Oracle Enterprise Manager Oracle Trace User's Guide

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Overview

Using Oracle Trace
Collecting Event Data
Managing Collections
Accessing Data
Joining Event Data from Multiple Products
Adding Instrumented Products

Oracle Trace is a general-purpose data collection system that collects data for any software product. Use Oracle Trace to collect a wide variety of data, such as performance statistics, diagnostics data, system resource usage, and business transaction details.

This chapter covers the following topics:

using the application programming interface
collecting event data
managing collections
accessing data
joining event data from multiple products
adding instrumented products

Using Oracle Trace

Oracle Trace has an Application Programming Interface (API) that contains data collection service calls. Software developers can use the Oracle Trace API to pre-configure their products for Oracle Trace data collection. Users of a product containing the Oracle Trace API calls can then use Oracle Trace to collect data about specific events that occur in that product.

Using the API, Oracle Trace collects data for specific software events, such as an application transaction, a user log on, or any event particular to the host product. To focus data collection, you can organize events into logical sets, such as a performance event set or an auditing event set.

Oracle Corporation is currently using the Oracle Trace data collection API in two products:

Oracle Server release 7.3 (for performance data collection)
SQL*Net release 2.3 (for diagnostics data collection)

The Oracle Server performance data collected by Oracle Trace includes SQL statements, detailed statistics on SQL events, transaction events, and other useful information.

Oracle Trace provides a graphical Oracle Trace Manager application to create, schedule, and administer Oracle Trace collections for host products containing the Oracle Trace API. You can store data collected by Oracle Trace in Oracle database tables for access by SQL reporting tools and other products.

Most Oracle Trace users will be performing collections for products that already include the Oracle Trace API. Therefore, most users only need to be familiar with the data that can be collected for the host product and how to use the Oracle Trace Collection Manager application to create and administer data collections.

Developers who want to use the Oracle Trace API in their product must be familiar with instrumenting. Instrumenting is the process of embedding Oracle Trace API calls in a product. A developer who instruments a product must also create an Oracle Trace definition file that is used to define and control the event data that can be collected.

Collecting Event Data

An event is the occurrence of some activity within a product. Oracle Trace collects data for specific, predefined events that occur within a software product that is instrumented with the Oracle Trace API.

There are two types of events:

point events

: Point events represent an instantaneous occurrence of something in the instrumented product. An example of a point event is an error occurrence.

duration events

: Duration events have a beginning and ending. An example of a duration event is a transaction. Duration events can have other events occur within them; for example, the occurrence of an error within a transaction.

Items are specific pieces of information about an event. You define data items for each event. These include items that are specific to the instrumented product, such as a transaction's start and end time, and a transaction type or dollar amount. Data items can also include statistics on the resources used by that event, such as the CPU time and number of input/output operations (I/Os) performed by the event.

For example, the Oracle Server release 7.3 is instrumented for 13 events. Two of these events are:

Database Connection ¯ A point event that records data such as the server login username
SQL Parse ¯ One of the series of SQL processing duration events. This event records a large set of statistics such as sorts, reads, and cursor number.

A complete list of the server events and data items is contained in Appendix A.

Oracle Trace events can be organized into event sets for specific purposes. This allows you to easily focus the collection on specific events. You can establish event sets for performance monitoring, auditing, diagnostics, or any logical event grouping. For example, the Oracle Server includes an event set known as the EXPERT set. This set includes SQL event data used by the Oracle Expert tuning application.

You can use the same events in multiple event sets within a product's Oracle Trace definition file. Every instrumented product has an ALL event set which, as the name suggests, includes all of the events defined for the product.

Managing Collections

The use and control of Oracle Trace revolves around the concept of a collection. You define and manage Oracle Trace collections. You create a collection object to define the attributes of the collection, such as the collection name, the products and event sets to be included in the collection, and the start and end time.

Once you create a collection object, it can be used immediately, scheduled to execute at a specific time, or executed at specified intervals. When a collection executes, it produces a file containing the event data for the products that participated in the collection. You can also use a collection object to create other similar collections.

You create and administer Oracle Trace collections through the Oracle Trace Manager application. This is a client-based Windows application that runs on the Oracle Enterprise Manager console. The Oracle Trace Manager automatically discovers Oracle Trace instrumented products that are installed on all nodes that are known to the Oracle Enterprise Manager console. It includes a Collection Wizard that quickly and easily creates and executes collections.

Note:

Some instrumented applications also provide their own mechanism for starting and stopping Oracle Trace collections. For example, Oracle Server release 7.3 provides a set of database initialization parameters that you can use to start and stop an Oracle Trace collection. In some situations, using an instrumented product's own controls may be useful. However, you should control most Oracle Trace collections using the Oracle Trace Manager application.

Accessing Data

During a collection, Oracle Trace buffers event data in memory and systematically stores it in a collection binary file. This method ensures low overhead associated with the collection process. You can access the event data collected in the binary file in two ways:

by running the Oracle Trace Detail report
by formatting the data to Oracle tables

The Oracle Trace Detail report provides a basic mechanism for viewing a collection's results. The Detail report takes the data directly from the collection binary file. You have limited control over what data is reported and how it is presented.

The preferred method for accessing Oracle Trace data is by formatting it to Oracle tables. This makes the data available for fast, flexible access. The formatting process takes the data from the collection binary file and inserts it into predefined Oracle tables. A collection can be formatted while it is occurring. Once the data is formatted, you can access the data using SQL reporting tools, scripts, and other applications. For example, the Oracle Expert database tuning application can automatically access and analyze Oracle Server SQL event data from the Oracle Trace formatter tables.

Joining Event Data from Multiple Products

Multiple instrumented products can participate in the same collection. Oracle Trace can join event data from multiple products that are participating in some common activity, for example, a transaction that spans an application and a database server. Oracle Trace does this through a set of cross-product data items. Each instrumented product is assigned a specific cross-product data item. The product uses this data item to log some unique identification information. Oracle Trace then passes this identification information to other products participating in the collection, where the identification information is captured as event data in the other participating product's events.

This capability allows the Oracle Trace user to track a transaction or some other activity across multiple products. Resource usage and process time can be tracked for each product and event participating in the transaction, allowing performance bottlenecks to be easily identified.

To use this advanced capability, you must instrument all products participating in the collection with the Oracle Trace cross-product API calls. The Oracle Server release 7.3 and SQL*Net release 2.3 products include cross-product instrumentation. Additional Oracle products and third-party applications that are instrumented with the Oracle Trace API can also take advantage of this feature.

Adding Instrumented Products

As more products are instrumented with the Oracle Trace API, you can add them to your Oracle Trace environment. Instrumented products that are installed on nodes managed by the Oracle Enterprise Manager can be automatically discovered and used by the Oracle Trace Manager. This includes third-party products as well as your own applications.

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