tablespace. The only undo management that you must perform is the creation of the undo tablespace. All other undo management is performed automatically.
An RMAN channel that is connected to an auxiliary instance. An auxiliary channel is specified with the AUXILIARY keyword of the ALLOCATE CHANNEL or CONFIGURE CHANNEL command.
(1) A database created from target database backups with the RMAN DUPLICATE command.
(2) A temporary database that is restored to a new location and then started with a new instance name during tablespace point-in-time recovery (TSPITR). A TSPITR auxiliary database contains the recovery set and auxiliary set.
In a transportable tablespace operation, the location on disk where auxiliary set files such as the parameter file, data files (other than those of the tablespaces being transported), control files, and online redo logs of the auxiliary instance can be stored.
The Oracle instance associated with an auxiliary database, or the temporary instance used in tablespace point-in-time recovery (TSPITR) or a transportable tablespace operation.
In TSPITR, the set of files that is not in the recovery set but which must be restored in the auxiliary database for the TSPITR operation to be successful. In a transportable tablespace operation, the auxiliary set includes data files and other files required for the tablespace transport but which are not themselves part of the recovery set.
(1) A backup copy of data, that is, a database, tablespace, table, data file, control file, or archived redo log. Backups can be physical (at the database file level) or logical (at the database object level). Physical backups can be created by using RMAN to back up one or more data files, control files or archived redo log files. You can create logical backups with Data Pump Export.
(2) In an RMAN context, the output of the BACKUP command. The output format of a backup can be a backup set, proxy copy, or image copy. Logs archived by the database are considered copies rather than backups.
The set of concepts, procedures, and strategies involved in protecting the database against data loss due to media failure or users errors.
A backup of the control file. You can back up the control file with the RMAN backup command or with the SQL statement ALTER DATABASE BACKUP CONTROLFILE TO 'filename'.
The encryption of backup sets by using an algorithm listed in V$RMAN_ENCRYPTION_ALGORITHMS. RMAN can transparently encrypt data written to backup sets and decrypt those backup sets when they are needed in a RESTORE operation. RMAN offers three modes of encryption: transparent, password-protected, and dual-mode.
The database mode (also called hot backup mode) initiated when you issue the ALTER TABLESPACE ... BEGIN BACKUP or ALTER DATABASE BEGIN BACKUP command before taking an online backup. You take a tablespace out of backup mode when you issue the ALTER TABLESPACE ... END BACKUP or ALTER DATABASE END BACKUP command.
When making a user-managed backup of data files in an online tablespace, you must place the tablespace in backup mode to protect against the possibility of a fractured block. In backup mode, updates to the database create more than the usual amount of redo. Each time a block in the buffer cache becomes dirty, the database must write an image of the changed block to the redo log file, in addition to recording the changes to the data. RMAN does not require you to put the database in backup mode.
See Also: corrupt block
A configuration enabling RMAN to automatically skip backups of files that it has already backed up. You enable and disable backup optimization with the CONFIGURE command.
The physical file format used to store an RMAN backup set. Each logical backup set contains one or more physical backup pieces.
A user-defined policy for determining how long backups and archived logs must be retained for media recovery. You can define a retention policy in terms of backup redundancy or a recovery window. RMAN retains the data file backups required to satisfy the current retention policy, and any archived redo logs required for complete recovery of those data file backups.
A backup of one or more data files, control files, server parameter files, and archived redo log files. Each backup set consists of one or more binary files. Each binary file is called a backup piece. Backup pieces are written in a proprietary format that can only be created or restored by RMAN.
Backup sets are produced by the RMAN BACKUP command. A backup set usually consists of only one backup piece. RMAN divides the contents of a backup set among multiple backup pieces only if you limit the backup piece size using the MAXPIECESIZE option of the ALLOCATE CHANNEL or CONFIGURE CHANNEL command.
See Also: unused block compression, multiplexing, RMAN
The exclusion of undo not needed for recovery of an RMAN backup because it describes and contains committed transactions. Backup undo optimization applies to level 0 and full backups. It is built-in RMAN behavior and cannot be disabled.
For example, a user updates the SALARIES table in the USERS tablespace. The change is written to the USERS tablespace, while the before image of the data is written to the UNDO tablespace. A subsequent RMAN backup of the UNDO tablespace may not include the undo for the salary change.
A duplicate database that is created by restoring and recovering backups of the target database. This technique is an alternative to active database duplication.
The entirety of the recovery catalog schema. The base recovery catalog is distinguished from a virtual private catalog, which is a subset of a recovery catalog.
A technique whereby RMAN applies a compression algorithm to data in backup sets.
A database option that causes Oracle to track data file blocks affected by each database update. The tracking information is stored in a block change tracking file. When block change tracking is enabled, RMAN uses the record of changed blocks from the change tracking file to improve incremental backup performance by only reading those blocks known to have changed, instead of reading data files in their entirety.
A binary file used by RMAN to record changed blocks to improve incremental backup performance. You create and rename this file with the ALTER DATABASE statement.
The recovery of specified blocks within a data file with the Recovery Manager RECOVER ... BLOCK command. Block media recovery leaves the affected data files online and restores and recovers only the damaged or corrupted blocks.
The termination of a disk mirroring procedure so that a mirror image is no longer kept up-do-date.
An RMAN channel represents one stream of data to or from a backup device. A channel can either be a DISK channel (used to perform disk I/O) or an SBT channel (used to perform I/O through a third-party media manager). Each allocated channel starts a new Oracle Database session. The session then performs backup, restore, and recovery operations.
See Also: target database
An invocation of a checker, which is a diagnostic procedure registered with the Health Monitor.
A data structure that defines an SCN in the redo thread of a database. Checkpoints are recorded in the control file and each data file header, and are a crucial element of recovery.
A number calculated by the database from all the bytes stored in a data or redo block. If the DB_BLOCK_CHECKSUM initialization parameter is enabled, then the database calculates the checksum for every data file or online redo log block and stores it in the block header when writing to disk. The database can use the checksum value to check consistency.
Control file records containing information used by RMAN for backups and recovery operations. These records are arranged in a logical ring. When all available record slots are full, Oracle either expands the control file to make room for a new records or overwrites the oldest record. The CONTROL_FILE_RECORD_KEEP_TIME initialization parameter controls how many days records must be kept before they can be overwritten. The default for CONTROL_FILE_RECORD_KEEP_TIME is 7 days.
See Also: noncircular reuse records
A backup of one or more database files taken while the database is closed. Typically, closed backups are whole database backups. If you closed the database consistently, then all the files in the backup are consistent. Otherwise, the backups are inconsistent.
See Also: consistent shutdown, consistent backup
See closed backup
In an RMAN context, a client-side text file containing a sequence of RMAN commands. You can run command files with the @ or @@ commands from within RMAN or from the operating system prompt with the @ or CMDFILE parameters.
Recovery of one or more data files that applies all redo generated after the restored backup. Typically, you perform complete media recovery when media failure damages one or more data files or control files. You fully recover the damaged files using all redo generated since the restored backup was taken.
See Also: incomplete recovery
A whole database backup that you can open with the RESETLOGS option without performing media recovery. You do not need to apply redo to this backup to make it consistent. Unless you apply the redo generated since the consistent backup was created, however, you lose all transactions since the time of the consistent backup.
You can only take consistent backups after you have performed a consistent shutdown of the database. The database must not be re-opened until the backup has completed.
See Also: fuzzy file, inconsistent backup
A database shut down with the IMMEDIATE, TRASACTIONAL, or NORMAL options of the statement. A database shut down cleanly does not require recovery; it is already in a consistent state.
The automatic backup of the current control file and server parameter file that RMAN makes after backups and, if the database is in ARCHIVELOG mode, after structural changes.
The control file autobackup has a default file name that allows RMAN to restore it even if the control file and recovery catalog are lost. You can override the default file name.
A script generated by the CONVERT DATABASE command that you can use to convert data file formats on the destination host.
To back up a bit-for-bit image of an Oracle file (Oracle data files, control files, and archived redo logs) onto disk. You can copy in two ways:
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Using operating system utilities (for example, the UNIX cp or dd)
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Using the RMAN BACKUP AS COPY command
See Also: backup
An Oracle block that is not in a recognized Oracle format, or whose contents are not internally consistent. Typically, corruptions are caused by faulty hardware or operating system problems. Oracle identifies corrupt blocks as either logically corrupt (an Oracle internal error) or media corrupt (the block format is not correct).
You can repair a media corrupt block with block media recovery, or dropping the database object that contains the corrupt block so that its blocks are reused for another object. If media corruption is due to faulty hardware, then neither solution works until the hardware fault is corrected.
The automatic application of online redo records to a database after either a single-instance database crashes or all instances of an Oracle Real Applications Cluster configuration crash. Crash recovery only requires redo from the online logs: archived redo logs are not required.
See Also: recover
A check to determine whether files on disk or in the media management catalog correspond to the data in the RMAN repository. Because the media manager can mark tapes as expired or unusable, and because files can be deleted from disk or otherwise become corrupted, the RMAN repository can contain outdated information about backups. Run the CROSSCHECK command to perform a crosscheck.
