link:
http://www.eygle.com/internal/shared_pool-3.htm
|
基本命令：
ALTER SESSION SET EVENTS 'immediate trace name LIBRARY_CACHE level LL';
其中LL代表Level级别,对于9.2.0及以后版本,不同Level含义如下:
Level =1 ,转储Library cache统计信息
Level =2 ,转储hash table概要
Level =4 ,转储Library cache对象，只包含基本信息
Level =8 ,转储Library cache对象，包含详细信息(包括child references,pin waiters等)
Level =16,增加heap sizes信息
Level =32,增加heap信息
Library cache由一个hash表组成,而hash表是一个由hash buckets组成的数组.
每个hash bucket都是包含library cache handle的一个双向链表。
Library Cache Handle指向Library Cache Object和一个引用列表.
library cache对象进一步分为:依赖表、子表和授权表等
我们看一下library cache的结构:
通过
ALTER SESSION SET EVENTS 'immediate trace name LIBRARY_CACHE level 4'
获得以下输出(这部分信息来自Oracle8i,Trace文件可以从 www.eygle.com 上找到)
点击这里下载: hsbi_ora_4614.trc
第一部分(等价于Level 1):
|
>
> LIBRARY CACHE STATISTICS:
> > gets hit ratio pins hit ratio reloads invalids namespace
> > ---------- --------- ---------- --------- ---------- ---------- ---------
> > 619658171 0.9999160 2193292112 0.9999511 9404 380 CRSR
> > 79698558 0.9998832 424614847 0.9999108 13589 0 TABL/PRCD/TYPE
> > 163399 0.9979926 163402 0.9978948 16 0 BODY/TYBD
> > 0 0.0000000 0 0.0000000 0 0 TRGR
> > 34 0.0294118 35 0.0571429 0 0 INDX
> > 18948 0.9968862 24488 0.9953855 0 0 CLST
> > 0 0.0000000 0 0.0000000 0 0 OBJE
> > 0 0.0000000 0 0.0000000 0 0 PIPE
> > 0 0.0000000 0 0.0000000 0 0 LOB
> > 0 0.0000000 0 0.0000000 0 0 DIR
> > 0 0.0000000 0 0.0000000 0 0 QUEU
> > 0 0.0000000 0 0.0000000 0 0 OBJG
> > 0 0.0000000 0 0.0000000 0 0 PROP
> > 0 0.0000000 0 0.0000000 0 0 JVSC
> > 0 0.0000000 0 0.0000000 0 0 JVRE
> > 0 0.0000000 0 0.0000000 0 0 ROBJ
> > 0 0.0000000 0 0.0000000 0 0 REIP
> > 0 0.0000000 0 0.0000000 0 0 CPOB
> > 115071 0.9992179 115071 0.9930999 704 0 EVNT
> > 0 0.0000000 0 0.0000000 0 0 SUMM
> > 0 0.0000000 0 0.0000000 0 0 DIMN
> > 0 0.0000000 0 0.0000000 0 0 CTX
> > 0 0.0000000 0 0.0000000 0 0 OUTL
> > 0 0.0000000 0 0.0000000 0 0 RULS
> > 0 0.0000000 0 0.0000000 0 0 RMGR
> > 0 0.0000000 0 0.0000000 0 0 UNUSED
> > 0 0.0000000 0 0.0000000 0 0 PPLN
> > 0 0.0000000 0 0.0000000 0 0 PCLS
> > 0 0.0000000 0 0.0000000 0 0 SUBS
> > 0 0.0000000 0 0.0000000 0 0 LOCS
> > 0 0.0000000 0 0.0000000 0 0 RMOB
> > 0 0.0000000 0 0.0000000 0 0 RSMD
> > 699654181 0.9999117 2618209955 0.9999440 23713 380 CUMULATIVE
这部分信息也就是v$librarycache中显示的.
