1 Introduction

17

1.1 Tuning Methods

17

1.2 Structure of the Book

19

1.3 How to Use This Book

20

2 SAP System Architecture for ABAP Developers

21

2.1 SAP System Architecture

21

2.1.1 Three-Layer Architecture

22

2.1.2 Distribution of the Three Layers

23

2.2 Performance Aspects of the Architecture

25

2.2.1 Frontend

26

2.2.2 Application Layer

26

2.2.3 Database

27

2.2.4 Summary

27

3 Performance Analysis Tools

29

3.1 Overview of Tools

29

3.2 Usage Time of Tools

31

3.3 Analysis and Tools in Detail

34

3.3.1 SAP Code Inspector (Transaction SCI)

34

3.3.2 Selectivity Analysis (Transaction DB05)

40

3.3.3 Process Analysis (Transactions SM50/SM66) — Status of a Program

44

3.3.4 Debugger — Memory Analysis

47

3.3.5 Memory Inspector (Transaction S_MEMORY_INSPECTOR)

49

3.3.6 Transaction ST10 — Table Call Statistics

51

3.3.7 Performance Trace — General Information (Transaction ST05)

54

3.3.8 Performance Trace — SQL Trace (Transaction ST05)

57

3.3.9 Performance Trace — RFC Trace (Transaction ST05)

70

3.3.10 Performance Trace — Enqueue Trace (Transaction ST05)

72

3.3.11 Performance Trace — Table Buffer Trace (Transaction ST05)

74

3.3.12 ABAP Trace (Transaction SE30)

77

3.3.13 Single Transaction Analysis (Transaction ST12)

89

3.3.14 E2E Trace

101

3.3.15 Single Record Statistics (Transaction STAD)

109

3.3.16 Dump Analysis (Transaction ST22)

119

3.4 Tips for the Performance Analysis

123

3.4.1 Consistency Checks

123

3.4.2 Time-Based Analysis

123

3.4.3 Prevention

123

3.4.4 Optimization

124

3.4.5 Runtime Behavior of Mass Data

124

3.5 Summary

124

4 Parallel Processing

127

4.1 Packaging

127

4.2 Parallel Processing

129

4.2.1 Background

130

4.2.2 Challenges and Solution Approaches for Parallelized Programs

131

4.2.3 Parallel Processing Technologies

140

4.2.4 Summary

145

5 Data Processing with SQL

147

5.1 The Architecture of a Database

147

5.2 Execution of SQL

151

5.2.1 Execution in SAP NetWeaver AS ABAP

151

5.2.2 Execution in the Database

153

5.3 Efficient SQL: Basic Principles

155

5.4 Access Strategies

155

5.4.1 Logical Structures

155

5.4.2 Indexes as Search Helps

158

5.4.3 Operators

167

5.4.4 Decision for an Access Path

169

5.4.5 Analysis and Optimization in ABAP

170

5.4.6 Summary

184

5.5 Resulting Set

185

5.5.1 Reducing the Columns

188

5.5.2 Reducing the Rows

190

5.5.3 Reading a Defined Number of Rows

191

5.5.4 Aggregating

193

5.5.5 Existence Checks

195

5.5.6 Updates

196

5.5.7 Summary

197

5.6 Index Design

198

5.6.1 Read or Write Processing

200

5.6.2 How is Data Accessed

202

5.6.3 Summary

204

5.7 Execution Frequency

205

5.7.1 View

209

5.7.2 Join

210

5.7.3 FOR ALL ENTRIES

211

5.8 Used API

215

5.8.1 Static Open SQL

216

5.8.2 Dynamic Open SQL

216

5.8.3 Static Native SQL

216

5.8.4 Summary

217

5.9 Special Cases and Exceptions

217

5.9.1 Sorting

217

5.9.2 Pool and Cluster Tables

218

5.9.3 Hints and Adapting Statistics

220

6 Buffering of Data

223

6.1 SAP Memory Architecture from the Developer’s Point of View

223

6.1.1 User-Specific Memory

225

6.1.2 Cross-User Memory

225

6.2 User-Specific Buffering Types

227

6.2.1 Buffering in the Internal Session

227

6.2.2 Buffering Across Internal Sessions

230

6.2.3 Buffering Across External Sessions

231

6.2.4 Summary

231

6.3 Cross-User Buffering Types

232

6.3.1 Buffering in the Shared Buffer

232

6.3.2 Buffering in the Shared Memory

233

6.3.3 Buffering via the Shared Objects

234

6.3.4 Summary

235

6.4 SAP Table Buffering

236

6.4.1 Architecture and Overview

237

6.4.2 What Tables Can Be Buffered

243

6.4.3 Performance Aspects of Table Buffering

244

6.4.4 Analysis Options

251

6.5 Summary

251

7 Processing of Internal Tables

253

7.1 Overview of Internal Tables

253

7.2 Organization in the Main Memory

255

7.3 Table Types

258

7.4 Performance Aspects

265

7.4.1 Fill

265

7.4.2 Read

268

7.4.3 Modify

273

7.4.4 Delete

274

7.4.5 Condense

275

7.4.6 Sort

276

7.4.7 Copy Cost-Reduced or Copy Cost-Free Access

277

7.4.8 Secondary Indexes

278

7.4.9 Copy

279

7.4.10 Nested Loops and Nonlinear Runtime Behavior

282

7.4.11 Summary

284

8 Communication with Other Systems

287

8.1 RFC Communication Between ABAP Systems

288

8.1.1 Synchronous RFC

288

8.1.2 Asynchronous RFC

288

8.2 Performance Aspects for the RFC Communication

290

8.3 Summary

293

9 Special Topics

295

9.1 Local Update

295

9.1.1 Asynchronous Update

295

9.1.2 Local Update

297

9.2 Parameter Passings

298

9.3 Type Conversions

299

9.4 Index Tables

299

9.5 Saving Frontend Resources

300

9.6 Saving Enqueue and Message Service

301

10 Outlook

303

10.1 Important Changes to the Tools for the Performance Analysis

303

10.1.1 Performance Trace (Transaction ST05)

303

10.1.2 ABAP Trace (Transaction SAT)

309

10.2 Important Changes to Internal Tables (Secondary Key)

314

10.2.1 Definition

314

10.2.2 Administration Costs and Lazy Index Update

315

10.2.3 Read Accesses

315

10.2.4 Active Key Protection

317

10.2.5 Delayed Index Update for Incremental Key Changes

317

10.2.6 Summary

318

Appendices

319

A Execution Plans of Different Databases

319

A.1 General Information on Execution Plans

319

A.2 IBM DB2 (IBM DB2 for zSeries)

320

A.3 IBM DB2 (DB2 for iSeries)

323

A.4 IBM DB2 (DB2 for LUW)

326

A.5 SAP MaxDB

329

A.6 Oracle

332

A.7 Microsoft SQL Server

336

B The Author

339