See Also: validation
● cumulative incremental backup
An incremental backup that backs up all the blocks changed since the most recent backup at level 0. When recovering with cumulative incremental backups, only the most recent cumulative incremental backup must be applied.
See Also: differential incremental backup, incremental backup
The database incarnation in which the database is currently generating redo.
The online redo log file in which the LGWR background process is currently logging redo records.
See Also: redo log, redo log group
The use of media recovery or Oracle Flashback Technology to recover lost or corrupted data.
An Oracle Database tool that automatically diagnoses persistent data failures, presents repair options to the user, and executes repairs at the user's request.
A location for the Oracle managed data files, control files, and online redo log files. The database area is specified by the DB_CREATE_FILE_DEST initialization parameter.
The thread checkpoint that has the lowest SCN. All changes in all enabled redo threads with SCNs before the database checkpoint SCN are guaranteed to have been written to disk.
See Also: checkpoint, data file checkpoint
See DBID
● database point-in-time recovery (DBPITR)
The recovery of an entire database to a specified past target time, SCN, or log sequence number.
See Also: incomplete recovery, tablespace point-in-time recovery (TSPITR)
See registration
A data structure that defines an SCN in the redo thread of a database for a particular data file. Every data file has a checkpoint SCN, which you can view in V$DATAFILE.CHECKPOINT_CHANGE#. All changes with an SCN lower than this SCN are guaranteed to be in the data file.
The application of redo records to a restored data file to roll it forward to a more current time. Unless you are doing block media recovery, the data file must be offline while being recovered.
An internal, uniquely generated number that differentiates databases. Oracle creates this number automatically when you create the database.
The computer on which a duplicate database resides.
When using the RMAN CONVERT command, the platform on which the destination database is running. The destination database is the database into which you are transporting data.
● differential incremental backup
A type of incremental backup that backs up all blocks that have changed since the most recent backup at level 1 or level 0. For example, in a differential level 1 backup RMAN determines which level 1 or level 0 incremental backup is most recent and then backs up all blocks changed since that backup. Differential backups are the default type of incremental backup. When recovering using differential incremental backups, RMAN must apply all differential incremental level 1 backups since the restored data file backup.
See Also: cumulative incremental backup, incremental backup
When multiple OPEN RESETLOGS operations have been performed, the incarnation path that includes the parent incarnation of the current database incarnation and each ancestor incarnation of the current incarnation.
A strategic response to the loss of all data associated with a database installation. For example, a fire may destroy a server in a data center, forcing you to reinstall Oracle Database on a new server and recover the lost database from backups.
A collection of disks that are managed as a unit by Automatic Storage Management (ASM). The components of a disk group include disks, files, and allocation units.
A user-specified limit to the size of the fast recovery area. When the disk quota is reached, Oracle automatically deletes files that are no longer needed.
In RMAN, a duplexed backup set is an RMAN-generated identical copy of a backup set. Each backup piece is in the original backup set is copied, with each copy getting a unique copy number (for example, 0tcm8u2s_1_1 and 0tcm8u2s_1_2).
A database created from target database backups using the RMAN duplicate command.
See Also: auxiliary database
A backup whose status in the RMAN repository is EXPIRED, which means that the backup was not found. RMAN marks backups and copies as expired when you run a CROSSCHECK command and the files are absent or inaccessible.
The extraction of logical data (that is, not physical files) from a database into a binary file using Data Pump Export. You can then use Data Pump Import to import the data into a database.
See Also: logical backup
A file created by the Data Pump Export utility. The dump file set is made up of one or more disk files that contain table data, database object metadata, and control information. The files are written in a proprietary, binary format.
For Data Recovery Advisor, a failure is a persistent data corruption that has been diagnosed by the database. A failure can manifest itself as observable symptoms such as error messages and alerts, but a failure is different from a symptom because it represents a diagnosed problem. Failures are recorded in a repository for diagnostic data located outside of the database.
For each failure, Data Recovery Advisor generates a problem statement that unambiguously describes it. Examples of failures include inaccessible data files and corrupted undo segments. Data Recovery Advisor maps every failure to a repair option or set of repair options.
The priority of a failure diagnosed by Data Recovery Advisor. Every failure that is not closed has CRITICAL, HIGH, or LOW status. You can manually change the status of HIGH and LOW failures with the CHANGE command.
The status of a failure diagnosed by Data Recovery Advisor. Every failure has OPEN or CLOSED status.
A contiguous range of blocks in a data file. A multisection backup processes a large file in parallel by copying each section to a separate backup piece.
An optional disk location that you can use to store recovery-related files such as control file and online redo log copies, archived redo log files, flashback logs, and RMAN backups. Oracle Database and RMAN manage the files in the fast recovery area automatically. You can specify the disk quota, which is the maximum size of the fast recovery area. Formerly referred to as flash recovery area.
A historical repository of transactional changes to every record in a table for the duration of the record's lifetime. A flashback data archive enables you to use some logical flashback features to transparently access historical data from far in the past.
The range of SCNs for which there is currently enough flashback log data to support the FLASHBACK DATABASE command. The flashback database window cannot extend further back than the earliest SCN in the available flashback logs.
Oracle-generated logs used to perform flashback database operations. The database can only write flashback logs to the fast recovery area. Flashback logs are written sequentially and are not archived. They cannot be backed up to disk.
A user-specified time or SCN that specifies how far into the past you want to be able to perform a flashback of the database.
An archived redo log received by a logical standby database for a LogMiner session. Unlike normal archived logs, foreign archived logs have a different DBID. For this reason, they cannot be backed up or restored on a logical standby database.
A block in which the header and footer are not consistent at a given SCN. In a user-managed backup, an operating system utility can back up a data file at the same time that DBWR is updating the file. It is possible for the operating system utility to read a block in a half-updated state, so that the block that is copied to the backup media is updated in its first half, while the second half contains older data. In this case, the block is fractured.
For non-RMAN backups, the ALTER TABLESPACE ... BEGIN BACKUP or ALTER DATABASE BEGIN BACKUP command is the solution for the fractured block problem. When a tablespace is in backup mode, and a change is made to a data block, the database logs a copy of the entire block image before the change so that the database can reconstruct this block if media recovery finds that this block was fractured.
A non-incremental RMAN backup. The word "full" does not refer to how much of the database is backed up, but to the fact that the backup is not incremental. Consequently, you can make a full backup of one data file.
An RMAN operation that updates the recovery catalog with all changed metadata in the database's control file. You can initiate a full catalog resynchronization by issuing the RMAN command RESYNC CATALOG. (It is rarely necessary to use RESYNC CATALOG because RMAN automatically performs resynchronizations when needed.)
A data file that contains at least one block with an SCN greater than or equal to the checkpoint SCN in the data file header. Fuzzy files are possible because database writer does not update the SCN in the file header with each file block write. For example, this situation occurs when Oracle updates a data file that is in backup mode. A fuzzy file that is restored always requires media recovery.
A restore point for which the database is guaranteed to retain the flashback logs for an Oracle Flashback Database operation. Unlike a normal restore point, a guaranteed restore point does not age out of the control file and must be explicitly dropped. Guaranteed restore points use space in the fast recovery area, which must be defined.
See online backup
See backup mode
A bit-for-bit copy of a single data file, archived redo log file, or control file that is:
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Usable as-is to perform recovery (unlike a backup set, which uses unused block compression and is in an RMAN-specific format)
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Generated with the RMAN BACKUP AS COPY command, an operating system command such as the UNIX cp, or by the Oracle archiver process
A separate version of a database. The incarnation of the database changes when you open it with the RESETLOGS option, but you can recover backups from a prior incarnation so long as the necessary redo is available.
A synonym for database point-in-time recovery (DBPITR).
See Also: complete recovery, media recovery, recover
A backup in which some files in the backup contain changes that were made after the files were checkpointed. This type of backup needs recovery before it can be made consistent. Inconsistent backups are usually created by taking online database backups. You can also make an inconsistent backup by backing up data files while a database is closed, either:
-
Immediately after the crash of an Oracle instance (or, in an Oracle RAC configuration, all instances)
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After shutting down the database using SHUTDOWN ABORT
Inconsistent backups are only useful if the database is in ARCHIVELOG mode and all archived redo logs created since the backup are available.
See Also: consistent backup, online backup, system change number (SCN), whole database backup
An RMAN backup in which only modified blocks are backed up. Incremental backups are classified by level. A level 0 incremental backup performs the same function as a full backup in that they both back up all blocks that have ever been used. The difference is that a full backup does not affect blocks backed up by subsequent incremental backups, whereas an incremental backup does affect blocks backed up by subsequent incremental backups.
Incremental backups at level 1 back up only blocks that have changed since previous incremental backups. Blocks that have not changed are not backed up. An incremental backup can be either a differential incremental backup or a cumulative incremental backup.
● incrementally updated backup
An RMAN data file copy that is updated by an incremental backup. An effective backup strategy is to copy a data file, make an incremental backup, and then merge the incremental backup into the image copy. This strategy reduces the time required for media recovery because the image copy is updated with the latest data block changes.
The termination of an Oracle instance due to a hardware failure, Oracle internal error, or SHUTDOWN ABORT statement. Crash or instance recovery is always required after an instance failure.
