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193 | <h1>Hadoop Map/Reduceæçš</h1> |
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207 | </li> |
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208 | <li> |
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209 | <a href="#%E4%BE%8B%E5%AD%90%EF%BC%9AWordCount+v1.0">äŸåïŒWordCount v1.0</a> |
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210 | <ul class="minitoc"> |
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211 | <li> |
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217 | <li> |
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218 | <a href="#%E8%A7%A3%E9%87%8A">解é</a> |
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220 | </ul> |
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221 | </li> |
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222 | <li> |
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223 | <a href="#Map%2FReduce+-+%E7%94%A8%E6%88%B7%E7%95%8C%E9%9D%A2">Map/Reduce - çšæ·çé¢</a> |
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224 | <ul class="minitoc"> |
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225 | <li> |
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227 | <ul class="minitoc"> |
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228 | <li> |
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229 | <a href="#Mapper">Mapper</a> |
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230 | </li> |
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231 | <li> |
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232 | <a href="#Reducer">Reducer</a> |
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233 | </li> |
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234 | <li> |
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235 | <a href="#Partitioner">Partitioner</a> |
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236 | </li> |
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237 | <li> |
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238 | <a href="#Reporter">Reporter</a> |
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239 | </li> |
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240 | <li> |
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241 | <a href="#OutputCollector">OutputCollector</a> |
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242 | </li> |
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280 | </li> |
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283 | <ul class="minitoc"> |
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284 | <li> |
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285 | <a href="#Counters">Counters</a> |
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287 | <li> |
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288 | <a href="#DistributedCache">DistributedCache</a> |
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289 | </li> |
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293 | <li> |
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294 | <a href="#IsolationRunner">IsolationRunner</a> |
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297 | <a href="#Profiling">Profiling</a> |
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298 | </li> |
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313 | <a href="#%E4%BE%8B%E5%AD%90%EF%BC%9AWordCount+v2.0">äŸåïŒWordCount v2.0</a> |
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314 | <ul class="minitoc"> |
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332 | <div class="section"> |
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333 | <p>è¿ç¯æçšä»çšæ·çè§åºŠåºåïŒå
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334 | </div> |
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335 | |
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336 | |
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337 | <a name="N10017"></a><a name="%E5%85%88%E5%86%B3%E6%9D%A1%E4%BB%B6"></a> |
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338 | <h2 class="h3">å
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339 | <div class="section"> |
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340 | <p>请å
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341 | <ul> |
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342 | |
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343 | <li> |
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344 | |
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345 | <a href="quickstart.html">Hadoopå¿«éå
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346 | </li> |
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347 | |
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348 | <li> |
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350 | <a href="cluster_setup.html">Hadoopé矀æ建</a>对倧è§æš¡ååžåŒé矀ã |
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355 | |
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356 | |
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357 | <a name="N10032"></a><a name="%E6%A6%82%E8%BF%B0"></a> |
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358 | <h2 class="h3">æŠè¿°</h2> |
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359 | <div class="section"> |
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360 | <p>Hadoop Map/Reduceæ¯äžäžªäœ¿çšç®æç蜯件æ¡æ¶ïŒåºäºå®ååºæ¥çåºçšçšåºèœå€è¿è¡åšç±äžå䞪åçšæºåšç»æç倧åé矀äžïŒå¹¶ä»¥äžç§å¯é 容éçæ¹åŒå¹¶è¡å€çäžT级å«çæ°æ®éã</p> |
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眮信æ¯ç»<span class="codefrag">JobTracker</span>ïŒåè
èŽèŽ£ååè¿äºèœ¯ä»¶åé
眮信æ¯ç»slaveãè°åºŠä»»å¡å¹¶çæ§å®ä»¬çæ§è¡ïŒåæ¶æäŸç¶æåè¯æä¿¡æ¯ç»job-clientã</p> |
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368 | <p>èœç¶Hadoopæ¡æ¶æ¯çšJava<sup>TM</sup>å®ç°çïŒäœMap/Reduceåºçšçšåºåäžäžå®èŠçš |
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369 | Javaæ¥å ã</p> |
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370 | <ul> |
---|
371 | |
---|
372 | <li> |
---|
373 | |
---|
374 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/streaming/package-summary.html"> |
---|
375 | Hadoop Streaming</a>æ¯äžç§è¿è¡äœäžçå®çšå·¥å
·ïŒå®å
讞çšæ·å建åè¿è¡ä»»äœå¯æ§è¡çšåº |
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376 | ïŒäŸåŠïŒShellå·¥å
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377 | </li> |
---|
378 | |
---|
379 | <li> |
---|
380 | |
---|
381 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/pipes/package-summary.html"> |
---|
382 | Hadoop Pipes</a>æ¯äžäžªäž<a href="http://www.swig.org/">SWIG</a>å
Œå®¹çC++ API |
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383 | ïŒæ²¡æåºäºJNI<sup>TM</sup>ææ¯ïŒïŒå®ä¹å¯çšäºå®ç°Map/Reduceåºçšçšåºã |
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384 | </li> |
---|
385 | |
---|
386 | </ul> |
---|
387 | </div> |
---|
388 | |
---|
389 | |
---|
390 | <a name="N10082"></a><a name="%E8%BE%93%E5%85%A5%E4%B8%8E%E8%BE%93%E5%87%BA"></a> |
---|
391 | <h2 class="h3">èŸå
¥äžèŸåº</h2> |
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392 | <div class="section"> |
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393 | <p>Map/Reduceæ¡æ¶è¿èœ¬åš<span class="codefrag"><key, value></span> é®åŒå¯¹äžïŒä¹å°±æ¯è¯ŽïŒ |
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394 | æ¡æ¶æäœäžçèŸå
¥ç䞺æ¯äžç»<span class="codefrag"><key, value></span> é®åŒå¯¹ïŒåæ ·ä¹äº§åºäžç» |
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395 | <span class="codefrag"><key, value></span> é®åŒå¯¹å䞺äœäžçèŸåºïŒè¿äž€ç»é®åŒå¯¹çç±»åå¯èœäžåã</p> |
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396 | <p>æ¡æ¶éèŠå¯¹<span class="codefrag">key</span>å<span class="codefrag">value</span>çç±»(classes)è¿è¡åºååæäœïŒ |
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397 | å æ€ïŒè¿äºç±»éèŠå®ç° <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/io/Writable.html">Writable</a>æ¥å£ã |
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398 | åŠå€ïŒäžºäºæ¹äŸ¿æ¡æ¶æ§è¡æåºæäœïŒ<span class="codefrag">key</span>ç±»å¿
é¡»å®ç° |
---|
399 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/io/WritableComparable.html"> |
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400 | WritableComparable</a>æ¥å£ã |
---|
401 | </p> |
---|
402 | <p>äžäžªMap/Reduce äœäžçèŸå
¥åèŸåºç±»ååŠäžæ瀺ïŒ</p> |
---|
403 | <p> |
---|
404 | (input) <span class="codefrag"><k1, v1></span> |
---|
405 | -> |
---|
406 | <strong>map</strong> |
---|
407 | -> |
---|
408 | <span class="codefrag"><k2, v2></span> |
---|
409 | -> |
---|
410 | <strong>combine</strong> |
---|
411 | -> |
---|
412 | <span class="codefrag"><k2, v2></span> |
---|
413 | -> |
---|
414 | <strong>reduce</strong> |
---|
415 | -> |
---|
416 | <span class="codefrag"><k3, v3></span> (output) |
---|
417 | </p> |
---|
418 | </div> |
---|
419 | |
---|
420 | |
---|
421 | <a name="N100C4"></a><a name="%E4%BE%8B%E5%AD%90%EF%BC%9AWordCount+v1.0"></a> |
---|
422 | <h2 class="h3">äŸåïŒWordCount v1.0</h2> |
---|
423 | <div class="section"> |
---|
424 | <p>åšæ·±å
¥ç»èä¹åïŒè®©æ们å
çäžäžªMap/Reduceçåºçšç€ºäŸïŒä»¥äŸ¿å¯¹å®ä»¬çå·¥äœæ¹åŒæäžäžªåæ¥ç讀è¯ã</p> |
---|
425 | <p> |
---|
426 | <span class="codefrag">WordCount</span>æ¯äžäžªç®åçåºçšïŒå®å¯ä»¥è®¡ç®åºæå®æ°æ®éäžæ¯äžäžªåè¯åºç°ç次æ°ã</p> |
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427 | <p>è¿äžªåºçšéçšäº |
---|
428 | <a href="quickstart.html#Standalone+Operation">åæºæš¡åŒ</a>ïŒ |
---|
429 | <a href="quickstart.html#SingleNodeSetup">䌪ååžåŒæš¡åŒ</a> æ |
---|
430 | <a href="quickstart.html#Fully-Distributed+Operation">å®å
šååžåŒæš¡åŒ</a> |
---|
431 | äžç§Hadoopå®è£
æ¹åŒã</p> |
---|
432 | <a name="N100E1"></a><a name="%E6%BA%90%E4%BB%A3%E7%A0%81"></a> |
---|
433 | <h3 class="h4">æºä»£ç </h3> |
---|
434 | <table class="ForrestTable" cellspacing="1" cellpadding="4"> |
---|
435 | |
---|
436 | <tr> |
---|
437 | |
---|
438 | <th colspan="1" rowspan="1"></th> |
---|
439 | <th colspan="1" rowspan="1">WordCount.java</th> |
---|
440 | |
---|
441 | </tr> |
---|
442 | |
---|
443 | <tr> |
---|
444 | |
---|
445 | <td colspan="1" rowspan="1">1.</td> |
---|
446 | <td colspan="1" rowspan="1"> |
---|
447 | <span class="codefrag">package org.myorg;</span> |
---|
448 | </td> |
---|
449 | |
---|
450 | </tr> |
---|
451 | |
---|
452 | <tr> |
---|
453 | |
---|
454 | <td colspan="1" rowspan="1">2.</td> |
---|
455 | <td colspan="1" rowspan="1"></td> |
---|
456 | |
---|
457 | </tr> |
---|
458 | |
---|
459 | <tr> |
---|
460 | |
---|
461 | <td colspan="1" rowspan="1">3.</td> |
---|
462 | <td colspan="1" rowspan="1"> |
---|
463 | <span class="codefrag">import java.io.IOException;</span> |
---|
464 | </td> |
---|
465 | |
---|
466 | </tr> |
---|
467 | |
---|
468 | <tr> |
---|
469 | |
---|
470 | <td colspan="1" rowspan="1">4.</td> |
---|
471 | <td colspan="1" rowspan="1"> |
---|
472 | <span class="codefrag">import java.util.*;</span> |
---|
473 | </td> |
---|
474 | |
---|
475 | </tr> |
---|
476 | |
---|
477 | <tr> |
---|
478 | |
---|
479 | <td colspan="1" rowspan="1">5.</td> |
---|
480 | <td colspan="1" rowspan="1"></td> |
---|
481 | |
---|
482 | </tr> |
---|
483 | |
---|
484 | <tr> |
---|
485 | |
---|
486 | <td colspan="1" rowspan="1">6.</td> |
---|
487 | <td colspan="1" rowspan="1"> |
---|
488 | <span class="codefrag">import org.apache.hadoop.fs.Path;</span> |
---|
489 | </td> |
---|
490 | |
---|
491 | </tr> |
---|
492 | |
---|
493 | <tr> |
---|
494 | |
---|
495 | <td colspan="1" rowspan="1">7.</td> |
---|
496 | <td colspan="1" rowspan="1"> |
---|
497 | <span class="codefrag">import org.apache.hadoop.conf.*;</span> |
---|
498 | </td> |
---|
499 | |
---|
500 | </tr> |
---|
501 | |
---|
502 | <tr> |
---|
503 | |
---|
504 | <td colspan="1" rowspan="1">8.</td> |
---|
505 | <td colspan="1" rowspan="1"> |
---|
506 | <span class="codefrag">import org.apache.hadoop.io.*;</span> |
---|
507 | </td> |
---|
508 | |
---|
509 | </tr> |
---|
510 | |
---|
511 | <tr> |
---|
512 | |
---|
513 | <td colspan="1" rowspan="1">9.</td> |
---|
514 | <td colspan="1" rowspan="1"> |
---|
515 | <span class="codefrag">import org.apache.hadoop.mapred.*;</span> |
---|
516 | </td> |
---|
517 | |
---|
518 | </tr> |
---|
519 | |
---|
520 | <tr> |
---|
521 | |
---|
522 | <td colspan="1" rowspan="1">10.</td> |
---|
523 | <td colspan="1" rowspan="1"> |
---|
524 | <span class="codefrag">import org.apache.hadoop.util.*;</span> |
---|
525 | </td> |
---|
526 | |
---|
527 | </tr> |
---|
528 | |
---|
529 | <tr> |
---|
530 | |
---|
531 | <td colspan="1" rowspan="1">11.</td> |
---|
532 | <td colspan="1" rowspan="1"></td> |
---|
533 | |
---|
534 | </tr> |
---|
535 | |
---|
536 | <tr> |
---|
537 | |
---|
538 | <td colspan="1" rowspan="1">12.</td> |
---|
539 | <td colspan="1" rowspan="1"> |
---|
540 | <span class="codefrag">public class WordCount {</span> |
---|
541 | </td> |
---|
542 | |
---|
543 | </tr> |
---|
544 | |
---|
545 | <tr> |
---|
546 | |
---|
547 | <td colspan="1" rowspan="1">13.</td> |
---|
548 | <td colspan="1" rowspan="1"></td> |
---|
549 | |
---|
550 | </tr> |
---|
551 | |
---|
552 | <tr> |
---|
553 | |
---|
554 | <td colspan="1" rowspan="1">14.</td> |
---|
555 | <td colspan="1" rowspan="1"> |
---|
556 | |
---|
557 | <span class="codefrag"> |
---|
558 | public static class Map extends MapReduceBase |
---|
559 | implements Mapper<LongWritable, Text, Text, IntWritable> { |
---|
560 | </span> |
---|
561 | </td> |
---|
562 | |
---|
563 | </tr> |
---|
564 | |
---|
565 | <tr> |
---|
566 | |
---|
567 | <td colspan="1" rowspan="1">15.</td> |
---|
568 | <td colspan="1" rowspan="1"> |
---|
569 | |
---|
570 | <span class="codefrag"> |
---|
571 | private final static IntWritable one = new IntWritable(1); |
---|
572 | </span> |
---|
573 | </td> |
---|
574 | |
---|
575 | </tr> |
---|
576 | |
---|
577 | <tr> |
---|
578 | |
---|
579 | <td colspan="1" rowspan="1">16.</td> |
---|
580 | <td colspan="1" rowspan="1"> |
---|
581 | |
---|
582 | <span class="codefrag">private Text word = new Text();</span> |
---|
583 | </td> |
---|
584 | |
---|
585 | </tr> |
---|
586 | |
---|
587 | <tr> |
---|
588 | |
---|
589 | <td colspan="1" rowspan="1">17.</td> |
---|
590 | <td colspan="1" rowspan="1"></td> |
---|
591 | |
---|
592 | </tr> |
---|
593 | |
---|
594 | <tr> |
---|
595 | |
---|
596 | <td colspan="1" rowspan="1">18.</td> |
---|
597 | <td colspan="1" rowspan="1"> |
---|
598 | |
---|
599 | <span class="codefrag"> |
---|
600 | public void map(LongWritable key, Text value, |
---|
601 | OutputCollector<Text, IntWritable> output, |
---|
602 | Reporter reporter) throws IOException { |
---|
603 | </span> |
---|
604 | </td> |
---|
605 | |
---|
606 | </tr> |
---|
607 | |
---|
608 | <tr> |
---|
609 | |
---|
610 | <td colspan="1" rowspan="1">19.</td> |
---|
611 | <td colspan="1" rowspan="1"> |
---|
612 | |
---|
613 | <span class="codefrag">String line = value.toString();</span> |
---|
614 | </td> |
---|
615 | |
---|
616 | </tr> |
---|
617 | |
---|
618 | <tr> |
---|
619 | |
---|
620 | <td colspan="1" rowspan="1">20.</td> |
---|
621 | <td colspan="1" rowspan="1"> |
---|
622 | |
---|
623 | <span class="codefrag">StringTokenizer tokenizer = new StringTokenizer(line);</span> |
---|
624 | </td> |
---|
625 | |
---|
626 | </tr> |
---|
627 | |
---|
628 | <tr> |
---|
629 | |
---|
630 | <td colspan="1" rowspan="1">21.</td> |
---|
631 | <td colspan="1" rowspan="1"> |
---|
632 | |
---|
633 | <span class="codefrag">while (tokenizer.hasMoreTokens()) {</span> |
---|
634 | </td> |
---|
635 | |
---|
636 | </tr> |
---|
637 | |
---|
638 | <tr> |
---|
639 | |
---|
640 | <td colspan="1" rowspan="1">22.</td> |
---|
641 | <td colspan="1" rowspan="1"> |
---|
642 | |
---|
643 | <span class="codefrag">word.set(tokenizer.nextToken());</span> |
---|
644 | </td> |
---|
645 | |
---|
646 | </tr> |
---|
647 | |
---|
648 | <tr> |
---|
649 | |
---|
650 | <td colspan="1" rowspan="1">23.</td> |
---|
651 | <td colspan="1" rowspan="1"> |
---|
652 | |
---|
653 | <span class="codefrag">output.collect(word, one);</span> |
---|
654 | </td> |
---|
655 | |
---|
656 | </tr> |
---|
657 | |
---|
658 | <tr> |
---|
659 | |
---|
660 | <td colspan="1" rowspan="1">24.</td> |
---|
661 | <td colspan="1" rowspan="1"> |
---|
662 | |
---|
663 | <span class="codefrag">}</span> |
---|
664 | </td> |
---|
665 | |
---|
666 | </tr> |
---|
667 | |
---|
668 | <tr> |
---|
669 | |
---|
670 | <td colspan="1" rowspan="1">25.</td> |
---|
671 | <td colspan="1" rowspan="1"> |
---|
672 | |
---|
673 | <span class="codefrag">}</span> |
---|
674 | </td> |
---|
675 | |
---|
676 | </tr> |
---|
677 | |
---|
678 | <tr> |
---|
679 | |
---|
680 | <td colspan="1" rowspan="1">26.</td> |
---|
681 | <td colspan="1" rowspan="1"> |
---|
682 | |
---|
683 | <span class="codefrag">}</span> |
---|
684 | </td> |
---|
685 | |
---|
686 | </tr> |
---|
687 | |
---|
688 | <tr> |
---|
689 | |
---|
690 | <td colspan="1" rowspan="1">27.</td> |
---|