第二部分(等价于Level 2中的输出):
>
>
> >
> LIBRARY CACHE HASH TABLE: size=509 count=354
> > BUCKET 0:
> > BUCKET 1:
> > BUCKET 2: *
> > BUCKET 3:
> > BUCKET 4:
> > BUCKET 5: *
> > BUCKET 6: *
> > BUCKET 7:
> > BUCKET 8: **
> > BUCKET 9: ***
> > BUCKET 10: *
> > BUCKET 11: *
> > BUCKET 12: ***
> > BUCKET 13: *
> > BUCKET 14: *
> > BUCKET 15:
> > BUCKET 16: *
> > BUCKET 17:
> > BUCKET 18: *
> > BUCKET 19:
> > BUCKET 20:
> > BUCKET 21: *
> > BUCKET 22:
> > BUCKET 23:
> > BUCKET 24: *
> > BUCKET 25:
> > BUCKET 26:
> > BUCKET 27: ***
> > BUCKET 28:
> > BUCKET 29: **
> > BUCKET 30:
> > BUCKET 31:
> > BUCKET 32: ***
> > BUCKET 33: *
> > BUCKET 34:
> > BUCKET 35:
> > BUCKET 36: **
> > BUCKET 37:
> > BUCKET 38: **
> > BUCKET 39: *
> > BUCKET 40: *
> > BUCKET 41:
> > BUCKET 42:
> > BUCKET 43:
> > BUCKET 44:
> > BUCKET 45:
> > BUCKET 46: ****
> > BUCKET 47:
> > BUCKET 48:
> > BUCKET 49: *
> > BUCKET 50: *
> > BUCKET 51:
> > BUCKET 52: ***
> > BUCKET 53: **
> > BUCKET 54:
> > BUCKET 55: *
> > BUCKET 56:
> > BUCKET 57:
> > BUCKET 58:
> > BUCKET 59: *
> > BUCKET 60: **
> > BUCKET 61:
> > BUCKET 62: *
> > BUCKET 63:
> > BUCKET 64: *
> > BUCKET 65:
> > BUCKET 66:
> > BUCKET 67: *
> > BUCKET 68:
> > BUCKET 69: **
> > BUCKET 70:
> > BUCKET 71:
> > BUCKET 72: *
> > BUCKET 73:
> > BUCKET 74:
> > BUCKET 75: *
> > BUCKET 76: **
> > BUCKET 77:
> > BUCKET 78: ****
> > BUCKET 79:
> > BUCKET 80: *
> > BUCKET 81: *
> > BUCKET 82:
> > BUCKET 83: **
> > BUCKET 84: *
> > BUCKET 85:
> > BUCKET 86:
> > BUCKET 87:
> > BUCKET 88:
> > BUCKET 89: *
> > BUCKET 90: *
> > BUCKET 91:
> > BUCKET 92: *
> > BUCKET 93: *
> > BUCKET 94: *
> > BUCKET 95:
> > BUCKET 96: *
> > BUCKET 97:
> > BUCKET 98:
> > BUCKET 99: ***
> > BUCKET 100: *
> > BUCKET 101:
> > BUCKET 102: *
> > BUCKET 103:
> > BUCKET 104: *
> > BUCKET 105:
> > BUCKET 106:
> > BUCKET 107: ****
> > BUCKET 108:
> > BUCKET 109:
> > BUCKET 110:
> > BUCKET 111: *
> > BUCKET 112: **
> > BUCKET 113:
> > BUCKET 114:
> > BUCKET 115:
> > BUCKET 116: *
> > BUCKET 117:
> > BUCKET 118: *****
> > BUCKET 119:
> > BUCKET 120: *
> > BUCKET 121:
> > BUCKET 122:
> > BUCKET 123:
> > BUCKET 124:
> > BUCKET 125: *
> > BUCKET 126:
> > BUCKET 127:
> > BUCKET 128: *
> > BUCKET 129:
> > BUCKET 130: *
> > BUCKET 131: *
> > BUCKET 132:
> > BUCKET 133:
> > BUCKET 134:
> > BUCKET 135: *
> > BUCKET 136:
> > BUCKET 137:
> > BUCKET 138:
> > BUCKET 139: *
> > BUCKET 140: *
> > BUCKET 141: *
> > BUCKET 142:
> > BUCKET 143: *
> > BUCKET 144:
> > BUCKET 145: ***
> > BUCKET 146:
> > BUCKET 147: *
> > BUCKET 148:
> > BUCKET 149:
> > BUCKET 150: **
> > BUCKET 151:
> > BUCKET 152:
> > BUCKET 153: *
> > BUCKET 154:
> > BUCKET 155:
> > BUCKET 156:
> > BUCKET 157:
> > BUCKET 158:
> > BUCKET 159:
> > BUCKET 160:
> > BUCKET 161:
> > BUCKET 162:
> > BUCKET 163:
> > BUCKET 164: *
> > BUCKET 165: *
> > BUCKET 166:
> > BUCKET 167:
> > BUCKET 168:
> > BUCKET 169:
> > BUCKET 170: **
> > BUCKET 171:
> > BUCKET 172: *
> > BUCKET 173:
> > BUCKET 174:
> > BUCKET 175: *
> > BUCKET 176: *
> > BUCKET 177:
> > BUCKET 178:
> > BUCKET 179:
> > BUCKET 180:
> > BUCKET 181: *
> > BUCKET 182:
> > BUCKET 183:
> > BUCKET 184:
> > BUCKET 185: *
> > BUCKET 186:
> > BUCKET 187:
> > BUCKET 188: **
> > BUCKET 189:
> > BUCKET 190: *
> > BUCKET 191: *
> > BUCKET 192:
> > BUCKET 193:
> > BUCKET 194: *
> > BUCKET 195: **
> > BUCKET 196: *
> > BUCKET 197: **
> > BUCKET 198: ****
> > BUCKET 199: *
> > BUCKET 200: *
> > BUCKET 201: *
> > BUCKET 202: **
> > BUCKET 203:
> > BUCKET 204:
> > BUCKET 205: **
> > BUCKET 206:
> > BUCKET 207:
> > BUCKET 208: *
> > BUCKET 209: **
> > BUCKET 210:
> > BUCKET 211: *
> > BUCKET 212: *
> > BUCKET 213: *
> > BUCKET 214:
> > BUCKET 215:
> > BUCKET 216:
> > BUCKET 217: *
> > BUCKET 218: *
> > BUCKET 219:
> > BUCKET 220:
> > BUCKET 221: *
> > BUCKET 222:
> > BUCKET 223: *
> > BUCKET 224:
> > BUCKET 225:
> > BUCKET 226: *
> > BUCKET 227:
> > BUCKET 228: *
> > BUCKET 229: **
> > BUCKET 230: *
> > BUCKET 231:
> > BUCKET 232: **
> > BUCKET 233:
> > BUCKET 234: *
> > BUCKET 235: *
> > BUCKET 236:
> > BUCKET 237:
> > BUCKET 238: *
> > BUCKET 239:
> > BUCKET 240: **
> > BUCKET 241: **
> > BUCKET 242: **
> > BUCKET 243: ***
> > BUCKET 244:
> > BUCKET 245: *
> > BUCKET 246:
> > BUCKET 247:
> > BUCKET 248: **
> > BUCKET 249:
> > BUCKET 250:
> > BUCKET 251: **
> > BUCKET 252:
> > BUCKET 253: *
> > BUCKET 254: *
> > BUCKET 255:
> > BUCKET 256:
> > BUCKET 257: **
> > BUCKET 258: *
> > BUCKET 259:
> > BUCKET 260:
> > BUCKET 261: *
> > BUCKET 262: **
> > BUCKET 263: ***
> > BUCKET 264:
> > BUCKET 265: *
> > BUCKET 266:
> > BUCKET 267: *
> > BUCKET 268: *
> > BUCKET 269:
> > BUCKET 270:
> > BUCKET 271: **
> > BUCKET 272: *
> > BUCKET 273:
> > BUCKET 274: *
> > BUCKET 275: *
> > BUCKET 276: **
> > BUCKET 277:
> > BUCKET 278:
> > BUCKET 279:
> > BUCKET 280:
> > BUCKET 281: **
> > BUCKET 282: *
> > BUCKET 283: *
> > BUCKET 284: *
> > BUCKET 285: *
> > BUCKET 286:
> > BUCKET 287: *
> > BUCKET 288:
> > BUCKET 289:
> > BUCKET 290: **
> > BUCKET 291:
> > BUCKET 292: *
> > BUCKET 293:
> > BUCKET 294: *
> > BUCKET 295:
> > BUCKET 296: *
> > BUCKET 297:
> > BUCKET 298:
> > BUCKET 299: **
> > BUCKET 300: *
> > BUCKET 301:
> > BUCKET 302: *
> > BUCKET 303: *
> > BUCKET 304: **
> > BUCKET 305: **
> > BUCKET 306:
> > BUCKET 307:
> > BUCKET 308: *
> > BUCKET 309:
> > BUCKET 310:
> > BUCKET 311: **
> > BUCKET 312: *
> > BUCKET 313:
> > BUCKET 314: *
> > BUCKET 315:
> > BUCKET 316:
> > BUCKET 317:
> > BUCKET 318:
> > BUCKET 319: ***
> > BUCKET 320: *
> > BUCKET 321: **
> > BUCKET 322: **
> > BUCKET 323:
> > BUCKET 324: *
> > BUCKET 325:
> > BUCKET 326: *
> > BUCKET 327: *
> > BUCKET 328: **
> > BUCKET 329:
> > BUCKET 330: *
> > BUCKET 331:
> > BUCKET 332:
> > BUCKET 333: *
> > BUCKET 334: *
> > BUCKET 335: ***
> > BUCKET 336: *
> > BUCKET 337: **
> > BUCKET 338: *
> > BUCKET 339: *
> > BUCKET 340:
> > BUCKET 341: *
> > BUCKET 342: *
> > BUCKET 343: **
> > BUCKET 344:
> > BUCKET 345:
> > BUCKET 346:
> > BUCKET 347: *
> > BUCKET 348:
> > BUCKET 349: ***
> > BUCKET 350: *
> > BUCKET 351:
> > BUCKET 352:
> > BUCKET 353:
> > BUCKET 354: *
> > BUCKET 355: **
> > BUCKET 356:
> > BUCKET 357:
> > BUCKET 358: **
> > BUCKET 359: *
> > BUCKET 360: *
> > BUCKET 361: **
> > BUCKET 362:
> > BUCKET 363:
> > BUCKET 364: *
> > BUCKET 365: *
> > BUCKET 366: **
> > BUCKET 367: *
> > BUCKET 368:
> > BUCKET 369: *
> > BUCKET 370:
> > BUCKET 371: ***
> > BUCKET 372:
> > BUCKET 373: *
> > BUCKET 374:
> > BUCKET 375:
> > BUCKET 376: *
> > BUCKET 377:
> > BUCKET 378:
> > BUCKET 379:
> > BUCKET 380:
> > BUCKET 381:
> > BUCKET 382:
> > BUCKET 383: **
> > BUCKET 384:
> > BUCKET 385:
> > BUCKET 386:
> > BUCKET 387: ***
> > BUCKET 388: *
> > BUCKET 389:
> > BUCKET 390:
> > BUCKET 391:
> > BUCKET 392:
> > BUCKET 393: *
> > BUCKET 394: *
> > BUCKET 395: *
> > BUCKET 396:
> > BUCKET 397:
> > BUCKET 398:
> > BUCKET 399:
> > BUCKET 400: **
> > BUCKET 401:
> > BUCKET 402:
> > BUCKET 403:
> > BUCKET 404:
> > BUCKET 405:
> > BUCKET 406:
> > BUCKET 407: *
> > BUCKET 408: *
> > BUCKET 409: *
> > BUCKET 410:
> > BUCKET 411: *
> > BUCKET 412:
> > BUCKET 413:
> > BUCKET 414:
> > BUCKET 415:
> > BUCKET 416: *
> > BUCKET 417:
> > BUCKET 418: *
> > BUCKET 419:
> > BUCKET 420: **
> > BUCKET 421: *
> > BUCKET 422:
> > BUCKET 423: **
> > BUCKET 424: ***
> > BUCKET 425:
> > BUCKET 426: *
> > BUCKET 427: *
> > BUCKET 428: **
> > BUCKET 429:
> > BUCKET 430:
> > BUCKET 431:
> > BUCKET 432:
> > BUCKET 433: *
> > BUCKET 434:
> > BUCKET 435: **
> > BUCKET 436: *
> > BUCKET 437: *
> > BUCKET 438:
> > BUCKET 439: *
> > BUCKET 440:
> > BUCKET 441:
> > BUCKET 442:
> > BUCKET 443: *
> > BUCKET 444:
> > BUCKET 445: *
> > BUCKET 446:
> > BUCKET 447: *
> > BUCKET 448:
> > BUCKET 449: *
> > BUCKET 450:
> > BUCKET 451:
> > BUCKET 452: *
> > BUCKET 453: *
> > BUCKET 454: *
> > BUCKET 455:
> > BUCKET 456:
> > BUCKET 457:
> > BUCKET 458: *
> > BUCKET 459: **
> > BUCKET 460:
> > BUCKET 461: **
> > BUCKET 462: *
> > BUCKET 463:
> > BUCKET 464: *
> > BUCKET 465: *
> > BUCKET 466:
> > BUCKET 467:
> > BUCKET 468:
> > BUCKET 469: *