In an Oracle RAC configuration, the application of redo data to an open database by an instance when this instance discovers that another instance has crashed.
See Also: recover
A type of block corruption in which the corruption occurs between blocks rather than within the block itself. This type of corruption can only be logical corruption.
A type of block corruption in which the corruption occurs within the block itself. this type of corruption can be either a physical corruption or logical corruption.
An RMAN incremental backup that backs up all data blocks in the data files being backed up. An incremental backup at level 0 is identical in content to a full backup, but unlike a full backup the level 0 backup is considered a part of the incremental backup strategy.
The number of input files simultaneously read and then written into the same RMAN backup piece.
A utility that enables log files to be read, analyzed, and interpreted with SQL statements.
See Also: archived redo log
A number that uniquely identifies a set of redo records in a redo log file. When Oracle fills one online redo log file and switches to a different one, Oracle automatically assigns the new file a log sequence number.
See Also: log switch, redo log
The point at which LGWR stops writing to the active redo log file and switches to the next available redo log file. LGWR switches when either the active log file is filled with redo records or you force a switch manually.
See Also: redo log
A backup of database schema objects, such as tables. Logical backups are created and restored with the Oracle Data Pump Export utility. You can restore objects from logical backups using the Data Pump Import utility.
The set of Oracle Flashback Technology features other than Oracle Flashback Database. The logical features enable you to view or rewind individual database objects or transactions to a past time.
A type of corruption in which the block has a valid checksum, the header and footer match, and so on, but the contents are logically inconsistent.
A backup that you want to exclude from a backup retention policy, but want to record in the recovery catalog. Typically, long-term backups are snapshots of the database that you may want to use in the future for report generation.
A write to persistent storage that the database believes has occurred based on information from the I/O subsystem, when in fact the write has not occurred.
Damage to the disks containing any of the files used by Oracle, such as the data files, archived redo log files, or control file. When Oracle detects media failure, it takes the affected files offline.
See Also: media recovery
A third-party networked backup system that can be integrated with Recovery Manager so that database backups can be written directly to tertiary storage.
Multiplexing in which the media manager rather than RMAN manages the mixing of blocks during an RMAN backup. One type of media manager multiplexing occurs when the media manager writes the concurrent output from multiple RMAN channels to a single sequential device. Another type occurs when a backup mixes database files and non-database files on the same tape.
A catalog of records maintained by a media manager. This catalog is completely independent from the RMAN recovery catalog. The Oracle Secure Backup catalog is an example of a media management catalog.
A software library that RMAN can use to back up to tertiary storage. An SBT interface conforms to a published API and is supplied by a media management vendor. Oracle Secure Backup includes an SBT interface for use with RMAN.
The application of redo or incremental backups to a restored backup data file or individual data block.
When performing media recovery, you can recover a database, tablespace, data file, or set of blocks within a data file. Media recovery can be either complete recovery (in which all changes in the redo logs are applied) or incomplete recovery (in which only changes up to a specified point in time are applied). Media recovery is only possible when the database is in ARCHIVELOG mode.
See Also: block media recovery, recover
Maintaining identical copies of data on one or more disks. Typically, mirroring is performed on duplicate hard disks at the operating system level, so that if a disk is unavailable, then the other disk can continue to service requests without interruptions. When mirroring files, Oracle Database writes once while the operating system writes to multiple disks. When multiplexing files, Oracle Database writes the same data to multiple files.
A backup set that contains blocks from multiple input files. For example, you could multiplex 10 data files into one backup set. Only whole files, never partial files, are included in a backup set.
The meaning of the term depends on which files are multiplexed:
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online redo logs
The automated maintenance of multiple identical copies of the online redo log.
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control file
The automated maintenance of multiple identical copies of a database control file.
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backup set
The RMAN technique of reading database files simultaneously from the disks and then writing the blocks to the same backup piece.
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archived redo logs
The Oracle archiver process can archive multiple copies of a redo log.
See Also: mirroring
An RMAN backup set in which each backup piece contains a file section, which is a contiguous range of blocks in a data file. A multisection backup set contains multiple backup pieces, but a backup set never contains only a part of a data file.
You create a multisection backup by specifying the SECTION SIZE parameter on the BACKUP command. An RMAN channel can process each file section independently, either serially or in parallel. Thus, in a multisection backup, multiple channels can back up a single file.
In a tape drive, the speed of writing to a tape without compression. This speed represents the upper limit of the backup rate.
The mode of the database in which Oracle does not require filled online redo logs to be archived before they can be overwritten. Specify the mode at database creation or change it with the ALTER DATABASE NOARCHIVELOG command.
If you run in NOARCHIVELOG mode, it severely limits the possibilities for recovery of lost or damaged data.
See Also: archived redo log, ARCHIVELOG mode
Control file records containing critical information needed by the Oracle database. These records are never automatically overwritten. Some examples of information in noncircular reuse records include the locations of data files and online redo logs.
See Also: circular reuse records
A label for an SCN or time. For commands that support an SCN or time, you can often specify a restore point. Normal restore points exist in the circular list and can be overwritten in the control file. However, if the restore point pertains to an archival backup, then it is preserved in the recovery catalog.
A backup that is not needed to satisfy the current backup retention policy. For example, if your retention policy dictates that you must maintain one backup of each data file, but you have two backups of data file 1, then the second backup of data file 1 is considered obsolete.
A tablespace is offline normal when taken offline with the ALTER TABLESPACE ... OFFLINE NORMAL statement. The data files in the tablespace are checkpointed and do not require recovery before being brought online. If a tablespace is not taken offline normal, then its data files must be recovered before being brought online.
An SBT backup that requires retrieval by the media manager before RMAN can restore it. You can list offsite backups with RESTORE ... PREVIEW.
A backup of one or more data files taken while a database is open and the data files are online. When you make a user-managed backup while the database is open, you must put the tablespaces in backup mode by issuing an ALTER TABLESPACE BEGIN BACKUP command. (You can also use ALTER DATABASE BEGIN BACKUP to put all tablespaces in your database into backup mode in one step.)
You should not put tablespaces in backup mode when performing backups with RMAN.
The online redo log is a set of two or more files that record all changes made to the database. Whenever a change is made to the database, Oracle generates a redo record in the redo buffer. The LGWR process writes the contents of the redo buffer into the online redo log.
The current online redo log is the one being written to by LGWR. When LGWR gets to the end of the file, it performs a log switch and begins writing to a new log file. If you run the database in ARCHIVELOG mode, then each filled online redo log file must be copied to one or more archiving locations before LGWR can overwrite them.
See Also: archived redo log
The Oracle online redo log consists of two or more online redo log groups. Each group contains one or more identical online redo log members. An online redo log member is a physical file containing the redo records.
A physical online redo log file within an online redo log group. Each log group must have one or more members. Each member of a group is identical.
The return of the whole database to a prior consistent SCN by the FLASHBACK DATABASE command in RMAN or SQL. A database flashback is different from traditional media recovery because it does not involve the restore of physical files, instead restoring your current data files to past states using saved images of changed data blocks. This feature uses flashback logs and archived redo logs.
A set of Oracle Database features that provide an additional layer of data protection. These features include Oracle Flashback Query, Oracle Flashback Version Query, Oracle Flashback Transaction Query, Oracle Flashback Transaction, Oracle Flashback Table, Oracle Flashback Drop, and Oracle Flashback Database.
You can use flashback features to view past states of data and rewind parts or all of your database. In general, flashback features are more efficient and less disruptive than media recovery in most situations in which they apply.
A service that automates naming, location, creation, and deletion of database files such as control files, redo log files, data files and others, based on a few initialization parameters. You can use Oracle managed files on top of a traditional file system supported by the host operating system, for example, VxFS or ODM. It can simplify many aspects of the database administration by eliminating the need to devise your own policies for such details.
An Oracle media manager that supplies reliable data protection through file system backup to tape. The Oracle Secure Backup SBT interface also enables you to use RMAN to back up Oracle databases. All major tape drives and tape libraries in SAN, Gigabit Ethernet, and SCSI environments are supported.
A service on Windows systems that acts as coordinator between an Oracle database instance and other Volume Shadow Copy Service (VSS) components, enabling data providers to create a shadow copy of files managed by the Oracle instance. For example, the Oracle VSS writer can place data files in hot backup mode to provide a recoverable copy of these data files in a shadow copy set.
● Oracle-suggested backup strategy
A backup strategy available through a wizard in Oracle Enterprise Manager. The strategy involves periodically applying a level 1 incremental backup to a level 0 backup to create an incrementally updated backup. If run daily, this strategy provides 24 hour point-in-time recovery from disk.
Backups that were not made in the direct ancestral path of the current incarnation of the database. Orphaned backups cannot be used in the current incarnation.
A form of recovery in which several processes simultaneously apply changes from redo log files. The RECOVERY_PARALLELISM initialization parameter determines the level of parallelism for instance and crash recovery. You can use the PARALLEL and NOPARALLEL options of the RECOVER command to control parallelism for media recovery.Oracle Database automatically chooses the optimum degree of recovery parallelism. Manually setting the level of parallelism for instance, crash, or media recovery is usually not recommended or necessary.