691 | <td colspan="1" rowspan="1"></td> |
---|
692 | |
---|
693 | </tr> |
---|
694 | |
---|
695 | <tr> |
---|
696 | |
---|
697 | <td colspan="1" rowspan="1">28.</td> |
---|
698 | <td colspan="1" rowspan="1"> |
---|
699 | |
---|
700 | <span class="codefrag"> |
---|
701 | public static class Reduce extends MapReduceBase implements |
---|
702 | Reducer<Text, IntWritable, Text, IntWritable> { |
---|
703 | </span> |
---|
704 | </td> |
---|
705 | |
---|
706 | </tr> |
---|
707 | |
---|
708 | <tr> |
---|
709 | |
---|
710 | <td colspan="1" rowspan="1">29.</td> |
---|
711 | <td colspan="1" rowspan="1"> |
---|
712 | |
---|
713 | <span class="codefrag"> |
---|
714 | public void reduce(Text key, Iterator<IntWritable> values, |
---|
715 | OutputCollector<Text, IntWritable> output, |
---|
716 | Reporter reporter) throws IOException { |
---|
717 | </span> |
---|
718 | </td> |
---|
719 | |
---|
720 | </tr> |
---|
721 | |
---|
722 | <tr> |
---|
723 | |
---|
724 | <td colspan="1" rowspan="1">30.</td> |
---|
725 | <td colspan="1" rowspan="1"> |
---|
726 | |
---|
727 | <span class="codefrag">int sum = 0;</span> |
---|
728 | </td> |
---|
729 | |
---|
730 | </tr> |
---|
731 | |
---|
732 | <tr> |
---|
733 | |
---|
734 | <td colspan="1" rowspan="1">31.</td> |
---|
735 | <td colspan="1" rowspan="1"> |
---|
736 | |
---|
737 | <span class="codefrag">while (values.hasNext()) {</span> |
---|
738 | </td> |
---|
739 | |
---|
740 | </tr> |
---|
741 | |
---|
742 | <tr> |
---|
743 | |
---|
744 | <td colspan="1" rowspan="1">32.</td> |
---|
745 | <td colspan="1" rowspan="1"> |
---|
746 | |
---|
747 | <span class="codefrag">sum += values.next().get();</span> |
---|
748 | </td> |
---|
749 | |
---|
750 | </tr> |
---|
751 | |
---|
752 | <tr> |
---|
753 | |
---|
754 | <td colspan="1" rowspan="1">33.</td> |
---|
755 | <td colspan="1" rowspan="1"> |
---|
756 | |
---|
757 | <span class="codefrag">}</span> |
---|
758 | </td> |
---|
759 | |
---|
760 | </tr> |
---|
761 | |
---|
762 | <tr> |
---|
763 | |
---|
764 | <td colspan="1" rowspan="1">34.</td> |
---|
765 | <td colspan="1" rowspan="1"> |
---|
766 | |
---|
767 | <span class="codefrag">output.collect(key, new IntWritable(sum));</span> |
---|
768 | </td> |
---|
769 | |
---|
770 | </tr> |
---|
771 | |
---|
772 | <tr> |
---|
773 | |
---|
774 | <td colspan="1" rowspan="1">35.</td> |
---|
775 | <td colspan="1" rowspan="1"> |
---|
776 | |
---|
777 | <span class="codefrag">}</span> |
---|
778 | </td> |
---|
779 | |
---|
780 | </tr> |
---|
781 | |
---|
782 | <tr> |
---|
783 | |
---|
784 | <td colspan="1" rowspan="1">36.</td> |
---|
785 | <td colspan="1" rowspan="1"> |
---|
786 | |
---|
787 | <span class="codefrag">}</span> |
---|
788 | </td> |
---|
789 | |
---|
790 | </tr> |
---|
791 | |
---|
792 | <tr> |
---|
793 | |
---|
794 | <td colspan="1" rowspan="1">37.</td> |
---|
795 | <td colspan="1" rowspan="1"></td> |
---|
796 | |
---|
797 | </tr> |
---|
798 | |
---|
799 | <tr> |
---|
800 | |
---|
801 | <td colspan="1" rowspan="1">38.</td> |
---|
802 | <td colspan="1" rowspan="1"> |
---|
803 | |
---|
804 | <span class="codefrag"> |
---|
805 | public static void main(String[] args) throws Exception { |
---|
806 | </span> |
---|
807 | </td> |
---|
808 | |
---|
809 | </tr> |
---|
810 | |
---|
811 | <tr> |
---|
812 | |
---|
813 | <td colspan="1" rowspan="1">39.</td> |
---|
814 | <td colspan="1" rowspan="1"> |
---|
815 | |
---|
816 | <span class="codefrag"> |
---|
817 | JobConf conf = new JobConf(WordCount.class); |
---|
818 | </span> |
---|
819 | </td> |
---|
820 | |
---|
821 | </tr> |
---|
822 | |
---|
823 | <tr> |
---|
824 | |
---|
825 | <td colspan="1" rowspan="1">40.</td> |
---|
826 | <td colspan="1" rowspan="1"> |
---|
827 | |
---|
828 | <span class="codefrag">conf.setJobName("wordcount");</span> |
---|
829 | </td> |
---|
830 | |
---|
831 | </tr> |
---|
832 | |
---|
833 | <tr> |
---|
834 | |
---|
835 | <td colspan="1" rowspan="1">41.</td> |
---|
836 | <td colspan="1" rowspan="1"></td> |
---|
837 | |
---|
838 | </tr> |
---|
839 | |
---|
840 | <tr> |
---|
841 | |
---|
842 | <td colspan="1" rowspan="1">42.</td> |
---|
843 | <td colspan="1" rowspan="1"> |
---|
844 | |
---|
845 | <span class="codefrag">conf.setOutputKeyClass(Text.class);</span> |
---|
846 | </td> |
---|
847 | |
---|
848 | </tr> |
---|
849 | |
---|
850 | <tr> |
---|
851 | |
---|
852 | <td colspan="1" rowspan="1">43.</td> |
---|
853 | <td colspan="1" rowspan="1"> |
---|
854 | |
---|
855 | <span class="codefrag">conf.setOutputValueClass(IntWritable.class);</span> |
---|
856 | </td> |
---|
857 | |
---|
858 | </tr> |
---|
859 | |
---|
860 | <tr> |
---|
861 | |
---|
862 | <td colspan="1" rowspan="1">44.</td> |
---|
863 | <td colspan="1" rowspan="1"></td> |
---|
864 | |
---|
865 | </tr> |
---|
866 | |
---|
867 | <tr> |
---|
868 | |
---|
869 | <td colspan="1" rowspan="1">45.</td> |
---|
870 | <td colspan="1" rowspan="1"> |
---|
871 | |
---|
872 | <span class="codefrag">conf.setMapperClass(Map.class);</span> |
---|
873 | </td> |
---|
874 | |
---|
875 | </tr> |
---|
876 | |
---|
877 | <tr> |
---|
878 | |
---|
879 | <td colspan="1" rowspan="1">46.</td> |
---|
880 | <td colspan="1" rowspan="1"> |
---|
881 | |
---|
882 | <span class="codefrag">conf.setCombinerClass(Reduce.class);</span> |
---|
883 | </td> |
---|
884 | |
---|
885 | </tr> |
---|
886 | |
---|
887 | <tr> |
---|
888 | |
---|
889 | <td colspan="1" rowspan="1">47.</td> |
---|
890 | <td colspan="1" rowspan="1"> |
---|
891 | |
---|
892 | <span class="codefrag">conf.setReducerClass(Reduce.class);</span> |
---|
893 | </td> |
---|
894 | |
---|
895 | </tr> |
---|
896 | |
---|
897 | <tr> |
---|
898 | |
---|
899 | <td colspan="1" rowspan="1">48.</td> |
---|
900 | <td colspan="1" rowspan="1"></td> |
---|
901 | |
---|
902 | </tr> |
---|
903 | |
---|
904 | <tr> |
---|
905 | |
---|
906 | <td colspan="1" rowspan="1">49.</td> |
---|
907 | <td colspan="1" rowspan="1"> |
---|
908 | |
---|
909 | <span class="codefrag">conf.setInputFormat(TextInputFormat.class);</span> |
---|
910 | </td> |
---|
911 | |
---|
912 | </tr> |
---|
913 | |
---|
914 | <tr> |
---|
915 | |
---|
916 | <td colspan="1" rowspan="1">50.</td> |
---|
917 | <td colspan="1" rowspan="1"> |
---|
918 | |
---|
919 | <span class="codefrag">conf.setOutputFormat(TextOutputFormat.class);</span> |
---|
920 | </td> |
---|
921 | |
---|
922 | </tr> |
---|
923 | |
---|
924 | <tr> |
---|
925 | |
---|
926 | <td colspan="1" rowspan="1">51.</td> |
---|
927 | <td colspan="1" rowspan="1"></td> |
---|
928 | |
---|
929 | </tr> |
---|
930 | |
---|
931 | <tr> |
---|
932 | |
---|
933 | <td colspan="1" rowspan="1">52.</td> |
---|
934 | <td colspan="1" rowspan="1"> |
---|
935 | |
---|
936 | <span class="codefrag">FileInputFormat.setInputPaths(conf, new Path(args[0]));</span> |
---|
937 | </td> |
---|
938 | |
---|
939 | </tr> |
---|
940 | |
---|
941 | <tr> |
---|
942 | |
---|
943 | <td colspan="1" rowspan="1">53.</td> |
---|
944 | <td colspan="1" rowspan="1"> |
---|
945 | |
---|
946 | <span class="codefrag">FileOutputFormat.setOutputPath(conf, new Path(args[1]));</span> |
---|
947 | </td> |
---|
948 | |
---|
949 | </tr> |
---|
950 | |
---|
951 | <tr> |
---|
952 | |
---|
953 | <td colspan="1" rowspan="1">54.</td> |
---|
954 | <td colspan="1" rowspan="1"></td> |
---|
955 | |
---|
956 | </tr> |
---|
957 | |
---|
958 | <tr> |
---|
959 | |
---|
960 | <td colspan="1" rowspan="1">55.</td> |
---|
961 | <td colspan="1" rowspan="1"> |
---|
962 | |
---|
963 | <span class="codefrag">JobClient.runJob(conf);</span> |
---|
964 | </td> |
---|
965 | |
---|
966 | </tr> |
---|
967 | |
---|
968 | <tr> |
---|
969 | |
---|
970 | <td colspan="1" rowspan="1">57.</td> |
---|
971 | <td colspan="1" rowspan="1"> |
---|
972 | |
---|
973 | <span class="codefrag">}</span> |
---|
974 | </td> |
---|
975 | |
---|
976 | </tr> |
---|
977 | |
---|
978 | <tr> |
---|
979 | |
---|
980 | <td colspan="1" rowspan="1">58.</td> |
---|
981 | <td colspan="1" rowspan="1"> |
---|
982 | <span class="codefrag">}</span> |
---|
983 | </td> |
---|
984 | |
---|
985 | </tr> |
---|
986 | |
---|
987 | <tr> |
---|
988 | |
---|
989 | <td colspan="1" rowspan="1">59.</td> |
---|
990 | <td colspan="1" rowspan="1"></td> |
---|
991 | |
---|
992 | </tr> |
---|
993 | |
---|
994 | </table> |
---|
995 | <a name="N10463"></a><a name="%E7%94%A8%E6%B3%95"></a> |
---|
996 | <h3 class="h4">çšæ³</h3> |
---|
997 | <p>å讟ç¯å¢åé<span class="codefrag">HADOOP_HOME</span>对åºå®è£
æ¶çæ ¹ç®åœïŒ<span class="codefrag">HADOOP_VERSION</span>对åºHadoopçåœåå®è£
çæ¬ïŒçŒè¯<span class="codefrag">WordCount.java</span>æ¥å建jarå
ïŒå¯åŠäžæäœïŒ</p> |
---|
998 | <p> |
---|
999 | |
---|
1000 | <span class="codefrag">$ mkdir wordcount_classes</span> |
---|
1001 | <br> |
---|
1002 | |
---|
1003 | <span class="codefrag"> |
---|
1004 | $ javac -classpath ${HADOOP_HOME}/hadoop-${HADOOP_VERSION}-core.jar |
---|
1005 | -d wordcount_classes WordCount.java |
---|
1006 | </span> |
---|
1007 | <br> |
---|
1008 | |
---|
1009 | <span class="codefrag">$ jar -cvf /usr/joe/wordcount.jar -C wordcount_classes/ .</span> |
---|
1010 | |
---|
1011 | </p> |
---|
1012 | <p>å讟ïŒ</p> |
---|
1013 | <ul> |
---|
1014 | |
---|
1015 | <li> |
---|
1016 | |
---|
1017 | <span class="codefrag">/usr/joe/wordcount/input</span> - æ¯HDFSäžçèŸå
¥è·¯åŸ |
---|
1018 | </li> |
---|
1019 | |
---|
1020 | <li> |
---|
1021 | |
---|
1022 | <span class="codefrag">/usr/joe/wordcount/output</span> - æ¯HDFSäžçèŸåºè·¯åŸ |
---|
1023 | </li> |
---|
1024 | |
---|
1025 | </ul> |
---|
1026 | <p>çšç€ºäŸææ¬æ件å䞺èŸå
¥ïŒ</p> |
---|
1027 | <p> |
---|
1028 | |
---|
1029 | <span class="codefrag">$ bin/hadoop dfs -ls /usr/joe/wordcount/input/</span> |
---|
1030 | <br> |
---|
1031 | |
---|
1032 | <span class="codefrag">/usr/joe/wordcount/input/file01</span> |
---|
1033 | <br> |
---|
1034 | |
---|
1035 | <span class="codefrag">/usr/joe/wordcount/input/file02</span> |
---|
1036 | <br> |
---|
1037 | |
---|
1038 | <br> |
---|
1039 | |
---|
1040 | <span class="codefrag">$ bin/hadoop dfs -cat /usr/joe/wordcount/input/file01</span> |
---|
1041 | <br> |
---|
1042 | |
---|
1043 | <span class="codefrag">Hello World Bye World</span> |
---|
1044 | <br> |
---|
1045 | |
---|
1046 | <br> |
---|
1047 | |
---|
1048 | <span class="codefrag">$ bin/hadoop dfs -cat /usr/joe/wordcount/input/file02</span> |
---|
1049 | <br> |
---|
1050 | |
---|
1051 | <span class="codefrag">Hello Hadoop Goodbye Hadoop</span> |
---|
1052 | |
---|
1053 | </p> |
---|
1054 | <p>è¿è¡åºçšçšåºïŒ</p> |
---|
1055 | <p> |
---|
1056 | |
---|
1057 | <span class="codefrag"> |
---|
1058 | $ bin/hadoop jar /usr/joe/wordcount.jar org.myorg.WordCount |
---|
1059 | /usr/joe/wordcount/input /usr/joe/wordcount/output |
---|
1060 | </span> |
---|
1061 | |
---|
1062 | </p> |
---|
1063 | <p>èŸåºæ¯ïŒ</p> |
---|
1064 | <p> |
---|
1065 | |
---|
1066 | <span class="codefrag"> |
---|
1067 | $ bin/hadoop dfs -cat /usr/joe/wordcount/output/part-00000 |
---|
1068 | </span> |
---|
1069 | |
---|
1070 | <br> |
---|
1071 | |
---|
1072 | <span class="codefrag">Bye 1</span> |
---|
1073 | <br> |
---|
1074 | |
---|
1075 | <span class="codefrag">Goodbye 1</span> |
---|
1076 | <br> |
---|
1077 | |
---|
1078 | <span class="codefrag">Hadoop 2</span> |
---|
1079 | <br> |
---|
1080 | |
---|
1081 | <span class="codefrag">Hello 2</span> |
---|
1082 | <br> |
---|
1083 | |
---|
1084 | <span class="codefrag">World 2</span> |
---|
1085 | <br> |
---|
1086 | |
---|
1087 | </p> |
---|
1088 | <p> åºçšçšåºèœå€äœ¿çš<span class="codefrag">-files</span>é项æ¥æå®äžäžªç±éå·åéçè·¯åŸåè¡šïŒè¿äºè·¯åŸæ¯taskçåœåå·¥äœç®åœã䜿çšé项<span class="codefrag">-libjars</span>å¯ä»¥åmapåreduceçclasspathäžæ·»å jarå
ã䜿çš<span class="codefrag">-archives</span>é项çšåºå¯ä»¥äŒ éæ¡£æ¡æ件å䞺åæ°ïŒè¿äºæ¡£æ¡æ件äŒè¢«è§£å并äžåštaskçåœåå·¥äœç®åœäžäŒå建äžäžªæå解åçæçç®åœç笊å·éŸæ¥ïŒä»¥å猩å
çåååœåïŒã |
---|
1089 | æå
³åœä»€è¡é项çæŽå€ç»è请åè |
---|
1090 | <a href="commands_manual.html">Commands manual</a>ã</p> |
---|
1091 | <p>䜿çš<span class="codefrag">-libjars</span>å<span class="codefrag">-files</span>è¿è¡<span class="codefrag">wordcount</span>äŸåïŒ<br> |
---|
1092 | |
---|
1093 | <span class="codefrag"> hadoop jar hadoop-examples.jar wordcount -files cachefile.txt |
---|
1094 | -libjars mylib.jar input output </span> |
---|
1095 | |
---|
1096 | </p> |
---|
1097 | <a name="N10504"></a><a name="%E8%A7%A3%E9%87%8A"></a> |
---|
1098 | <h3 class="h4">解é</h3> |
---|
1099 | <p> |
---|
1100 | <span class="codefrag">WordCount</span>åºçšçšåºéåžžçŽæªäºåœã</p> |
---|
1101 | <p> |
---|
1102 | <span class="codefrag">Mapper</span>(14-26è¡)äžç<span class="codefrag">map</span>æ¹æ³(18-25è¡)éè¿æå®ç |
---|
1103 | <span class="codefrag">TextInputFormat</span>(49è¡)äžæ¬¡å€çäžè¡ãç¶åïŒå®éè¿<span class="codefrag">StringTokenizer</span> |
---|
1104 | ä»¥ç©ºæ Œäžºåé笊å°äžè¡åå䞺è¥å¹²tokensïŒä¹åïŒèŸåº<span class="codefrag">< <word>, 1></span> |
---|
1105 | 圢åŒçé®åŒå¯¹ã</p> |
---|
1106 | <p> |
---|
1107 | 对äºç€ºäŸäžç第äžäžªèŸå
¥ïŒmapèŸåºæ¯ïŒ<br> |
---|
1108 | |
---|
1109 | <span class="codefrag">< Hello, 1></span> |
---|
1110 | <br> |
---|
1111 | |
---|
1112 | <span class="codefrag">< World, 1></span> |
---|
1113 | <br> |
---|
1114 | |
---|
1115 | <span class="codefrag">< Bye, 1></span> |
---|
1116 | <br> |
---|
1117 | |
---|
1118 | <span class="codefrag">< World, 1></span> |
---|
1119 | <br> |
---|
1120 | |
---|
1121 | </p> |
---|
1122 | <p> |
---|
1123 | 第äºäžªèŸå
¥ïŒmapèŸåºæ¯ïŒ<br> |
---|
1124 | |
---|
1125 | <span class="codefrag">< Hello, 1></span> |
---|
1126 | <br> |
---|
1127 | |
---|
1128 | <span class="codefrag">< Hadoop, 1></span> |
---|
1129 | <br> |
---|
1130 | |
---|
1131 | <span class="codefrag">< Goodbye, 1></span> |
---|
1132 | <br> |
---|
1133 | |
---|
1134 | <span class="codefrag">< Hadoop, 1></span> |
---|
1135 | <br> |
---|
1136 | |
---|
1137 | </p> |
---|
1138 | <p>å
³äºç»æäžäžªæå®äœäžçmapæ°ç®çç¡®å®ïŒä»¥ååŠäœä»¥æŽç²Ÿç»çæ¹åŒå»æ§å¶è¿äºmapïŒæ们å°åšæçšçåç»éšååŠä¹ å°æŽå€çå
容ã</p> |
---|
1139 | <p> |
---|
1140 | <span class="codefrag">WordCount</span>è¿æå®äºäžäžª<span class="codefrag">combiner</span> (46è¡)ãå æ€ïŒæ¯æ¬¡mapè¿è¡ä¹åïŒäŒå¯¹èŸåºæç
§<em>key</em>è¿è¡æåºïŒç¶åæèŸåºäŒ éç»æ¬å°çcombinerïŒæç
§äœäžçé
眮äžReduceräžæ ·ïŒïŒè¿è¡æ¬å°èåã</p> |
---|
1141 | <p> |
---|
1142 | 第äžäžªmapçèŸåºæ¯ïŒ<br> |
---|
1143 | |
---|
1144 | <span class="codefrag">< Bye, 1></span> |
---|
1145 | <br> |
---|
1146 | |
---|
1147 | <span class="codefrag">< Hello, 1></span> |
---|
1148 | <br> |
---|
1149 | |
---|
1150 | <span class="codefrag">< World, 2></span> |
---|
1151 | <br> |
---|
1152 | |
---|
1153 | </p> |
---|
1154 | <p> |
---|
1155 | 第äºäžªmapçèŸåºæ¯ïŒ<br> |
---|
1156 | |
---|
1157 | <span class="codefrag">< Goodbye, 1></span> |
---|
1158 | <br> |
---|
1159 | |
---|
1160 | <span class="codefrag">< Hadoop, 2></span> |
---|
1161 | <br> |
---|
1162 | |
---|
1163 | <span class="codefrag">< Hello, 1></span> |
---|
1164 | <br> |
---|
1165 | |
---|
1166 | </p> |
---|
1167 | <p> |
---|
1168 | <span class="codefrag">Reducer</span>(28-36è¡)äžç<span class="codefrag">reduce</span>æ¹æ³(29-35è¡) |
---|
1169 | ä»
æ¯å°æ¯äžªkeyïŒæ¬äŸäžå°±æ¯åè¯ïŒåºç°ç次æ°æ±åã |
---|
1170 | </p> |
---|
1171 | <p> |
---|
1172 | å æ€è¿äžªäœäžçèŸåºå°±æ¯ïŒ<br> |
---|
1173 | |
---|
1174 | <span class="codefrag">< Bye, 1></span> |
---|
1175 | <br> |
---|
1176 | |
---|
1177 | <span class="codefrag">< Goodbye, 1></span> |
---|
1178 | <br> |
---|
1179 | |
---|
1180 | <span class="codefrag">< Hadoop, 2></span> |
---|
1181 | <br> |
---|
1182 | |
---|
1183 | <span class="codefrag">< Hello, 2></span> |
---|
1184 | <br> |
---|
1185 | |
---|
1186 | <span class="codefrag">< World, 2></span> |
---|
1187 | <br> |
---|
1188 | |
---|
1189 | </p> |
---|
1190 | <p>代ç äžç<span class="codefrag">run</span>æ¹æ³äžæå®äºäœäžçå 䞪æ¹é¢ïŒ |
---|
1191 | äŸåŠïŒéè¿åœä»€è¡äŒ éè¿æ¥çèŸå
¥/èŸåºè·¯åŸãkey/valueçç±»åãèŸå
¥/èŸåºçæ ŒåŒçç<span class="codefrag">JobConf</span>äžçé
眮信æ¯ãéåçšåºè°çšäº<span class="codefrag">JobClient.runJob</span>(55è¡)æ¥æ亀äœäžå¹¶äžçæ§å®çæ§è¡ã</p> |
---|
1192 | <p>æ们å°åšæ¬æçšçåç»éšååŠä¹ æŽå€çå
³äº<span class="codefrag">JobConf</span>ïŒ <span class="codefrag">JobClient</span>ïŒ |
---|
1193 | <span class="codefrag">Tool</span>åå
¶ä»æ¥å£åç±»(class)ã</p> |
---|
1194 | </div> |
---|
1195 | |
---|
1196 | |
---|
1197 | <a name="N105B5"></a><a name="Map%2FReduce+-+%E7%94%A8%E6%88%B7%E7%95%8C%E9%9D%A2"></a> |
---|
1198 | <h2 class="h3">Map/Reduce - çšæ·çé¢</h2> |
---|
1199 | <div class="section"> |
---|
1200 | <p>è¿éšåæ档䞺çšæ·å°äŒé¢äžŽçMap/Reduceæ¡æ¶äžçå䞪ç¯èæäŸäºéåœçç»èãè¿åºè¯¥äŒåž®å©çšæ·æŽç»ç²åºŠå°å»å®ç°ãé
眮åè°äŒäœäžãç¶èïŒè¯·æ³šææ¯äžªç±»/æ¥å£çjavadocææ¡£æäŸæå
šé¢çææ¡£ïŒæ¬æåªæ¯æ³èµ·å°æåçäœçšã |
---|
1201 | </p> |
---|
1202 | <p>æ们äŒå
çç<span class="codefrag">Mapper</span>å<span class="codefrag">Reducer</span>æ¥å£ãåºçšçšåºéåžžäŒéè¿æäŸ<span class="codefrag">map</span>å<span class="codefrag">reduce</span>æ¹æ³æ¥å®ç°å®ä»¬ã |
---|
1203 | </p> |
---|
1204 | <p>ç¶åïŒæ们äŒè®šè®ºå
