Oracle Database 11 g Performance Tuning. Recipes. Sam R. Alapati Darl Kuhn Bill Padfield. Apress*

Transcription

1 Oracle Database 11 g Performance Tuning Recipes Sam R. Alapati Darl Kuhn Bill Padfield Apress*

2 Contents About the Authors About the Technical Reviewer Acknowledgments xvi xvii xviii Chapter 1: Optimizing Table Performance Building a Database That Maximizes Performance Creating Tablespaces to Maximize Performance Matching Table Types to Business Requirements Choosing Table Features for Performance Avoiding Extent Allocation Delays When Creating Tables Maximizing Data Loading Speeds Efficiently Removing Table Data Displaying Automated Segment Advisor Advice Manually Generating Segment Advisor Advice Automatically ing Segment Advisor Output Rebuilding Rows Spanning Multiple Blocks Freeing Unused Table Space Compressing Data for Direct Path Loading Compressing Data for All DML Compressing Data at the Column Level Monitoring Table Usage 40

3 . Chapter IB CONTENTS 2: Choosing and Optimizing Indexes..., Understanding B-tree Indexes Deciding Which Columns to Index Creating a Primary Key Index Creating a Unique Index Indexing Foreign Key Columns Deciding When to Use a Concatenated Index Reducing Index Size Through Compression Implementing a Function-Based Index Indexing a Virtual Column Avoiding Concentrated I/O for Index Adding an Index Without Impacting Existing Applications Creating a Bitmap Index in Support of a Star Schema Creating a Bitmap Join Index Creating an Index-Organized Table Monitoring Index Usage Maximizing Index Creation Speed Reclaiming Unused Index Space 78 Chapter 3: Optimizing Instance Memory Automating Memory Management Managing Multiple Buffer Pools Setting Minimum Values for Memory Monitoring Memory Resizing Operations Optimizing Memory Usage Tuning PGA Memory Allocation Configuring the Server Query Cache 95

4 mcontents 3-8. Managing the Server Result Cache Caching SQL Query Results Caching Client Result Sets Caching PL/SQL Function Results Configuring the Oracle Database Smart Flash Cache Tuning the Redo Log Buffer 110 Chapter 4: Monitoring System Performance Implementing Automatic Workload Repository (AWR) Modifying the Statistics Interval and Retention Periods Generating an AWR Report Manually Generating an AWR Report via Enterprise Manager Generating an AWR Report for a Single SQL Statement Creating a Statistical Baseline for Your Database Managing AWR Baselines via Enterprise Manager Managing AWR Statistics Repository Creating AWR Baselines Automatically Quickly Analyzing AWR Output Manually Getting Active Session Information Getting ASH Information from Enterprise Manager Getting ASH Information from the Data Dictionary 142 Chapter 5: Minimizing System Contention Understanding Response Time Identifying SQL Statements with the Most Waits Analyzing Wait Events Understanding Wait Class Events Examining Session Waits 153

5 CONTENTS 5-6. Examining Wait Events by Class Resolving Buffer Busy Waits Resolving Log File Sync Waits Minimizing read by other session Wait Events Reducing Direct Path Read Wait Events Minimizing Recovery Writer Waits Finding Out Who's Holding a Blocking Lock Identifying Blocked and Blocking Sessions Dealing with a Blocking Lock Identifying a Locked Object Resolving enq: TM Lock Contention Identifying Recently Locked Sessions Analyzing Recent Wait Events in a Database Identifying Time Spent Waiting Due to Locking Minimizing Latch Contention Managing Locks from Oracle Enterprise Manager Analyzing Waits from Oracle Enterprise Manager 182 Chapter 6: Analyzing Operating System Performance Detecting Disk Space Issues Identifying System Bottlenecks (vmstat) Identifying System Bottlenecks (Solaris) Identifying Top Server-Consuming Resources (top) Identifying CPU and Memory Bottlenecks (ps) Identifying I/O Bottlenecks Identifying Network-Intensive Processes Troubleshooting Database Network Connectivity 202 viii

6 :> CONTENTS 6-9. Mapping a Resource-Intensive Process to a Database Process Terminating a Resource-Intensive Process 207 Chapter 7: Troubleshooting the Database Determining the Optimal Undo Retention Period Finding What's Consuming the Most Undo Resolving an ORA Error Monitoring Temporary Tablespace Usage Identifying Who Is Using the Temporary Tablespace Resolving the "Unable to Extend Temp Segment" Error Resolving Open Cursor Errors Resolving a Hung Database Invoking the Automatic Diagnostic Repository Command Interpreter Viewing an Alert Log from ADRCI Viewing Incidents with ADRCI Packaging Incidents for Oracle Support Running a Database Health Check Creating a SQL Test Case Generating an AWR Report Comparing Database Performance Between Two Periods Analyzing an AWR Report 248 Chapter 8: Creating Efficient SQL Retrieving All Rows from a Table Retrieve a Subset of Rows from a Table Joining Tables with Corresponding Rows Joining Tables When Corresponding Rows May Be Missing Constructing Simple Subqueries 263