The database incarnation from which the current incarnation branched following an OPEN RESETLOGS operation.
A type of resynchronization in which RMAN transfers data about archived logs, backup sets, and data file copies from the target control file to the recovery catalog.
A file created by the ORAPWD command, and required if you want to connect using the SYSDBA or SYSOPER privileges over a network. For details on password files, see the Oracle Database Administrator's Guide.
A backup of physical files. A physical backup contrasts with a logical backup such as a table export.
A type of corruption in which the database does not recognize a corrupt block. The database may not recognize the block because the checksum is invalid, the block contains all zeros, or the header and footer of the block do not match.
The data files, control files, and redo logs in a database at a given time. Issue the RMAN REPORT SCHEMA command to obtain a list of tablespaces and data files.
A copy of a production database that you can use for disaster protection.
The incomplete recovery of database files to a noncurrent time. Point-in-time recovery is also known as incomplete recovery.
See Also: media recovery, recover
A critical error in the database that is recorded in the Automatic Diagnostic Repository (ADR). Critical errors include internal errors and other severe errors. Each problem has a problem key, which is a set of attributes that describe the problem. The problem key includes the ORA error number, error parameter values, and other information.
A backup in which the media manager manages the transfer of data between the media storage device and disk during RMAN backup and restore operations.
A disk or partition without a file system. Thus, you cannot use ls, Windows Explorer, and so on to view their contents. The raw partition appears to Oracle Database as a single file.
To recover a database file or a database is typically to perform media recovery, crash recovery, or instance recovery. This term can also be used generically to refer to reconstructing or re-creating lost data by any means.
See Also: complete recovery, incomplete recovery
When used to refer to a database file or a database, the application of redo data or incremental backups to database files to reconstruct lost changes. The three types of recovery are instance recovery, crash recovery, and media recovery. Oracle Database performs the first two types of recovery automatically using online redo records; only media recovery requires you to restore a backup and issue commands.
See Also: complete recovery, incomplete recovery
A set of Oracle tables and views used by RMAN to store RMAN repository information about one or more Oracle databases. RMAN uses this metadata to manage the backup, restore, and recovery of Oracle databases.
Use of a recovery catalog is optional although it is highly recommended. For example, starting with Oracle Database 11g, a single recovery catalog schema can keep track of database file names for all databases in a Data Guard environment. This catalog schema also keeps track of where the online redo logs, standby redo logs, temp files, archived redo logs, backup sets, and image copies are created for all databases.
The primary storage for RMAN repository information for a database is always in the control file of the database. A recovery catalog is periodically updated with RMAN repository data from the control file. In the event of the loss of your control file, the recovery catalog can provide most or all of the lost metadata required for restore and recovery of your database. The recovery catalog can also store records of archival backups and RMAN stored scripts for use with target databases.
See Also: recovery catalog database
An Oracle database that contains a recovery catalog schema. You should not store the recovery catalog in the target database.
The recovery catalog database schema that contains the recovery catalog tables and views.
The primary utility for physical backup and recovery of Oracle databases. RMAN keeps records of Oracle databases in its own structure called an RMAN repository, manages storage of backups, validates backups. You can use it with or without the central information repository called a recovery catalog. If you do not use a recovery catalog, then RMAN uses the database's control file to store information necessary for backup and recovery operations. You can use RMAN with third-party media management software to back up files to tertiary storage.
See Also: backup piece, backup set, copy, media manager, recovery catalog
One or more tablespaces that are being recovered to an earlier point in time during tablespace point-in-time recovery (TSPITR). After TSPITR, all database objects in the recovery set have been recovered to the same point in time.
See Also: auxiliary set
A recovery window is one type of RMAN backup retention policy, in which the DBA specifies a period of time and RMAN ensures retention of backups and archived redo logs required for point-in-time recovery to any time during the recovery window. The interval always ends with the current time and extends back in time for the number of days specified by the user.
For example, if the retention policy is set for a recovery window of seven days, and the current time is 11:00 AM on Tuesday, RMAN retains the backups required to allow point-in-time recovery back to 11:00 AM on the previous Tuesday.
A data dictionary table containing information about dropped objects. Dropped tables and any associated objects such as indexes, constraints, nested tables, and so on are not removed and still occupy space. The Flashback Drop feature uses the recycle bin to retrieve dropped objects.
A redo log can be either an online redo log or an archived redo log. The online redo log is a set of two or more redo log groups that records all changes made to Oracle data files and control files. An archived redo log is a copy of an online redo log that has been written to an offline destination.
Each online redo log member (which corresponds to an online redo log file) belongs to a redo log group. Redo log groups contain one or more members. A redo log group with multiple members is called a multiplexed redo log group. The contents of all members of a redo log group are identical.
The redo generated by an instance. If the database runs in a single instance configuration, then the database has only one thread of redo.
In a retention policy, the setting that determines many copies of each backed-up file to keep. A redundancy-based retention policy is contrasted with retention policy that uses a recovery window.
A set of backups enabling you to recover from the failure or loss of any Oracle database file.
In RMAN, the execution of a REGISTER DATABASE command to record the existence of a target database in the recovery catalog. A target database is uniquely identified in the catalog by its DBID. You can register multiple databases in the same catalog, and also register the same database in multiple catalogs.
For Data Recovery Advisor, a repair is an action or set of actions that fixes one or more failures. Examples repairs include block media recovery, data file media recovery, Oracle Flashback Database, and so on.
For Data Recovery Advisor, one possible technique for repairing a failure. Different repair options are intended to fix the same problem, but represent different advantages and disadvantages in terms of repair time and data loss.
A technique for opening a database that archives any current online redo logs (if using ARCHIVELOG mode), resets the log sequence number to 1, and clears the online redo logs. An ALTER DATABASE OPEN RESETLOGS statement begins a new database incarnation. The starting SCN for the new incarnation, sometimes called the RESETLOGS SCN, is the incomplete recovery SCN of the media recovery preceding the OPEN RESETLOGS, plus one.
An ALTER DATABASE OPEN RESETLOGS statement is required after incomplete recovery or recovery with a backup control file. An OPEN RESETLOGS operation does not affect the recoverability of the database. Backups from before the OPEN RESETLOGS operation remain valid and can be used along with backups taken after the OPEN RESETLOGS operation to repair any damage to the database.
The process of making the contents of a split mirror identical with the contents of the storage devices from which the mirror was split. The operating system or the hardware managing the mirror refreshes a broken mirror from the half that is up-to-date and then maintains both sides of the mirror.
The feature that enables RMAN to back up only those files that have not been backed up since a specified date. The unit of restartability is last completed backup set or image copy. You can use this feature after a backup fails to back up the parts of the database missed by the failed backup.
The replacement of a lost or damaged file with a backup. You can restore files either with commands such as UNIX cp or the RMAN RESTORE command.
The automatic search by RMAN for usable backups in a restore operation if a corrupted or inaccessible backup is found.
The default behavior in which RMAN avoids restoring data files from backup when possible.
A user-defined a name associated with an SCN of the database corresponding to the time of the creation of the restore point. A restore point can be a guaranteed restore point or a normal restore point.
The operation that updates the recovery catalog with current metadata from the target database control file. You can initiate a full resynchronization of the catalog by issuing a RESYNC CATALOG command. A partial resynchronization transfers information to the recovery catalog about archived redo log files, backup sets, and data file copies. RMAN resynchronizes the recovery catalog automatically when needed.
In a Data Guard environment, the updating of a primary or standby database control file with metadata obtained from the recovery catalog. For example, if you configure persistent RMAN settings for a standby database that is not the connected target database, then RMAN performs a reverse resynchronization the next time RMAN connects as target to the standby database. In this way, the recovery catalog keeps the metadata in the control files in a Data Guard environment up to date.
The set of BACKUP commands executed within a single RMAN session. For example, assume that you start the RMAN client, execute BACKUP DATABASE, BACKUP ARCHIVELOG, and RECOVER COPY, and then exit the RMAN client. The RMAN backup job consists of the database backup and the archived redo log backup.
An Oracle Database executable that interprets commands, directs server sessions to execute those commands, and records its activity in the target database control file. The RMAN executable is automatically installed with the database and is typically located in the same directory as the other database executables. For example, the RMAN client on Linux is named rman and is located in $ORACLE_HOME/bin.
The set of RMAN commands executed in an RMAN session. For example, assume that you start the RMAN client, execute BACKUP DATABASE, BACKUP ARCHIVELOG, and RECOVER COPY, and then exit the RMAN client. The RMAN job consists of the two backups and the roll forward of the data file copy.
Commands that you can use to manage RMAN metadata records and backups. The maintenance commands are CATALOG, CHANGE, CROSSCHECK, and DELETE.
The record of RMAN metadata about backup and recovery operations on the target database. The authoritative copy of the RMAN repository is always stored in the control file of the target database. A recovery catalog can also be used for longer-term storage of the RMAN repository, and can serve as an alternate source of RMAN repository data if the control file of your database is lost.
See Also: recovery catalog database, resynchronization
An RMAN session begins when the RMAN client is started and ends when you exit from the client or the RMAN process is terminated. Multiple RMAN commands can be executed in a single RMAN session.