¶ä»çæ žå¿æ¥å£ïŒå
¶äžå
æ¬ïŒ |
---|
1205 | <span class="codefrag">JobConf</span>ïŒ<span class="codefrag">JobClient</span>ïŒ<span class="codefrag">Partitioner</span>ïŒ |
---|
1206 | <span class="codefrag">OutputCollector</span>ïŒ<span class="codefrag">Reporter</span>ïŒ |
---|
1207 | <span class="codefrag">InputFormat</span>ïŒ<span class="codefrag">OutputFormat</span>ççã</p> |
---|
1208 | <p>æåïŒæ们å°éè¿è®šè®ºæ¡æ¶äžäžäºæçšçåèœç¹ïŒäŸåŠïŒ<span class="codefrag">DistributedCache</span>ïŒ |
---|
1209 | <span class="codefrag">IsolationRunner</span>ççïŒæ¥æ¶å°Ÿã</p> |
---|
1210 | <a name="N105EE"></a><a name="%E6%A0%B8%E5%BF%83%E5%8A%9F%E8%83%BD%E6%8F%8F%E8%BF%B0"></a> |
---|
1211 | <h3 class="h4">æ žå¿åèœæè¿°</h3> |
---|
1212 | <p>åºçšçšåºéåžžäŒéè¿æäŸ<span class="codefrag">map</span>å<span class="codefrag">reduce</span>æ¥å®ç° |
---|
1213 | <span class="codefrag">Mapper</span>å<span class="codefrag">Reducer</span>æ¥å£ïŒå®ä»¬ç»æäœäžçæ žå¿ã</p> |
---|
1214 | <a name="N10603"></a><a name="Mapper"></a> |
---|
1215 | <h4>Mapper</h4> |
---|
1216 | <p> |
---|
1217 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Mapper.html"> |
---|
1218 | Mapper</a>å°èŸå
¥é®åŒå¯¹(key/value pair)æ å°å°äžç»äžéŽæ ŒåŒçé®åŒå¯¹éåã</p> |
---|
1219 | <p>Mapæ¯äžç±»å°èŸå
¥è®°åœé蜬æ¢äžºäžéŽæ ŒåŒè®°åœéçç¬ç«ä»»å¡ã |
---|
1220 | è¿ç§èœ¬æ¢çäžéŽæ ŒåŒè®°åœéäžéèŠäžèŸå
¥è®°åœéçç±»åäžèŽãäžäžªç»å®çèŸå
¥é®åŒå¯¹å¯ä»¥æ å°æ0䞪æå€äžªèŸåºé®åŒå¯¹ã</p> |
---|
1221 | <p>Hadoop Map/Reduceæ¡æ¶äžºæ¯äžäžª<span class="codefrag">InputSplit</span>产çäžäžªmapä»»å¡ïŒèæ¯äžª<span class="codefrag">InputSplit</span>æ¯ç±è¯¥äœäžç<span class="codefrag">InputFormat</span>产ççã</p> |
---|
1222 | <p>æŠæ¬å°è¯ŽïŒå¯¹<span class="codefrag">Mapper</span>çå®ç°è
éèŠéå |
---|
1223 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConfigurable.html#configure(org.apache.hadoop.mapred.JobConf)"> |
---|
1224 | JobConfigurable.configure(JobConf)</a>æ¹æ³ïŒè¿äžªæ¹æ³éèŠäŒ éäžäžª<span class="codefrag">JobConf</span>åæ°ïŒç®çæ¯å®æMapperçåå§åå·¥äœãç¶åïŒæ¡æ¶äžºè¿äžªä»»å¡ç<span class="codefrag">InputSplit</span>äžæ¯äžªé®åŒå¯¹è°çšäžæ¬¡ |
---|
1225 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Mapper.html#map(K1, V1, org.apache.hadoop.mapred.OutputCollector, org.apache.hadoop.mapred.Reporter)"> |
---|
1226 | map(WritableComparable, Writable, OutputCollector, Reporter)</a>æäœãåºçšçšåºå¯ä»¥éè¿éå<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/io/Closeable.html#close()">Closeable.close()</a>æ¹æ³æ¥æ§è¡çžåºçæž
çå·¥äœã</p> |
---|
1227 | <p>èŸåºé®åŒå¯¹äžéèŠäžèŸå
¥é®åŒå¯¹çç±»åäžèŽãäžäžªç»å®çèŸå
¥é®åŒå¯¹å¯ä»¥æ å°æ0䞪æå€äžªèŸåºé®åŒå¯¹ãéè¿è°çš<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/OutputCollector.html#collect(K, V)"> |
---|
1228 | OutputCollector.collect(WritableComparable,Writable)</a>å¯ä»¥æ¶éèŸåºçé®åŒå¯¹ã</p> |
---|
1229 | <p>åºçšçšåºå¯ä»¥äœ¿çš<span class="codefrag">Reporter</span>æ¥åè¿åºŠïŒè®Ÿå®åºçšçº§å«çç¶ææ¶æ¯ïŒæŽæ°<span class="codefrag">Counters</span>ïŒè®¡æ°åšïŒïŒæè
ä»
æ¯è¡šæèªå·±è¿è¡æ£åžžã</p> |
---|
1230 | <p>æ¡æ¶éåäŒæäžäžäžªç¹å®keyå
³èçææäžéŽè¿çšçåŒïŒvalueïŒåæç»ïŒç¶åæå®ä»¬äŒ ç»<span class="codefrag">Reducer</span>以产åºæç»çç»æãçšæ·å¯ä»¥éè¿ |
---|
1231 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setOutputKeyComparatorClass(java.lang.Class)"> |
---|
1232 | JobConf.setOutputKeyComparatorClass(Class)</a>æ¥æå®å
·äœèŽèŽ£åç»ç |
---|
1233 | <span class="codefrag">Comparator</span>ã</p> |
---|
1234 | <p> |
---|
1235 | <span class="codefrag">Mapper</span>çèŸåºè¢«æåºåïŒå°±è¢«ååç»æ¯äžª<span class="codefrag">Reducer</span>ãååçæ»æ°ç®åäžäžªäœäžçreduceä»»å¡çæ°ç®æ¯äžæ ·çãçšæ·å¯ä»¥éè¿å®ç°èªå®ä¹ç <span class="codefrag">Partitioner</span>æ¥æ§å¶åªäžªkey被åé
ç»åªäžª <span class="codefrag">Reducer</span>ã</p> |
---|
1236 | <p>çšæ·å¯éæ©éè¿<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setCombinerClass(java.lang.Class)"> |
---|
1237 | JobConf.setCombinerClass(Class)</a>æå®äžäžª<span class="codefrag">combiner</span>ïŒå®èŽèŽ£å¯¹äžéŽè¿çšçèŸåºè¿è¡æ¬å°çèéïŒè¿äŒæå©äºéäœä»<span class="codefrag">Mapper</span>å° |
---|
1238 | <span class="codefrag">Reducer</span>æ°æ®äŒ èŸéã |
---|
1239 | </p> |
---|
1240 | <p>è¿äºè¢«æ奜åºçäžéŽè¿çšçèŸåºç»æä¿åçæ ŒåŒæ¯(key-len, key, value-len, value)ïŒåºçšçšåºå¯ä»¥éè¿<span class="codefrag">JobConf</span>æ§å¶å¯¹è¿äºäžéŽç»ææ¯åŠè¿è¡å猩以åæä¹å猩ïŒäœ¿çšåªç§<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/io/compress/CompressionCodec.html"> |
---|
1241 | CompressionCodec</a>ã |
---|
1242 | </p> |
---|
1243 | <a name="N1067B"></a><a name="%E9%9C%80%E8%A6%81%E5%A4%9A%E5%B0%91%E4%B8%AAMap%EF%BC%9F"></a> |
---|
1244 | <h5>éèŠå€å°äžªMapïŒ</h5> |
---|
1245 | <p>Mapçæ°ç®éåžžæ¯ç±èŸå
¥æ°æ®ç倧å°å³å®çïŒäžè¬å°±æ¯ææèŸå
¥æ件çæ»åïŒblockïŒæ°ã</p> |
---|
1246 | <p>Mapæ£åžžç并è¡è§æš¡å€§èŽæ¯æ¯äžªèç¹ïŒnodeïŒå€§çºŠ10å°100䞪mapïŒå¯¹äºCPU |
---|
1247 | æ¶èèŸå°çmapä»»å¡å¯ä»¥è®Ÿå°300䞪巊å³ãç±äºæ¯äžªä»»å¡åå§åéèŠäžå®çæ¶éŽïŒå æ€ïŒæ¯èŸåççæ
åµæ¯mapæ§è¡çæ¶éŽè³å°è¶
è¿1åéã</p> |
---|
1248 | <p>è¿æ ·ïŒåŠæäœ èŸå
¥10TBçæ°æ®ïŒæ¯äžªåïŒblockïŒç倧å°æ¯128MBïŒäœ å°éèŠå€§çºŠ82,000䞪mapæ¥å®æä»»å¡ïŒé€éäœ¿çš |
---|
1249 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setNumMapTasks(int)"> |
---|
1250 | setNumMapTasks(int)</a>ïŒæ³šæïŒè¿éä»
ä»
æ¯å¯¹æ¡æ¶è¿è¡äºäžäžªæ瀺(hint)ïŒå®é
å³å®å çŽ è§<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setNumMapTasks(int)">è¿é</a>ïŒå°è¿äžªæ°åŒè®Ÿçœ®åŸæŽé«ã</p> |
---|
1251 | <a name="N10694"></a><a name="Reducer"></a> |
---|
1252 | <h4>Reducer</h4> |
---|
1253 | <p> |
---|
1254 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Reducer.html"> |
---|
1255 | Reducer</a>å°äžäžäžªkeyå
³èçäžç»äžéŽæ°åŒéåœçºŠïŒreduceïŒäžºäžäžªæŽå°çæ°åŒéã</p> |
---|
1256 | <p>çšæ·å¯ä»¥éè¿<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setNumReduceTasks(int)"> |
---|
1257 | JobConf.setNumReduceTasks(int)</a>讟å®äžäžªäœäžäžreduceä»»å¡çæ°ç®ã</p> |
---|
1258 | <p>æŠæ¬å°è¯ŽïŒå¯¹<span class="codefrag">Reducer</span>çå®ç°è
éèŠéå |
---|
1259 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConfigurable.html#configure(org.apache.hadoop.mapred.JobConf)"> |
---|
1260 | JobConfigurable.configure(JobConf)</a>æ¹æ³ïŒè¿äžªæ¹æ³éèŠäŒ éäžäžª<span class="codefrag">JobConf</span>åæ°ïŒç®çæ¯å®æReducerçåå§åå·¥äœãç¶åïŒæ¡æ¶äžºæç»çèŸå
¥æ°æ®äžçæ¯äžª<span class="codefrag"><key, (list of values)></span>对è°çšäžæ¬¡ |
---|
1261 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Reducer.html#reduce(K2, java.util.Iterator, org.apache.hadoop.mapred.OutputCollector, org.apache.hadoop.mapred.Reporter)"> |
---|
1262 | reduce(WritableComparable, Iterator, OutputCollector, Reporter)</a>æ¹æ³ãä¹åïŒåºçšçšåºå¯ä»¥éè¿éå<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/io/Closeable.html#close()">Closeable.close()</a>æ¥æ§è¡çžåºçæž
çå·¥äœã</p> |
---|
1263 | <p> |
---|
1264 | <span class="codefrag">Reducer</span>æ3䞪䞻èŠé¶æ®µïŒshuffleãsortåreduceã |
---|
1265 | </p> |
---|
1266 | <a name="N106C4"></a><a name="Shuffle"></a> |
---|
1267 | <h5>Shuffle</h5> |
---|
1268 | <p> |
---|
1269 | <span class="codefrag">Reducer</span>çèŸå
¥å°±æ¯Mapperå·²ç»æ奜åºçèŸåºãåšè¿äžªé¶æ®µïŒæ¡æ¶éè¿HTTP䞺æ¯äžªReducerè·åŸææMapperèŸåºäžäžä¹çžå
³çååã</p> |
---|
1270 | <a name="N106D0"></a><a name="Sort"></a> |
---|
1271 | <h5>Sort</h5> |
---|
1272 | <p>è¿äžªé¶æ®µïŒæ¡æ¶å°æç
§keyçåŒå¯¹<span class="codefrag">Reducer</span>çèŸå
¥è¿è¡åç» |
---|
1273 | ïŒå 䞺äžåmapperçèŸåºäžå¯èœäŒæçžåçkeyïŒã</p> |
---|
1274 | <p>ShuffleåSort䞀䞪é¶æ®µæ¯åæ¶è¿è¡çïŒmapçèŸåºä¹æ¯äžèŸ¹è¢«ååäžèŸ¹è¢«å并çã</p> |
---|
1275 | <a name="N106DF"></a><a name="Secondary+Sort"></a> |
---|
1276 | <h5>Secondary Sort</h5> |
---|
1277 | <p>åŠæéèŠäžéŽè¿çšå¯¹keyçåç»è§ååreduceå对keyçåç»è§åäžåïŒé£ä¹å¯ä»¥éè¿<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setOutputValueGroupingComparator(java.lang.Class)"> |
---|
1278 | JobConf.setOutputValueGroupingComparator(Class)</a>æ¥æå®äžäžª<span class="codefrag">Comparator</span>ãåå äž |
---|
1279 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setOutputKeyComparatorClass(java.lang.Class)"> |
---|
1280 | JobConf.setOutputKeyComparatorClass(Class)</a>å¯çšäºæ§å¶äžéŽè¿çšçkeyåŠäœè¢«åç»ïŒæ以ç»å䞀è
å¯ä»¥å®ç°<em>æåŒçäºæ¬¡æåº</em>ã |
---|
1281 | </p> |
---|
1282 | <a name="N106F8"></a><a name="Reduce"></a> |
---|
1283 | <h5>Reduce</h5> |
---|
1284 | <p>åšè¿äžªé¶æ®µïŒæ¡æ¶äžºå·²åç»çèŸå
¥æ°æ®äžçæ¯äžª |
---|
1285 | <span class="codefrag"><key, (list of values)></span>对è°çšäžæ¬¡ |
---|
1286 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Reducer.html#reduce(K2, java.util.Iterator, org.apache.hadoop.mapred.OutputCollector, org.apache.hadoop.mapred.Reporter)"> |
---|
1287 | reduce(WritableComparable, Iterator, OutputCollector, Reporter)</a>æ¹æ³ã</p> |
---|
1288 | <p>Reduceä»»å¡çèŸåºéåžžæ¯éè¿è°çš |
---|
1289 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/OutputCollector.html#collect(K, V)"> |
---|
1290 | OutputCollector.collect(WritableComparable, Writable)</a>åå
¥ |
---|
1291 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/fs/FileSystem.html"> |
---|
1292 | æ件系ç»</a>çã</p> |
---|
1293 | <p>åºçšçšåºå¯ä»¥äœ¿çš<span class="codefrag">Reporter</span>æ¥åè¿åºŠïŒè®Ÿå®åºçšçšåºçº§å«çç¶ææ¶æ¯ïŒæŽæ°<span class="codefrag">Counters</span>ïŒè®¡æ°åšïŒïŒæè
ä»
æ¯è¡šæèªå·±è¿è¡æ£åžžã</p> |
---|
1294 | <p> |
---|
1295 | <span class="codefrag">Reducer</span>çèŸåºæ¯<em>没ææåºç</em>ã</p> |
---|
1296 | <a name="N10725"></a><a name="%E9%9C%80%E8%A6%81%E5%A4%9A%E5%B0%91%E4%B8%AAReduce%EF%BC%9F"></a> |
---|
1297 | <h5>éèŠå€å°äžªReduceïŒ</h5> |
---|
1298 | <p>Reduceçæ°ç®å»ºè®®æ¯<span class="codefrag">0.95</span>æ<span class="codefrag">1.75</span>ä¹ä»¥ |
---|
1299 | (<<em>no. of nodes</em>> * |
---|
1300 | <span class="codefrag">mapred.tasktracker.reduce.tasks.maximum</span>)ã |
---|
1301 | </p> |
---|
1302 | <p>çš0.95ïŒææreduceå¯ä»¥åšmapsäžå®ææ¶å°±ç«å»å¯åšïŒåŒå§äŒ èŸmapçèŸåºç»æãçš1.75ïŒé床快çèç¹å¯ä»¥åšå®æ第äžèœ®reduceä»»å¡åïŒå¯ä»¥åŒå§ç¬¬äºèœ®ïŒè¿æ ·å¯ä»¥åŸå°æ¯èŸå¥œçèŽèœœåè¡¡çææã</p> |
---|
1303 | <p>å¢å reduceçæ°ç®äŒå¢å æŽäžªæ¡æ¶çåŒéïŒäœå¯ä»¥æ¹åèŽèœœåè¡¡ïŒéäœç±äºæ§è¡å€±èŽ¥åžŠæ¥çèŽé¢åœ±åã</p> |
---|
1304 | <p>äžè¿°æ¯äŸå åæ¯æŽäœæ°ç®çšå°äžäºæ¯äžºäºç»æ¡æ¶äžçæšæµæ§ä»»å¡ïŒspeculative-tasksïŒ |
---|
1305 | æ倱莥çä»»å¡é¢çäžäºreduceçèµæºã</p> |
---|
1306 | <a name="N10744"></a><a name="%E6%97%A0Reducer"></a> |
---|
1307 | <h5>æ Reducer</h5> |
---|
1308 | <p>åŠæ没æåœçºŠèŠè¿è¡ïŒé£ä¹è®Ÿçœ®reduceä»»å¡çæ°ç®äžº<em>é¶</em>æ¯åæ³çã</p> |
---|
1309 | <p>è¿ç§æ
åµäžïŒmapä»»å¡çèŸåºäŒçŽæ¥è¢«åå
¥ç± |
---|
1310 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileOutputFormat.html#setOutputPath(org.apache.hadoop.mapred.JobConf,%20org.apache.hadoop.fs.Path)"> |
---|
1311 | setOutputPath(Path)</a>æå®çèŸåºè·¯åŸãæ¡æ¶åšæå®ä»¬åå
¥<span class="codefrag">FileSystem</span>ä¹å没æ对å®ä»¬è¿è¡æåºã |
---|
1312 | </p> |
---|
1313 | <a name="N1075C"></a><a name="Partitioner"></a> |
---|
1314 | <h4>Partitioner</h4> |
---|
1315 | <p> |
---|
1316 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Partitioner.html"> |
---|
1317 | Partitioner</a>çšäºååé®åŒç©ºéŽïŒkey spaceïŒã</p> |
---|
1318 | <p>PartitionerèŽèŽ£æ§å¶mapèŸåºç»ækeyçåå²ãKeyïŒæè
äžäžªkeyåéïŒè¢«çšäºäº§çååºïŒé垞䜿çšçæ¯Hashåœæ°ãååºçæ°ç®äžäžäžªäœäžçreduceä»»å¡çæ°ç®æ¯äžæ ·çãå æ€ïŒå®æ§å¶å°äžéŽè¿çšçkeyïŒä¹å°±æ¯è¿æ¡è®°åœïŒåºè¯¥åéç»<span class="codefrag">m</span>䞪reduceä»»å¡äžçåªäžäžªæ¥è¿è¡reduceæäœã |
---|
1319 | </p> |
---|
1320 | <p> |
---|
1321 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/lib/HashPartitioner.html"> |
---|
1322 | HashPartitioner</a>æ¯é»è®€ç <span class="codefrag">Partitioner</span>ã </p> |
---|
1323 | <a name="N10778"></a><a name="Reporter"></a> |
---|
1324 | <h4>Reporter</h4> |
---|
1325 | <p> |
---|
1326 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Reporter.html"> |
---|
1327 | Reporter</a>æ¯çšäºMap/Reduceåºçšçšåºæ¥åè¿åºŠïŒè®Ÿå®åºçšçº§å«çç¶ææ¶æ¯ïŒ |
---|
1328 | æŽæ°<span class="codefrag">Counters</span>ïŒè®¡æ°åšïŒçæºå¶ã</p> |
---|
1329 | <p> |
---|
1330 | <span class="codefrag">Mapper</span>å<span class="codefrag">Reducer</span>çå®ç°å¯ä»¥å©çš<span class="codefrag">Reporter</span> |
---|
1331 | æ¥æ¥åè¿åºŠïŒæè
ä»
æ¯è¡šæèªå·±è¿è¡æ£åžžãåšé£ç§åºçšçšåºéèŠè±åŸé¿æ¶éŽå€ç䞪å«é®åŒå¯¹çåºæ¯äžïŒè¿ç§æºå¶æ¯åŸå
³é®çïŒå 䞺æ¡æ¶å¯èœäŒä»¥äžºè¿äžªä»»å¡è¶
æ¶äºïŒä»èå°å®åŒºè¡ææ»ãåŠäžäžªé¿å
è¿ç§æ
åµåççæ¹åŒæ¯ïŒå°é
眮åæ°<span class="codefrag">mapred.task.timeout</span>讟眮䞺äžäžªè¶³å€é«çåŒïŒæè
å¹²è讟眮䞺é¶ïŒå没æè¶
æ¶éå¶äºïŒã |
---|
1332 | </p> |
---|
1333 | <p>åºçšçšåºå¯ä»¥çš<span class="codefrag">Reporter</span>æ¥æŽæ°<span class="codefrag">Counter</span>ïŒè®¡æ°åšïŒã |
---|
1334 | </p> |
---|
1335 | <a name="N1079F"></a><a name="OutputCollector"></a> |
---|
1336 | <h4>OutputCollector</h4> |
---|
1337 | <p> |
---|
1338 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/OutputCollector.html"> |
---|
1339 | OutputCollector</a>æ¯äžäžªMap/Reduceæ¡æ¶æäŸççšäºæ¶é |
---|
1340 | <span class="codefrag">Mapper</span>æ<span class="codefrag">Reducer</span>èŸåºæ°æ®çéçšæºå¶ |
---|
1341 | ïŒå
æ¬äžéŽèŸåºç»æåäœäžçèŸåºç»æïŒã</p> |
---|
1342 | <p>Hadoop Map/Reduceæ¡æ¶é垊äºäžäžªå
å«è®žå€å®çšåçmapperãreduceråpartitioner |
---|
1343 | ç<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/lib/package-summary.html">ç±»åº</a>ã</p> |
---|
1344 | <a name="N107BA"></a><a name="%E4%BD%9C%E4%B8%9A%E9%85%8D%E7%BD%AE"></a> |
---|
1345 | <h3 class="h4">äœäžé
眮</h3> |
---|
1346 | <p> |
---|
1347 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html"> |
---|
1348 | JobConf</a>代衚äžäžªMap/Reduceäœäžçé
眮ã</p> |
---|
1349 | <p> |
---|
1350 | <span class="codefrag">JobConf</span>æ¯çšæ·åHadoopæ¡æ¶æè¿°äžäžªMap/ReduceäœäžåŠäœæ§è¡çäž»èŠæ¥å£ãæ¡æ¶äŒæç
§<span class="codefrag">JobConf</span>æè¿°çä¿¡æ¯å¿ å®å°å»å°è¯å®æè¿äžªäœäžïŒç¶èïŒ</p> |
---|
1351 | <ul> |
---|
1352 | |
---|
1353 | <li> |
---|
1354 | äžäºåæ°å¯èœäŒè¢«ç®¡çè
æ 记䞺<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/conf/Configuration.html#FinalParams"> |
---|
1355 | final</a>ïŒè¿æå³å®ä»¬äžèœè¢«æŽæ¹ã |
---|
1356 | </li> |
---|
1357 | |
---|
1358 | <li> |
---|
1359 | äžäºäœäžçåæ°å¯ä»¥è¢«çŽæªäºåœå°è¿è¡è®Ÿçœ®ïŒäŸåŠïŒ |
---|
1360 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setNumReduceTasks(int)"> |
---|
1361 | setNumReduceTasks(int)</a>ïŒïŒèåŠäžäºåæ°åäžæ¡æ¶æè
äœäžçå
¶ä»åæ°ä¹éŽåŸ®åŠå°çžäºåœ±åïŒå¹¶äžè®Ÿçœ®èµ·æ¥æ¯èŸå€æïŒäŸåŠïŒ<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setNumMapTasks(int)"> |
---|
1362 | setNumMapTasks(int)</a>ïŒã |
---|
1363 | </li> |
---|
1364 | |
---|
1365 | </ul> |
---|
1366 | <p>éåžžïŒ<span class="codefrag">JobConf</span>äŒææ<span class="codefrag">Mapper</span>ãCombiner(åŠææçè¯)ã |
---|
1367 | <span class="codefrag">Partitioner</span>ã<span class="codefrag">Reducer</span>ã<span class="codefrag">InputFormat</span>å |
---|
1368 | <span class="codefrag">OutputFormat</span>çå
·äœå®ç°ã<span class="codefrag">JobConf</span>è¿èœæå®äžç»èŸå
¥æ件 |
---|
1369 | (<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileInputFormat.html#setInputPaths(org.apache.hadoop.mapred.JobConf,%20org.apache.hadoop.fs.Path[])">setInputPaths(JobConf, Path...)</a> |
---|
1370 | /<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileInputFormat.html#addInputPath(org.apache.hadoop.mapred.JobConf,%20org.apache.hadoop.fs.Path)">addInputPath(JobConf, Path)</a>) |
---|
1371 | å(<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileInputFormat.html#setInputPaths(org.apache.hadoop.mapred.JobConf,%20java.lang.String)">setInputPaths(JobConf, String)</a> |
---|
1372 | /<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileInputFormat.html#addInputPath(org.apache.hadoop.mapred.JobConf,%20java.lang.String)">addInputPaths(JobConf, String)</a>) |
---|
1373 | 以åèŸåºæ件åºè¯¥ååšåªå¿ |
---|
1374 | (<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileOutputFormat.html#setOutputPath(org.apache.hadoop.mapred.JobConf,%20org.apache.hadoop.fs.Path)">setOutputPath(Path)</a>)ã</p> |
---|
1375 | <p> |
---|
1376 | <span class="codefrag">JobConf</span>å¯éæ©å°å¯¹äœäžè®Ÿçœ®äžäºé«çº§é项ïŒäŸåŠïŒè®Ÿçœ®<span class="codefrag">Comparator</span>ïŒ |
---|
1377 | æŸå°<span class="codefrag">DistributedCache</span>äžçæ件ïŒäžéŽç»ææè
äœäžèŸåºç»ææ¯åŠéèŠå猩以åæä¹åçŒ©ïŒ |
---|
1378 | å©çšçšæ·æäŸçèæ¬(<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMapDebugScript(java.lang.String)">setMapDebugScript(String)</a>/<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setReduceDebugScript(java.lang.String)">setReduceDebugScript(String)</a>) |
---|
1379 | è¿è¡è°è¯ïŒäœäžæ¯åŠå
讞<em>é¢é²æ§ïŒspeculativeïŒ</em>ä»»å¡çæ§è¡ |
---|
1380 | (<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMapSpeculativeExecution(boolean)">setMapSpeculativeExecution(boolean)</a>)/(<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setReduceSpeculativeExecution(boolean)">setReduceSpeculativeExecution(boolean)</a>) |
---|
1381 | ïŒæ¯äžªä»»å¡æ倧çå°è¯æ¬¡æ° |
---|
1382 | (<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMaxMapAttempts(int)">setMaxMapAttempts(int)</a>/<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMaxReduceAttempts(int)">setMaxReduceAttempts(int)</a>) |
---|
