Glossary

Oracle Enterprise Manager Oracle Expert User's Guide

access methods

One of the categories of application tuning. During access methods tuning, Oracle Expert determines what indexes are needed and generates the SQL statements to create, modify, and delete indexes as appropriate. Oracle Expert ensures that the indexing strategy is consistent with that of the Oracle cost-based optimizer. Oracle Expert addresses sorted, hashed, and bit-mapped indexes. See also SQL tuning.

advanced rules

Rules that you would rarely want to view or edit, for example, low-level constants that are factored into the algorithms used by the Oracle Expert rules. See also default rules and rules.

analysis

The process by which Oracle Expert examines the tuning data collected for a database and generates tuning recommendations.

Analysis report

A report that describes the Oracle Expert tuning recommendations. It provides a detailed explanation of the data Oracle Expert evaluated, how Oracle Expert interpreted the data, and any risks associated with implementing the recommendations.

Application

The workload category at the top of the workload hierarchy. See also Business Unit, Transaction, and Request.

application tuning session

A focused tuning session in which one or more application tuning categories (access methods or SQL tuning) is selected for one or more applications. See also access methods and SQL tuning.

attribute

A characteristic of a data object. You can view and edit attributes for objects using the Edit dialog box.

base index tuning

The part of access method tuning where Oracle Expert scans schemas selected for tuning for evidence of implicit search operations, such as constraints or views. If a constraint or view is found, Oracle Expert determines whether an index is necessary to improve performance when the constraint or view is executed.

Business Unit

The workload category below the Application level in the workload hierarchy. See also Application, Transaction, and Request.

cardinality

Can refer to either table cardinality (the number of rows in a table) or column cardinality (the number of distinct values in a column of a table).

category

See tuning category.

class

See collection class.

collection

The act of collecting the data that Oracle Expert analyzes to make tuning session recommendations.

collection class

A category of information that Oracle Expert collects and analyzes. The collection classes are Database, Instance, Schema, Environment, and Workload.

column cardinality

The number of distinct values in a column of a table.

comprehensive tuning session

A tuning session in which you have selected all the tuning categories at the same time. During analysis for a comprehensive tuning session, Oracle Expert generates all the tuning recommendations it is capable of (for all areas of your database environment).

control parameters

A group of parameters whose values provide useful information to Oracle Expert for tuning your database environment. Examples of control parameters for which you can supply values are the classes of workload (such as batch, OLTP, or decision support) and the tolerance for database downtime. Oracle Expert takes control parameter values into account when making tuning recommendations.

cycle

The interval of time during which a sequence of a recurring succession of events is completed. You can specify a cycle of shift, day, week, month, quarter, year, or none for workload elements (Applications, Business Units, Transactions, and Requests).

database tuning

A process that involves tasks such as balancing competing database resources so that important applications get the resources they need, identifying and eliminating resource bottlenecks, and optimizing the use of existing resources in the database environment.

default rules

A portion of the rules that make up the extensive Oracle Expert knowledge base. Each Oracle Expert rule exists at the Oracle Expert system level. Rules at the Oracle Expert system level are called default rules, and they have default values. A copy of a default rule can exist at one or more object levels. Oracle Expert allows you to view some default rules. Oracle Expert allows you to change the default value of any default rule it allows you to view. See also advanced rules and rules.

edit data

The act of viewing, modifying, adding, or deleting collected data that appears on the View/Edit page of the tuning session window.

environment

The physical resources of the database, for example, the system the database runs on and the logical devices used by the database. Data about a database's environment is collected in the Environment collection class.

focused tuning session

A tuning session in which you have not selected all of the Oracle Expert tuning categories at the same time. After an analysis is performed in a focused tuning session, Oracle Expert generates tuning recommendations for the selected tuning categories.

frequency

The number of times a workload element is executed by the workload element above it in the workload hierarchy. For example, for a workload Request, the frequency is the number of times the Request is executed during a workload Transaction.