The use of rollback segments to undo uncommitted changes applied to the database during the rolling forward stage of recovery.
The application of redo records or incremental backups to data files and control files to recover changes to those files.
See Also: rolling back
System Backup to Tape. This term specifies a nondisk backup device type, typically a tape library or tape drive. RMAN supports channels of type disk and SBT.
In the Volume Shadow Copy Service (VSS) infrastructure on Windows, a consistent snapshot of a component or volume.
A copy of a database control file created in an operating system-specific location by Recovery Manager. RMAN creates the snapshot control file so that it has a consistent version of a control file to use when either resynchronizing the recovery catalog or backing up the control file.
The database that you are copying when you create a duplicate database.
The host on which a source database resides.
When using the RMAN CONVERT command, the platform on which the source database is running. The source database contains the data to be transported to a database running on a different platform.
A backup of database files that were previously mirrored. Some third-party tools allow you to use mirroring a set of disks or logical devices, that is, maintain an exact duplicate of the primary data in another location. Splitting a mirror involves separating the file copies so that you can use them independently. With the ALTER SYSTEM SUSPEND/RESUME database feature, you can suspend I/O to the database, split the mirror, and make a backup of the split mirror.
A sequence of RMAN commands stored in the recovery catalog. Stored scripts can be global or local. Global scripts can be shared by all databases registered in the recovery catalog.
A server process can perform only one task at a time while RMAN is either reading or writing data.
A stamp that defines a committed version of a database at a point in time. Oracle assigns every committed transaction a unique SCN.
In a transportable tablespace operation, the location on disk which (by default) contains the data file copies and other output files when the tablespace transport command completes.
● tablespace point-in-time recovery (TSPITR)
The recovery of one or more non-SYSTEM tablespaces to a noncurrent time. You use RMAN to perform TSPITR.
Identifier for an RMAN backup. If you generate a backup set, then the tag is assigned to each backup piece rather than to the backup set. If you do not specify a tag for a backup, then RMAN assigns one automatically.
In an RMAN environment, the database to which you are connected as TARGET. The target database is the database on which you are performing RMAN operations.
The computer on which a target database resides.
In an RMAN environment, the instance associated with a target database.
A file that belongs to a temporary tablespace and is created with the TEMPFILE option. Temporary tablespaces cannot contain permanent database objects such as tables, and are typically used for sorting. Because temp files cannot contain permanent objects, RMAN does not back them up. RMAN does keep track of the locations of temp files in the control file, however, and during recovery re-creates the temp files as needed at those locations.
A script generated by the CONVERT DATABASE command. This script contains SQL statements used to create the new database on the destination platform.
A feature that transports a set of tablespaces from one database to another, or from one database to itself. Transporting a tablespace into a database is like creating a tablespace with loaded data.
● transportable tablespace set
Data files for the set of tablespaces in a transportable tablespace operation, and an export file containing metadata for the set of tablespaces. You use Data Pump Export to perform the export.
A simulated recovery initiated with the RECOVER ... TEST command in RMAN or SQL*Plus. A trial recovery applies redo in a way similar to normal media recovery, but it never writes its changes to disk and it always rolls back its changes. Trial recovery occurs only in memory.
The minimum amount of time that Oracle Database attempts to retain old undo data in the undo tablespace before overwriting it. Old (committed) undo data that is older than the current undo retention period is said to be expired. Old undo data with an age that is less than the current undo retention period is said to be unexpired.
A dedicated tablespace that stores only undo information when the database is run in automatic undo management mode.
A feature by which RMAN reduces the size of data file backup sets by skipping data blocks. RMAN always skips blocks that have never been used. Under certain conditions, which are described in the BACKUP AS BACKUPSET entry in Oracle Database Backup and Recovery Reference, RMAN also skips previously used blocks that are not currently being used.
A backups made using a non-RMAN method, for example, using an operating system utility. For example, you can make a user-managed backup by running the cp command on Linux or the COPY command on Windows. A user-managed backup is also called an operating system backup.
● user-managed backup and recovery
A backup and recovery strategy for an Oracle database that does not use RMAN. This term is equivalent to operating system backup and recovery. You can back up and restore database files using operating system utilities (for example, the cp command in UNIX), and recover using the SQL*Plus RECOVER command.
In an RMAN context, a test that checks database files for block corruption or checks a backup set to determine whether it can be restored. RMAN can check for both physical and logical block corruption.
A subset of the metadata in a base recovery catalog to which a database user is granted access. The owner of a base recovery catalog can grant or revoke restricted access to the recovery catalog to other database users. Each restricted user has full read/write access to his own virtual private catalog.
● Volume Shadow Copy Service (VSS)
An infrastructure on Windows server platforms that enables requestors, writers, and providers to participate in the creation of a consistent snapshot called a shadow copy. The VSS service uses well-defined COM interfaces. See Oracle Database Platform Guide for Microsoft Windows to learn how to use RMAN with VSS.
A backup of the control file and all data files that belong to a database.
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GlossaryGlossary
● Component Object Model (COM)
A binary standard that enables objects to interact with other objects, regardless of the programming language that each object was written in.
A consumer is any application or tool that calls to a data source or the interfaces of provider to access data. See provider.
The Oracle client/server communication software that offers transparent operation to Oracle tools or databases over any type of network protocol and operating system.
A provider is an interface or set of components that provides data to a consumer. As the term is used with Oracle Provider for OLE DB, a data provider is a set of COM components that transfer data from a data source to a consumer, by placing the data in a tabular format when called for. See consumer.
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GlossaryGlossary
● Oracle Automatic Storage Management disk group
A set of disk devices that Oracle Automatic Storage Management (Oracle ASM) manages as a unit. Each disk device can be an individual physical disk, a multiple disk device such as a RAID storage array or logical volume, or even a partition on a physical disk. You can create the Oracle ASM disk group when you create the Oracle Automatic Storage Management instance, or with Oracle Database Configuration Assistant.
● Oracle Automatic Storage Management instance
The Oracle instance that manages an Oracle Automatic Storage Management disk group. It is created automatically when you install and configure Oracle Automatic Storage Management. See also Oracle system identifier (SID).
● Oracle Automatic Storage Management
Enables creation of a single disk group from a collection of individual disk devices. It balances I/O to the disk group across all of the devices in the disk group. It also implements striping and mirroring to improve I/O performance and data reliability.
● automatic undo management mode
A mode of Oracle Database in which undo data is stored in a dedicated undo tablespace. Unlike in manual undo management mode, the only undo management that you must perform is the creation of the undo tablespace. All other undo management is performed automatically.
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 the Oracle Database or its Oracle system identifier (SID) for Oracle release 11.2 databases. The network route provides, at a minimum, the location of the listener through use of a network address.
A name, 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 want to connect, for example:
SQL> CONNECT user_name@connect_identifier Enter password: password
Files that record the physical structure of a database and contain the database name, the names and locations of associated datafiles and online undo tablespace, the time stamp of the database creation, the current log sequence number, and checkpoint information.
The network domain within which most client requests take place. It can be the domain where the client resides, or a domain from which the client often requests network services. The default domain is also the client configuration parameter that determines what domain to append to unqualified network name requests. A name request is unqualified if it does not have a "." character within it.
A naming method that specifies a directory server to resolve a net service name into a connect descriptor. The net service name is stored centrally in a directory server.
A Lightweight Directory Access Protocol (LDAP)-compliant directory server. A directory can provide centralized storage and retrieval of database network components, user and corporate policies preferences, user authentication, and security information, replacing client-side and server-side localized files.
Procedure or function written in the C programming language and stored in a shared library. An Oracle server can call external procedures or functions using PL/SQL routines. For Oracle Database to connect to external procedures, the server must be configured with a net service name and the listener must be configured with protocol address and service information.
The full database name that uniquely distinguishes it from any other database in your network domain.
For example:
sales.us.example.com
where sales is the name you want to call your database and us.example.com is the network domain in which the database is located.
● initialization parameter file
An ASCII text file that contains information needed to initialize a database and instance.
Process associated with a running Oracle Database instance. When a database is started on a database server (regardless of the type of computer), Oracle Database allocates a memory area called the System Global Area and starts one or more Oracle Database processes. This combination of the System Global Area and Oracle Database processes is called an instance. The memory and processes of an instance manage the associated database's data efficiently and serve the users of the database.
A predefined component set that automatically selects which components to install. See "Oracle Database Editions" for a list of installation types available with each top-level component.
● Interprocess Communication (IPC)
A protocol that client applications use that resides on the same node as the listener to communicate with the database. IPC can provide a faster local connection than TCP/IP.
A process that resides on the server and whose responsibility is to listen for incoming client connection requests and manage the traffic to the server.
When a client requests a network session with a database server, a listener receives the actual request. If the client information matches the listener information, then the listener grants a connection to the database server.
A configuration file for the listener that identifies the:
-
Listener name
-
Protocol addresses on which it is accepting connection requests
-
Services for which it is listening
The listener.ora file resides in the $ORACLE_HOME/network/admin directory.