> > BUCKET 470: *
> > BUCKET 471:
> > BUCKET 472: **
> > BUCKET 473: **
> > BUCKET 474:
> > BUCKET 475:
> > BUCKET 476:
> > BUCKET 477: *
> > BUCKET 478:
> > BUCKET 479: *
> > BUCKET 480: *
> > BUCKET 481: ***
> > BUCKET 482: **
> > BUCKET 483:
> > BUCKET 484:
> > BUCKET 485: **
> > BUCKET 486: **
> > BUCKET 487:
> > BUCKET 488: *
> > BUCKET 489: *
> > BUCKET 490:
> > BUCKET 491: **
> > BUCKET 492: *
> > BUCKET 493:
> > BUCKET 494:
> > BUCKET 495: *
> > BUCKET 496:
> > BUCKET 497:
> > BUCKET 498:
> > BUCKET 499:
> > BUCKET 500: ***
> > BUCKET 501:
> > BUCKET 502: *
> > BUCKET 503: *
> > BUCKET 504: *
> > BUCKET 505:
> > BUCKET 506: *
> > BUCKET 507:
> > BUCKET 508:
> > BUCKET 509:
> > BUCKET 510:
> > BUCKET 511:
> >
在Oracle8i中,Oracle以一个很长的LIBRARY CACHE HASH TABLE来记录Library Cache的使用情况
"*"代表该Bucket中包含的对象的个数
在以上输出中我们看到Bucket 198中包含四个对象.
我们在第三部分中可以找到bucket 198:
>
>
> >
> BUCKET 198:
> > LIBRARY OBJECT HANDLE: handle=2c2b4ac4
> > name=
> > SELECT a.statement_id, a.timestamp, a.remarks, a.operation, a.options,
> > a.object_node, a.object_owner, a.object_name, a.object_instance,
> > a.object_type, a.optimizer, a.search_columns, a.id, a.parent_id,
> > a.position, a.cost, a.cardinality, a.bytes, a.other_tag,
> > a.partition_start, a.partition_stop, a.partition_id, a.other,
> > a.distribution
> > , ROWID
> > FROM plan_table a
> > hash=60dd47a1 timestamp=08-27-2004 10:19:28
> > namespace=CRSR flags=RON/TIM/PN0/LRG/[10010001]
> > kkkk-dddd-llll=0000-0001-0001 lock=0 pin=0 latch=0
> > lwt=2c2b4adc[2c2b4adc,2c2b4adc] ltm=2c2b4ae4[2c2b4ae4,2c2b4ae4]
> > pwt=2c2b4af4[2c2b4af4,2c2b4af4] ptm=2c2b4b4c[2c2b4b4c,2c2b4b4c]
> > ref=2c2b4acc[2c2b4acc,2c2b4acc]
> > LIBRARY OBJECT: object=2c0b1430
> > type=CRSR flags=EXS[0001] pflags= [00] status=VALD load=0
> > CHILDREN: size=16
> > child# table reference handle
> > ------ -------- --------- --------
> > 0 2c0b15ec 2c0b15b4 2c2c0d50
> > DATA BLOCKS:
> > data# heap pointer status pins change
> > ----- -------- -------- ------ ---- ------
> > 0 2c362290 2c0b14b4 I/-/A 0 NONE
> > LIBRARY OBJECT HANDLE: handle=2c3675d4
> > name=SYS.DBMS_STANDARD
> > hash=50748ddb timestamp=NULL
> > namespace=BODY/TYBD flags=TIM/SML/[02000000]
> > kkkk-dddd-llll=0000-0011-0011 lock=0 pin=0 latch=0
> > lwt=2c3675ec[2c3675ec,2c3675ec] ltm=2c3675f4[2c3675f4,2c3675f4]
> > pwt=2c367604[2c367604,2c367604] ptm=2c36765c[2c36765c,2c36765c]
> > ref=2c3675dc[2c3675dc,2c3675dc]
> > LIBRARY OBJECT: object=2c1528e8
> > flags=NEX[0002] pflags= [00] status=VALD load=0
> > DATA BLOCKS:
> > data# heap pointer status pins change
> > ----- -------- -------- ------ ---- ------
> > 0 2c367564 2c1529cc I/-/A 0 NONE
> > 4 2c15297c 0 -/P/- 0 NONE