7 % CONTENTS 8-6. Constructing Correlated Subqueries Comparing Two Tables to Finding Missing Rows Comparing Two Tables to Finding Matching Rows Combining Results from Similar SELECT Statements Searching for a Range of Values Handling Null Values Searching for Partial Column Values Re-using SQL Statements Within the Shared Pool Avoiding Accidental Full Table Scans Creating Efficient Temporary Views Avoiding the NOT Clause Controlling Transaction Sizes 295 IChapter 9: Manually Tuning SQL Displaying an Execution Plan for a Query Customizing Execution Plan Output Graphically Displaying an Execution Plan Reading an Execution Plan Monitoring Long-Running SQL Statements Identifying Resource-Consuming SQL Statements That Are Currently Executing Seeing Execution Statistics for Currently Running SQL Monitoring Progress of a SQL Execution Plan Identifying Resource-Consuming SQL Statements That Have Executed in the Past Comparing SQL Performance After a System Change 321 X

8 = COMTENTS IlChapter 10: Tracing SQL Execution Preparing Your Environment Tracing a Specific SQL Statement Enabling Tracing in Your Own Session Finding the Trace Files Examining a Raw SQL Trace File Analyzing Oracle Trace Files Formatting Trace Files with TKPROF Analyzing TKPROF Output Analyzing Trace Files with Oracle Trace Analyzer Tracing a Parallel Query Tracing Specific Parallel Query Processes Tracing Parallel Queries in a RAC System Consolidating Multiple Trace Files Finding the Correct Session for Tracing Tracing a SQL Session Tracing a Session by Process ID Tracing Multiple Sessions Tracing an Instance or a Database Generating an Event Trace for a Session Generating an Event Trace for an Instance Setting a Trace in a Running Session Enabling Tracing in a Session After a Login Tracing the Optimizer's Execution Path Generating Automatic Oracle Error Traces Tracing a Background Process 362

9 CONTENTS Enabling Oracle Listener Tracing Setting Archive Tracing for Data Guard 365 Chapter 11: Automated SQL Tuning Displaying Automatic SQL Tuning Job Details Displaying Automatic SQL Tuning Advice Generating a SQL Script to Implement Automatic Tuning Advice Modifying Automatic SQL Tuning Features Disabling and Enabling Automatic SQL Tuning Modifying Maintenance Window Attributes Creating a SQL Tuning Set Object Viewing Resource-Intensive SQL in the AWR Viewing Resource-Intensive SQL in Memory Populating SQL Tuning Set from High-Resource SQL in AWR Populating a SQL Tuning Set from Resource-Consuming SQL in Memory Populating SQL Tuning Set with All SQL in Memory Displaying the Contents of a SQL Tuning Set Selectively Deleting Statements from a SQL Tuning Set Transporting a SQL Tuning Set Creating a Tuning Task Manually Running SQL Tuning Advisor Getting SQL Tuning Advice from the Automatic Database Diagnostic Monitor..404 Chapter 12: Execution Plan Optimization and Consistency Creating and Accepting a SQL Profile Automatically Accepting SQL Profiles Displaying SQL Profile Information Disabling a SQL Profile 421 xii

10 S CONTENTS Dropping a SQL Profile Moving a SQL Profile Automatically Adding Plan Baselines Creating a Plan Baseline for One SQL Statement Creating Plan Baselines for SQL Contained in SQL Tuning Set Altering a Plan Baseline Determining If Plan Baselines Exist Displaying Plan Baseline Execution Plans Adding a New Plan to Plan Baseline (Evolving) Disabling Plan Baselines Removing Plan Baseline Information Transporting Plan Baselines 444 Chapter 13: Configuring the Optimizer Choosing an Optimizer Goal Enabling Automatic Statistics Gathering Setting Manually Generating Preferences for Statistics Collection 451 Statistics Locking Statistics Handling Missing Statistics Exporting Statistics Restoring Previous Versions of Statistics Gathering System Statistics Validating New Statistics Forcing the Optimizer to Use an Index Enabling Query Optimizer Features Keeping the Database from Creating Histograms 472

11 CONTENTS Improving Performance When Not Using Bind Variables Understanding Adaptive Cursor Sharing Creating Statistics on Expressions Creating Statistics for Related Columns Automatically Creating Column Groups Maintaining Statistics on Partitioned Tables Concurrent Statistics Collection for Large Tables 488 Chapter 14: Implementing Query Hints Writing a Hint Changing the Access Path Changing the Join Order Changing the Join Method Changing the Optimizer Version Choosing Between a Fast Response and Overall Optimization Performing a Direct-Path Insert Placing Hints in Views Caching Query Results Directing a Distributed Query to a Specific Database Gathering Extended Query Execution Statistics Enabling Query Rewrite Improving Star Schema Query Performance 521 Chapter 15: Executing SQL in Parallel Enabling Parallelism for a Specific Query Enabling Parallelism at Object Creation Enabling Parallelism for an Existing Object Implementing Parallel DML 533 xiv

12 CONTENTS Creating Tables in Parallel Creating Indexes in Parallel Rebuilding Indexes in Parallel Moving Partitions in Parallel Splitting Partitions in Parallel Enabling Automatic Degree of Parallelism Examining Parallel Explain Plans Monitoring Parallel Operations Finding Bottlenecks in Parallel Processes Getting Detailed Information on Parallel Sessions 552 Index 555 XV