An Oracle Database 11g Release 2 (11.2) does not require identification of the database service because of service registration. However, static service configuration is required for an Oracle Database 11g Release 2 (11.2) if you plan to use Oracle Enterprise Manager.
A naming method that resolves a net service name into a connect descriptor. This name is configured and stored in the tnsnames.ora file on each individual client.
A mode of the database in which undo blocks are stored in user-managed rollback segments.
A resolution method used by a client application to resolve a connect identifier to a network address when attempting to connect to a database service. Oracle Net Services supports the following naming methods:
-
Local naming
-
Directory naming
-
Host naming
-
External naming
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 want to connect:
SQL> CONNECT user_name@net_service_name Enter password: password
Depending on your needs, net service names can be stored in a variety of places, including:
-
Local configuration file, tnsnames.ora, on each client
-
Directory server
-
External naming service, such as Network Information Service (NIS) or Cell Directory Service (CDS)
Acronym for operating system specific. The initialization file parameter OS_AUTHENT_PREFIX enables users to specify a prefix that Oracle uses to authenticate users attempting to connect to the database. Oracle concatenates the value of this parameter to the beginning of the user's operating system account name. When a connection request is attempted, Oracle compares the prefixed user name with Oracle user names in the database.
The default value of this parameter is "" (a null string), thereby eliminating the addition of any prefix to operating system account names. In earlier releases, OPS$ was the default setting.
ORACLE_BASE is the root of the Oracle Database directory tree. The Oracle Base directory is the top level directory that you can use to install the various oracle software products. You can use the same Oracle base directory for multiple installations. For example, /u01/app/oracle is an Oracle base directory created by the oracle user.
Corresponds to the environment in which Oracle Database products run. If you install an OFA-compliant database, using Oracle Universal Installer defaults, Oracle home (known as $ORACLE_HOME in this guide) is located beneath $ORACLE_BASE. The default Oracle home is db_n where n is the Oracle home number. It contains subdirectories for Oracle Database software executables and network files. See also Oracle home.
The directory path to install Oracle components (for example, /u01/app/oracle/product/11.2.0/db_n). You are prompted to enter an Oracle home in the Path field of the Specify File Locations window. See also ORACLE_HOME.
A set of rules that determine what can be stored in an LDAP-compliant directory server. Oracle has its own schema that is applied to many types of Oracle entries, including Oracle Net Services entries. The Oracle schema for Oracle Net Services entries includes the attributes the entries may contain.
A networking communication layer that establishes and maintains the connection between the client application and server, and also exchanging messages between them.
An address that identifies the network address of a network object.
When a connection is made, the client and the receiver of the request, such as the listener, or Oracle Connection Manager, are configured with identical protocol addresses. The client uses this address to send the connection request to a particular network object location, and the recipient "listens" for requests on this address. It is important to install the same protocols for the client and the connection recipient, and to configure the same addresses.
Portions of a physical disk that are accessed at the lowest possible disk (block) level.
Files that contain a record of all changes made to data in the database buffer cache. If an instance failure occurs, then an administrator can use the redo log files to recover the modified data that was in memory.
A set of tables located in any Oracle database accessible to the Oracle Management Server. Oracle Management Server uses a repository to store all system data and application data, information about the state of managed nodes distributed throughout the environment, and information about the separately licensable management packs.
A feature by which the PMON process (an instance background process) automatically registers information with a listener. Because this information is registered with the listener, the listener.ora file does not have to be configured with this static information.
Service registration provides the listener with the following information:
-
Service names for each running instance of the database
-
Instance names of the database
-
Service handlers (dispatchers and dedicated servers) available for each instance to enable the listener to direct a client's request appropriately.
-
Dispatcher, instance, and node load information
To enable the listener to determine which dispatcher can best handle a client connection's request. If all dispatchers are blocked, the listener can spawn a dedicated server for the connection.
This information enables the listener to determine how best to service a client connection request.
The Oracle system identifier that distinguishes the database from all other databases on your computer. The SID automatically defaults to the database name portion of the global database name (sales in the example sales.us.example.com) until you reach eight characters or enter a period. You can accept or change the default value.
The SID can also refer to an Oracle ASM instance SID, available when you install Oracle Automatic Storage Management.
A configuration file for the client or server that specifies the:
-
Client domain to append to unqualified service names or net service names
-
Order of naming methods for the client to use when resolving a name
-
Logging and tracing features to use
-
Route of connections
-
External naming parameters
-
Oracle Advanced Security parameters
The sqlnet.ora file resides in $ORACLE_HOME/network/admin.
An industry standard protocol designed by Netscape Communications Corporation for securing network connections. SSL provides authentication, encryption, and data integrity using public key infrastructure (PKI).
A group of shared memory structures that contain data and control information for an Oracle Database instance.
See SID.
A logical storage unit within a database. Tablespaces are divided into logical units of storage called segments, which are further divided into extents.
A configuration file that contains net service names mapped to connect descriptors. This file is used for the local naming method. The tnsnames.ora file resides in $ORACLE_BASE/network/admin.
A tablespace that contains one or more undo segments. The creation of any other types of segment (for example, tables, indexes) in undo tablespaces is not allowed.
In the automatic mode, each Oracle instance is assigned one and only one undo tablespace. Each undo tablespace is composed of a set of undo files. Undo blocks are grouped in extents. At any point in time, an extent is either allocated to (and used by) a transaction table, or is free.
Blocks in undo tablespaces are grouped into the following categories:
-
File control blocks, bitmap blocks, and so forth used for space management
-
Undo segments containing transaction table blocks, undo blocks, and extent-map blocks used for transaction management
-
Free blocks that are unallocated to file control or undo segments
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GlossaryGlossary
See current version.
A workspace created from its parent workspace.
See also parent workspace and workspace hierarchy.
Differences in data values resulting from changes to rows in the child and parent workspace. Conflicts are detected at merge time and presented to the user in conflict views.
See also merging (a workspace).
Information about the workspace that determines what data the session can see in the workspace. The context can be retrieved using the GetSessionInfo procedure
A Workspace Manager lock mode that prevents any other user from changing a locked row.
See also locks.
A savepoint that is explicitly created. It can later be used to perform partial rollbacks in workspaces.
See also savepoint, implicit savepoint, and removable savepoint.
Causing the condition in which no changes can be made to data in version-enabled rows in a workspace, and access to the workspace is restricted.
A savepoint that is created automatically whenever a new workspace is created.
See also savepoint, explicit savepoint, and removable savepoint.
The name of the logical savepoint that refers to the latest version in the workspace.
See also savepoint.
Version locks provided by Workspace Manager, separate from locks provided by conventional Oracle database transactions. These locks are primarily intended to eliminate row conflicts between a parent workspace and a child workspace. Locking is enabled at a session level and is a session property independent of the workspace in which the session is. When locking is enabled for a session, it locks rows in all workspaces in which it participates.
A master site in a multimaster group in a Workspace Manager replication environment that is not the writer site. A nonwriter site cannot perform any write operations, but can perform all read operations, such as CreateSavepoint or SELECT queries on version-enabled tables.
See also writer site.
A workspace from which another workspace (a child workspace) was created.
See also child workspace and workspace hierarchy.
A set of privileges for Workspace Manager that are separate from standard Oracle database privileges. Workspace-level privileges (with names in the form xxx_WORKSPACE) that allow the user to affect a specified workspace. System-level privileges (with names in the form xxx_ANY_WORKSPACE) that allow the user to affect any workspace.
A workspace that can be deleted by the CompressWorkspace, CompressWorkspaceTree, and DeleteSavepoint procedures. A savepoint is removable if it is an explicit savepoint or if it is an implicit savepoint that does not have any child dependencies.
See also savepoint, explicit savepoint, and implicit savepoint.
Deleting either all changes made in the workspace or all changes made after a savepoint (that is, an explicit savepoint).
A point in the workspace to which operations can be rolled back. It is analogous to a firewall, in that by creating a savepoint you can prevent any damage to the "other side" of the wall (that is, operations performed in the workspace before the savepoint was created).
See also explicit savepoint, implicit savepoint, and removable savepoint.
See context.
A Workspace Manager lock mode that allows only users in the workspace in which the row was locked to modify the row.
See also locks.
Reversing the effect of a freeze operation.
See also freezing (a workspace).
The time during which a record is valid, or the ability to specify the time for which a record is valid. Also called effective dating.
A time that is applied to queries against version-enabled tables that have valid time support. When a valid time filter is set for the current session, only rows that are valid for the specified time are returned.
A table in the database in which all rows in the table can now support multiple versions of data. The versioning infrastructure is not visible to the database users. After a table has been version-enabled, users automatically see the correct version of the record in which they are interested.
A virtual environment that one or more users can share to make changes to the data in the database. Workspace management involves managing one or more workspaces that can be shared by many users.
The hierarchy of workspaces in the database. For example, a workspace can be a parent to one or more workspaces. By default, when a workspace is created, it is created from the topmost, or LIVE, database workspace.
The ability of the database to hold different versions of the same record (that is, row) in one or more workspaces.
The master definition site in a Workspace Manager replication environment. Only the writer site can perform workspace operations and DML and DDL operations on version-enabled tables. All other sites in the multimaster group are nonwriter sites.