1383 | ïŒäžäžªäœäžèœå®¹å¿çä»»å¡å€±èŽ¥ççŸåæ¯ |
---|
1384 | (<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMaxMapTaskFailuresPercent(int)">setMaxMapTaskFailuresPercent(int)</a>/<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMaxReduceTaskFailuresPercent(int)">setMaxReduceTaskFailuresPercent(int)</a>) |
---|
1385 | ïŒççã</p> |
---|
1386 | <p>åœç¶ïŒçšæ·èœäœ¿çš |
---|
1387 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/conf/Configuration.html#set(java.lang.String, java.lang.String)">set(String, String)</a>/<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/conf/Configuration.html#get(java.lang.String, java.lang.String)">get(String, String)</a> |
---|
1388 | æ¥è®Ÿçœ®æè
ååŸåºçšçšåºéèŠçä»»æåæ°ãç¶èïŒ<span class="codefrag">DistributedCache</span>ç䜿çšæ¯é¢å倧è§æš¡åªè¯»æ°æ®çã</p> |
---|
1389 | <a name="N1084C"></a><a name="%E4%BB%BB%E5%8A%A1%E7%9A%84%E6%89%A7%E8%A1%8C%E5%92%8C%E7%8E%AF%E5%A2%83"></a> |
---|
1390 | <h3 class="h4">ä»»å¡çæ§è¡åç¯å¢</h3> |
---|
1391 | <p> |
---|
1392 | <span class="codefrag">TaskTracker</span>æ¯åšäžäžªåç¬çjvmäžä»¥åè¿çšç圢åŒæ§è¡ |
---|
1393 | <span class="codefrag">Mapper</span>/<span class="codefrag">Reducer</span>ä»»å¡ïŒTaskïŒçã |
---|
1394 | </p> |
---|
1395 | <p>åä»»å¡äŒç»§æ¿ç¶<span class="codefrag">TaskTracker</span>çç¯å¢ãçšæ·å¯ä»¥éè¿JobConfäžç |
---|
1396 | <span class="codefrag">mapred.child.java.opts</span>é
眮åæ°æ¥è®Ÿå®åjvmäžçéå é项ïŒäŸåŠïŒ |
---|
1397 | éè¿<span class="codefrag">-Djava.library.path=<></span> å°äžäžªéæ åè·¯åŸè®Ÿäžºè¿è¡æ¶çéŸæ¥çšä»¥æ玢å
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å«äžäžªç¬Šå·<em>@taskid@</em>ïŒ |
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1398 | å®äŒè¢«æ¿æ¢æmap/reduceçtaskidçåŒã</p> |
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1399 | <p>äžé¢æ¯äžäžªå
å«å€äžªåæ°åæ¿æ¢çäŸåïŒå
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1400 | JVM JMX代ççšåºä»¥æ å¯ç çæ¹åŒå¯åšïŒè¿æ ·å®å°±èœè¿æ¥å°jconsoleäžïŒä»èå¯ä»¥æ¥çåè¿çšçå
åå线çšïŒåŸå°çº¿çšçdumpïŒè¿æåjvmçæ倧å 尺寞讟眮䞺512MBïŒ |
---|
1401 | 并䞺åjvmç<span class="codefrag">java.library.path</span>æ·»å äºäžäžªéå è·¯åŸã</p> |
---|
1402 | <p> |
---|
1403 | |
---|
1404 | <span class="codefrag"><property></span> |
---|
1405 | <br> |
---|
1406 | <span class="codefrag"><name>mapred.child.java.opts</name></span> |
---|
1407 | <br> |
---|
1408 | <span class="codefrag"><value></span> |
---|
1409 | <br> |
---|
1410 | <span class="codefrag"> |
---|
1411 | -Xmx512M -Djava.library.path=/home/mycompany/lib |
---|
1412 | -verbose:gc -Xloggc:/tmp/@taskid@.gc</span> |
---|
1413 | <br> |
---|
1414 | <span class="codefrag"> |
---|
1415 | -Dcom.sun.management.jmxremote.authenticate=false |
---|
1416 | -Dcom.sun.management.jmxremote.ssl=false</span> |
---|
1417 | <br> |
---|
1418 | <span class="codefrag"></value></span> |
---|
1419 | <br> |
---|
1420 | |
---|
1421 | <span class="codefrag"></property></span> |
---|
1422 | |
---|
1423 | </p> |
---|
1424 | <p>çšæ·æ管çåä¹å¯ä»¥äœ¿çš<span class="codefrag">mapred.child.ulimit</span>讟å®è¿è¡çåä»»å¡çæ倧èæå
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须倧äºæçäº-Xmxåæ°äŒ ç»JavaVMçåŒïŒåŠåVMäŒæ æ³å¯åšã</p> |
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1425 | <p>泚æïŒ<span class="codefrag">mapred.child.java.opts</span>åªçšäºè®Ÿçœ®task trackerå¯åšçåä»»å¡ã䞺å®æ€è¿çšè®Ÿçœ®å
åé项请æ¥ç |
---|
1426 | <a href="cluster_setup.html#%E9%85%8D%E7%BD%AEHadoop%E5%AE%88%E6%8A%A4%E8%BF%9B%E7%A8%8B%E7%9A%84%E8%BF%90%E8%A1%8C%E7%8E%AF%E5%A2%83"> |
---|
1427 | cluster_setup.html </a> |
---|
1428 | </p> |
---|
1429 | <p> |
---|
1430 | <span class="codefrag"> ${mapred.local.dir}/taskTracker/</span>æ¯task trackerçæ¬å°ç®åœïŒ |
---|
1431 | çšäºå建æ¬å°çŒååjobãå®å¯ä»¥æå®å€äžªç®åœïŒè·šè¶å€äžªç£çïŒïŒæ件äŒåéæºçä¿åå°æ¬å°è·¯åŸäžçæ䞪ç®åœãåœjobå¯åšæ¶ïŒtask trackeræ ¹æ®é
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1432 | <ul> |
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1433 | |
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1434 | <li> |
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1435 | <span class="codefrag">${mapred.local.dir}/taskTracker/archive/</span> :ååžåŒçŒåãè¿äžªç®åœä¿åæ¬å°çååžåŒçŒåãå æ€æ¬å°ååžåŒçŒåæ¯åšæætaskåjobéŽå
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1436 | |
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1437 | <li> |
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1438 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/</span> : |
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1439 | æ¬å°jobç®åœã |
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1440 | <ul> |
---|
1441 | |
---|
1442 | <li> |
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1443 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/work/</span>: |
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1444 | jobæå®çå
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1445 | JobConf.getJobLocalDir()</a>æ¥è®¿é®ãå®ä¹å¯ä»¥è¢«å䞺系ç»å±æ§è·åŸãå æ€ïŒçšæ·ïŒæ¯åŠè¿è¡streamingïŒå¯ä»¥è°çš<span class="codefrag">System.getProperty("job.local.dir")</span>è·åŸè¯¥ç®åœã |
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1446 | </li> |
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1447 | |
---|
1448 | <li> |
---|
1449 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/jars/</span>: |
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1450 | åæŸjarå
çè·¯åŸïŒçšäºåæŸäœäžçjaræ件åå±åŒçjarã<span class="codefrag">job.jar</span>æ¯åºçšçšåºçjaræ件ïŒå®äŒè¢«èªåšååå°åå°æºåšïŒåštaskå¯åšåäŒè¢«èªåšå±åŒã䜿çšapi |
---|
1451 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#getJar()"> |
---|
1452 | JobConf.getJar() </a>åœæ°å¯ä»¥åŸå°job.jarçäœçœ®ã䜿çšJobConf.getJar().getParent()å¯ä»¥è®¿é®åæŸå±åŒçjarå
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1453 | </li> |
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1454 | |
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1455 | <li> |
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1456 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/job.xml</span>ïŒ |
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1457 | äžäžªjob.xmlæ件ïŒæ¬å°çéçšçäœäžé
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---|
1458 | </li> |
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1459 | |
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1460 | <li> |
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1461 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/$taskid</span>ïŒ |
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1462 | æ¯äžªä»»å¡æäžäžªç®åœ<span class="codefrag">task-id</span>ïŒå®éé¢æåŠäžçç®åœç»æïŒ |
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1463 | <ul> |
---|
1464 | |
---|
1465 | <li> |
---|
1466 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/$taskid/job.xml</span>ïŒ |
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1467 | äžäžªjob.xmlæ件ïŒæ¬å°åçä»»å¡äœäžé
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1468 | </li> |
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1469 | |
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1470 | <li> |
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1471 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/$taskid/output</span> |
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1472 | äžäžªåæŸäžéŽè¿çšçèŸåºæ件çç®åœãå®ä¿åäºç±framwork产çç䞎æ¶map reduceæ°æ®ïŒæ¯åŠmapçèŸåºæ件çã</li> |
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1473 | |
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1474 | <li> |
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1475 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/$taskid/work</span>ïŒ |
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1476 | taskçåœåå·¥äœç®åœã</li> |
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1477 | |
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1478 | <li> |
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1479 | <span class="codefrag">${mapred.local.dir}/taskTracker/jobcache/$jobid/$taskid/work/tmp</span>ïŒ |
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1480 | taskç䞎æ¶ç®åœãïŒçšæ·å¯ä»¥è®Ÿå®å±æ§<span class="codefrag">mapred.child.tmp</span> |
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1481 | æ¥äžºmapåreduce task讟å®äžŽæ¶ç®åœã猺çåŒæ¯<span class="codefrag">./tmp</span>ãåŠæè¿äžªåŒäžæ¯ç»å¯¹è·¯åŸïŒ |
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1482 | å®äŒætaskçå·¥äœè·¯åŸå å°è¯¥è·¯åŸåé¢äœäžºtaskç䞎æ¶æ件路åŸãåŠæè¿äžªåŒæ¯ç»å¯¹è·¯åŸåçŽæ¥äœ¿çšè¿äžªåŒã |
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1483 | åŠææå®çç®åœäžååšïŒäŒèªåšå建该ç®åœãä¹åïŒæç
§é项 |
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1484 | <span class="codefrag">-Djava.io.tmpdir='䞎æ¶æ件çç»å¯¹è·¯åŸ'</span>æ§è¡javaåä»»å¡ã |
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1485 | pipesåstreamingç䞎æ¶æ件路åŸæ¯éè¿ç¯å¢åé<span class="codefrag">TMPDIR='the absolute path of the tmp dir'</span>讟å®çïŒã |
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1486 | åŠæ<span class="codefrag">mapred.child.tmp</span>æ<span class="codefrag">./tmp</span>åŒïŒè¿äžªç®åœäŒè¢«å建ã</li> |
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1487 | |
---|
1488 | </ul> |
---|
1489 | |
---|
1490 | </li> |
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1491 | |
---|
1492 | </ul> |
---|
1493 | |
---|
1494 | </li> |
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1495 | |
---|
1496 | </ul> |
---|
1497 | <p>äžé¢çå±æ§æ¯äžºæ¯äžªtaskæ§è¡æ¶äœ¿çšçæ¬å°åæ°ïŒå®ä»¬ä¿ååšæ¬å°åçä»»å¡äœäžé
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1498 | <table class="ForrestTable" cellspacing="1" cellpadding="4"> |
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1499 | |
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1500 | <tr> |
---|
1501 | <th colspan="1" rowspan="1">å称</th><th colspan="1" rowspan="1">ç±»å</th><th colspan="1" rowspan="1">æè¿°</th> |
---|
1502 | </tr> |
---|
1503 | |
---|
1504 | <tr> |
---|
1505 | <td colspan="1" rowspan="1">mapred.job.id</td><td colspan="1" rowspan="1">String</td><td colspan="1" rowspan="1">job id</td> |
---|
1506 | </tr> |
---|
1507 | |
---|
1508 | <tr> |
---|
1509 | <td colspan="1" rowspan="1">mapred.jar</td><td colspan="1" rowspan="1">String</td> |
---|
1510 | <td colspan="1" rowspan="1">jobç®åœäžjob.jarçäœçœ®</td> |
---|
1511 | </tr> |
---|
1512 | |
---|
1513 | <tr> |
---|
1514 | <td colspan="1" rowspan="1">job.local.dir</td><td colspan="1" rowspan="1"> String</td> |
---|
1515 | <td colspan="1" rowspan="1">jobæå®çå
±äº«ååšç©ºéŽ</td> |
---|
1516 | </tr> |
---|
1517 | |
---|
1518 | <tr> |
---|
1519 | <td colspan="1" rowspan="1">mapred.tip.id</td><td colspan="1" rowspan="1"> String</td> |
---|
1520 | <td colspan="1" rowspan="1"> task id</td> |
---|
1521 | </tr> |
---|
1522 | |
---|
1523 | <tr> |
---|
1524 | <td colspan="1" rowspan="1">mapred.task.id</td><td colspan="1" rowspan="1"> String</td> |
---|
1525 | <td colspan="1" rowspan="1"> taskå°è¯id</td> |
---|
1526 | </tr> |
---|
1527 | |
---|
1528 | <tr> |
---|
1529 | <td colspan="1" rowspan="1">mapred.task.is.map</td><td colspan="1" rowspan="1"> boolean </td> |
---|
1530 | <td colspan="1" rowspan="1">æ¯åŠæ¯map task</td> |
---|
1531 | </tr> |
---|
1532 | |
---|
1533 | <tr> |
---|
1534 | <td colspan="1" rowspan="1">mapred.task.partition</td><td colspan="1" rowspan="1"> int </td> |
---|
1535 | <td colspan="1" rowspan="1">taskåšjobäžçid</td> |
---|
1536 | </tr> |
---|
1537 | |
---|
1538 | <tr> |
---|
1539 | <td colspan="1" rowspan="1">map.input.file</td><td colspan="1" rowspan="1"> String</td> |
---|
1540 | <td colspan="1" rowspan="1"> map读åçæ件å</td> |
---|
1541 | </tr> |
---|
1542 | |
---|
1543 | <tr> |
---|
1544 | <td colspan="1" rowspan="1">map.input.start</td><td colspan="1" rowspan="1"> long</td> |
---|
1545 | <td colspan="1" rowspan="1"> mapèŸå
¥çæ°æ®åçèµ·å§äœçœ®å移</td> |
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1546 | </tr> |
---|
1547 | |
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1548 | <tr> |
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1549 | <td colspan="1" rowspan="1">map.input.length </td><td colspan="1" rowspan="1">long </td> |
---|
1550 | <td colspan="1" rowspan="1">mapèŸå
¥çæ°æ®åçåèæ°</td> |
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1551 | </tr> |
---|
1552 | |
---|
1553 | <tr> |
---|
1554 | <td colspan="1" rowspan="1">mapred.work.output.dir</td><td colspan="1" rowspan="1"> String </td> |
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1555 | <td colspan="1" rowspan="1">task䞎æ¶èŸåºç®åœ</td> |
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1556 | </tr> |
---|
1557 | |
---|
1558 | </table> |
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1559 | <p>taskçæ åèŸåºåé误èŸåºæµäŒè¢«è¯»å°TaskTrackeräžïŒå¹¶äžè®°åœå° |
---|
1560 | <span class="codefrag">${HADOOP_LOG_DIR}/userlogs</span> |
---|
1561 | </p> |
---|
1562 | <p> |
---|
1563 | <a href="#DistributedCache">DistributedCache</a> |
---|
1564 | å¯çšäºmapæreduce taskäžååjarå
åæ¬å°åºãåjvmæ»æ¯æ |
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1565 | <em>åœåå·¥äœç®åœ</em> å å° |
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1566 | <span class="codefrag">java.library.path</span> å <span class="codefrag">LD_LIBRARY_PATH</span>ã |
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1567 | å æ€ïŒå¯ä»¥éè¿ |
---|
1568 | <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/lang/System.html#loadLibrary(java.lang.String)"> |
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1569 | System.loadLibrary</a>æ |
---|
1570 | <a href="http://java.sun.com/j2se/1.5.0/docs/api/java/lang/System.html#load(java.lang.String)"> |
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1571 | System.load</a>è£
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1572 | <a href="native_libraries.html#%E4%BD%BF%E7%94%A8DistributedCache+%E5%8A%A0%E8%BD%BD%E6%9C%AC%E5%9C%B0%E5%BA%93"> |
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1573 | native_libraries.html</a> |
---|
1574 | </p> |
---|
1575 | <a name="N109E3"></a><a name="%E4%BD%9C%E4%B8%9A%E7%9A%84%E6%8F%90%E4%BA%A4%E4%B8%8E%E7%9B%91%E6%8E%A7"></a> |
---|
1576 | <h3 class="h4">äœäžçæ亀äžçæ§</h3> |
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1577 | <p> |
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1578 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobClient.html"> |
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1579 | JobClient</a>æ¯çšæ·æ亀çäœäžäž<span class="codefrag">JobTracker</span>亀äºçäž»èŠæ¥å£ã |
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1580 | </p> |
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1581 | <p> |
---|
1582 | <span class="codefrag">JobClient</span> æäŸæ亀äœäžïŒè¿œèžªè¿çšïŒè®¿é®åä»»å¡çæ¥å¿è®°åœïŒè·åŸMap/Reduceé矀ç¶æä¿¡æ¯çåèœã |
---|
1583 | </p> |
---|
1584 | <p>äœäžæ亀è¿çšå
æ¬ïŒ </p> |
---|
1585 | <ol> |
---|
1586 | |
---|
1587 | <li>æ£æ¥äœäžèŸå
¥èŸåºæ ·åŒç»è</li> |
---|
1588 | |
---|
1589 | <li>䞺äœäžè®¡ç®<span class="codefrag">InputSplit</span>åŒã</li> |
---|
1590 | |
---|
1591 | <li> |
---|
1592 | åŠæéèŠçè¯ïŒäžºäœäžç<span class="codefrag">DistributedCache</span>建ç«å¿
é¡»çç»è®¡ä¿¡æ¯ã |
---|
1593 | </li> |
---|
1594 | |
---|
1595 | <li> |
---|
1596 | æ·èŽäœäžçjarå
åé
眮æ件å°<span class="codefrag">FileSystem</span>äžçMap/Reduceç³»ç»ç®åœäžã |
---|
1597 | </li> |
---|
1598 | |
---|
1599 | <li> |
---|
1600 | æ亀äœäžå°<span class="codefrag">JobTracker</span>并äžçæ§å®çç¶æã |
---|
1601 | </li> |
---|
1602 | |
---|
1603 | </ol> |
---|
1604 | <p>äœäžçåå²æ件记åœå°æå®ç®åœç"_logs/history/"åç®åœäžãè¿äžªæå®ç®åœç±<span class="codefrag">hadoop.job.history.user.location</span>讟å®ïŒé»è®€æ¯äœäžèŸåºçç®åœãå æ€é»è®€æ
åµäžïŒæ件äŒåæŸåšmapred.output.dir/_logs/historyç®åœäžãçšæ·å¯ä»¥è®Ÿçœ®<span class="codefrag">hadoop.job.history.user.location</span>䞺<span class="codefrag">none</span>æ¥åæ¢æ¥å¿è®°åœã |
---|
1605 | </p> |
---|
1606 | <p> çšæ·äœ¿çšäžé¢çåœä»€å¯ä»¥çå°åšæå®ç®åœäžçåå²æ¥å¿è®°åœçæèŠã |
---|
1607 | <br> |
---|
1608 | |
---|
1609 | <span class="codefrag">$ bin/hadoop job -history output-dir</span> |
---|
1610 | <br> |
---|
1611 | è¿äžªåœä»€äŒæå°åºäœäžçç»èïŒä»¥å倱莥çå被ææ»çä»»å¡ç»èã<br> |
---|
1612 | èŠæ¥çæå
³äœäžçæŽå€ç»èäŸåŠæåçä»»å¡ãæ¯äžªä»»å¡å°è¯ç次æ°ïŒtask attemptïŒçïŒå¯ä»¥äœ¿çšäžé¢çåœä»€ |
---|
1613 | <br> |
---|
1614 | |
---|
1615 | <span class="codefrag">$ bin/hadoop job -history all output-dir</span> |
---|
1616 | <br> |
---|
1617 | </p> |
---|
1618 | <p>çšæ·å¯ä»¥äœ¿çš |
---|
1619 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/OutputLogFilter.html">OutputLogFilter</a> |
---|
1620 | ä»èŸåºç®åœåè¡šäžçéæ¥å¿æ件ã</p> |
---|
1621 | <p>äžè¬æ
åµïŒçšæ·å©çš<span class="codefrag">JobConf</span>å建åºçšçšåºå¹¶é
眮äœäžå±æ§ïŒ |
---|
1622 | ç¶åçš |
---|
1623 | <span class="codefrag">JobClient</span> æ亀äœäžå¹¶çè§å®çè¿çšã</p> |
---|
1624 | <a name="N10A44"></a><a name="%E4%BD%9C%E4%B8%9A%E7%9A%84%E6%8E%A7%E5%88%B6"></a> |
---|
1625 | <h4>äœäžçæ§å¶</h4> |
---|