implementation

The process during which Oracle Expert generates implementation files and implementation scripts that can help you put the Oracle Expert tuning recommendations into effect. See also implementation files and implementation scripts.

implementation files

Files (such as parameter files for instances) that Oracle Expert generates to help you put its tuning recommendations into effect.

implementation scripts

Scripts generated by Oracle Expert that you can run to put the Oracle Expert tuning recommendations into effect.

importance

The importance (or priority) value assigned to a workload element relative to the other workload elements at the same level of the workload hierarchy. For example, given two workload Applications, where one is a production, high-availability application and the other is a maintenance application, you would assign the first a higher importance value than the second. Oracle Expert uses this value to ensure that higher priority Applications, Business Units, Transactions, and Requests are favored over less important ones during the optimization process. The range of importance values is from 1 to 9999, with 1 being the lowest importance. See also relative importance.

initial configuration tuning session

A tuning session in which Oracle Expert is used to help configure a new database.

instance tuning session

A focused tuning session in which one or more categories of instance tuning (SGA parameters, I/O parameters, parallel query parameters, or sort parameters) is selected for one or more instances. See also I/O parameters, parallel query parameters, SGA parameters, and sort parameters.

instantiation

Making a copy of a default rule at an object level. This makes the object the owner of the copy of the rule. Oracle Expert uses an object's values for instantiated rules during an analysis. See also default rules and rules.

I/O parameters

These instance parameters affect the throughput or distribution of I/O for the instance. Examples of these parameters include the checkpoint_process and db_file_multiblock_read_count parameters. These parameters can be selected as a category to be tuned as part of an instance tuning session. See also instance tuning session, parallel query parameters, SGA parameters, and sort parameters.

parallel query parameters

These instance parameters are specific to the parallel query behavior for the instance. Examples of these parameters include the parallel_min_servers and parallel_max_servers parameters. Selecting the parallel query parameters category for tuning is relevant only if the parallel query option is installed. These parameters can be selected as a category to be tuned as part of an instance tuning session. See also instance tuning session, I/O parameters, SGA parameters, and sort parameters.

placement

A category of structure tuning. Oracle Expert makes recommendations about placement of structures, such as segment partitioning and placement of database files. Oracle Expert may recommend separating segments into different tablespaces to minimize tablespace free space fragmentation and maximize administrative flexibility. Oracle Expert may also recommend distributing database files across drives, which reduces the service and queue times per I/O and the number of I/Os. See also sizing.

relative importance

A value that ranks a workload element's importance compared to all the other workload elements. Oracle Expert computes the relative importance for each workload element. The factors that Oracle Expert takes into account when computing a relative importance value for a workload element are the element's workload category (Application, Business Unit, Transaction, or Request), importance value, and frequency value. See also importance.

reports

Information that Oracle Expert can generate about the collected data for a tuning session (Session Data report) or the recommendations it has generated (Analysis report). See also Analysis report and Session Data report.

repository

A schema in an Oracle database that stores the data associated with each Oracle Expert tuning session.

representative workload

A workload that includes a representative set of the SQL statements that execute during a period for which you want Oracle Expert to optimize database performance. You would typically provide valid importance values for the elements in a representative workload to allow Oracle Expert to optimize performance for the statements with the highest relative importance.

Request

A SQL statement. Requests are the elements at the lowest level of the workload hierarchy, below Transactions. See also Application, Business Unit, and Transaction.

rules

Pieces of knowledge used by Oracle Expert to analyze collected data for a tuning session. Oracle Expert allows you to view some of its rules, and you can modify the value of any rule you view. Modifying rule values may change the behavior of Oracle Expert during an analysis and also its recommendations. See also advanced rules and default rules.

scope

A setting that determines the categories of database tuning Oracle Expert will address for a given tuning session. You choose the scope when you create a new tuning session and can modify the scope for a tuning session. You can choose one or more tuning categories from one or more of the tuning types; instance tuning, application tuning, and structure tuning. See also instance tuning session, application tuning session, and structure tuning session.

session

See tuning session.