> > LIBRARY OBJECT HANDLE: handle=2c347dd8
> > name=select pos#,intcol#,col#,spare1 from icol$ where obj#=:1
> > hash=fa15ebe3 timestamp=07-28-2004 18:04:43
> > namespace=CRSR flags=RON/TIM/PN0/SML/[12010000]
> > kkkk-dddd-llll=0000-0001-0001 lock=0 pin=0 latch=0
> > lwt=2c347df0[2c347df0,2c347df0] ltm=2c347df8[2c347df8,2c347df8]
> > pwt=2c347e08[2c347e08,2c347e08] ptm=2c347e60[2c347e60,2c347e60]
> > ref=2c347de0[2c347de0,2c347de0]
> > LIBRARY OBJECT: object=2c1cd1a0
> > type=CRSR flags=EXS[0001] pflags= [00] status=VALD load=0
> > CHILDREN: size=16
> > child# table reference handle
> > ------ -------- --------- --------
> > 0 2c1cd35c 2c1cd324 2c281678
> > 1 2c1cd35c 2c352c50 2c0eeb8c
> > 2 2c1cd35c 2c352c6c 2c2bb05c
> > DATA BLOCKS:
> > data# heap pointer status pins change
> > ----- -------- -------- ------ ---- ------
> > 0 2c2e8c58 2c1cd224 I/-/A 0 NONE
> > LIBRARY OBJECT HANDLE: handle=2c3a6484
> > name=SYS.TS$
> > hash=bb42852e timestamp=04-24-2002 00:04:15
> > namespace=TABL/PRCD/TYPE flags=PKP/TIM/KEP/SML/[02900000]
> > kkkk-dddd-llll=0111-0111-0119 lock=0 pin=0 latch=0
> > lwt=2c3a649c[2c3a649c,2c3a649c] ltm=2c3a64a4[2c3a64a4,2c3a64a4]
> > pwt=2c3a64b4[2c3a64b4,2c3a64b4] ptm=2c3a650c[2c3a650c,2c3a650c]
> > ref=2c3a648c[2c0d4b14,2c09353c]
> > LIBRARY OBJECT: object=2c3a626c
> > type=TABL flags=EXS/LOC[0005] pflags= [00] status=VALD load=0
> > DATA BLOCKS:
> > data# heap pointer status pins change
> > ----- -------- -------- ------ ---- ------
> > 0 2c3a8ea4 2c3a63b0 I/P/A 0 NONE
> > 3 2c3a5828 0 -/P/- 0 NONE
> > 4 2c3a6300 2c3a5960 I/P/A 0 NONE
> > 8 2c3a6360 2c3a4f00 I/P/A 0 NONE
>
>
>
> >
我们看到这里包含了四个对象.
我们再来看看Oracle9i中的情况:
参考文件: hsjf_ora_15800.trc
>
>
> >
> LIBRARY CACHE HASH TABLE: size=131072 count=217
> > Buckets with more than 20 objects:
> > NONE
> > Hash Chain Size Number of Buckets
> > --------------- -----------------
> > 0 130855
> > 1 217
> > 2 0
> > 3 0
> > 4 0
> > 5 0
> > 6 0
> > 7 0
> > 8 0
> > 9 0
> > 10 0
> > 11 0
> > 12 0
> > 13 0
> > 14 0
> > 15 0
> > 16 0
> > 17 0
> > 18 0
> > 19 0
> > 20 0
> > >20 0
>
>
>
> >
Oracle9i中通过新的方式记录Library Cache的使用状况.
按不同的Hash Chain Size代表Library Cache中包含不同对象的个数.
0表示Free的Bucket,>20表示包含超过20个对象的Bucket的个数.
从以上列表中我们看到,包含一个对象的Buckets有217个,包含0个对象的Buckets有130855个.
我们来验证一下:
>
>
> >
> [oracle@jumper udump]$ cat hsjf_ora_15800.trc |grep BUCKET|more
> > BUCKET 12:
> > BUCKET 12 total object count=1
> > BUCKET 385:
> > BUCKET 385 total object count=1
> > BUCKET 865:
> > BUCKET 865 total object count=1
> > ...
> >
> [oracle@jumper udump]$ cat hsjf_ora_15800.trc |grep BUCKET|wc -l
> >
> 434
> >
> [oracle@jumper udump]$
>
>
>
> >
434/2 = 217，证实了我们的猜想.
通过HASH TABLE算法的改进,Oracle Library Cache管理的效率大大提高.