Sybase 12.4.2 User Manual

Page 14

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Contents

xiv

Working space for inserting, deleting, and synchronizing ..... 447

Options for tuning resource use ................................................... 448

Restricting concurrent queries............................................... 448
Limiting a query’s memory use.............................................. 449
Limiting queries by rows returned ......................................... 449
Forcing cursors to be non-scrolling ....................................... 449
Limiting the number of cursors .............................................. 450
Limiting the number of statements ........................................ 450
Lowering a connection’s priority ............................................ 450
Prefetching cache pages....................................................... 450
Optimizing for typical usage .................................................. 451

Other ways to improve resource use ........................................... 451

Restricting database access ................................................. 451
Disk caching .......................................................................... 451
Using RAM disk..................................................................... 452

Indexing tips ................................................................................. 452

Picking the right index type ................................................... 452
Using join indexes ................................................................. 453
Allowing enough disk space for deletions ............................. 453

Managing database size and structure ........................................ 454

Managing the size of your database ..................................... 454
Denormalizing for performance ............................................. 454
Denormalization has risks ..................................................... 455
Disadvantages of denormalization ........................................ 455
Performance benefits of denormalization.............................. 455
Deciding to denormalize........................................................ 456

Improving your queries................................................................. 456

Tips for structuring queries.................................................... 456
Planning queries.................................................................... 457
Setting query optimization options ........................................ 458

Network performance ................................................................... 459

Improving large data transfers............................................... 459
Isolate heavy network users.................................................. 460
Put small amounts of data in small packets .......................... 461
Put large amounts of data in large packets ........................... 462
Process at the server level .................................................... 463

CHAPTER 13

Monitoring and Tuning Performance ......................................... 465

Viewing the Adaptive Server IQ environment .............................. 465

Getting information using stored procedures ........................ 465

Monitoring the buffer caches ........................................................ 467

Starting the buffer cache monitor .......................................... 467
Stopping the buffer cache monitor ........................................ 472
Examining and saving monitor results................................... 472

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