PART I Core Ideas and Elements of PL/SQL Performance Tuning

Transcription

1 Contents at a Glance PART I Core Ideas and Elements of PL/SQL Performance Tuning 1 The Role of PL/SQL in Contemporary Development DBA/Developer Borderline: Tools and Features Code Instrumentation in PL/SQL PART II Linking SQL and PL/SQL 4 Expanding the SQL Horizons Thinking in Sets Pulling the Trigger PART III Tuner s Toolkit 7 Going Beyond Scalar Datatypes Keeping the Cache Shooting at a Moving Target vii

2 viii Oracle PL/SQL Performance Tuning Tips & Techniques PART IV PL/SQL in Daily Life 10 Tales from the Trenches Code Management in Real-World Systems Extra Tips, Tricks, and Ideas Index

3 Contents Foreword... xv Acknowledgments... xix Introduction...xxiii PART I Core Ideas and Elements of PL/SQL Performance Tuning 1 The Role of PL/SQL in Contemporary Development... 3 Typical Web Application Process Flow... 4 Web Application Performance Problem Areas... 5 Step 1: Client Machine Performance Problems... 5 Step 2: Client Machine to Application Server Transmission Problems... 6 Step 3: Application Server Performance Problems... 6 Step 4: Application Server to Database Transmission Problems... 6 Step 5: Database Performance Problems... 7 Step 6: Database to Application Server Transmission Problems... 7 Step 7: Application Server Processing Performance Problems... 8 Step 8: Application Server to Client Machine Transmission Problems... 8 Step 9: Client Machine Performance Problems... 8 Finding the Cause of Slowly Performing Web Applications... 8 Using Timers to Gather Data About Performance... 9 Measuring Performance Solving Web Application Performance Problems Solving Client Machine Performance Problems (Steps 1 and 9) Resolving Performance Issues Between the Client Machine and Application Server (Step 2) Solving Performance Problems in the Application Server (Steps 3 and 7) ix

4 x Oracle PL/SQL Performance Tuning Tips & Techniques Solving Performance Problems in the Client Machine (Step 9) Lessons Learned Summary DBA/Developer Borderline: Tools and Features Data Dictionary Views Oracle Logging and Tracing Logging Basics Tracing Basics Logging/Tracing Example PL/SQL Hierarchical Profiler RUNSTATS PL/SQL Environment Settings PLSQL_OPTIMIZE_LEVEL PLSQL_CODE_TYPE PLSQL_WARNINGS PLSQL_CCFLAGS PL/Scope Summary Code Instrumentation in PL/SQL Is the Problem Really in the Database? Application Logging Built-in Code Navigation APIs User-Driven Logging Code Instrumentation Best Practices Placing Process Markers Placing Error Markers Summary PART II Linking SQL and PL/SQL 4 Expanding the SQL Horizons Stepping Outside the SQL Box Making Life Simpler by Switching to PL/SQL Using PL/SQL to Fill Functionality Gaps Calling Functions Within SQL Single-Table Problems Multi-Table Problems PL/SQL-Related Statistics and Their Impact on Execution Plans Hardware Costs of PL/SQL Functions Cardinality of PL/SQL Functions Selectivity of PL/SQL Functions... 94

5 Contents xi Oracle Database 12c Only Features PRAGMA UDF Clause Adding Functions Inside the WITH Clause Summary Thinking in Sets Cursors Loading Sets from SQL to PL/SQL Oracle Database 12c: Implicit Pagination vs. Continuous Fetch Merging Sets Using PL/SQL And Justice FORALL! Staying Up to Date with Syntax: Sparse Collections Direct Inserts FORALL and Table Triggers Summary Pulling the Trigger DML Triggers Data Protection: Constraints vs. Triggers Default Values Cost of Denormalization INSTEAD OF Triggers Basic DML Operations Dangers of Logical Primary Keys Handling UPDATE Statements Summary PART III Tuner s Toolkit 7 Going Beyond Scalar Datatypes Managing LOBs Access to LOBs Storage Mechanisms I/O Tuning Considerations SecureFile-Only Features Managing XML Storing XML Manipulating XML Summary Keeping the Cache Built-in Caching Techniques Deterministic Functions Scalar Subquery Caching PL/SQL Function Result Cache...193

6 xii Oracle PL/SQL Performance Tuning Tips & Techniques Manual Caching Techniques PL/SQL Collections Oracle Context Summary Shooting at a Moving Target Expanding the Knowledge Base CLOB Input Cursor Transformation PL/SQL Function Result Cache Integration Support for Complex Datatypes Digging Deeper More About Search IN-LIST Trap Challenging Dynamic SQL Myths Myth #1: Dynamic SQL Is Always a Security Risk Myth #2: Dynamic SQL Is Always Slower Than Regular SQL Myth #3: Dynamic SQL Always Causes Parsing Myth #4: DDL Statements Are Only for DBAs Summary PART IV PL/SQL in Daily Life 10 Tales from the Trenches Third-Party Wrapped Code Stateless Issues Unknown UNDO The Curse of Recursion Recursion and Cursors Recursion and Variables Summary Code Management in Real-World Systems The Problem of Code Management Versioning Lite for DBAs Homegrown Versioning Edition-Based Redefinition and Performance Tuning Understanding Edition-Based Redefinition Important Changes to EBR Introduced in Oracle Database 12c System Environment Differences and Performance-Related Code Management Summary...268

7 Contents xiii 12 Extra Tips, Tricks, and Ideas Back to Basics VARCHAR2 Memory Allocation The Cost of Current Date BINARY Datatypes Text Manipulation Checking Text Strings for Valid Characters Similarity of Words VARCHAR2 and Views Increasing Processing Complexity NOCACHE Optimization ACCESSIBLE BY Clause More About Pipelined Functions Summary Index...291