Expert Oracle Exadata

Transcription

1 Expert Oracle Exadata Kerry Osborne Randy Johnson Tanel Poder Apress

2 Contents J m About the Authors About the Technical Reviewer a Acknowledgments Introduction xvi xvii xviii xix Chapter 1: What Is Exadata? 1 An Overview of Exadata 2 History of Exadata 3 Alternative Views of What Exadata Is 5 Data Warehouse Appliance 5 OLTP Machine 6 Consolidation Platform 6 Configuration Options 7 Exadata Database Machine X2-2 7 Exadata Database Machine X2-8 8 Hardware Components 9 Operating Systems 10 Database Servers 11 Storage Servers 11 InfiniBand 11 Flash Cache 12 Disks 12

3 Bits and Pieces 12 Software Components 12 Database Server Software 12 Storage Server Software 16 Software Architecture 18 Summary 21 Chapter 2: Offloading / Smart Scan 23 Why Offloading Is Important 23 What Offloading Includes 27 Column Projection 27 Predicate Filtering 32 Storage Indexes 33 Simple Joins (Bloom Filters) 34 Function Offloading 37 Compression/Decompression 39 Encryption/Decryption 40 Virtual Columns 41 Data Mining Model Scoring 43 Non-Smart Scan Offloading 44 Smart Scan Prerequisites 45 Full Scans 45 Direct Path Reads 45 Exadata Storage 46 Smart Scan Disablers 49 Simply Unavailable 49 Reverting to Block Shipping 49 Skipping Some Offloading 50 vi

4 How to Verify That Smart Scan is Happening Trace 51 Performance Statistics (v$sessstat) 52 Offload Eligible Bytes 54 SQL Monitoring 58 Parameters 61 Summary 64 Chapter 3: Hybrid Columnar Compression 65 Oracle Storage Review 65 Oracle Compression Mechanisms 68 BASIC 68 OLTP 68 HCC 69 HCC Mechanics 72 HCC Performance 73 Load Performance 73 Query Performance 78 DML Performance 83 Expected Compression Ratios 91 Compression Advisor 91 Real World Examples 94 Restrictions/Challenges 100 Moving Data to a non-exadata Platform 100 Disabling Serial Direct Path Reads 100 Locking Issues 101 Single Row Access 102 Common Usage Scenarios 102 vii

5 Summary 104 Chapter 4: Storage Indexes 105 Structure 105 Monitoring Storage Indexes 107 Database Statistics 107 Tracing 108 Monitoring Wrap Up 111 Controlling Storage Indexes 111 _kcfis_storageidx_disabled 111 _kcfis_storageidx_diag_mode 112 _cell_storidx_mode 112 Storage Software Parameters 112 Behavior 113 Performance 114 Special Optimization for Nulls 116 Physical Distribution of Values 117 Potential Issues 118 Incorrect Results 119 Moving Target 119 Partition Size 122 Incompatible Coding Techniques 122 Summary 124 Chapter 5: Exadata Smart Flash Cache 125 Hardware 125 Cache vs. Flash Disk 127 Using Flash Memory as Cache 128 HowESFCis Created 132 viii

6 Controlling ESFC Usage 134 Monitoring 135 At the Storage Layer 135 At the Database Layer 139 Performance 140 Summary 141 Chapter 6: Exadata Parallel Operations 143 Parameters 143 Parallelization at the Storage Tier 145 AutoDOP 146 Operation and Configuration 146 I/O Calibration 149 AutoDOP Wrap Up 152 Parallel Statement Queuing 152 The Old Way 153 The New Way 153 Controlling Parallel Queuing 157 Parallel Statement Queuing Wrap Up 165 In-Memory Parallel Execution 165 Summary Chapter 7: Resource Management 175 Database Resource Manager 176 Consumer Groups 178 Plan Directives 181 Resource Plan 183 Resource Manager Views 184 The Wait Event: resmgr: cpu quantum 185

7 DBRM Example 185 Testing a Resource Plan 190 Instance Caging 198 Configuring and Testing Instance Caging 199 Over-Provisioning 204 I/O Resource Manager 204 How I0RM Works 206 Methods for Managing I/O on Exadata 209 Bringing It All Together 215 IORM Monitoring and Metrics 219 Summary 235 Chapter 8: Configuring Exadata 237 Exadata Network Components 237 The Management Network 237 The Client Access Network 238 The Private Network 239 About the Configuration Process 240 Configuring Exadata 241 Step 1: The Configuration Worksheet 242 Step 2: The DBM Configurator 253 Step 3: Upload Parameter and Deployment Files 254 Step 4: CheckIP (checkip. sh) 258 Step 5: Firstboot 260 Step 6: Staging the Installation Media 262 Step 7: Running OneCommand 263 Upgrading Exadata 268 Creating a New RAC Cluster 268 Upgrading the Existing Cluster 270 x