Session Data report

A report that describes all the collected data for an Oracle Expert tuning session. You can read this report before starting an analysis of the collected data to confirm that you provided Oracle Expert with all the data it expects for your tuning session.

SGA parameters

These instance parameters affect the total size of the instance's System Global Area (SGA). The appropriate setting of these parameters results in efficient utilization of memory and prevents reparsing SQL statements except when necessary. Examples of these parameters include the db_block_buffers and shared_pool_reserved_size parameters. These parameters can be tuned as part of an instance tuning session. See also instance tuning session, I/O parameters, parallel query parameters, and sort parameters.

sizing

A category of structure tuning. Oracle Expert makes recommendations for some of the default storage parameters of a tablespace. These parameters provide default initial allocation and growth rate of segments created within that tablespace. See also placement.

sort parameters

These parameters influence how the Oracle Server performs sort operations on behalf of the user. Examples of these parameters include the sort_direct_write and sort_area_retained_size parameters. These parameters can be selected as a category to be tuned as part of an instance tuning session. See also instance tuning session, I/O parameters, parallel query parameters, and SGA parameters.

SQL statement matching

Part of SQL tuning. The Oracle Server maintains only one copy of a distinct SQL statement within the library cache to maximize memory and minimize redundant parsing and validating. To effectively use this feature, you must write duplicate SQL statements using identical structure and form (two statements are considered the same only when they match character for character, including spaces and punctuation). Oracle Expert compares your workload statements to determine if any can be rewritten to take advantage of the cache behavior and reports its findings.

SQL tuning

One of the categories of application tuning. When SQL tuning is selected, Oracle Expert performs SQL statement matching. See also access methods and SQL statement matching.

structure tuning session

A focused tuning session in which one or more categories of structure tuning is selected for one or more database structures. See also placement and sizing.

system data

Data about the machine on which an instance runs. You need to provide Oracle Expert with data such as the memory allocation and CPU utilization of the machine on which the instance runs.

table cardinality

The number of rows in a table.

Transaction

A logical unit of work that consists of one or more SQL statements. A transaction begins with a user's first executable SQL statement and ends when the transaction is explicitly committed or rolled back. Transactions appear at the level below Business Unit in the workload hierarchy. See also Application, Business Unit, and Request.

tuning category

One of the specific tuning areas that Oracle Expert addresses for a tuning type. Two or more tuning categories are associated with each Oracle Expert tuning type. See also tuning type.

tuning scope

See scope, comprehensive tuning session, focused tuning session, and initial configuration tuning session.

tuning session

The framework within which Oracle Expert performs its tuning activities. The steps in a tuning session include creating the session, specifying the session's tuning scope, collecting data, editing data, analyzing data, generating recommendations, validating recommendations, and implementing recommendations.

tuning type

One of the general areas of the database environment that Oracle Expert can tune. The three tuning types are instance tuning, application tuning, and structure tuning. Two or more tuning categories are associated with each tuning type. See also tuning category.

type

See tuning type.

validation

The process of verifying, for a collected object, that other objects referenced by or dependent upon the collected object have also been collected. If other objects referenced by or dependent upon a collected object have not been collected, the collected object is marked as invalid. The international No symbol is used to mark invalid objects on the View/Edit page of the tuning session window.

what-if scenario

A tuning session in which you modify the values of collected data such as disks, memory, CPU, or cardinality to a value you expect will be correct in the future. This type of tuning allows you to determine the effect of changes on a database before the changes are actually made.

workload

Data that describes to Oracle Expert the nature, frequency, and importance of SQL statements that access a database. You should collect a representative workload for each tuning session that requires a workload. Workload data is displayed hierarchically on the View/Edit page of the tuning session window. See also representative workload, Application, Business Unit, Transaction, and Request.

.XDL file

An Oracle Expert Definition Language file. Oracle Expert creates an .XDL file when it exports database, instance, schema, environment, or workload data.

Copyright © 1996 Oracle Corporation.
All Rights Reserved.