|Oracle® Database Performance Tuning Guide
10g Release 1 (10.1)
Part Number B10752-01
This section describes new performance features of Oracle Database 10g Release 1 (10.1) and provides pointers to additional information. The features and enhancements described in this section comprise the overall effort to optimize server performance.
For a summary of all new features for Oracle Database 10g Release 1 (10.1), see Oracle Database New Features.
The new and updated performance features in 10g Release 1 (10.1) include the following:
These features include Automatic Statistics Collection, Automatic Database Diagnostic Monitoring, and Automatic SQL Tuning. The Automatic Workload Repository collects, processes, and maintains performance statistics for problem detection and self-tuning purposes.The Automatic Database Diagnostic Monitor (ADDM) reduces the amount of effort that is required to diagnose and tune Oracle systems. The SQL Tuning Advisor feature allows a quick and efficient technique for optimizing SQL statements. See "Introduction to Performance Tuning Features and Tools" for a brief summary of the new performance features and tools.
Application End to End Tracing identifies the source of an excessive workload, such as a high load SQL statement, by client identifier, service, module, or action. This feature simplifies the debugging of performance problems in multitier environments. See "End to End Application Tracing".
trcsess command-line utility consolidates trace information from selected trace files based on specified criteria. See "Using the trcsess Utility".
This feature automates the collection of optimizer statistics for objects. Objects with stale or no statistics are automatically analyzed, so administrators no longer need to keep track of what does and what does not need to be analyzed, nor to perform analysis by hand. See "Automatic Statistics Gathering".
Automatic Shared Memory Management simplifies the configuration of System Global Area (SGA) memory-related parameters through self-tuning algorithms. It simplifies database configuration, ensures most efficient utilization of available memory and improves performance. See "Automatic Shared Memory Management".
RBO as a functionality is no longer supported. RBO still exists in Oracle 10g Release 1, but is an unsupported feature. No code changes have been made to RBO and no bug fixes are provided. Oracle supports only the query optimizer, and all applications running on Oracle Database 10g Release 1 (10.1) should use that optimizer. Please review the following Oracle Metalink desupport notice (189702.1) for RBO:
You can also access desupport notice 189702.1 and related notices by searching for "desupport of RBO" at:
Notice 189702.1 provides details about the desupport of RBO and the migration of applications based on RBO to query optimization.
Some consequences of the desupport of RBO are:
RULEare no longer supported as
OPTIMIZER_MODEinitialization parameter values and a warning is displayed in the alert log if the value is set to
CHOOSE. The functionalities of those parameter values still exist but will be removed in a future release. See "OPTIMIZER_MODE Initialization Parameter" for information optimizer mode parameters.
ALL_ROWSis the default value for the
RULEoptimizer hints are no longer supported. The functionalities of those hints still exist but will be removed in a future release.
The default setting for the
OPTIMIZER_DYNAMIC_SAMPLING initialization parameter is now
2. See "Estimating Statistics with Dynamic Sampling" for information about when and how to use dynamic sampling.
STAR hints have been deprecated and should not be used.
New and updated dynamic performance views are available. Existing
V$SESSION_WAIT views were modified. New
V$TEMP_HISTOGRAM were added.
The sample clause can now be present in complex select statements. See "Sample Table Scans".
New hash method can improve performance of indexes where a small number leaf blocks in the index have high contention in multiuser OLTP environment. See "Using Partitioned Indexes for Performance".
Oracle Trace as a functionality is no longer available. For the tracing of database activity, use SQL Trace or
TKPROF instead. The chapter on Oracle Trace has been removed from this book. See Chapter 20, "Using Application Tracing Tools".