1626 | <p>ææ¶åïŒçšäžäžªåç¬çMap/Reduceäœäžå¹¶äžèœå®æäžäžªå€æçä»»å¡ïŒçšæ·ä¹è®žèŠéŸæ¥å€äžªMap/Reduceäœäžæè¡ãè¿æ¯å®¹æå®ç°çïŒå 䞺äœäžéåžžèŸåºå°ååžåŒæ件系ç»äžçïŒæ以å¯ä»¥æè¿äžªäœäžçèŸåºäœäžºäžäžäžªäœäžçèŸå
¥å®ç°äž²èã |
---|
1627 | </p> |
---|
1628 | <p>ç¶èïŒè¿ä¹æå³çïŒç¡®ä¿æ¯äžäœäžå®æ(æåæ倱莥)ç莣任就çŽæ¥èœåšäºå®¢æ·èº«äžãåšè¿ç§æ
åµäžïŒå¯ä»¥çšçæ§å¶äœäžçé项æïŒ |
---|
1629 | </p> |
---|
1630 | <ul> |
---|
1631 | |
---|
1632 | <li> |
---|
1633 | |
---|
1634 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobClient.html#runJob(org.apache.hadoop.mapred.JobConf)"> |
---|
1635 | runJob(JobConf)</a>ïŒæ亀äœäžïŒä»
åœäœäžå®ææ¶è¿åã |
---|
1636 | </li> |
---|
1637 | |
---|
1638 | <li> |
---|
1639 | |
---|
1640 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobClient.html#submitJob(org.apache.hadoop.mapred.JobConf)"> |
---|
1641 | submitJob(JobConf)</a>ïŒåªæ亀äœäžïŒä¹åéèŠäœ 蜮询å®è¿åç |
---|
1642 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/RunningJob.html"> |
---|
1643 | RunningJob</a>å¥æçç¶æïŒå¹¶æ ¹æ®æ
åµè°åºŠã |
---|
1644 | </li> |
---|
1645 | |
---|
1646 | <li> |
---|
1647 | |
---|
1648 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setJobEndNotificationURI(java.lang.String)"> |
---|
1649 | JobConf.setJobEndNotificationURI(String)</a>ïŒè®Ÿçœ®äžäžªäœäžå®æéç¥ïŒå¯é¿å
蜮询ã |
---|
1650 | |
---|
1651 | </li> |
---|
1652 | |
---|
1653 | </ul> |
---|
1654 | <a name="N10A6E"></a><a name="%E4%BD%9C%E4%B8%9A%E7%9A%84%E8%BE%93%E5%85%A5"></a> |
---|
1655 | <h3 class="h4">äœäžçèŸå
¥</h3> |
---|
1656 | <p> |
---|
1657 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/InputFormat.html"> |
---|
1658 | InputFormat</a> 䞺Map/Reduceäœäžæè¿°èŸå
¥çç»èè§èã |
---|
1659 | </p> |
---|
1660 | <p>Map/Reduceæ¡æ¶æ ¹æ®äœäžç<span class="codefrag">InputFormat</span>æ¥ïŒ |
---|
1661 | </p> |
---|
1662 | <ol> |
---|
1663 | |
---|
1664 | <li>æ£æ¥äœäžèŸå
¥çæææ§ã</li> |
---|
1665 | |
---|
1666 | <li> |
---|
1667 | æèŸå
¥æ件ååæå€äžªé»èŸ<span class="codefrag">InputSplit</span>å®äŸïŒ |
---|
1668 | 并ææ¯äžå®äŸåå«ååç»äžäžª |
---|
1669 | <span class="codefrag">Mapper</span>ã |
---|
1670 | </li> |
---|
1671 | |
---|
1672 | <li> |
---|
1673 | æäŸ<span class="codefrag">RecordReader</span>çå®ç°ïŒè¿äžªRecordReaderä»é»èŸ<span class="codefrag">InputSplit</span>äžè·åŸèŸå
¥è®°åœïŒ |
---|
1674 | è¿äºè®°åœå°ç±<span class="codefrag">Mapper</span>å€çã |
---|
1675 | </li> |
---|
1676 | |
---|
1677 | </ol> |
---|
1678 | <p>åºäºæ件ç<span class="codefrag">InputFormat</span>å®ç°ïŒéåžžæ¯ |
---|
1679 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileInputFormat.html"> |
---|
1680 | FileInputFormat</a>çåç±»ïŒ |
---|
1681 | é»è®€è¡äžºæ¯æç
§èŸå
¥æ件çåè倧å°ïŒæèŸå
¥æ°æ®ååæé»èŸååïŒ<em>logical</em> |
---|
1682 | <span class="codefrag">InputSplit</span> ïŒã |
---|
1683 | å
¶äžèŸå
¥æ件æåšç<span class="codefrag">FileSystem</span>çæ°æ®å尺寞æ¯åå倧å°çäžéãäžéå¯ä»¥è®Ÿçœ®<span class="codefrag">mapred.min.split.size</span> |
---|
1684 | çåŒã</p> |
---|
1685 | <p>èèå°èŸ¹çæ
åµïŒå¯¹äºåŸå€åºçšçšåºæ¥è¯ŽïŒåŸææŸæç
§æ件倧å°è¿è¡é»èŸåå²æ¯äžèœæ»¡è¶³éæ±çã |
---|
1686 | åšè¿ç§æ
åµäžïŒåºçšçšåºéèŠå®ç°äžäžª<span class="codefrag">RecordReader</span>æ¥å€çè®°åœç蟹ç并䞺æ¯äžªä»»å¡æäŸäžäžªé»èŸååçé¢åè®°åœçè§åŸã |
---|
1687 | </p> |
---|
1688 | <p> |
---|
1689 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/TextInputFormat.html"> |
---|
1690 | TextInputFormat</a> æ¯é»è®€ç<span class="codefrag">InputFormat</span>ã</p> |
---|
1691 | <p>åŠæäžäžªäœäžç<span class="codefrag">Inputformat</span>æ¯<span class="codefrag">TextInputFormat</span>ïŒ |
---|
1692 | 并äžæ¡æ¶æ£æµå°èŸå
¥æ件çåçŒæ¯<em>.gz</em>å<em>.lzo</em>ïŒå°±äŒäœ¿çšå¯¹åºç<span class="codefrag">CompressionCodec</span>èªåšè§£å猩è¿äºæ件ã |
---|
1693 | äœæ¯éèŠæ³šæïŒäžè¿°åžŠåçŒçå猩æ件äžäŒè¢«ååïŒå¹¶äžæŽäžªå猩æ件äŒåç»äžäžªmapperæ¥å€çã |
---|
1694 | </p> |
---|
1695 | <a name="N10AD2"></a><a name="InputSplit"></a> |
---|
1696 | <h4>InputSplit</h4> |
---|
1697 | <p> |
---|
1698 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/InputSplit.html"> |
---|
1699 | InputSplit</a> æ¯äžäžªåç¬ç<span class="codefrag">Mapper</span>èŠå€ççæ°æ®åã</p> |
---|
1700 | <p>äžè¬ç<span class="codefrag">InputSplit</span> æ¯åèæ ·åŒèŸå
¥ïŒç¶åç±<span class="codefrag">RecordReader</span>å€ç并蜬åæè®°åœæ ·åŒã |
---|
1701 | </p> |
---|
1702 | <p> |
---|
1703 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileSplit.html"> |
---|
1704 | FileSplit</a> æ¯é»è®€ç<span class="codefrag">InputSplit</span>ã å®æ |
---|
1705 | <span class="codefrag">map.input.file</span> 讟å®äžºèŸå
¥æ件çè·¯åŸïŒèŸå
¥æ件æ¯é»èŸååæ件ã |
---|
1706 | </p> |
---|
1707 | <a name="N10AF7"></a><a name="RecordReader"></a> |
---|
1708 | <h4>RecordReader</h4> |
---|
1709 | <p> |
---|
1710 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/RecordReader.html"> |
---|
1711 | RecordReader</a> ä»<span class="codefrag">InputSlit</span>读å
¥<span class="codefrag"><key, value></span>对ã |
---|
1712 | </p> |
---|
1713 | <p>äžè¬çïŒ<span class="codefrag">RecordReader</span> æç±<span class="codefrag">InputSplit</span> |
---|
1714 | æäŸçåèæ ·åŒçèŸå
¥æ件ïŒèœ¬åæç±<span class="codefrag">Mapper</span>å€ççè®°åœæ ·åŒçæ件ã |
---|
1715 | å æ€<span class="codefrag">RecordReader</span>èŽèŽ£å€çè®°åœç蟹çæ
åµåææ°æ®è¡šç€ºækeys/values对圢åŒã |
---|
1716 | </p> |
---|
1717 | <a name="N10B1A"></a><a name="%E4%BD%9C%E4%B8%9A%E7%9A%84%E8%BE%93%E5%87%BA"></a> |
---|
1718 | <h3 class="h4">äœäžçèŸåº</h3> |
---|
1719 | <p> |
---|
1720 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/OutputFormat.html"> |
---|
1721 | OutputFormat</a> æè¿°Map/ReduceäœäžçèŸåºæ ·åŒã |
---|
1722 | </p> |
---|
1723 | <p>Map/Reduceæ¡æ¶æ ¹æ®äœäžç<span class="codefrag">OutputFormat</span>æ¥ïŒ |
---|
1724 | </p> |
---|
1725 | <ol> |
---|
1726 | |
---|
1727 | <li> |
---|
1728 | æ£éªäœäžçèŸåºïŒäŸåŠæ£æ¥èŸåºè·¯åŸæ¯åŠå·²ç»ååšã |
---|
1729 | </li> |
---|
1730 | |
---|
1731 | <li> |
---|
1732 | æäŸäžäžª<span class="codefrag">RecordWriter</span>çå®ç°ïŒçšæ¥èŸåºäœäžç»æã |
---|
1733 | èŸåºæ件ä¿ååš<span class="codefrag">FileSystem</span>äžã |
---|
1734 | </li> |
---|
1735 | |
---|
1736 | </ol> |
---|
1737 | <p> |
---|
1738 | <span class="codefrag">TextOutputFormat</span>æ¯é»è®€ç |
---|
1739 | <span class="codefrag">OutputFormat</span>ã</p> |
---|
1740 | <a name="N10B43"></a><a name="%E4%BB%BB%E5%8A%A1%E7%9A%84Side-Effect+File"></a> |
---|
1741 | <h4>ä»»å¡çSide-Effect File</h4> |
---|
1742 | <p>åšäžäºåºçšçšåºäžïŒåä»»å¡éèŠäº§çäžäºside-fileïŒè¿äºæ件äžäœäžå®é
èŸåºç»æçæ件äžåã |
---|
1743 | </p> |
---|
1744 | <p>åšè¿ç§æ
åµäžïŒåäžäžª<span class="codefrag">Mapper</span>æè
<span class="codefrag">Reducer</span>ç䞀䞪å®äŸïŒæ¯åŠé¢é²æ§ä»»å¡ïŒåæ¶æåŒæè
å |
---|
1745 | <span class="codefrag">FileSystem</span>äžçåäžæ件就äŒäº§çå²çªãå æ€åºçšçšåºåšåæ件çæ¶åéèŠäžºæ¯æ¬¡ä»»å¡å°è¯ïŒäžä»
ä»
æ¯æ¯æ¬¡ä»»å¡ïŒæ¯äžªä»»å¡å¯ä»¥å°è¯æ§è¡åŸå€æ¬¡ïŒéåäžäžªç¬äžæ äºçæ件å(䜿çšattemptidïŒäŸåŠ<span class="codefrag">task_200709221812_0001_m_000000_0</span>)ã |
---|
1746 | </p> |
---|
1747 | <p>䞺äºé¿å
å²çªïŒMap/Reduceæ¡æ¶äžºæ¯æ¬¡å°è¯æ§è¡ä»»å¡éœå»ºç«å绎æ€äžäžªç¹æ®ç |
---|
1748 | <span class="codefrag">${mapred.output.dir}/_temporary/_${taskid}</span>åç®åœïŒè¿äžªç®åœäœäºæ¬æ¬¡å°è¯æ§è¡ä»»å¡èŸåºç»ææåšç<span class="codefrag">FileSystem</span>äžïŒå¯ä»¥éè¿ |
---|
1749 | <span class="codefrag">${mapred.work.output.dir}</span>æ¥è®¿é®è¿äžªåç®åœã |
---|
1750 | 对äºæåå®æçä»»å¡å°è¯ïŒåªæ<span class="codefrag">${mapred.output.dir}/_temporary/_${taskid}</span>äžçæ件äŒ<em>移åš</em>å°<span class="codefrag">${mapred.output.dir}</span>ãåœç¶ïŒæ¡æ¶äŒäž¢åŒé£äºå€±èŽ¥çä»»å¡å°è¯çåç®åœãè¿ç§å€çè¿çšå¯¹äºåºçšçšåºæ¥è¯Žæ¯å®å
šéæçã</p> |
---|
1751 | <p>åšä»»å¡æ§è¡æéŽïŒåºçšçšåºåšåæ件æ¶å¯ä»¥å©çšè¿äžªç¹æ§ïŒæ¯åŠ |
---|
1752 | éè¿<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileOutputFormat.html#getWorkOutputPath(org.apache.hadoop.mapred.JobConf)"> |
---|
1753 | FileOutputFormat.getWorkOutputPath()</a>è·åŸ<span class="codefrag">${mapred.work.output.dir}</span>ç®åœïŒ |
---|
1754 | 并åšå
¶äžå建任æä»»å¡æ§è¡æ¶æéçside-fileïŒæ¡æ¶åšä»»å¡å°è¯æåæ¶äŒé©¬äžç§»åšè¿äºæ件ïŒå æ€äžéèŠåšçšåºå
䞺æ¯æ¬¡ä»»å¡å°è¯éåäžäžªç¬äžæ äºçååã |
---|
1755 | </p> |
---|
1756 | <p>泚æïŒåšæ¯æ¬¡ä»»å¡å°è¯æ§è¡æéŽïŒ<span class="codefrag">${mapred.work.output.dir}</span> çåŒå®é
äžæ¯ |
---|
1757 | <span class="codefrag">${mapred.output.dir}/_temporary/_{$taskid}</span>ïŒè¿äžªåŒæ¯Map/Reduceæ¡æ¶å建çã |
---|
1758 | æ以䜿çšè¿äžªç¹æ§çæ¹æ³æ¯ïŒåš<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileOutputFormat.html#getWorkOutputPath(org.apache.hadoop.mapred.JobConf)"> |
---|
1759 | FileOutputFormat.getWorkOutputPath() </a> |
---|
1760 | è·¯åŸäžå建side-fileå³å¯ã |
---|
1761 | </p> |
---|
1762 | <p>对äºåªäœ¿çšmapäžäœ¿çšreduceçäœäžïŒè¿äžªç»è®ºä¹æç«ãè¿ç§æ
åµäžïŒmapçèŸåºç»æçŽæ¥çæå°HDFSäžã |
---|
1763 | </p> |
---|
1764 | <a name="N10B8B"></a><a name="RecordWriter"></a> |
---|
1765 | <h4>RecordWriter</h4> |
---|
1766 | <p> |
---|
1767 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/RecordWriter.html"> |
---|
1768 | RecordWriter</a> çæ<span class="codefrag"><key, value></span> |
---|
1769 | 对å°èŸåºæ件ã</p> |
---|
1770 | <p>RecordWriterçå®ç°æäœäžçèŸåºç»æåå° |
---|
1771 | <span class="codefrag">FileSystem</span>ã</p> |
---|
1772 | <a name="N10BA2"></a><a name="%E5%85%B6%E4%BB%96%E6%9C%89%E7%94%A8%E7%9A%84%E7%89%B9%E6%80%A7"></a> |
---|
1773 | <h3 class="h4">å
¶ä»æçšçç¹æ§</h3> |
---|
1774 | <a name="N10BA8"></a><a name="Counters"></a> |
---|
1775 | <h4>Counters</h4> |
---|
1776 | <p> |
---|
1777 | <span class="codefrag">Counters</span> æ¯å€äžªç±Map/Reduceæ¡æ¶æè
åºçšçšåºå®ä¹çå
šå±è®¡æ°åšã |
---|
1778 | æ¯äžäžª<span class="codefrag">Counter</span>å¯ä»¥æ¯ä»»äœäžç§ |
---|
1779 | <span class="codefrag">Enum</span>ç±»åãåäžç¹å®<span class="codefrag">Enum</span>ç±»åçCounterå¯ä»¥æ±éå°äžäžªç»ïŒå
¶ç±»å䞺<span class="codefrag">Counters.Group</span>ã</p> |
---|
1780 | <p>åºçšçšåºå¯ä»¥å®ä¹ä»»æ(Enumç±»å)ç<span class="codefrag">Counters</span>并äžå¯ä»¥éè¿ <span class="codefrag">map</span> æè
|
---|
1781 | <span class="codefrag">reduce</span>æ¹æ³äžç |
---|
1782 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Reporter.html#incrCounter(java.lang.Enum, long)"> |
---|
1783 | Reporter.incrCounter(Enum, long)</a>æè
|
---|
1784 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/Reporter.html#incrCounter(java.lang.String, java.lang.String, long amount)"> |
---|
1785 | Reporter.incrCounter(String, String, long)</a> |
---|
1786 | æŽæ°ãä¹åæ¡æ¶äŒæ±æ»è¿äºå
šå±countersã |
---|
1787 | </p> |
---|
1788 | <a name="N10BD4"></a><a name="DistributedCache"></a> |
---|
1789 | <h4>DistributedCache</h4> |
---|
1790 | <p> |
---|
1791 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html"> |
---|
1792 | DistributedCache</a> å¯å°å
·äœåºçšçžå
³çã倧尺寞çãåªè¯»çæ件ææå°ååžæŸçœ®ã |
---|
1793 | </p> |
---|
1794 | <p> |
---|
1795 | <span class="codefrag">DistributedCache</span> æ¯Map/Reduceæ¡æ¶æäŸçåèœïŒèœå€çŒååºçšçšåºæéçæ件 |
---|
1796 | ïŒå
æ¬ææ¬ïŒæ¡£æ¡æ件ïŒjaræ件çïŒã |
---|
1797 | </p> |
---|
1798 | <p>åºçšçšåºåš<span class="codefrag">JobConf</span>äžéè¿url(hdfs://)æå®éèŠè¢«çŒåçæ件ã |
---|
1799 | <span class="codefrag">DistributedCache</span>åå®ç±hdfs://æ ŒåŒurlæå®çæ件已ç»åš |
---|
1800 | <span class="codefrag">FileSystem</span>äžäºã</p> |
---|
1801 | <p>Map-Redcueæ¡æ¶åšäœäžææä»»å¡æ§è¡ä¹åäŒæå¿
èŠçæ件æ·èŽå°slaveèç¹äžã |
---|
1802 | å®è¿è¡é«ææ¯å 䞺æ¯äžªäœäžçæ件åªæ·èŽäžæ¬¡å¹¶äžäžºé£äºæ²¡æææ¡£çslaveèç¹çŒåææ¡£ã |
---|
1803 | </p> |
---|
1804 | <p> |
---|
1805 | <span class="codefrag">DistributedCache</span> æ ¹æ®çŒåæ档修æ¹çæ¶éŽæ³è¿è¡è¿œèžªã |
---|
1806 | åšäœäžæ§è¡æéŽïŒåœååºçšçšåºæè
å€éšçšåºäžèœä¿®æ¹çŒåæ件ã |
---|
1807 | </p> |
---|
1808 | <p> |
---|
1809 | <span class="codefrag">distributedCache</span>å¯ä»¥ååç®åçåªè¯»æ°æ®æææ¬æ件ïŒä¹å¯ä»¥ååå€æç±»åçæ件äŸåŠåœæ¡£æ件åjaræ件ãåœæ¡£æ件(zip,tar,tgzåtar.gzæ件)åšslaveèç¹äžäŒè¢«<em>解档ïŒun-archivedïŒ</em>ã |
---|
1810 | è¿äºæ件å¯ä»¥è®Ÿçœ®<em>æ§è¡æé</em>ã</p> |
---|
1811 | <p>çšæ·å¯ä»¥éè¿è®Ÿçœ®<span class="codefrag">mapred.cache.{files|archives}</span>æ¥ååæ件ã |
---|
1812 | åŠæèŠååå€äžªæ件ïŒå¯ä»¥äœ¿çšéå·åéæ件æåšè·¯åŸãä¹å¯ä»¥å©çšAPIæ¥è®Ÿçœ®è¯¥å±æ§ïŒ |
---|
1813 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html#addCacheFile(java.net.URI,%20org.apache.hadoop.conf.Configuration)"> |
---|
1814 | DistributedCache.addCacheFile(URI,conf)</a>/ |
---|
1815 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html#addCacheArchive(java.net.URI,%20org.apache.hadoop.conf.Configuration)"> |
---|
1816 | DistributedCache.addCacheArchive(URI,conf)</a> and |
---|
1817 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html#setCacheFiles(java.net.URI[],%20org.apache.hadoop.conf.Configuration)"> |
---|
1818 | DistributedCache.setCacheFiles(URIs,conf)</a>/ |
---|
1819 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html#setCacheArchives(java.net.URI[],%20org.apache.hadoop.conf.Configuration)"> |
---|
1820 | DistributedCache.setCacheArchives(URIs,conf)</a> |
---|
1821 | å
¶äžURIç圢åŒæ¯ |
---|
1822 | <span class="codefrag">hdfs://host:port/absolute-path#link-name</span> |
---|
1823 | åšStreamingçšåºäžïŒå¯ä»¥éè¿åœä»€è¡é项 |
---|
1824 | <span class="codefrag">-cacheFile/-cacheArchive</span> |
---|
1825 | ååæ件ã</p> |
---|
1826 | <p> |
---|
1827 | çšæ·å¯ä»¥éè¿<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html#createSymlink(org.apache.hadoop.conf.Configuration)"> |
---|
1828 | DistributedCache.createSymlink(Configuration)</a>æ¹æ³è®©<span class="codefrag">DistributedCache</span> |
---|
1829 | åš<em>åœåå·¥äœç®åœ</em>äžå建å°çŒåæ件ç笊å·éŸæ¥ã |
---|
1830 | æè
éè¿è®Ÿçœ®é
眮æ件å±æ§<span class="codefrag">mapred.create.symlink</span>䞺<span class="codefrag">yes</span>ã |
---|
1831 | ååžåŒçŒåäŒæªåURIçç段äœäžºéŸæ¥çååã |
---|
1832 | äŸåŠïŒURIæ¯ <span class="codefrag">hdfs://namenode:port/lib.so.1#lib.so</span>ïŒ |
---|
1833 | ååštaskåœåå·¥äœç®åœäŒæå䞺<span class="codefrag">lib.so</span>çéŸæ¥ïŒ |
---|
1834 | å®äŒéŸæ¥ååžåŒçŒåäžç<span class="codefrag">lib.so.1</span>ã |
---|
1835 | </p> |
---|
1836 | <p> |
---|
1837 | <span class="codefrag">DistributedCache</span>å¯åšmap/reduceä»»å¡äžäœäžº |
---|
1838 | äžç§åºç¡èœ¯ä»¶ååæºå¶äœ¿çšãå®å¯ä»¥è¢«çšäºååjarå
åæ¬å°åºïŒnative librariesïŒã |
---|
1839 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html#addArchiveToClassPath(org.apache.hadoop.fs.Path,%20org.apache.hadoop.conf.Configuration)"> |
---|
1840 | DistributedCache.addArchiveToClassPath(Path, Configuration)</a>å |
---|
1841 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/filecache/DistributedCache.html#addFileToClassPath(org.apache.hadoop.fs.Path,%20org.apache.hadoop.conf.Configuration)"> |
---|
1842 | DistributedCache.addFileToClassPath(Path, Configuration)</a> APIèœå€è¢«çšäº |
---|
1843 | çŒåæ件åjarå
ïŒå¹¶æå®ä»¬å å
¥åjvmç<em>classpath</em>ãä¹å¯ä»¥éè¿è®Ÿçœ®é
眮ææ¡£éçå±æ§ |
---|
1844 | <span class="codefrag">mapred.job.classpath.{files|archives}</span>蟟å°çžåçææãçŒåæ件å¯çšäºåååè£
蜜æ¬å°åºã |
---|
1845 | </p> |
---|
1846 | <a name="N10C50"></a><a name="Tool"></a> |
---|
1847 | <h4>Tool</h4> |
---|
1848 | <p> |
---|
1849 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/util/Tool.html">Tool</a> |
---|
1850 | æ¥å£æ¯æå€çåžžçšçHadoopåœä»€è¡é项ã |
---|
1851 | </p> |
---|
1852 | <p> |
---|
1853 | <span class="codefrag">Tool</span> æ¯Map/Reduceå·¥å
·æåºçšçæ åãåºçšçšåºåºåªå€çå
¶å®å¶åæ°ïŒ |
---|
1854 | èŠææ ååœä»€è¡é项éè¿ |
---|
1855 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/util/ToolRunner.html#run(org.apache.hadoop.util.Tool, java.lang.String[])"> ToolRunner.run(Tool, String[])</a> |
---|
1856 | å§æç» |
---|
1857 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/util/GenericOptionsParser.html"> |
---|
1858 | GenericOptionsParser</a>å€çã |
---|
1859 | </p> |
---|
1860 | <p> |
---|
1861 | Hadoopåœä»€è¡çåžžçšé项æïŒ<br> |
---|
1862 | |
---|
1863 | <span class="codefrag"> |
---|
1864 | -conf <configuration file> |
---|
1865 | </span> |
---|
1866 | |
---|
1867 | <br> |
---|
1868 | |
---|
1869 | <span class="codefrag"> |
---|
1870 | -D <property=value> |
---|
1871 | </span> |
---|
1872 | |
---|
1873 | <br> |
---|
1874 | |
---|
1875 | <span class="codefrag"> |
---|
1876 | -fs <local|namenode:port> |
---|
1877 | </span> |
---|
1878 | |
---|
1879 | <br> |
---|
1880 | |
---|
1881 | <span class="codefrag"> |
---|
1882 | -jt <local|jobtracker:port> |
---|
1883 | </span> |
---|
1884 | |
---|
1885 | </p> |
---|
1886 | <a name="N10C81"></a><a name="IsolationRunner"></a> |
---|
1887 | <h4>IsolationRunner</h4> |
---|
1888 | <p> |
---|
1889 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/IsolationRunner.html"> |
---|
1890 | IsolationRunner</a> æ¯åž®å©è°è¯Map/Reduceçšåºçå·¥å
·ã</p> |
---|
1891 | <p>䜿çš<span class="codefrag">IsolationRunner</span>çæ¹æ³æ¯ïŒéŠå
讟眮 |
---|
1892 | <span class="codefrag">keep.failed.tasks.files</span>å±æ§äžº<span class="codefrag">true</span> |
---|
1893 | ïŒåæ¶åè<span class="codefrag">keep.tasks.files.pattern</span>ïŒã</p> |
---|
1894 | <p> |
---|
1895 | ç¶åïŒç»åœå°ä»»å¡è¿è¡å€±èŽ¥çèç¹äžïŒè¿å
¥ |
---|
1896 | <span class="codefrag">TaskTracker</span>çæ¬å°è·¯åŸè¿è¡ |
---|