8 * CONTENTS Summary 273 Chapter 9: Recovering Exadata 275 Exadata Diagnostic Tools 275 Sun Diagnostics: sundiag.sh 276 HealthCheck 278 CellCLI 279 Backing Up Exadata 284 Backing Up the Database Servers 284 Backing Up the Storage Cell 287 Backing Up the Database 293 Disk-Based Backups 293 Tape-Based Backups 293 Backup from Standby Database 294 Exadata Optimizations for RMAN 295 Recovering Exadata 296 Restoring the Database Server 296 Recovering the Storage Cell 299 Summary 318 m Chapter 10: Exadata Wait Events 319 Events Specific to Exadata 319 The "cell" Events 320 Plan Steps That Trigger Events 321 Exadata Wait Events in the User I/O Class 323 cell smart table scan 323 cell smart index scan 326 cell single block physical read 328 cell multiblock physical read 330 xi

9 cell list of blocks physical read 331 cell smart file creation 332 cell statistics gather 333 Exadata Wait Events in the System I/O Class 333 cell smart incremental backup 334 cell smart restore from backup 335 Exadata Wait Events in the Other and Idle Classes 337 cell smart flash unkeep 337 Old Events 338 direct path read 338 enq: KO fast object checkpoint 339 reliable message 340 Resource Manager Events 341 resmgrxpu quantum 341 resmgnpq queued 342 Summary 343 Chapter 11: Understanding Exadata Performance Metrics Measuring Exadata's Performance Metrics 345 Revisiting the Prerequisites for Exadata Smart Scans 346 Exadata Smart Scan Performance 346 Understanding Exadata Smart Scan Metrics and Performance Counters 350 Exadata Dynamic Performance Counters 350 When and How to Use Performance Counters 351 The Meaning and Explanation of Exadata Performance Counters 354 Exadata Performance Counter Reference i 356 Understanding SQL Statement Performance 374 Summary 377 xii

10 Chapter 12: Monitoring Exadata Performance A Systematic Approach 379 Monitoring SQL Statement Response Time 380 Monitoring SQL Statements with Real-Time SQL Monitoring Reports 381 Monitoring SQL Statements using V$SQL and V$SQLSTATS 393 Monitoring the Storage Cell Layer 395 Accessing Cell Metrics In the Cell Layer Using CellCLI 395 Accessing Cell Metrics Using the Grid Control Exadata Storage Server Plug-In 396 Which Cell Metrics to Use? 405 Monitoring Exadata Storage Cell OS-level Metrics 406 Summary 418 Chapter 13: Migrating to Exadata 419 Migration Strategies 420 Logical Migration 421 Extract and Load 422 Copying Data over a Database Link 427 Replication-Based Migration 443 Logical Migration Wrap Up 451 Physical Migration 451 Backup and Restore 452 Full Backup and Restore 452 Incremental Backup 454 Transportable Tablespaces (and XTTS) 455 Physical Standby 458 ASM Rebalance 460 Post-Migration Tasks 463 Wrap Up Physical Migration Section 464 xiii

11 Summary 465 Chapter 14: Storage Layout 467 Exadata Disk Architecture 467 Failure Groups 469 Grid Disks 471 Storage Allocation 473 Creating Grid Disks 477 Creating Grid Disks 478 Grid Disk Sizing 479 Creating FlashDisk-Based Grid Disks 483 Storage Strategies 484 Configuration Options 485 Isolating Storage Cell Access 485 Cell Security 487 Cell Security Terminology 488 Cell Security Best Practices 489 Configuring ASM-Scoped Security 489 Configuring Database-Scoped Security 490 Removing Cell Security 493 Summary 495 Chapter 15: Compute Node Layout 497 Provisioning Considerations 497 Non-RAC Configuration 500 RAC Clusters 504 Typical Exadata Configuration 506 Exadata Clusters 507 Summary 509 xiv

12 «CONTENTS Chapter 16: Unlearning Some Things We Thought We Knew 511 A Tale of Two Systems 511 OLTP-Oriented Workloads 512 Exadata Smart Flash Cache (ESFC) 512 Scalability 513 Write-lntensive OLTP Workloads 513 DW-Oriented Workloads 514 Enabling Smart Scans 514 Things that Can Cripple Smart Scans 516 Other Things to Keep in Mind 526 Mixed Workloads 528 To Index or Not to Index? 529 The Optimizer Doesn't Know. 530 Using Resource Manager 533 Summary 534 Appendix A: CellCLI and deli 535 CellCLI Command Syntax 535 Getting Familiar with CellCLI 536 Sending Commands from the Operating System 540 Configuring and Managing the Storage Cell 540 deli Command Syntax 542 Summary Appendix B: Online Exadata Resources 545 Exadata MOS Support Notes 545 Helpful Exadata MOS Support Notes 545 Exadata Bulletins and Blogs 546 Appendix C: Diagnostic Scripts 547 Index 551 XV