Oracle Database 11 g - Online Public Access Catalog

More documents

Recommendations

Info

196 CHAPTER 4 ■ PERFORMANCE MANAGEMENTAccessing Intermediate ResultsAs you are probably aware, the SQL Access Advisor takes a considerable amount of time toexecute, especially when you run it in comprehensive mode. In Oracle Database 11g, you canaccess the intermediate results while the advisor is still executing. This gives you the opportunityto cut short an advisor run if the intermediate results aren’t appealing to you. Similarly,if the intermediate results show evidence that the recommendations will lead to a significantbenefit, you can cut short the advisor run by interrupting it midstream.The SQL Access Advisor bases its partitioning recommendations on its analysis of a significantproportion of the workload. Thus, if you interrupt an advisor task early in the game, theadvisor may not include any base table partitioning recommendations in the intermediate results.If you decide to interrupt, wait for a substantial portion of the workload to complete so you canget the partitioning recommendations as well.To accept the intermediate results, you must formally interrupt the advisor task. The advisorwill then stop executing the task and mark it as interrupted. Following this, you can either askthe advisor to complete the recommendation process or choose to accept the recommendationsand generate scripts for implementing them.New DBMS_ADVISOR ProceduresTwo new procedures in the DBMS_ADVISOR package have a bearing on the SQL Access Advisor.These are the add_sts_ref and copy_sqlwkld_to_sts procedures.ADD_STS_REF ProcedureYou can use the add_sts_ref procedure to link a SQL Access Advisor task to the SQL tuning set.The advisor task can use this link to access the SQL tuning set for analysis purposes. Here’s thestructure of the add_sts_ref procedure:Argument Name Type In/Out Default?-------------------- -------------- --------- ---------TASK_NAME VARCHAR2 INSTS_OWNER VARCHAR2 INWORKLOAD_NAME VARCHAR2 INHere’s an example showing how to use the add_sts_ref procedure to link a task (task1) toa SQL tuning set (sts_1):SQL> exec dbms_advisor.add_sts_ref ("task1', 'hr', 'sts_1');Once you create a link between the advisor task and the SQL Tuning Advisor task, the STScan’t be altered or deleted, thus providing a stable view of the workload for the advisor.COPY_SQLWKLD_TO_STS ProcedureThe copy_sqlwkld_to_sts procedure transfers the contents of a SQL workload object to an STS. Thecopy_sqlwkld_to_sts procedure has the following attributes:
CHAPTER 4 ■ PERFORMANCE MANAGEMENT 197Argument Name Type In/Out Default?----------------- --------------- ---------- ------------WORKLOAD_NAME VARCHAR2 INSTS_NAME VARCHAR2 INIMPORT_MODE VARCHAR2 IN DEFAULTThe workload_name attribute refers to the source SQL workload, and the sts_name attributepoints to the target STS into which you’ll be importing the SQL Workload object. The import_modeattribute can take the value append, new, or replace and determines the handling of the data inthe target STS upon the import of the SQL Workload object. Here’s an example showing how touse the copy_sqlwkload_to_sts procedure:SQL> exec dbms_advisor.copy_sqlwkld_to_sts ('workload_1','sts_1', 'new');Oracle will create a new STS if the STS you specify doesn’t exist.Optimizer and Statistics CollectionEnhancementsOracle Database 11g provides several enhancements in the optimizer statistics collection area.One of the important new features is the extended statistics feature, which lets the optimizercollect statistics on correlated columns in a table, thus providing better selectivity estimates.You can also collect expression statistics on expression functions. The statistics that you cancollect for column groups and expressions are called extended statistics. The other importantenhancement is the new concept of private and public statistics, with private statistics beingstatistics that you’ve collected but not yet published for use by the cost optimizer. We’ll coverthe interesting new features in the following sections.Multicolumn StatisticsOne of the key things the cost optimizer considers during its execution plan evaluation is theselectivity (or cardinality) of the column in the where clause of a query. The number of differentvalues in a column determines the column’s selectivity. When a column in a table has manydifferent values, that column has good selectivity, and a column with many values that are thesame has poor selectivity. If you build an index on a column with good selectivity, the optimizeris able to access the necessary row faster than it will access a row with lower selectivity.If a column has poor selectivity—for example, a certain value that’s the same in more than95 percent of the table’s rows—it’s likely that the cost optimizer will opt for a full table scan,regardless of the existence of an index on that column. If, on the other hand, there are severaldistinct column values such that no column value is in more than 1 or 2 percent of the table’srows, the optimizer is likely to choose the index for accessing the rows when you issue a querythat contains a where clause containing this column.Several queries, however, contain multiple columns from a table, each with a differentdegree of selectivity. Some of these columns are related, but the optimizer doesn’t know aboutthe nature of these relationships. For example, in a table containing products and their prices,some products have higher prices than others. However, the cost optimizer, which bases its
Page 1:
The EXPERT’s VOIce ® IN ORACLEAl
Page 7:
Contents at a GlanceAbout the Autho
Page 11 and 12:
■CONTENTSixSQL*Plus New Features
Page 13 and 14:
■CONTENTSxiEnterprise Manager Int
Page 15 and 16:
■CONTENTSxiiiCombined Capture and
Page 17:
■CONTENTSxvImprovements in Redo T
Page 21:
About the Authors■SAM ALAPATI is
Page 24 and 25:
xxii■ACKNOWLEDGMENTSNothing I do
Page 26 and 27:
xxiv■INTRODUCTIONPerformance Mana
Page 28 and 29:
xxvi■INTRODUCTION• The easy add
Page 30 and 31:
xxviii■INTRODUCTION• The flashb
Page 32 and 33:
2 CHAPTER 1 ■ INSTALLING, UPGRADI
Page 34 and 35:
Page 36 and 37:
Page 38 and 39:
Page 40 and 41:
10 CHAPTER 1 ■ INSTALLING, UPGRAD
Page 42 and 43:
Page 44 and 45:
Page 46 and 47:
Page 48 and 49:
Page 50 and 51:
Page 52 and 53:
Page 54 and 55:
Page 56 and 57:
Page 58 and 59:
Page 60 and 61:
Page 62 and 63:
Page 64 and 65:
Page 66 and 67:
Page 68 and 69:
Page 70 and 71:
Page 72 and 73:
Page 74 and 75:
Page 76 and 77:
Page 78 and 79:
Page 80 and 81:
Page 82 and 83:
Page 84 and 85:
Page 86 and 87:
Page 88 and 89:
58 CHAPTER 2 ■ DATABASE DIAGNOSAB
Page 90 and 91:
Page 92 and 93:
Page 94 and 95:
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102 and 103:
Page 104 and 105:
Page 106 and 107:
Page 108 and 109:
Page 110 and 111:
Page 112 and 113:
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124 and 125:
Page 126 and 127:
Page 128 and 129:
Page 130 and 131:
100 CHAPTER 3 ■ DATABASE ADMINIST
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148 and 149:
Page 150 and 151:
Page 152 and 153:
Page 154 and 155:
Page 156 and 157:
Page 158 and 159:
Page 160 and 161:
Page 162 and 163:
Page 164 and 165:
Page 166 and 167:
Page 168 and 169:
Page 170 and 171:
Page 172 and 173:
Page 174 and 175:
Page 176 and 177: 146 CHAPTER 3 ■ DATABASE ADMINIST
Page 198 and 199: 168 CHAPTER 4 ■ PERFORMANCE MANAG
Page 256 and 257: 226 CHAPTER 5 ■ DATABASE SECURITY
Page 276 and 277:
246 CHAPTER 5 ■ DATABASE SECURITY
Page 278 and 279:
Page 280 and 281:
Page 282 and 283:
Page 284 and 285:
Page 286 and 287:
Page 288 and 289:
Page 290 and 291:
Page 292 and 293:
Page 294 and 295:
Page 296 and 297:
266 CHAPTER 6 ■ BACKUP AND RECOVE
Page 298 and 299:
Page 300 and 301:
Page 302 and 303:
Page 304 and 305:
Page 306 and 307:
Page 308 and 309:
Page 310 and 311:
Page 312 and 313:
Page 314 and 315:
Page 316 and 317:
Page 318 and 319:
Page 320 and 321:
Page 322 and 323:
Page 324 and 325:
Page 326 and 327:
Page 328 and 329:
Page 330 and 331:
Page 332 and 333:
Page 334 and 335:
Page 336 and 337:
Page 338 and 339:
Page 340 and 341:
Page 343 and 344:
CHAPTER 7■ ■ ■Data PumpDBAs a
Page 345 and 346:
CHAPTER 7 ■ DATA PUMP 315if test
Page 347 and 348:
CHAPTER 7 ■ DATA PUMP 317DBA11g1
Page 349 and 350:
CHAPTER 7 ■ DATA PUMP 319Encrypti
Page 351 and 352:
CHAPTER 7 ■ DATA PUMP 321Please b
Page 353 and 354:
CHAPTER 7 ■ DATA PUMP 323Remappin
Page 355 and 356:
CHAPTER 7 ■ DATA PUMP 325SELECT d
Page 357 and 358:
CHAPTER 7 ■ DATA PUMP 327Document
Page 359 and 360:
CHAPTER 7 ■ DATA PUMP 329SQL> sel
Page 361 and 362:
CHAPTER 7 ■ DATA PUMP 331SQL> sel
Page 363 and 364:
CHAPTER 7 ■ DATA PUMP 333DBMS_OUT
Page 365:
CHAPTER 7 ■ DATA PUMP 335If you a
Page 368 and 369:
338 CHAPTER 8 ■ ORACLE STREAMSLat
Page 370 and 371:
340 CHAPTER 8 ■ ORACLE STREAMSA s
Page 372 and 373:
342 CHAPTER 8 ■ ORACLE STREAMSSQL
Page 374 and 375:
344 CHAPTER 8 ■ ORACLE STREAMSThe
Page 376 and 377:
346 CHAPTER 8 ■ ORACLE STREAMSStr
Page 378 and 379:
348 CHAPTER 8 ■ ORACLE STREAMSDBM
Page 380 and 381:
350 CHAPTER 8 ■ ORACLE STREAMSPle
Page 382 and 383:
352 CHAPTER 8 ■ ORACLE STREAMSa p
Page 384 and 385:
354 CHAPTER 8 ■ ORACLE STREAMSSpl
Page 386 and 387:
356 CHAPTER 8 ■ ORACLE STREAMSpro
Page 388 and 389:
358 CHAPTER 8 ■ ORACLE STREAMSSup
Page 391 and 392:
CHAPTER 9■ ■ ■Storage Managem
Page 393 and 394:
CHAPTER 9 ■ STORAGE MANAGEMENT 36
Page 395 and 396:
Page 397 and 398:
Page 399 and 400:
Page 401 and 402:
Page 403 and 404:
Page 405 and 406:
Page 407 and 408:
Page 409 and 410:
Page 411 and 412:
Page 413 and 414:
Page 415 and 416:
Page 417 and 418:
Page 419 and 420:
Page 421 and 422:
Page 423 and 424:
Page 425 and 426:
Page 427 and 428:
Page 429 and 430:
Page 431 and 432:
Page 433 and 434:
Page 435 and 436:
Page 437 and 438:
Page 439 and 440:
Page 441 and 442:
Page 443:
Page 446 and 447:
416 CHAPTER 10 ■ DATA GUARD• Lo
Page 448 and 449:
418 CHAPTER 10 ■ DATA GUARDsql ch
Page 450 and 451:
420 CHAPTER 10 ■ DATA GUARDDBA11g
Page 452 and 453:
422 CHAPTER 10 ■ DATA GUARDWhile
Page 454 and 455:
424 CHAPTER 10 ■ DATA GUARDSQL> c
Page 456 and 457:
426 CHAPTER 10 ■ DATA GUARDSQL> a
Page 458 and 459:
428 CHAPTER 10 ■ DATA GUARD7. Swi
Page 460 and 461:
430 CHAPTER 10 ■ DATA GUARDwho ha
Page 462 and 463:
432 CHAPTER 10 ■ DATA GUARDSQL> s
Page 464 and 465:
434 CHAPTER 10 ■ DATA GUARDDynami
Page 466 and 467:
436 CHAPTER 10 ■ DATA GUARDSQL> B
Page 468 and 469:
438 CHAPTER 10 ■ DATA GUARDcomman
Page 470 and 471:
440 CHAPTER 10 ■ DATA GUARDCustom
Page 472 and 473:
442 CHAPTER 10 ■ DATA GUARDselect
Page 474 and 475:
444 CHAPTER 10 ■ DATA GUARDby Dat
Page 476 and 477:
446 CHAPTER 11 ■ APPLICATION DEVE
Page 478 and 479:
Page 480 and 481:
Page 482 and 483:
Page 484 and 485:
Page 486 and 487:
Page 488 and 489:
Page 490 and 491:
Page 492 and 493:
Page 494 and 495:
Page 496 and 497:
Page 498 and 499:
Page 500 and 501:
Page 502 and 503:
Page 504 and 505:
Page 506 and 507:
Page 508 and 509:
Page 510 and 511:
Page 512 and 513:
Page 514 and 515:
Page 516 and 517:
Page 518 and 519:
Page 520 and 521:
Page 522 and 523:
Page 524 and 525:
Page 526 and 527:
Page 528 and 529:
Page 530 and 531:
Page 532 and 533:
Page 534 and 535:
Page 536 and 537:
Page 538 and 539:
Page 540 and 541:
Page 542 and 543:
Page 545 and 546:
CHAPTER 12■ ■ ■Data Warehousi
Page 547 and 548:
CHAPTER 12 ■ DATA WAREHOUSING 517
Page 549 and 550:
Page 551 and 552:
Page 553 and 554:
Page 555 and 556:
Page 557 and 558:
Page 559 and 560:
Page 561 and 562:
Page 563 and 564:
Page 565 and 566:
Page 567 and 568:
Page 569 and 570:
Page 571 and 572:
Page 573 and 574:
Page 575 and 576:
Page 577 and 578:
Page 579 and 580:
Page 581 and 582:
Page 583 and 584:
Page 585 and 586:
Page 587 and 588:
Page 589 and 590:
Page 591 and 592:
Page 593:
Page 596 and 597:
566 ■INDEXadvise failure command,
Page 598 and 599:
568 ■INDEXDBMS_ADDM package, 216-
Page 600 and 601:
570 ■INDEXcdump diagnostic direct
Page 602 and 603:
572 ■INDEXcursor_sharing paramete
Page 604 and 605:
574 ■INDEXdb_file_name_convert 's
Page 606 and 607:
576 ■INDEXDBMS-WORKLOAD_REPOSITOR
Page 608 and 609:
578 ■INDEXencrypt keyword, 243ENC
Page 610 and 611:
580 ■INDEXdefined, 112-114enablin
Page 612 and 613:
582 ■INDEXinsert command, 114, 56
Page 614 and 615:
584 ■INDEXmanually loaded plans,
Page 616 and 617:
586 ■INDEXOCISessionGet( ) method
Page 618 and 619:
588 ■INDEXusability improvements,
Page 620 and 621:
590 ■INDEXpga_aggregate_target in
Page 622 and 623:
592 ■INDEXreader farm, 421read-on
Page 624 and 625:
594 ■INDEXrestoring backup contro
Page 626 and 627:
596 ■INDEXserver_file_system opti
Page 628 and 629:
598 ■INDEXsynchronous capture, 33
Page 630 and 631:
600 ■INDEXOracle Audit Vault, 259
Page 632:
602 ■INDEXxmldiff command-line ut
show all

Oracle Database 11 g - Online Public Access Catalog

Create successful ePaper yourself

Delete template?

Save as template?