1897 | <span class="codefrag">IsolationRunner</span>ïŒ<br> |
---|
1898 | |
---|
1899 | <span class="codefrag">$ cd <local path>/taskTracker/${taskid}/work</span> |
---|
1900 | <br> |
---|
1901 | |
---|
1902 | <span class="codefrag"> |
---|
1903 | $ bin/hadoop org.apache.hadoop.mapred.IsolationRunner ../job.xml |
---|
1904 | </span> |
---|
1905 | |
---|
1906 | </p> |
---|
1907 | <p> |
---|
1908 | <span class="codefrag">IsolationRunner</span>äŒæ倱莥çä»»å¡æŸåšåç¬çäžäžªèœå€è°è¯çjvmäžè¿è¡ïŒå¹¶äžéçšåä¹åå®å
šäžæ ·çèŸå
¥æ°æ®ã |
---|
1909 | </p> |
---|
1910 | <a name="N10CB4"></a><a name="Profiling"></a> |
---|
1911 | <h4>Profiling</h4> |
---|
1912 | <p>Profilingæ¯äžäžªå·¥å
·ïŒå®äœ¿çšå
眮çjava profilerå·¥å
·è¿è¡åæè·åŸ(2-3䞪)mapæreduceæ ·äŸè¿è¡åææ¥åã</p> |
---|
1913 | <p>çšæ·å¯ä»¥éè¿è®Ÿçœ®å±æ§<span class="codefrag">mapred.task.profile</span>æå®ç³»ç»æ¯åŠééprofilerä¿¡æ¯ã |
---|
1914 | å©çšapi<a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setProfileEnabled(boolean)"> |
---|
1915 | JobConf.setProfileEnabled(boolean)å¯ä»¥ä¿®æ¹å±æ§åŒ</a>ãåŠæ讟䞺<span class="codefrag">true</span>ïŒ |
---|
1916 | ååŒå¯profilingåèœãprofilerä¿¡æ¯ä¿ååšçšæ·æ¥å¿ç®åœäžã猺çæ
åµïŒprofilingåèœæ¯å
³éçã</p> |
---|
1917 | <p>åŠæçšæ·è®Ÿå®äœ¿çšprofilingåèœïŒå¯ä»¥äœ¿çšé
眮ææ¡£éçå±æ§ |
---|
1918 | <span class="codefrag">mapred.task.profile.{maps|reduces}</span> |
---|
1919 | 讟眮èŠprofile map/reduce taskçèåŽã讟眮该å±æ§åŒçapiæ¯ |
---|
1920 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setProfileTaskRange(boolean,%20java.lang.String)"> |
---|
1921 | JobConf.setProfileTaskRange(boolean,String)</a>ã |
---|
1922 | èåŽç猺çåŒæ¯<span class="codefrag">0-2</span>ã</p> |
---|
1923 | <p>çšæ·å¯ä»¥éè¿è®Ÿå®é
眮ææ¡£éçå±æ§<span class="codefrag">mapred.task.profile.params</span> |
---|
1924 | æ¥æå®profileré
眮åæ°ãä¿®æ¹å±æ§èŠäœ¿çšapi |
---|
1925 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setProfileParams(java.lang.String)"> |
---|
1926 | JobConf.setProfileParams(String)</a>ãåœè¿è¡taskæ¶ïŒåŠæå笊䞲å
å«<span class="codefrag">%s</span>ã |
---|
1927 | å®äŒè¢«æ¿æ¢æprofileingçèŸåºæ件åãè¿äºåæ°äŒåšåœä»€è¡éäŒ éå°åJVMäžã猺ççprofiling |
---|
1928 | åæ°æ¯ |
---|
1929 | <span class="codefrag">-agentlib:hprof=cpu=samples,heap=sites,force=n,thread=y,verbose=n,file=%s</span>ã |
---|
1930 | </p> |
---|
1931 | <a name="N10CE8"></a><a name="%E8%B0%83%E8%AF%95"></a> |
---|
1932 | <h4>è°è¯</h4> |
---|
1933 | <p>Map/Reduceæ¡æ¶èœå€è¿è¡çšæ·æäŸççšäºè°è¯çèæ¬çšåºã |
---|
1934 | åœmap/reduceä»»å¡å€±èŽ¥æ¶ïŒçšæ·å¯ä»¥éè¿è¿è¡èæ¬åšä»»å¡æ¥å¿ïŒäŸåŠä»»å¡çæ åèŸåºãæ åé误ãç³»ç»æ¥å¿ä»¥åäœäžé
眮æ件ïŒäžååç»å€çå·¥äœãçšæ·æäŸçè°è¯èæ¬çšåºçæ åèŸåºåæ åé误äŒèŸåºäžºè¯ææ件ãåŠæéèŠçè¯è¿äºèŸåºç»æä¹å¯ä»¥æå°åšçšæ·çé¢äžã</p> |
---|
1935 | <p> åšæ¥äžæ¥çç« èïŒæ们讚论åŠäœäžäœäžäžèµ·æ亀è°è¯èæ¬ã䞺äºæ亀è°è¯èæ¬ïŒ |
---|
1936 | éŠå
èŠæè¿äžªèæ¬åååºå»ïŒèäžè¿èŠåšé
眮æ件é讟眮ã |
---|
1937 | </p> |
---|
1938 | <a name="N10CF4"></a><a name="%E5%A6%82%E4%BD%95%E5%88%86%E5%8F%91%E8%84%9A%E6%9C%AC%E6%96%87%E4%BB%B6%EF%BC%9A"></a> |
---|
1939 | <h5> åŠäœååèæ¬æ件ïŒ</h5> |
---|
1940 | <p>çšæ·èŠçš |
---|
1941 | <a href="mapred_tutorial.html#DistributedCache">DistributedCache</a> |
---|
1942 | æºå¶æ¥<em>åå</em>å<em>éŸæ¥</em>èæ¬æ件</p> |
---|
1943 | <a name="N10D08"></a><a name="%E5%A6%82%E4%BD%95%E6%8F%90%E4%BA%A4%E8%84%9A%E6%9C%AC%EF%BC%9A"></a> |
---|
1944 | <h5> åŠäœæ亀èæ¬ïŒ</h5> |
---|
1945 | <p> äžäžªå¿«éæ亀è°è¯èæ¬çæ¹æ³æ¯åå«äžºéèŠè°è¯çmapä»»å¡åreduceä»»å¡è®Ÿçœ® |
---|
1946 | "mapred.map.task.debug.script" å "mapred.reduce.task.debug.script" |
---|
1947 | å±æ§çåŒãè¿äºå±æ§ä¹å¯ä»¥éè¿ |
---|
1948 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMapDebugScript(java.lang.String)"> |
---|
1949 | JobConf.setMapDebugScript(String) </a>å |
---|
1950 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setReduceDebugScript(java.lang.String)"> |
---|
1951 | JobConf.setReduceDebugScript(String) </a>APIæ¥è®Ÿçœ®ã对äºstreamingïŒ |
---|
1952 | å¯ä»¥åå«äžºéèŠè°è¯çmapä»»å¡åreduceä»»å¡äœ¿çšåœä»€è¡é项-mapdebug å -reducedegugæ¥æ亀è°è¯èæ¬ã |
---|
1953 | </p> |
---|
1954 | <p>èæ¬çåæ°æ¯ä»»å¡çæ åèŸåºãæ åé误ãç³»ç»æ¥å¿ä»¥åäœäžé
眮æ件ãåšè¿è¡map/reduce倱莥çèç¹äžè¿è¡è°è¯åœä»€æ¯ïŒ |
---|
1955 | <br> |
---|
1956 | |
---|
1957 | <span class="codefrag"> $script $stdout $stderr $syslog $jobconf </span> |
---|
1958 | </p> |
---|
1959 | <p> Pipes çšåºæ ¹æ®ç¬¬äºäžªåæ°è·åŸc++çšåºåã |
---|
1960 | å æ€è°è¯pipesçšåºçåœä»€æ¯<br> |
---|
1961 | |
---|
1962 | <span class="codefrag">$script $stdout $stderr $syslog $jobconf $program </span> |
---|
1963 | |
---|
1964 | </p> |
---|
1965 | <a name="N10D2A"></a><a name="%E9%BB%98%E8%AE%A4%E8%A1%8C%E4%B8%BA"></a> |
---|
1966 | <h5> é»è®€è¡äžº </h5> |
---|
1967 | <p> 对äºpipesïŒé»è®€çèæ¬äŒçšgdbå€çcore dumpïŒ |
---|
1968 | æå° stack trace并äžç»åºæ£åšè¿è¡çº¿çšçä¿¡æ¯ã</p> |
---|
1969 | <a name="N10D35"></a><a name="JobControl"></a> |
---|
1970 | <h4>JobControl</h4> |
---|
1971 | <p> |
---|
1972 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/jobcontrol/package-summary.html"> |
---|
1973 | JobControl</a>æ¯äžäžªå·¥å
·ïŒå®å°è£
äºäžç»Map/Reduceäœäžä»¥åä»ä»¬ä¹éŽçäŸèµå
³ç³»ã |
---|
1974 | </p> |
---|
1975 | <a name="N10D42"></a><a name="%E6%95%B0%E6%8D%AE%E5%8E%8B%E7%BC%A9"></a> |
---|
1976 | <h4>æ°æ®å猩</h4> |
---|
1977 | <p>Hadoop Map/Reduceæ¡æ¶äžºåºçšçšåºçåå
¥æ件æäœæäŸå猩工å
·ïŒè¿äºå·¥å
·å¯ä»¥äžºmapèŸåºçäžéŽæ°æ®åäœäžæç»èŸåºæ°æ®ïŒäŸåŠreduceçèŸåºïŒæäŸæ¯æãå®è¿é垊äºäžäº |
---|
1978 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/io/compress/CompressionCodec.html"> |
---|
1979 | CompressionCodec</a>çå®ç°ïŒæ¯åŠå®ç°äº |
---|
1980 | <a href="http://www.zlib.net/">zlib</a>å<a href="http://www.oberhumer.com/opensource/lzo/">lzo</a>å猩ç®æ³ã |
---|
1981 | Hadoopåæ ·æ¯æ<a href="http://www.gzip.org/">gzip</a>æä»¶æ ŒåŒã |
---|
1982 | </p> |
---|
1983 | <p>èèå°æ§èœé®é¢ïŒzlibïŒä»¥åJavaç±»åºç猺倱ïŒlzoïŒçå çŽ ïŒHadoopä¹äžºäžè¿°å猩解åç®æ³æäŸæ¬å°åºçå®ç°ãæŽå€çç»è请åè |
---|
1984 | <a href="native_libraries.html">è¿é</a>ã</p> |
---|
1985 | <a name="N10D62"></a><a name="%E4%B8%AD%E9%97%B4%E8%BE%93%E5%87%BA"></a> |
---|
1986 | <h5>äžéŽèŸåº</h5> |
---|
1987 | <p>åºçšçšåºå¯ä»¥éè¿ |
---|
1988 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setCompressMapOutput(boolean)"> |
---|
1989 | JobConf.setCompressMapOutput(boolean)</a>apiæ§å¶mapèŸåºçäžéŽç»æïŒå¹¶äžå¯ä»¥éè¿ |
---|
1990 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/JobConf.html#setMapOutputCompressorClass(java.lang.Class)"> |
---|
1991 | JobConf.setMapOutputCompressorClass(Class)</a>apiæå® |
---|
1992 | <span class="codefrag">CompressionCodec</span>ã |
---|
1993 | </p> |
---|
1994 | <a name="N10D77"></a><a name="%E4%BD%9C%E4%B8%9A%E8%BE%93%E5%87%BA"></a> |
---|
1995 | <h5>äœäžèŸåº</h5> |
---|
1996 | <p>åºçšçšåºå¯ä»¥éè¿ |
---|
1997 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileOutputFormat.html#setCompressOutput(org.apache.hadoop.mapred.JobConf,%20boolean)"> |
---|
1998 | FileOutputFormat.setCompressOutput(JobConf, boolean)</a> |
---|
1999 | apiæ§å¶èŸåºæ¯åŠéèŠå猩并äžå¯ä»¥äœ¿çš |
---|
2000 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/FileOutputFormat.html#setOutputCompressorClass(org.apache.hadoop.mapred.JobConf,%20java.lang.Class)"> |
---|
2001 | FileOutputFormat.setOutputCompressorClass(JobConf, Class)</a>apiæå®<span class="codefrag">CompressionCodec</span>ã</p> |
---|
2002 | <p>åŠæäœäžèŸåºèŠä¿åæ |
---|
2003 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/SequenceFileOutputFormat.html"> |
---|
2004 | SequenceFileOutputFormat</a>æ ŒåŒïŒéèŠäœ¿çš |
---|
2005 | <a href="http://hadoop.apache.org/core/docs/r0.18.2/api/org/apache/hadoop/mapred/SequenceFileOutputFormat.html#setOutputCompressionType(org.apache.hadoop.mapred.JobConf,%20org.apache.hadoop.io.SequenceFile.CompressionType)"> |
---|
2006 | SequenceFileOutputFormat.setOutputCompressionType(JobConf, |
---|
2007 | SequenceFile.CompressionType)</a>apiïŒæ¥è®Ÿå® |
---|
2008 | <span class="codefrag">SequenceFile.CompressionType</span> (i.e. <span class="codefrag">RECORD</span> / |
---|
2009 | <span class="codefrag">BLOCK</span> - é»è®€æ¯<span class="codefrag">RECORD</span>)ã |
---|
2010 | </p> |
---|
2011 | </div> |
---|
2012 | |
---|
2013 | |
---|
2014 | <a name="N10DA6"></a><a name="%E4%BE%8B%E5%AD%90%EF%BC%9AWordCount+v2.0"></a> |
---|
2015 | <h2 class="h3">äŸåïŒWordCount v2.0</h2> |
---|
2016 | <div class="section"> |
---|
2017 | <p>è¿éæ¯äžäžªæŽå
šé¢ç<span class="codefrag">WordCount</span>äŸåïŒå®äœ¿çšäºæ们已ç»è®šè®ºè¿çåŸå€Map/Reduceæ¡æ¶æäŸçåèœã |
---|
2018 | </p> |
---|
2019 | <p>è¿è¡è¿äžªäŸåéèŠHDFSçæäºåèœïŒç¹å«æ¯ |
---|
2020 | <span class="codefrag">DistributedCache</span>çžå
³åèœãå æ€è¿äžªäŸååªèœè¿è¡åš |
---|
2021 | <a href="quickstart.html#SingleNodeSetup">䌪ååžåŒ</a> æè
|
---|
2022 | <a href="quickstart.html#Fully-Distributed+Operation">å®å
šååžåŒæš¡åŒ</a>ç |
---|
2023 | Hadoopäžã</p> |
---|
2024 | <a name="N10DC0"></a><a name="%E6%BA%90%E4%BB%A3%E7%A0%81-N10DC0"></a> |
---|
2025 | <h3 class="h4">æºä»£ç </h3> |
---|
2026 | <table class="ForrestTable" cellspacing="1" cellpadding="4"> |
---|
2027 | |
---|
2028 | <tr> |
---|
2029 | |
---|
2030 | <th colspan="1" rowspan="1"></th> |
---|
2031 | <th colspan="1" rowspan="1">WordCount.java</th> |
---|
2032 | |
---|
2033 | </tr> |
---|
2034 | |
---|
2035 | <tr> |
---|
2036 | |
---|
2037 | <td colspan="1" rowspan="1">1.</td> |
---|
2038 | <td colspan="1" rowspan="1"> |
---|
2039 | <span class="codefrag">package org.myorg;</span> |
---|
2040 | </td> |
---|
2041 | |
---|
2042 | </tr> |
---|
2043 | |
---|
2044 | <tr> |
---|
2045 | |
---|
2046 | <td colspan="1" rowspan="1">2.</td> |
---|
2047 | <td colspan="1" rowspan="1"></td> |
---|
2048 | |
---|
2049 | </tr> |
---|
2050 | |
---|
2051 | <tr> |
---|
2052 | |
---|
2053 | <td colspan="1" rowspan="1">3.</td> |
---|
2054 | <td colspan="1" rowspan="1"> |
---|
2055 | <span class="codefrag">import java.io.*;</span> |
---|
2056 | </td> |
---|
2057 | |
---|
2058 | </tr> |
---|
2059 | |
---|
2060 | <tr> |
---|
2061 | |
---|
2062 | <td colspan="1" rowspan="1">4.</td> |
---|
2063 | <td colspan="1" rowspan="1"> |
---|
2064 | <span class="codefrag">import java.util.*;</span> |
---|
2065 | </td> |
---|
2066 | |
---|
2067 | </tr> |
---|
2068 | |
---|
2069 | <tr> |
---|
2070 | |
---|
2071 | <td colspan="1" rowspan="1">5.</td> |
---|
2072 | <td colspan="1" rowspan="1"></td> |
---|
2073 | |
---|
2074 | </tr> |
---|
2075 | |
---|
2076 | <tr> |
---|
2077 | |
---|
2078 | <td colspan="1" rowspan="1">6.</td> |
---|
2079 | <td colspan="1" rowspan="1"> |
---|
2080 | <span class="codefrag">import org.apache.hadoop.fs.Path;</span> |
---|
2081 | </td> |
---|
2082 | |
---|
2083 | </tr> |
---|
2084 | |
---|
2085 | <tr> |
---|
2086 | |
---|
2087 | <td colspan="1" rowspan="1">7.</td> |
---|
2088 | <td colspan="1" rowspan="1"> |
---|
2089 | <span class="codefrag">import org.apache.hadoop.filecache.DistributedCache;</span> |
---|
2090 | </td> |
---|
2091 | |
---|
2092 | </tr> |
---|
2093 | |
---|
2094 | <tr> |
---|
2095 | |
---|
2096 | <td colspan="1" rowspan="1">8.</td> |
---|
2097 | <td colspan="1" rowspan="1"> |
---|
2098 | <span class="codefrag">import org.apache.hadoop.conf.*;</span> |
---|
2099 | </td> |
---|
2100 | |
---|
2101 | </tr> |
---|
2102 | |
---|
2103 | <tr> |
---|
2104 | |
---|
2105 | <td colspan="1" rowspan="1">9.</td> |
---|
2106 | <td colspan="1" rowspan="1"> |
---|
2107 | <span class="codefrag">import org.apache.hadoop.io.*;</span> |
---|
2108 | </td> |
---|
2109 | |
---|
2110 | </tr> |
---|
2111 | |
---|
2112 | <tr> |
---|
2113 | |
---|
2114 | <td colspan="1" rowspan="1">10.</td> |
---|
2115 | <td colspan="1" rowspan="1"> |
---|
2116 | <span class="codefrag">import org.apache.hadoop.mapred.*;</span> |
---|
2117 | </td> |
---|
2118 | |
---|
2119 | </tr> |
---|
2120 | |
---|
2121 | <tr> |
---|
2122 | |
---|
2123 | <td colspan="1" rowspan="1">11.</td> |
---|
2124 | <td colspan="1" rowspan="1"> |
---|
2125 | <span class="codefrag">import org.apache.hadoop.util.*;</span> |
---|
2126 | </td> |
---|
2127 | |
---|
2128 | </tr> |
---|
2129 | |
---|
2130 | <tr> |
---|
2131 | |
---|
2132 | <td colspan="1" rowspan="1">12.</td> |
---|
2133 | <td colspan="1" rowspan="1"></td> |
---|
2134 | |
---|
2135 | </tr> |
---|
2136 | |
---|
2137 | <tr> |
---|
2138 | |
---|
2139 | <td colspan="1" rowspan="1">13.</td> |
---|
2140 | <td colspan="1" rowspan="1"> |
---|
2141 | <span class="codefrag">public class WordCount extends Configured implements Tool {</span> |
---|
2142 | </td> |
---|
2143 | |
---|
2144 | </tr> |
---|
2145 | |
---|
2146 | <tr> |
---|
2147 | |
---|
2148 | <td colspan="1" rowspan="1">14.</td> |
---|
2149 | <td colspan="1" rowspan="1"></td> |
---|
2150 | |
---|
2151 | </tr> |
---|
2152 | |
---|
2153 | <tr> |
---|
2154 | |
---|
2155 | <td colspan="1" rowspan="1">15.</td> |
---|
2156 | <td colspan="1" rowspan="1"> |
---|
2157 | |
---|
2158 | <span class="codefrag"> |
---|
2159 | public static class Map extends MapReduceBase |
---|
2160 | implements Mapper<LongWritable, Text, Text, IntWritable> { |
---|
2161 | </span> |
---|
2162 | </td> |
---|
2163 | |
---|
2164 | </tr> |
---|
2165 | |
---|
2166 | <tr> |
---|
2167 | |
---|
2168 | <td colspan="1" rowspan="1">16.</td> |
---|
2169 | <td colspan="1" rowspan="1"></td> |
---|
2170 | |
---|
2171 | </tr> |
---|
2172 | |
---|
2173 | <tr> |
---|
2174 | |
---|
2175 | <td colspan="1" rowspan="1">17.</td> |
---|
2176 | <td colspan="1" rowspan="1"> |
---|
2177 | |
---|
2178 | <span class="codefrag"> |
---|
2179 | static enum Counters { INPUT_WORDS } |
---|
2180 | </span> |
---|
2181 | </td> |
---|
2182 | |
---|
2183 | </tr> |
---|
2184 | |
---|
2185 | <tr> |
---|
2186 | |
---|
2187 | <td colspan="1" rowspan="1">18.</td> |
---|
2188 | <td colspan="1" rowspan="1"></td> |
---|
2189 | |
---|
2190 | </tr> |
---|
2191 | |
---|
2192 | <tr> |
---|
2193 | |
---|
2194 | <td colspan="1" rowspan="1">19.</td> |
---|
2195 | <td colspan="1" rowspan="1"> |
---|
2196 | |
---|
2197 | <span class="codefrag"> |
---|
2198 | private final static IntWritable one = new IntWritable(1); |
---|
2199 | </span> |
---|
2200 | </td> |
---|
2201 | |
---|
2202 | </tr> |
---|
2203 | |
---|
2204 | <tr> |
---|
2205 | |
---|
2206 | <td colspan="1" rowspan="1">20.</td> |
---|
2207 | <td colspan="1" rowspan="1"> |
---|
2208 | |
---|
2209 | <span class="codefrag">private Text word = new Text();</span> |
---|
2210 | </td> |
---|
2211 | |
---|
2212 | </tr> |
---|
2213 | |
---|
2214 | <tr> |
---|
2215 | |
---|
2216 | <td colspan="1" rowspan="1">21.</td> |
---|
2217 | <td colspan="1" rowspan="1"></td> |
---|
2218 | |
---|
2219 | </tr> |
---|
2220 | |
---|
2221 | <tr> |
---|
2222 | |
---|
2223 | <td colspan="1" rowspan="1">22.</td> |
---|
2224 | <td colspan="1" rowspan="1"> |
---|
2225 | |
---|
2226 | <span class="codefrag">private boolean caseSensitive = true;</span> |
---|
2227 | </td> |
---|
2228 | |
---|
2229 | </tr> |
---|
2230 | |
---|
2231 | <tr> |
---|
2232 | |
---|
2233 | <td colspan="1" rowspan="1">23.</td> |
---|
2234 | <td colspan="1" rowspan="1"> |
---|
2235 | |
---|
2236 | <span class="codefrag">private Set<String> patternsToSkip = new HashSet<String>();</span> |
---|
2237 | </td> |
---|
2238 | |
---|
2239 | </tr> |
---|
2240 | |
---|
2241 | <tr> |
---|
2242 | |
---|
2243 | <td colspan="1" rowspan="1">24.</td> |
---|
2244 | <td colspan="1" rowspan="1"></td> |
---|
2245 | |
---|
2246 | </tr> |
---|
2247 | |
---|
2248 | <tr> |
---|
2249 | |
---|
2250 | <td colspan="1" rowspan="1">25.</td> |
---|
2251 | <td colspan="1" rowspan="1"> |
---|
2252 | |
---|
2253 | <span class="codefrag">private long numRecords = 0;</span> |
---|
2254 | </td> |
---|
2255 | |
---|
2256 | </tr> |
---|
2257 | |
---|
2258 | <tr> |
---|
2259 | |
---|
2260 | <td colspan="1" rowspan="1">26.</td> |
---|
2261 | <td colspan="1" rowspan="1"> |
---|
2262 | |
---|
2263 | <span class="codefrag">private String inputFile;</span> |
---|
2264 | </td> |
---|
2265 | |
---|
2266 | </tr> |
---|
2267 | |
---|
2268 | <tr> |
---|
2269 | |
---|
2270 | <td colspan="1" rowspan="1">27.</td> |
---|
2271 | <td colspan="1" rowspan="1"></td> |
---|
2272 | |
---|
2273 | </tr> |
---|
2274 | |
---|
2275 | <tr> |
---|
2276 | |
---|
2277 | <td colspan="1" rowspan="1">28.</td> |
---|
2278 | <td colspan="1" rowspan="1"> |
---|
2279 | |
---|
2280 | <span class="codefrag">public void configure(JobConf job) {</span> |
---|
2281 | </td> |
---|
2282 | |
---|
2283 | </tr> |
---|
2284 | |
---|
2285 | <tr> |
---|
2286 | |
---|
2287 | <td colspan="1" rowspan="1">29.</td> |
---|
2288 | <td colspan="1" rowspan="1"> |
---|
2289 | |
---|
2290 | <span class="codefrag"> |
---|
2291 | caseSensitive = job.getBoolean("wordcount.case.sensitive", true); |
---|
2292 | </span> |
---|
2293 | </td> |
---|
2294 | |
---|
2295 | </tr> |
---|
2296 | |
---|
2297 | <tr> |
---|
2298 | |
---|
2299 | <td colspan="1" rowspan="1">30.</td> |
---|
2300 | <td colspan="1" rowspan="1"> |
---|
2301 | |
---|
2302 | <span class="codefrag">inputFile = job.get("map.input.file");</span> |
---|