See also nonwriter site.
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GlossaryGlossary
Delete cache instances from the cache tables of a cache group after a specified period of time (time-based) or when a specified level of database usage is reached (LRU).
● asynchronous writethrough (AWT) cache group
A cache group in which committed updates on TimesTen cache tables are automatically and asynchronously propagated to the cached Oracle Database tables. The commit on the TimesTen database occurs asynchronously from the commit on the Oracle database.
Committed updates on cached Oracle Database tables are automatically refreshed to the TimesTen cache tables.
A read-only cache group or a user managed cache group that uses the AUTOREFRESH MODE INCREMENTAL cache group attribute.
Propagate committed updates on TimesTen cache tables to the cached Oracle Database tables, and refresh committed updates on cached Oracle Database tables to the TimesTen cache tables.
Oracle Database user that creates and maintains Oracle Database objects that store information used to manage cache grids and enforce predefined behaviors of particular cache group types.
A TimesTen process that processes cache group operations, such as automatic refresh, loading a cache group, and passing through statements to the Oracle database for execution.
Defines the data from the Oracle Database tables to cache in a TimesTen database. A cache group can cache all or a subset of a single Oracle Database table or a set of related Oracle Database tables. If multiple Oracle Database tables are cached, each cache table (except for the root table) must reference another cache table in the cache group through foreign key constraints.
A set of distributed grid members consisting of TimesTen in-memory databases that work together to cache data from a single Oracle database and guarantee cache coherence among the TimesTen databases.
A specific row of data identified by the primary key in the cache group's root table. If there are multiple tables in the cache group, the cache instance consists of the set of rows in the child tables associated by foreign key relationships with the row in the root table.
TimesTen user that performs cache grid and cache group operations such as creating and configuring a cache grid, and creating cache groups.
A cache table that has a foreign key reference to either the primary key of the root table or another child table that either directly or indirectly references the root table. The table hierarchy in your cache group can designate child tables to be parents of other child tables. No cache table can be a child to more than one parent in the cache group.
A cache group category for which data in its cache tables can be loaded on demand, manually loaded or automatically loaded.
The transfer of data into the local grid member from Oracle Database tables when a query cannot be satisfied with data in the cache grid members.
● explicitly loaded cache group
A cache group category for which data in its cache tables are manually or automatically loaded.
To manually propagate committed inserts or updates on TimesTen cache tables in a user managed cache group to the cached Oracle Database tables.
A cache group classification where data in its cache tables are shared across multiple TimesTen databases within a cache grid.
Transfer of the cache instance from remote grid members to the local grid member in response to a query that cannot be satisfied by data in the cache tables on the local grid member.
A component of a cache grid consisting of either a standalone TimesTen database or an active standby pair.
A TimesTen database of a grid member that is either a standalone database, or the active database or standby database of an active standby pair.
Copy new cache instances from the cached Oracle Database tables to the TimesTen cache tables. Cache instances that are already exist in the cache tables are not updated or deleted.
A cache group classification where data in its cache tables are not shared across multiple TimesTen databases even if the databases are members of the same cache grid.
● Oracle Database schema users
Oracle Database users who own Oracle Database tables to be cached in a TimesTen database.
● Oracle Database timesten user
Oracle Database user who owns Oracle Database tables that store information about cache grids.
Transmit committed updates on TimesTen cache tables to the cached Oracle Database tables.
A cache group in which committed updates on cached Oracle Database tables are automatically refreshed to the TimesTen cache tables. You cannot update cache tables directly in a read-only cache group.
For an explicitly loaded cache group, unload and then load the cache group.
For a dynamic cache group, replace existing cache instances in the cache tables with the most current data from the cached Oracle Database tables.
Replication at each master and subscriber TimesTen database is controlled by a replication agent process. The replication agent on the master database reads the transaction log records and transmits any committed updates on replicated elements to the replication agent on the subscriber database. The replication agent on the subscriber database then applies the updates to its database.
For an AWT cache group, the replication agent transmits committed updates on its cache tables to the cached Oracle Database tables.
The parent table in the cache group that does not reference any other table in the cache group through a foreign key constraint. The primary key of the root table is the primary key of the cache group.
● synchronous writethrough (SWT) cache group
A cache group in which committed updates on TimesTen cache tables are automatically and synchronously propagated to the cached Oracle Database tables. When an application commits a transaction, it is committed on Oracle Database before it is committed on TimesTen.
System managed cache groups enforce predefined behaviors. The types of system managed cache groups are read-only, synchronous writethrough and asynchronous writethrough.
Role granted to the cache administration user that defines privileges on the Oracle Database tables owned by the timesten user which store information about cache grids.
A cache group that implements customized behavior such as bidirectional transmit.
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Glossary| Oracle? Services for Microsoft Transaction Server Developer's Guide 11g Release 2 (11.2) for Microsoft Windows E26104-02 |
Glossary
● Atomicity, Consistency, Isolation, and Durability (ACID)
ACID consists of the four primary attributes provided to any transaction by a transaction manager (also called a transaction manager).
● component object model (COM)
A binary standard that enables objects to interact with other objects, regardless of the programming language in which each object was written.
● distributed component object model (DCOM)
An extension of COM that enables objects to interact with other objects across a network.
The category of SQL statements that query and update database data. Common DML statements are SELECT, INSERT, UPDATE, and DELETE.
This initialization parameter specifies the maximum number of DBMS_JOB jobs and Oracle Scheduler (DBMS_SCHEDULER) jobs running concurrently on an instance. This parameter must be set to at least 1 to run Oracle Scheduler or DBMS_JOB jobs and to use database features that depend on these jobs
A listener configuration file that identifies the following for a listener:
-
Unique name
-
Protocol addresses on which it accepts connection requests
-
Services for which it is listening
Microsoft .NET is a set of Microsoft software technologies used to connect information, people, systems, and devices through web services to each other and to larger applications over the Internet.
An Oracle Call Interface (OCI) implementation of the Visual C++ Sample Bank package that ships with Microsoft Transaction Server on Windows.
● Microsoft Distributed Transaction Coordinator (MS DTC)
The focal point of the transaction process is a component of Microsoft Transaction Server called Microsoft Distributed Transaction Coordinator (MS DTC).
● Microsoft Transaction Server
A COM-based transaction processing system that runs on an Internet or network server.
The default Microsoft Transaction Server administrator username. In releases prior to Oracle9i Database release 1 (9.0.1), this was the username for the OraMTS.
The name used by clients to identify an Oracle Net server and the specific system identifier (SID) or database for the Oracle Net connection. A net service name is mapped to a port number and protocol. A net service name is also known as a connect string, database alias, host string, or service name.
This also identifies the specific SID or database to which the connection is attaching, and not just the Oracle Net server.
An application programming interface that enables you to manipulate data and schemas in a database. You compile and link an OCI program in the same way that you compile and link a nondatabase application. There is no requirement for a separate preprocessing or precompilation step.
● Oracle Data Provider for .NET (ODP.NET)
Oracle Data Provider for .NET (ODP.NET) features optimized data access to the Oracle Database from a .NET environment. ODP.NET includes support for connection pooling, PL/SQL, LOBs, RefCursors, globalization/localization, proxy user authentication/ parameter array binding, named parameters, and safe type mapping between Oracle types and .NET types.
Ensures that if a failure occurs on one cluster node, then the databases and applications running on that node fail over (move) automatically and quickly to a surviving node.
The Oracle MTS Recovery Service resolves in-doubt transactions on the computer that started the failed transaction. A scheduled recovery job for each Microsoft Transaction Server-enabled database lets the Oracle MTS Recovery Service resolve in-doubt transactions.
● Oracle Objects for OLE (OO4O)
Oracle Objects for OLE (OO4O) is a COM-based database connectivity tool that combines seamless and optimized access to Oracle Database instances with easy to use interfaces.
● Oracle Open Database Connectivity (ODBC) Driver
Oracle ODBC Driver provides a standard interface that allows one application to access many different data sources. The application's source code does not have to be recompiled for each data source. A database driver links the application to a specific data source. A database driver is a dynamic link library that an application can invoke on demand to gain access to a particular data source. Therefore, the application can access any data source for which a database driver exists.
Interfaces that offer high performance and efficient access to Oracle data by applications, compilers, and other database components.
● Oracle Services for Microsoft Transaction Server (OraMTS)
A component that provides full integration of the Oracle Database with Microsoft Transaction Server. This component enables you to develop and deploy COM-based applications using Microsoft Transaction Server.
● Optimal Flexible Architecture (OFA)
A set of file naming and placement guidelines for Oracle software and databases.
Microsoft Transaction Server enlists the database to act as a resource manager (RM) in the transaction process.
A special database administration role that contains all system privileges with the ADMIN OPTION and the SYSOPER system privilege. SYSDBA also permits CREATE DATABASE actions and time-based recovery.
A special database administration role that permits a database administrator to perform STARTUP, SHUTDOWN, ALTER DATABASE OPEN/MOUNT, ALTER DATABASE BACKUP, ARCHIVE LOG, and RECOVER, and includes the RESTRICTED SESSION privilege.
A file that contains connect descriptors mapped to net service names. The file can be maintained centrally or locally for use by all or individual clients.