2303 | </td> |
---|
2304 | |
---|
2305 | </tr> |
---|
2306 | |
---|
2307 | <tr> |
---|
2308 | |
---|
2309 | <td colspan="1" rowspan="1">31.</td> |
---|
2310 | <td colspan="1" rowspan="1"></td> |
---|
2311 | |
---|
2312 | </tr> |
---|
2313 | |
---|
2314 | <tr> |
---|
2315 | |
---|
2316 | <td colspan="1" rowspan="1">32.</td> |
---|
2317 | <td colspan="1" rowspan="1"> |
---|
2318 | |
---|
2319 | <span class="codefrag">if (job.getBoolean("wordcount.skip.patterns", false)) {</span> |
---|
2320 | </td> |
---|
2321 | |
---|
2322 | </tr> |
---|
2323 | |
---|
2324 | <tr> |
---|
2325 | |
---|
2326 | <td colspan="1" rowspan="1">33.</td> |
---|
2327 | <td colspan="1" rowspan="1"> |
---|
2328 | |
---|
2329 | <span class="codefrag">Path[] patternsFiles = new Path[0];</span> |
---|
2330 | </td> |
---|
2331 | |
---|
2332 | </tr> |
---|
2333 | |
---|
2334 | <tr> |
---|
2335 | |
---|
2336 | <td colspan="1" rowspan="1">34.</td> |
---|
2337 | <td colspan="1" rowspan="1"> |
---|
2338 | |
---|
2339 | <span class="codefrag">try {</span> |
---|
2340 | </td> |
---|
2341 | |
---|
2342 | </tr> |
---|
2343 | |
---|
2344 | <tr> |
---|
2345 | |
---|
2346 | <td colspan="1" rowspan="1">35.</td> |
---|
2347 | <td colspan="1" rowspan="1"> |
---|
2348 | |
---|
2349 | <span class="codefrag"> |
---|
2350 | patternsFiles = DistributedCache.getLocalCacheFiles(job); |
---|
2351 | </span> |
---|
2352 | </td> |
---|
2353 | |
---|
2354 | </tr> |
---|
2355 | |
---|
2356 | <tr> |
---|
2357 | |
---|
2358 | <td colspan="1" rowspan="1">36.</td> |
---|
2359 | <td colspan="1" rowspan="1"> |
---|
2360 | |
---|
2361 | <span class="codefrag">} catch (IOException ioe) {</span> |
---|
2362 | </td> |
---|
2363 | |
---|
2364 | </tr> |
---|
2365 | |
---|
2366 | <tr> |
---|
2367 | |
---|
2368 | <td colspan="1" rowspan="1">37.</td> |
---|
2369 | <td colspan="1" rowspan="1"> |
---|
2370 | |
---|
2371 | <span class="codefrag"> |
---|
2372 | System.err.println("Caught exception while getting cached files: " |
---|
2373 | + StringUtils.stringifyException(ioe)); |
---|
2374 | </span> |
---|
2375 | </td> |
---|
2376 | |
---|
2377 | </tr> |
---|
2378 | |
---|
2379 | <tr> |
---|
2380 | |
---|
2381 | <td colspan="1" rowspan="1">38.</td> |
---|
2382 | <td colspan="1" rowspan="1"> |
---|
2383 | |
---|
2384 | <span class="codefrag">}</span> |
---|
2385 | </td> |
---|
2386 | |
---|
2387 | </tr> |
---|
2388 | |
---|
2389 | <tr> |
---|
2390 | |
---|
2391 | <td colspan="1" rowspan="1">39.</td> |
---|
2392 | <td colspan="1" rowspan="1"> |
---|
2393 | |
---|
2394 | <span class="codefrag">for (Path patternsFile : patternsFiles) {</span> |
---|
2395 | </td> |
---|
2396 | |
---|
2397 | </tr> |
---|
2398 | |
---|
2399 | <tr> |
---|
2400 | |
---|
2401 | <td colspan="1" rowspan="1">40.</td> |
---|
2402 | <td colspan="1" rowspan="1"> |
---|
2403 | |
---|
2404 | <span class="codefrag">parseSkipFile(patternsFile);</span> |
---|
2405 | </td> |
---|
2406 | |
---|
2407 | </tr> |
---|
2408 | |
---|
2409 | <tr> |
---|
2410 | |
---|
2411 | <td colspan="1" rowspan="1">41.</td> |
---|
2412 | <td colspan="1" rowspan="1"> |
---|
2413 | |
---|
2414 | <span class="codefrag">}</span> |
---|
2415 | </td> |
---|
2416 | |
---|
2417 | </tr> |
---|
2418 | |
---|
2419 | <tr> |
---|
2420 | |
---|
2421 | <td colspan="1" rowspan="1">42.</td> |
---|
2422 | <td colspan="1" rowspan="1"> |
---|
2423 | |
---|
2424 | <span class="codefrag">}</span> |
---|
2425 | </td> |
---|
2426 | |
---|
2427 | </tr> |
---|
2428 | |
---|
2429 | <tr> |
---|
2430 | |
---|
2431 | <td colspan="1" rowspan="1">43.</td> |
---|
2432 | <td colspan="1" rowspan="1"> |
---|
2433 | |
---|
2434 | <span class="codefrag">}</span> |
---|
2435 | </td> |
---|
2436 | |
---|
2437 | </tr> |
---|
2438 | |
---|
2439 | <tr> |
---|
2440 | |
---|
2441 | <td colspan="1" rowspan="1">44.</td> |
---|
2442 | <td colspan="1" rowspan="1"></td> |
---|
2443 | |
---|
2444 | </tr> |
---|
2445 | |
---|
2446 | <tr> |
---|
2447 | |
---|
2448 | <td colspan="1" rowspan="1">45.</td> |
---|
2449 | <td colspan="1" rowspan="1"> |
---|
2450 | |
---|
2451 | <span class="codefrag">private void parseSkipFile(Path patternsFile) {</span> |
---|
2452 | </td> |
---|
2453 | |
---|
2454 | </tr> |
---|
2455 | |
---|
2456 | <tr> |
---|
2457 | |
---|
2458 | <td colspan="1" rowspan="1">46.</td> |
---|
2459 | <td colspan="1" rowspan="1"> |
---|
2460 | |
---|
2461 | <span class="codefrag">try {</span> |
---|
2462 | </td> |
---|
2463 | |
---|
2464 | </tr> |
---|
2465 | |
---|
2466 | <tr> |
---|
2467 | |
---|
2468 | <td colspan="1" rowspan="1">47.</td> |
---|
2469 | <td colspan="1" rowspan="1"> |
---|
2470 | |
---|
2471 | <span class="codefrag"> |
---|
2472 | BufferedReader fis = |
---|
2473 | new BufferedReader(new FileReader(patternsFile.toString())); |
---|
2474 | </span> |
---|
2475 | </td> |
---|
2476 | |
---|
2477 | </tr> |
---|
2478 | |
---|
2479 | <tr> |
---|
2480 | |
---|
2481 | <td colspan="1" rowspan="1">48.</td> |
---|
2482 | <td colspan="1" rowspan="1"> |
---|
2483 | |
---|
2484 | <span class="codefrag">String pattern = null;</span> |
---|
2485 | </td> |
---|
2486 | |
---|
2487 | </tr> |
---|
2488 | |
---|
2489 | <tr> |
---|
2490 | |
---|
2491 | <td colspan="1" rowspan="1">49.</td> |
---|
2492 | <td colspan="1" rowspan="1"> |
---|
2493 | |
---|
2494 | <span class="codefrag">while ((pattern = fis.readLine()) != null) {</span> |
---|
2495 | </td> |
---|
2496 | |
---|
2497 | </tr> |
---|
2498 | |
---|
2499 | <tr> |
---|
2500 | |
---|
2501 | <td colspan="1" rowspan="1">50.</td> |
---|
2502 | <td colspan="1" rowspan="1"> |
---|
2503 | |
---|
2504 | <span class="codefrag">patternsToSkip.add(pattern);</span> |
---|
2505 | </td> |
---|
2506 | |
---|
2507 | </tr> |
---|
2508 | |
---|
2509 | <tr> |
---|
2510 | |
---|
2511 | <td colspan="1" rowspan="1">51.</td> |
---|
2512 | <td colspan="1" rowspan="1"> |
---|
2513 | |
---|
2514 | <span class="codefrag">}</span> |
---|
2515 | </td> |
---|
2516 | |
---|
2517 | </tr> |
---|
2518 | |
---|
2519 | <tr> |
---|
2520 | |
---|
2521 | <td colspan="1" rowspan="1">52.</td> |
---|
2522 | <td colspan="1" rowspan="1"> |
---|
2523 | |
---|
2524 | <span class="codefrag">} catch (IOException ioe) {</span> |
---|
2525 | </td> |
---|
2526 | |
---|
2527 | </tr> |
---|
2528 | |
---|
2529 | <tr> |
---|
2530 | |
---|
2531 | <td colspan="1" rowspan="1">53.</td> |
---|
2532 | <td colspan="1" rowspan="1"> |
---|
2533 | |
---|
2534 | <span class="codefrag"> |
---|
2535 | System.err.println("Caught exception while parsing the cached file '" + |
---|
2536 | patternsFile + "' : " + |
---|
2537 | StringUtils.stringifyException(ioe)); |
---|
2538 | |
---|
2539 | </span> |
---|
2540 | </td> |
---|
2541 | |
---|
2542 | </tr> |
---|
2543 | |
---|
2544 | <tr> |
---|
2545 | |
---|
2546 | <td colspan="1" rowspan="1">54.</td> |
---|
2547 | <td colspan="1" rowspan="1"> |
---|
2548 | |
---|
2549 | <span class="codefrag">}</span> |
---|
2550 | </td> |
---|
2551 | |
---|
2552 | </tr> |
---|
2553 | |
---|
2554 | <tr> |
---|
2555 | |
---|
2556 | <td colspan="1" rowspan="1">55.</td> |
---|
2557 | <td colspan="1" rowspan="1"> |
---|
2558 | |
---|
2559 | <span class="codefrag">}</span> |
---|
2560 | </td> |
---|
2561 | |
---|
2562 | </tr> |
---|
2563 | |
---|
2564 | <tr> |
---|
2565 | |
---|
2566 | <td colspan="1" rowspan="1">56.</td> |
---|
2567 | <td colspan="1" rowspan="1"></td> |
---|
2568 | |
---|
2569 | </tr> |
---|
2570 | |
---|
2571 | <tr> |
---|
2572 | |
---|
2573 | <td colspan="1" rowspan="1">57.</td> |
---|
2574 | <td colspan="1" rowspan="1"> |
---|
2575 | |
---|
2576 | <span class="codefrag"> |
---|
2577 | public void map(LongWritable key, Text value, |
---|
2578 | OutputCollector<Text, IntWritable> output, |
---|
2579 | Reporter reporter) throws IOException { |
---|
2580 | </span> |
---|
2581 | </td> |
---|
2582 | |
---|
2583 | </tr> |
---|
2584 | |
---|
2585 | <tr> |
---|
2586 | |
---|
2587 | <td colspan="1" rowspan="1">58.</td> |
---|
2588 | <td colspan="1" rowspan="1"> |
---|
2589 | |
---|
2590 | <span class="codefrag"> |
---|
2591 | String line = |
---|
2592 | (caseSensitive) ? value.toString() : |
---|
2593 | value.toString().toLowerCase(); |
---|
2594 | </span> |
---|
2595 | </td> |
---|
2596 | |
---|
2597 | </tr> |
---|
2598 | |
---|
2599 | <tr> |
---|
2600 | |
---|
2601 | <td colspan="1" rowspan="1">59.</td> |
---|
2602 | <td colspan="1" rowspan="1"></td> |
---|
2603 | |
---|
2604 | </tr> |
---|
2605 | |
---|
2606 | <tr> |
---|
2607 | |
---|
2608 | <td colspan="1" rowspan="1">60.</td> |
---|
2609 | <td colspan="1" rowspan="1"> |
---|
2610 | |
---|
2611 | <span class="codefrag">for (String pattern : patternsToSkip) {</span> |
---|
2612 | </td> |
---|
2613 | |
---|
2614 | </tr> |
---|
2615 | |
---|
2616 | <tr> |
---|
2617 | |
---|
2618 | <td colspan="1" rowspan="1">61.</td> |
---|
2619 | <td colspan="1" rowspan="1"> |
---|
2620 | |
---|
2621 | <span class="codefrag">line = line.replaceAll(pattern, "");</span> |
---|
2622 | </td> |
---|
2623 | |
---|
2624 | </tr> |
---|
2625 | |
---|
2626 | <tr> |
---|
2627 | |
---|
2628 | <td colspan="1" rowspan="1">62.</td> |
---|
2629 | <td colspan="1" rowspan="1"> |
---|
2630 | |
---|
2631 | <span class="codefrag">}</span> |
---|
2632 | </td> |
---|
2633 | |
---|
2634 | </tr> |
---|
2635 | |
---|
2636 | <tr> |
---|
2637 | |
---|
2638 | <td colspan="1" rowspan="1">63.</td> |
---|
2639 | <td colspan="1" rowspan="1"></td> |
---|
2640 | |
---|
2641 | </tr> |
---|
2642 | |
---|
2643 | <tr> |
---|
2644 | |
---|
2645 | <td colspan="1" rowspan="1">64.</td> |
---|
2646 | <td colspan="1" rowspan="1"> |
---|
2647 | |
---|
2648 | <span class="codefrag">StringTokenizer tokenizer = new StringTokenizer(line);</span> |
---|
2649 | </td> |
---|
2650 | |
---|
2651 | </tr> |
---|
2652 | |
---|
2653 | <tr> |
---|
2654 | |
---|
2655 | <td colspan="1" rowspan="1">65.</td> |
---|
2656 | <td colspan="1" rowspan="1"> |
---|
2657 | |
---|
2658 | <span class="codefrag">while (tokenizer.hasMoreTokens()) {</span> |
---|
2659 | </td> |
---|
2660 | |
---|
2661 | </tr> |
---|
2662 | |
---|
2663 | <tr> |
---|
2664 | |
---|
2665 | <td colspan="1" rowspan="1">66.</td> |
---|
2666 | <td colspan="1" rowspan="1"> |
---|
2667 | |
---|
2668 | <span class="codefrag">word.set(tokenizer.nextToken());</span> |
---|
2669 | </td> |
---|
2670 | |
---|
2671 | </tr> |
---|
2672 | |
---|
2673 | <tr> |
---|
2674 | |
---|
2675 | <td colspan="1" rowspan="1">67.</td> |
---|
2676 | <td colspan="1" rowspan="1"> |
---|
2677 | |
---|
2678 | <span class="codefrag">output.collect(word, one);</span> |
---|
2679 | </td> |
---|
2680 | |
---|
2681 | </tr> |
---|
2682 | |
---|
2683 | <tr> |
---|
2684 | |
---|
2685 | <td colspan="1" rowspan="1">68.</td> |
---|
2686 | <td colspan="1" rowspan="1"> |
---|
2687 | |
---|
2688 | <span class="codefrag">reporter.incrCounter(Counters.INPUT_WORDS, 1);</span> |
---|
2689 | </td> |
---|
2690 | |
---|
2691 | </tr> |
---|
2692 | |
---|
2693 | <tr> |
---|
2694 | |
---|
2695 | <td colspan="1" rowspan="1">69.</td> |
---|
2696 | <td colspan="1" rowspan="1"> |
---|
2697 | |
---|
2698 | <span class="codefrag">}</span> |
---|
2699 | </td> |
---|
2700 | |
---|
2701 | </tr> |
---|
2702 | |
---|
2703 | <tr> |
---|
2704 | |
---|
2705 | <td colspan="1" rowspan="1">70.</td> |
---|
2706 | <td colspan="1" rowspan="1"></td> |
---|
2707 | |
---|
2708 | </tr> |
---|
2709 | |
---|
2710 | <tr> |
---|
2711 | |
---|
2712 | <td colspan="1" rowspan="1">71.</td> |
---|
2713 | <td colspan="1" rowspan="1"> |
---|
2714 | |
---|
2715 | <span class="codefrag">if ((++numRecords % 100) == 0) {</span> |
---|
2716 | </td> |
---|
2717 | |
---|
2718 | </tr> |
---|
2719 | |
---|
2720 | <tr> |
---|
2721 | |
---|
2722 | <td colspan="1" rowspan="1">72.</td> |
---|
2723 | <td colspan="1" rowspan="1"> |
---|
2724 | |
---|
2725 | <span class="codefrag"> |
---|
2726 | reporter.setStatus("Finished processing " + numRecords + |
---|
2727 | " records " + "from the input file: " + |
---|
2728 | inputFile); |
---|
2729 | </span> |
---|
2730 | </td> |
---|
2731 | |
---|
2732 | </tr> |
---|
2733 | |
---|
2734 | <tr> |
---|
2735 | |
---|
2736 | <td colspan="1" rowspan="1">73.</td> |
---|
2737 | <td colspan="1" rowspan="1"> |
---|
2738 | |
---|
2739 | <span class="codefrag">}</span> |
---|
2740 | </td> |
---|
2741 | |
---|
2742 | </tr> |
---|
2743 | |
---|
2744 | <tr> |
---|
2745 | |
---|
2746 | <td colspan="1" rowspan="1">74.</td> |
---|
2747 | <td colspan="1" rowspan="1"> |
---|
2748 | |
---|
2749 | <span class="codefrag">}</span> |
---|
2750 | </td> |
---|
2751 | |
---|
2752 | </tr> |
---|
2753 | |
---|
2754 | <tr> |
---|
2755 | |
---|
2756 | <td colspan="1" rowspan="1">75.</td> |
---|
2757 | <td colspan="1" rowspan="1"> |
---|
2758 | |
---|
2759 | <span class="codefrag">}</span> |
---|
2760 | </td> |
---|
2761 | |
---|
2762 | </tr> |
---|
2763 | |
---|
2764 | <tr> |
---|
2765 | |
---|
2766 | <td colspan="1" rowspan="1">76.</td> |
---|
2767 | <td colspan="1" rowspan="1"></td> |
---|
2768 | |
---|
2769 | </tr> |
---|
2770 | |
---|
2771 | <tr> |
---|
2772 | |
---|
2773 | <td colspan="1" rowspan="1">77.</td> |
---|
2774 | <td colspan="1" rowspan="1"> |
---|
2775 | |
---|
2776 | <span class="codefrag"> |
---|
2777 | public static class Reduce extends MapReduceBase implements |
---|
2778 | Reducer<Text, IntWritable, Text, IntWritable> { |
---|
2779 | </span> |
---|
2780 | </td> |
---|
2781 | |
---|
2782 | </tr> |
---|
2783 | |
---|
2784 | <tr> |
---|
2785 | |
---|
2786 | <td colspan="1" rowspan="1">78.</td> |
---|
2787 | <td colspan="1" rowspan="1"> |
---|
2788 | |
---|
2789 | <span class="codefrag"> |
---|
2790 | public void reduce(Text key, Iterator<IntWritable> values, |
---|
2791 | OutputCollector<Text, IntWritable> output, |
---|
2792 | Reporter reporter) throws IOException { |
---|
2793 | </span> |
---|
2794 | </td> |
---|
2795 | |
---|
2796 | </tr> |
---|
2797 | |
---|
2798 | <tr> |
---|
2799 | |
---|
2800 | <td colspan="1" rowspan="1">79.</td> |
---|
2801 | <td colspan="1" rowspan="1"> |
---|
2802 | |
---|
2803 | <span class="codefrag">int sum = 0;</span> |
---|
2804 | </td> |
---|
2805 | |
---|
2806 | </tr> |
---|
2807 | |
---|
2808 | <tr> |
---|
2809 | |
---|
2810 | <td colspan="1" rowspan="1">80.</td> |
---|
2811 | <td colspan="1" rowspan="1"> |
---|
2812 | |
---|
2813 | <span class="codefrag">while (values.hasNext()) {</span> |
---|
2814 | </td> |
---|
2815 | |
---|
2816 | </tr> |
---|
2817 | |
---|
2818 | <tr> |
---|
2819 | |
---|
2820 | <td colspan="1" rowspan="1">81.</td> |
---|
2821 | <td colspan="1" rowspan="1"> |
---|
2822 | |
---|
2823 | <span class="codefrag">sum += values.next().get();</span> |
---|
2824 | </td> |
---|
2825 | |
---|
2826 | </tr> |
---|
2827 | |
---|
2828 | <tr> |
---|
2829 | |
---|
2830 | <td colspan="1" rowspan="1">82.</td> |
---|
2831 | <td colspan="1" rowspan="1"> |
---|
2832 | |
---|
2833 | <span class="codefrag">}</span> |
---|
2834 | </td> |
---|
2835 | |
---|
2836 | </tr> |
---|
2837 | |
---|
2838 | <tr> |
---|
2839 | |
---|
2840 | <td colspan="1" rowspan="1">83.</td> |
---|
2841 | <td colspan="1" rowspan="1"> |
---|
2842 | |
---|
2843 | <span class="codefrag">output.collect(key, new IntWritable(sum));</span> |
---|
2844 | </td> |
---|
2845 | |
---|
2846 | </tr> |
---|
2847 | |
---|
2848 | <tr> |
---|
2849 | |
---|
2850 | <td colspan="1" rowspan="1">84.</td> |
---|
2851 | <td colspan="1" rowspan="1"> |
---|
2852 | |
---|
2853 | <span class="codefrag">}</span> |
---|
2854 | </td> |
---|
2855 | |
---|
2856 | </tr> |
---|
2857 | |
---|
2858 | <tr> |
---|
2859 | |
---|
2860 | <td colspan="1" rowspan="1">85.</td> |
---|
2861 | <td colspan="1" rowspan="1"> |
---|
2862 | |
---|
2863 | <span class="codefrag">}</span> |
---|
2864 | </td> |
---|
2865 | |
---|
2866 | </tr> |
---|
2867 | |
---|
2868 | <tr> |
---|
2869 | |
---|
2870 | <td colspan="1" rowspan="1">86.</td> |
---|
2871 | <td colspan="1" rowspan="1"></td> |
---|
2872 | |
---|
2873 | </tr> |
---|
2874 | |
---|
2875 | <tr> |
---|
2876 | |
---|
2877 | <td colspan="1" rowspan="1">87.</td> |
---|
2878 | <td colspan="1" rowspan="1"> |
---|
2879 | |
---|
2880 | <span class="codefrag">public int run(String[] args) throws Exception {</span> |
---|
2881 | </td> |
---|
2882 | |
---|
2883 | </tr> |
---|
2884 | |
---|
2885 | <tr> |
---|
2886 | |
---|
2887 | <td colspan="1" rowspan="1">88.</td> |
---|
2888 | <td colspan="1" rowspan="1"> |
---|
2889 | |
---|
2890 | <span class="codefrag"> |
---|
2891 | JobConf conf = new JobConf(getConf(), WordCount.class); |
---|
2892 | </span> |
---|
2893 | </td> |
---|
2894 | |
---|
2895 | </tr> |
---|
2896 | |
---|
2897 | <tr> |
---|
2898 | |
---|
2899 | <td colspan="1" rowspan="1">89.</td> |
---|
2900 | <td colspan="1" rowspan="1"> |
---|
2901 | |
---|
2902 | <span class="codefrag">conf.setJobName("wordcount");</span> |
---|
2903 | </td> |
---|
2904 | |
---|
2905 | </tr> |
---|