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GlossaryGlossary
● application programming interface
The calling conventions by which an application program accesses operating system and other services.
An approximate system change number value, based on the current SCN of the database when a transaction that has enqueued messages into a commit-time queue is committed.
A process in a multitasking system is asynchronous if its execution can proceed independently in the background. Other processes can be started before the asynchronous process has finished. The opposite of synchronous.
An external binary file that exists outside the database tablespaces residing in the operating system.
A large object datatype whose content consists of binary data. This data is considered raw, because its structure is not recognized by the database.
See binary large object.
A publish/subscribe mode in which the message producer does not know the identity of any message consumer. This mode is similar to a radio or television station.
Buffered queues support queuing of messages with buffered attributes (buffered messages) and materialize them in memory. If the memory devoted to a buffered message is required for a newer message, or if a buffered message has exceeded a stipulated duration in memory, then that buffered message is swapped to the underlying queue table. The memory for buffered messages comes from a separate pool called the streams pool. Buffered messages cannot be recovered if the database is bounced. Messages that have no buffered attributes set are queued as persistent messages in the underlying persistent queue.
The large object datatype whose value is composed of character data corresponding to the database character set. A character large object can be indexed and searched by the Oracle Text search engine.
A ConnectionFactory encapsulates a set of connection configuration parameters that has been defined by an administrator. A client uses it to create a connection with a Java Message Service provider.
A user or application that can dequeue messages.
Data manipulation language (DML) statements manipulate database data. For example, querying, inserting, updating, and deleting rows of a table are all DML operations; locking a table or view and examining the execution plan of an SQL statement are also DML operations.
● Database Configuration Assistant
An Oracle Database tool for creating and deleting databases and for managing database templates.
To retrieve a message from a queue
Messages are transferred to an exception queue if they cannot be retrieved and processed for some reason.
Unlike an ordinary table whose data is stored as an unordered collection, data for an index-organized table is stored in a B-tree index structure sorted on a primary key. Besides storing the primary key column values of an index-organized table row, each index entry in the B-tree stores the nonkey column values as well.
● Internet Data Access Presentation
The Simple Object Access Protocol (SOAP) specification for Oracle Streams Advanced Queuing operations. IDAP defines the XML message structure for the body of the SOAP request. An IDAP-structured message is transmitted over the Internet using HTTP(S).
Exchange of data between one process and another, either within the same computer or over a network. It implies a protocol that guarantees a response to a request.
An industry-standard Java interface for connecting to a relational database from a Java program, defined by Sun Microsystems.
A messaging standard defined by Sun Microsystems, Oracle, IBM, and other vendors. JMS is a set of interfaces and associated semantics that define how a JMS client accesses the facilities of an enterprise messaging product.
● Java Naming and Directory Interface
A programming interface from Sun for connecting Java programs to naming and directory services.
The Java interpreter that converts the compiled Java bytecode into the machine language of the platform and runs it. JVMs can run on a client, in a browser, in a middle tier, on an intranet, on an application server such as Oracle Application Server 10g, or in a database server such as Oracle Database 10g.
The vendor-specific layer of Java Database Connectivity that provides access to a particular database. Oracle Database provides three JDBC drivers--Thin, OCI, and KPRB.
See Java Message Service.
An active connection of a client to its JMS provider, typically an open TCP/IP socket (or a set of open sockets) between a client and a provider's service daemon.
JMS messages consist of a header, one or more optional properties, and a message payload.
Equivalent to a multiconsumer queue in the other Oracle Streams Advanced Queuing interfaces.
● Lightweight Directory Access Protocol
A standard, extensible directory access protocol. It is a common language that LDAP clients and servers use to communicate. The framework of design conventions supporting industry-standard directory products, such as the Oracle Internet Directory.
See large object
A local consumer dequeues the message from the same queue into which the producer enqueued the message.
An object with a specific format that describes a database change, captured from the redo log by a capture process or user application. Capture processes enqueue messages containing logical change records (LCRs) only into ANYDATA queues. For improved performance, these LCRs are always stored in a buffered queue.
The smallest unit of information inserted into and retrieved from a queue. A message consists of control information (metadata) and payload (data).
A publish/subscribe mode in which the message producer knows the identity of each consumer. This mode is also known as point-to-multipoint.
● national character large object
The large object datatype whose value is composed of character data corresponding to the database national character set.
Nonpersistent queues store messages in memory. They are generally used to provide an asynchronous mechanism to send notifications to all users that are currently connected. Nonpersistent queues are deprecated in Oracle Streams Advanced Queuing 10g Release 2 (10.2). Oracle recommends that you use buffered messaging instead.
Allowing enqueuing and dequeuing of only one message at a time.
An object type encapsulates a data structure along with the functions and procedures needed to manipulate the data. When you define an object type using the CREATE TYPE statement, you create an abstract template that corresponds to a real-world object.
● Online Transaction Processing
Online transaction processing systems are optimized for fast and reliable transaction handling. Compared to data warehouse systems, most OLTP interactions involve a relatively small number of rows, but a larger group of tables.
An application programming interface that enables data and schema manipulation in Oracle Database.
Oracle Java Message Service (OJMS) provides a Java API for Oracle Streams Advanced Queuing based on the Java Message Service (JMS) standard. OJMS supports the standard JMS interfaces and has extensions to support the Oracle Streams Advanced Queuing administrative operations and other Oracle Streams Advanced Queuing features that are not a part of the standard.
A custom control (OCX or ActiveX) combined with an object linking and embedding (OLE) in-process server that lets you plug native Oracle Database functionality into your Windows applications.
A user or application that can enqueue messages.
A type of messaging in which a producer enqueues a message to one or more multiconsumer queues, and then the message is dequeued by several subscribers. The published message can have a wide dissemination mode called broadcast or a more narrowly aimed mode called multicast.
Queue monitor coordinator. It dynamically spawns slaves qXXX depending on the system load. The slaves do various background tasks.
A database table where queues are stored. Each queue table contains a default exception queue.
An agent authorized by the enqueuer or queue administrator to retrieve messages. The enqueuer can explicitly specify the consumers who can retrieve the message as recipients of the message. A queue administrator can specify a default list of recipients who can retrieve messages from a queue. A recipient specified in the default list is known as a subscriber. If a message is enqueued without specifying the recipients, then the message is sent to all the subscribers. Specific messages in a queue can be directed toward specific recipients, who may or may not be subscribers to the queue, thereby overriding the subscriber list.
If only the name of the recipient is specified, then the recipient must dequeue the message from the queue in which the message was enqueued. If the name and an address of the recipient are specified with a protocol value of 0, then the address should be the name of another queue in the same database or another installation of Oracle Database. If the recipient's name is NULL, then the message is propagated to the specified queue in the address and can be dequeued by any subscriber of the queue specified in the address. If the protocol field is nonzero, then the name and address are not interpreted by the system, and the message can be dequeued by a special consumer.
A remote consumer dequeues from a queue that is different from the queue where the message was enqueued.
Boolean expressions that define subscriber interest in subscribing to messages. The expressions use syntax similar to the WHERE clause of a SQL query and can include conditions on: message properties (currently priority and correlation identifier), user data properties (object payloads only), and functions. If a rule associated with a subscriber evaluates to TRUE for a message, then the message is sent to that subscriber even if the message does not have a specified recipient.
Oracle Database software that evaluates rules. Rules are database objects that enable a client to perform an action when an event occurs and a condition is satisfied. Rules are similar to conditions in WHERE clauses of SQL queries. Both user-created applications and Oracle Database features, such as Oracle Streams Advanced Queuing, can be clients of the rules engine.
A collection of database objects, including logical structures such as tables, views, sequences, stored procedures, synonyms, indexes, clusters, and database links. A schema has the name of the user who controls it.
The JMS equivalent of enqueue.
A Java program that runs as part of a network service and responds to requests from clients. It is typically an HTTP server.
See System Global Area.
● Simple Object Access Protocol
A minimal set of conventions for invoking code using XML over HTTP defined by World Wide Web Consortium.
An agent authorized by a queue administrator to retrieve messages from a queue.
A group of shared memory structures that contain data and control information for one Oracle Database instance. The SGA and Oracle Database processes constitute an Oracle Database instance. Oracle Database automatically allocates memory for an SGA whenever you start an instance and the operating system reclaims the memory when you shut down the instance. Each instance has one and only one SGA.
Two or more processes are synchronous if they depend upon the occurrences of specific events such as common timing signals. The opposite of asynchronous.
Allowing simultaneous enqueuing or dequeuing of multiple messages as part of a group.
A mapping from one Oracle data type to another, represented by a SQL function that takes the source data type as input and returns an object of the target data type. A transformation can be specified during enqueue, to transform the message to the correct type before inserting it into the queue. It can be specified during dequeue to receive the message in the wanted format. If specified with a remote consumer, then the message is transformed before propagating it to the destination queue.
An ordered set of data elements. All elements of a given array are of the same datatype. Each element has an index, which is a number corresponding to the element's position in the array. The number of elements in an array is the size of the array. Oracle Database allows arrays to be of variable size.
A special character or character sequence which matches any character in a string comparison.
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