2906 | |
---|
2907 | <tr> |
---|
2908 | |
---|
2909 | <td colspan="1" rowspan="1">90.</td> |
---|
2910 | <td colspan="1" rowspan="1"></td> |
---|
2911 | |
---|
2912 | </tr> |
---|
2913 | |
---|
2914 | <tr> |
---|
2915 | |
---|
2916 | <td colspan="1" rowspan="1">91.</td> |
---|
2917 | <td colspan="1" rowspan="1"> |
---|
2918 | |
---|
2919 | <span class="codefrag">conf.setOutputKeyClass(Text.class);</span> |
---|
2920 | </td> |
---|
2921 | |
---|
2922 | </tr> |
---|
2923 | |
---|
2924 | <tr> |
---|
2925 | |
---|
2926 | <td colspan="1" rowspan="1">92.</td> |
---|
2927 | <td colspan="1" rowspan="1"> |
---|
2928 | |
---|
2929 | <span class="codefrag">conf.setOutputValueClass(IntWritable.class);</span> |
---|
2930 | </td> |
---|
2931 | |
---|
2932 | </tr> |
---|
2933 | |
---|
2934 | <tr> |
---|
2935 | |
---|
2936 | <td colspan="1" rowspan="1">93.</td> |
---|
2937 | <td colspan="1" rowspan="1"></td> |
---|
2938 | |
---|
2939 | </tr> |
---|
2940 | |
---|
2941 | <tr> |
---|
2942 | |
---|
2943 | <td colspan="1" rowspan="1">94.</td> |
---|
2944 | <td colspan="1" rowspan="1"> |
---|
2945 | |
---|
2946 | <span class="codefrag">conf.setMapperClass(Map.class);</span> |
---|
2947 | </td> |
---|
2948 | |
---|
2949 | </tr> |
---|
2950 | |
---|
2951 | <tr> |
---|
2952 | |
---|
2953 | <td colspan="1" rowspan="1">95.</td> |
---|
2954 | <td colspan="1" rowspan="1"> |
---|
2955 | |
---|
2956 | <span class="codefrag">conf.setCombinerClass(Reduce.class);</span> |
---|
2957 | </td> |
---|
2958 | |
---|
2959 | </tr> |
---|
2960 | |
---|
2961 | <tr> |
---|
2962 | |
---|
2963 | <td colspan="1" rowspan="1">96.</td> |
---|
2964 | <td colspan="1" rowspan="1"> |
---|
2965 | |
---|
2966 | <span class="codefrag">conf.setReducerClass(Reduce.class);</span> |
---|
2967 | </td> |
---|
2968 | |
---|
2969 | </tr> |
---|
2970 | |
---|
2971 | <tr> |
---|
2972 | |
---|
2973 | <td colspan="1" rowspan="1">97.</td> |
---|
2974 | <td colspan="1" rowspan="1"></td> |
---|
2975 | |
---|
2976 | </tr> |
---|
2977 | |
---|
2978 | <tr> |
---|
2979 | |
---|
2980 | <td colspan="1" rowspan="1">98.</td> |
---|
2981 | <td colspan="1" rowspan="1"> |
---|
2982 | |
---|
2983 | <span class="codefrag">conf.setInputFormat(TextInputFormat.class);</span> |
---|
2984 | </td> |
---|
2985 | |
---|
2986 | </tr> |
---|
2987 | |
---|
2988 | <tr> |
---|
2989 | |
---|
2990 | <td colspan="1" rowspan="1">99.</td> |
---|
2991 | <td colspan="1" rowspan="1"> |
---|
2992 | |
---|
2993 | <span class="codefrag">conf.setOutputFormat(TextOutputFormat.class);</span> |
---|
2994 | </td> |
---|
2995 | |
---|
2996 | </tr> |
---|
2997 | |
---|
2998 | <tr> |
---|
2999 | |
---|
3000 | <td colspan="1" rowspan="1">100.</td> |
---|
3001 | <td colspan="1" rowspan="1"></td> |
---|
3002 | |
---|
3003 | </tr> |
---|
3004 | |
---|
3005 | <tr> |
---|
3006 | |
---|
3007 | <td colspan="1" rowspan="1">101.</td> |
---|
3008 | <td colspan="1" rowspan="1"> |
---|
3009 | |
---|
3010 | <span class="codefrag"> |
---|
3011 | List<String> other_args = new ArrayList<String>(); |
---|
3012 | </span> |
---|
3013 | </td> |
---|
3014 | |
---|
3015 | </tr> |
---|
3016 | |
---|
3017 | <tr> |
---|
3018 | |
---|
3019 | <td colspan="1" rowspan="1">102.</td> |
---|
3020 | <td colspan="1" rowspan="1"> |
---|
3021 | |
---|
3022 | <span class="codefrag">for (int i=0; i < args.length; ++i) {</span> |
---|
3023 | </td> |
---|
3024 | |
---|
3025 | </tr> |
---|
3026 | |
---|
3027 | <tr> |
---|
3028 | |
---|
3029 | <td colspan="1" rowspan="1">103.</td> |
---|
3030 | <td colspan="1" rowspan="1"> |
---|
3031 | |
---|
3032 | <span class="codefrag">if ("-skip".equals(args[i])) {</span> |
---|
3033 | </td> |
---|
3034 | |
---|
3035 | </tr> |
---|
3036 | |
---|
3037 | <tr> |
---|
3038 | |
---|
3039 | <td colspan="1" rowspan="1">104.</td> |
---|
3040 | <td colspan="1" rowspan="1"> |
---|
3041 | |
---|
3042 | <span class="codefrag"> |
---|
3043 | DistributedCache.addCacheFile(new Path(args[++i]).toUri(), conf); |
---|
3044 | </span> |
---|
3045 | </td> |
---|
3046 | |
---|
3047 | </tr> |
---|
3048 | |
---|
3049 | <tr> |
---|
3050 | |
---|
3051 | <td colspan="1" rowspan="1">105.</td> |
---|
3052 | <td colspan="1" rowspan="1"> |
---|
3053 | |
---|
3054 | <span class="codefrag"> |
---|
3055 | conf.setBoolean("wordcount.skip.patterns", true); |
---|
3056 | </span> |
---|
3057 | </td> |
---|
3058 | |
---|
3059 | </tr> |
---|
3060 | |
---|
3061 | <tr> |
---|
3062 | |
---|
3063 | <td colspan="1" rowspan="1">106.</td> |
---|
3064 | <td colspan="1" rowspan="1"> |
---|
3065 | |
---|
3066 | <span class="codefrag">} else {</span> |
---|
3067 | </td> |
---|
3068 | |
---|
3069 | </tr> |
---|
3070 | |
---|
3071 | <tr> |
---|
3072 | |
---|
3073 | <td colspan="1" rowspan="1">107.</td> |
---|
3074 | <td colspan="1" rowspan="1"> |
---|
3075 | |
---|
3076 | <span class="codefrag">other_args.add(args[i]);</span> |
---|
3077 | </td> |
---|
3078 | |
---|
3079 | </tr> |
---|
3080 | |
---|
3081 | <tr> |
---|
3082 | |
---|
3083 | <td colspan="1" rowspan="1">108.</td> |
---|
3084 | <td colspan="1" rowspan="1"> |
---|
3085 | |
---|
3086 | <span class="codefrag">}</span> |
---|
3087 | </td> |
---|
3088 | |
---|
3089 | </tr> |
---|
3090 | |
---|
3091 | <tr> |
---|
3092 | |
---|
3093 | <td colspan="1" rowspan="1">109.</td> |
---|
3094 | <td colspan="1" rowspan="1"> |
---|
3095 | |
---|
3096 | <span class="codefrag">}</span> |
---|
3097 | </td> |
---|
3098 | |
---|
3099 | </tr> |
---|
3100 | |
---|
3101 | <tr> |
---|
3102 | |
---|
3103 | <td colspan="1" rowspan="1">110.</td> |
---|
3104 | <td colspan="1" rowspan="1"></td> |
---|
3105 | |
---|
3106 | </tr> |
---|
3107 | |
---|
3108 | <tr> |
---|
3109 | |
---|
3110 | <td colspan="1" rowspan="1">111.</td> |
---|
3111 | <td colspan="1" rowspan="1"> |
---|
3112 | |
---|
3113 | <span class="codefrag">FileInputFormat.setInputPaths(conf, new Path(other_args.get(0)));</span> |
---|
3114 | </td> |
---|
3115 | |
---|
3116 | </tr> |
---|
3117 | |
---|
3118 | <tr> |
---|
3119 | |
---|
3120 | <td colspan="1" rowspan="1">112.</td> |
---|
3121 | <td colspan="1" rowspan="1"> |
---|
3122 | |
---|
3123 | <span class="codefrag">FileOutputFormat.setOutputPath(conf, new Path(other_args.get(1)));</span> |
---|
3124 | </td> |
---|
3125 | |
---|
3126 | </tr> |
---|
3127 | |
---|
3128 | <tr> |
---|
3129 | |
---|
3130 | <td colspan="1" rowspan="1">113.</td> |
---|
3131 | <td colspan="1" rowspan="1"></td> |
---|
3132 | |
---|
3133 | </tr> |
---|
3134 | |
---|
3135 | <tr> |
---|
3136 | |
---|
3137 | <td colspan="1" rowspan="1">114.</td> |
---|
3138 | <td colspan="1" rowspan="1"> |
---|
3139 | |
---|
3140 | <span class="codefrag">JobClient.runJob(conf);</span> |
---|
3141 | </td> |
---|
3142 | |
---|
3143 | </tr> |
---|
3144 | |
---|
3145 | <tr> |
---|
3146 | |
---|
3147 | <td colspan="1" rowspan="1">115.</td> |
---|
3148 | <td colspan="1" rowspan="1"> |
---|
3149 | |
---|
3150 | <span class="codefrag">return 0;</span> |
---|
3151 | </td> |
---|
3152 | |
---|
3153 | </tr> |
---|
3154 | |
---|
3155 | <tr> |
---|
3156 | |
---|
3157 | <td colspan="1" rowspan="1">116.</td> |
---|
3158 | <td colspan="1" rowspan="1"> |
---|
3159 | |
---|
3160 | <span class="codefrag">}</span> |
---|
3161 | </td> |
---|
3162 | |
---|
3163 | </tr> |
---|
3164 | |
---|
3165 | <tr> |
---|
3166 | |
---|
3167 | <td colspan="1" rowspan="1">117.</td> |
---|
3168 | <td colspan="1" rowspan="1"></td> |
---|
3169 | |
---|
3170 | </tr> |
---|
3171 | |
---|
3172 | <tr> |
---|
3173 | |
---|
3174 | <td colspan="1" rowspan="1">118.</td> |
---|
3175 | <td colspan="1" rowspan="1"> |
---|
3176 | |
---|
3177 | <span class="codefrag"> |
---|
3178 | public static void main(String[] args) throws Exception { |
---|
3179 | </span> |
---|
3180 | </td> |
---|
3181 | |
---|
3182 | </tr> |
---|
3183 | |
---|
3184 | <tr> |
---|
3185 | |
---|
3186 | <td colspan="1" rowspan="1">119.</td> |
---|
3187 | <td colspan="1" rowspan="1"> |
---|
3188 | |
---|
3189 | <span class="codefrag"> |
---|
3190 | int res = ToolRunner.run(new Configuration(), new WordCount(), |
---|
3191 | args); |
---|
3192 | </span> |
---|
3193 | </td> |
---|
3194 | |
---|
3195 | </tr> |
---|
3196 | |
---|
3197 | <tr> |
---|
3198 | |
---|
3199 | <td colspan="1" rowspan="1">120.</td> |
---|
3200 | <td colspan="1" rowspan="1"> |
---|
3201 | |
---|
3202 | <span class="codefrag">System.exit(res);</span> |
---|
3203 | </td> |
---|
3204 | |
---|
3205 | </tr> |
---|
3206 | |
---|
3207 | <tr> |
---|
3208 | |
---|
3209 | <td colspan="1" rowspan="1">121.</td> |
---|
3210 | <td colspan="1" rowspan="1"> |
---|
3211 | |
---|
3212 | <span class="codefrag">}</span> |
---|
3213 | </td> |
---|
3214 | |
---|
3215 | </tr> |
---|
3216 | |
---|
3217 | <tr> |
---|
3218 | |
---|
3219 | <td colspan="1" rowspan="1">122.</td> |
---|
3220 | <td colspan="1" rowspan="1"> |
---|
3221 | <span class="codefrag">}</span> |
---|
3222 | </td> |
---|
3223 | |
---|
3224 | </tr> |
---|
3225 | |
---|
3226 | <tr> |
---|
3227 | |
---|
3228 | <td colspan="1" rowspan="1">123.</td> |
---|
3229 | <td colspan="1" rowspan="1"></td> |
---|
3230 | |
---|
3231 | </tr> |
---|
3232 | |
---|
3233 | </table> |
---|
3234 | <a name="N11522"></a><a name="%E8%BF%90%E8%A1%8C%E6%A0%B7%E4%BE%8B"></a> |
---|
3235 | <h3 class="h4">è¿è¡æ ·äŸ</h3> |
---|
3236 | <p>èŸå
¥æ ·äŸïŒ</p> |
---|
3237 | <p> |
---|
3238 | |
---|
3239 | <span class="codefrag">$ bin/hadoop dfs -ls /usr/joe/wordcount/input/</span> |
---|
3240 | <br> |
---|
3241 | |
---|
3242 | <span class="codefrag">/usr/joe/wordcount/input/file01</span> |
---|
3243 | <br> |
---|
3244 | |
---|
3245 | <span class="codefrag">/usr/joe/wordcount/input/file02</span> |
---|
3246 | <br> |
---|
3247 | |
---|
3248 | <br> |
---|
3249 | |
---|
3250 | <span class="codefrag">$ bin/hadoop dfs -cat /usr/joe/wordcount/input/file01</span> |
---|
3251 | <br> |
---|
3252 | |
---|
3253 | <span class="codefrag">Hello World, Bye World!</span> |
---|
3254 | <br> |
---|
3255 | |
---|
3256 | <br> |
---|
3257 | |
---|
3258 | <span class="codefrag">$ bin/hadoop dfs -cat /usr/joe/wordcount/input/file02</span> |
---|
3259 | <br> |
---|
3260 | |
---|
3261 | <span class="codefrag">Hello Hadoop, Goodbye to hadoop.</span> |
---|
3262 | |
---|
3263 | </p> |
---|
3264 | <p>è¿è¡çšåºïŒ</p> |
---|
3265 | <p> |
---|
3266 | |
---|
3267 | <span class="codefrag"> |
---|
3268 | $ bin/hadoop jar /usr/joe/wordcount.jar org.myorg.WordCount |
---|
3269 | /usr/joe/wordcount/input /usr/joe/wordcount/output |
---|
3270 | </span> |
---|
3271 | |
---|
3272 | </p> |
---|
3273 | <p>èŸåºïŒ</p> |
---|
3274 | <p> |
---|
3275 | |
---|
3276 | <span class="codefrag"> |
---|
3277 | $ bin/hadoop dfs -cat /usr/joe/wordcount/output/part-00000 |
---|
3278 | </span> |
---|
3279 | |
---|
3280 | <br> |
---|
3281 | |
---|
3282 | <span class="codefrag">Bye 1</span> |
---|
3283 | <br> |
---|
3284 | |
---|
3285 | <span class="codefrag">Goodbye 1</span> |
---|
3286 | <br> |
---|
3287 | |
---|
3288 | <span class="codefrag">Hadoop, 1</span> |
---|
3289 | <br> |
---|
3290 | |
---|
3291 | <span class="codefrag">Hello 2</span> |
---|
3292 | <br> |
---|
3293 | |
---|
3294 | <span class="codefrag">World! 1</span> |
---|
3295 | <br> |
---|
3296 | |
---|
3297 | <span class="codefrag">World, 1</span> |
---|
3298 | <br> |
---|
3299 | |
---|
3300 | <span class="codefrag">hadoop. 1</span> |
---|
3301 | <br> |
---|
3302 | |
---|
3303 | <span class="codefrag">to 1</span> |
---|
3304 | <br> |
---|
3305 | |
---|
3306 | </p> |
---|
3307 | <p>泚ææ€æ¶çèŸå
¥äžç¬¬äžäžªçæ¬çäžåïŒèŸåºçç»æä¹æäžåã |
---|
3308 | </p> |
---|
3309 | <p>ç°åšéè¿<span class="codefrag">DistributedCache</span>æå
¥äžäžªæš¡åŒæ件ïŒæ件äžä¿åäºèŠè¢«å¿œç¥çåè¯æš¡åŒã |
---|
3310 | </p> |
---|
3311 | <p> |
---|
3312 | |
---|
3313 | <span class="codefrag">$ hadoop dfs -cat /user/joe/wordcount/patterns.txt</span> |
---|
3314 | <br> |
---|
3315 | |
---|
3316 | <span class="codefrag">\.</span> |
---|
3317 | <br> |
---|
3318 | |
---|
3319 | <span class="codefrag">\,</span> |
---|
3320 | <br> |
---|
3321 | |
---|
3322 | <span class="codefrag">\!</span> |
---|
3323 | <br> |
---|
3324 | |
---|
3325 | <span class="codefrag">to</span> |
---|
3326 | <br> |
---|
3327 | |
---|
3328 | </p> |
---|
3329 | <p>åè¿è¡äžæ¬¡ïŒè¿æ¬¡äœ¿çšæŽå€çé项ïŒ</p> |
---|
3330 | <p> |
---|
3331 | |
---|
3332 | <span class="codefrag"> |
---|
3333 | $ bin/hadoop jar /usr/joe/wordcount.jar org.myorg.WordCount |
---|
3334 | -Dwordcount.case.sensitive=true /usr/joe/wordcount/input |
---|
3335 | /usr/joe/wordcount/output -skip /user/joe/wordcount/patterns.txt |
---|
3336 | </span> |
---|
3337 | |
---|
3338 | </p> |
---|
3339 | <p>åºè¯¥åŸå°è¿æ ·çèŸåºïŒ</p> |
---|
3340 | <p> |
---|
3341 | |
---|
3342 | <span class="codefrag"> |
---|
3343 | $ bin/hadoop dfs -cat /usr/joe/wordcount/output/part-00000 |
---|
3344 | </span> |
---|
3345 | |
---|
3346 | <br> |
---|
3347 | |
---|
3348 | <span class="codefrag">Bye 1</span> |
---|
3349 | <br> |
---|
3350 | |
---|
3351 | <span class="codefrag">Goodbye 1</span> |
---|
3352 | <br> |
---|
3353 | |
---|
3354 | <span class="codefrag">Hadoop 1</span> |
---|
3355 | <br> |
---|
3356 | |
---|
3357 | <span class="codefrag">Hello 2</span> |
---|
3358 | <br> |
---|
3359 | |
---|
3360 | <span class="codefrag">World 2</span> |
---|
3361 | <br> |
---|
3362 | |
---|
3363 | <span class="codefrag">hadoop 1</span> |
---|
3364 | <br> |
---|
3365 | |
---|
3366 | </p> |
---|
3367 | <p>åè¿è¡äžæ¬¡ïŒè¿äžæ¬¡å
³é倧å°åæææ§ïŒcase-sensitivityïŒïŒ</p> |
---|
3368 | <p> |
---|
3369 | |
---|
3370 | <span class="codefrag"> |
---|
3371 | $ bin/hadoop jar /usr/joe/wordcount.jar org.myorg.WordCount |
---|
3372 | -Dwordcount.case.sensitive=false /usr/joe/wordcount/input |
---|
3373 | /usr/joe/wordcount/output -skip /user/joe/wordcount/patterns.txt |
---|
3374 | </span> |
---|
3375 | |
---|
3376 | </p> |
---|
3377 | <p>èŸåºïŒ</p> |
---|
3378 | <p> |
---|
3379 | |
---|
3380 | <span class="codefrag"> |
---|
3381 | $ bin/hadoop dfs -cat /usr/joe/wordcount/output/part-00000 |
---|
3382 | </span> |
---|
3383 | |
---|
3384 | <br> |
---|
3385 | |
---|
3386 | <span class="codefrag">bye 1</span> |
---|
3387 | <br> |
---|
3388 | |
---|
3389 | <span class="codefrag">goodbye 1</span> |
---|
3390 | <br> |
---|
3391 | |
---|
3392 | <span class="codefrag">hadoop 2</span> |
---|
3393 | <br> |
---|
3394 | |
---|
3395 | <span class="codefrag">hello 2</span> |
---|
3396 | <br> |
---|
3397 | |
---|
3398 | <span class="codefrag">world 2</span> |
---|
3399 | <br> |
---|
3400 | |
---|
3401 | </p> |
---|
3402 | <a name="N115F6"></a><a name="%E7%A8%8B%E5%BA%8F%E8%A6%81%E7%82%B9"></a> |
---|
3403 | <h3 class="h4">çšåºèŠç¹</h3> |
---|
3404 | <p> |
---|
3405 | éè¿äœ¿çšäžäºMap/Reduceæ¡æ¶æäŸçåèœïŒ<span class="codefrag">WordCount</span>ç第äºäžªçæ¬åšåå§çæ¬åºç¡äžæäºåŠäžçæ¹è¿ïŒ |
---|
3406 | </p> |
---|
3407 | <ul> |
---|
3408 | |
---|
3409 | <li> |
---|
3410 | å±ç€ºäºåºçšçšåºåŠäœåš<span class="codefrag">Mapper</span> (å<span class="codefrag">Reducer</span>)äžéè¿<span class="codefrag">configure</span>æ¹æ³ |
---|
3411 | ä¿®æ¹é
眮åæ°(28-43è¡)ã |
---|
3412 | </li> |
---|
3413 | |
---|
3414 | <li> |
---|
3415 | å±ç€ºäºäœäžåŠäœäœ¿çš<span class="codefrag">DistributedCache</span> æ¥åååªè¯»æ°æ®ã |
---|
3416 | è¿éå
讞çšæ·æå®åè¯çæš¡åŒïŒåšè®¡æ°æ¶å¿œç¥é£äºç¬Šåæš¡åŒçåè¯(104è¡)ã |
---|
3417 | </li> |
---|
3418 | |
---|
3419 | <li> |
---|
3420 | å±ç€º<span class="codefrag">Tool</span>æ¥å£å<span class="codefrag">GenericOptionsParser</span>å€çHadoopåœä»€è¡é项çåèœ |
---|
3421 | (87-116, 119è¡)ã |
---|
3422 | </li> |
---|
3423 | |
---|
3424 | <li> |
---|
3425 | å±ç€ºäºåºçšçšåºåŠäœäœ¿çš<span class="codefrag">Counters</span>(68è¡)ïŒåŠäœéè¿äŒ éç»<span class="codefrag">map</span>ïŒå<span class="codefrag">reduce</span>ïŒ |
---|
3426 | æ¹æ³ç<span class="codefrag">Reporter</span>å®äŸæ¥è®Ÿçœ®åºçšçšåºçç¶æä¿¡æ¯(72è¡)ã |
---|
3427 | </li> |
---|
3428 | |
---|
3429 | </ul> |
---|
3430 | </div> |
---|
3431 | |
---|
3432 | |
---|
3433 | <p> |
---|
3434 | |
---|
3435 | <em>JavaåJNIæ¯Sun Microsystems, Inc.åšçŸåœåå
¶å®åœå®¶ç泚ååæ ã</em> |
---|
3436 | |
---|
3437 | </p> |
---|
3438 | |
---|
3439 | |
---|
3440 | </div> |
---|
3441 | <!--+ |
---|
3442 | |end content |
---|
3443 | +--> |
---|
3444 | <div class="clearboth"> </div> |
---|
3445 | </div> |
---|
3446 | <div id="footer"> |
---|
3447 | <!--+ |
---|
3448 | |start bottomstrip |
---|
3449 | +--> |
---|
3450 | <div class="lastmodified"> |
---|
3451 | <script type="text/javascript"><!-- |
---|
3452 | document.write("Last Published: " + document.lastModified); |
---|
3453 | // --></script> |
---|
3454 | </div> |
---|
3455 | <div class="copyright"> |
---|
3456 | Copyright © |
---|
3457 | 2007 <a href="http://www.apache.org/licenses/">The Apache Software Foundation.</a> |
---|
3458 | </div> |
---|
3459 | <!--+ |
---|
3460 | |end bottomstrip |
---|
3461 | +--> |
---|
3462 | </div> |
---|
3463 | </body> |
---|
3464 | </html> |
---|