{"id":1351,"date":"2019-12-16T15:13:00","date_gmt":"2019-12-16T07:13:00","guid":{"rendered":"http:\/\/bloo.heing.fun\/?p=1351"},"modified":"2019-12-16T15:35:28","modified_gmt":"2019-12-16T07:35:28","slug":"mapreduce%e6%b5%85%e8%a7%a3%e6%9e%90","status":"publish","type":"post","link":"https:\/\/bloo.heing.fun\/?p=1351","title":{"rendered":"MapReduce\u6d45\u89e3\u6790"},"content":{"rendered":"
    \n
  1. 1.\u914d\u7f6em\u4e2aworker\u6765map\uff0cr\u4e2aworker\u6765reduce\u3002<\/li>\n
  2. 2.\u5c06\u6df7\u5408\u5747\u5300\u7684\u8f93\u5165\u6587\u4ef6\u5206\u6210m\u4e2a\u8f93\u5165\u6587\u4ef6\uff0c\u6bcf\u4e2a\u8f93\u5165\u6587\u4ef6\u5bf9\u5e94\u4e00\u4e2adoMap\u3002\u8fd9\u91cc\u7684\u6df7\u5408\u5747\u5300\u8868\u793a\u6bcf\u4efd\u8f93\u5165\u6587\u4ef6\u4e2d\u7684\u5185\u5bb9\u4e4b\u95f4\u6ca1\u6709\u8054\u7cfb\uff0c\u53ef\u4ee5\u62c6\u5206\u6210\u5c0f\u4efd\u4e00\u4efd\u4e00\u4efd\u7684\u5904\u7406\u3002<\/li>\n
  3. 3.\u5bf9\u6bcf\u4e2a\u8f93\u5165\u6587\u4ef6\u4f7f\u7528doMap\u8fdb\u884c\u904d\u5386\u3002\u6bcf\u4e2adoMap\u5bf9\u5e94\u4e00\u6b21mapF(filename string, content string) []KeyValue\u3002doMap\u9996\u5148\u5c06\u8f93\u5165\u6587\u4ef6\u540d\u548c\u6587\u4ef6\u5185\u5bb9\u4f20\u7ed9mapF\u5904\u7406\u3002mapF\u5904\u7406\u5b8c\u8fd9\u4e2a\u6587\u4ef6\uff0c\u8fd4\u56de\u5f88\u591a\u952e\u503c\u5bf9\uff0cdoMap\u63a5\u7740\u5c06\u8fd9\u4e9b\u6df7\u5408\u5747\u5300\u7684\u952e\u503c\u5bf9\u4eec\u5e73\u5747\u5206\u6210r\u4efd\uff0c1\u6bcf\u4efd\u6709\u591a\u4e2a\u952e\u503c\u5bf9\uff0c2\u6bcf\u4efd\u5bf9\u5e94\u7ed9\u4e00\u4e2adoReduce\u5904\u7406\uff0c 3\u6bcf\u4efd\u4fdd\u5b58\u5230\u4e00\u4e2a\u6587\u4ef6\uff0c\u6587\u4ef6\u540d\u683c\u5f0f\u4e3ajobName-mapTaskIndex-reduceTaskIndex\u3002———\u6ce8\u610f\uff1amapF\u8fd4\u56de\u7684<key, value>\u4e2d\u7684key\u4e0d\u662f\u4f5c\u4e3a\u53c2\u6570\u4f20\u7ed9mapF\u7684filename,\u800c\u662f\u53ef\u4ee5\u968f\u4fbf\u7684\u3002mapF\u8fd9\u91cc\u5c31\u76f8\u5f53\u4e8e\u4ece\u547d\u4ee4\u884c\u4e2d\u8bfb\u53d6\u5230\u4e86\u8f93\u5165\u3002<\/li>\n
  4. 4.\u904d\u5386m\u6b21doReduce\u3002doReduce\u8bfb\u53d6m\u4e2a\u6765\u81eam\u4e2adoMapTask\u7684\u6587\u4ef6\uff0c\uff08\u56e0\u4e3a\u6bcf\u4e2adoMapTask\u90fd\u4ea7\u751f\u4e00\u4e2a\u6587\u4ef6\u7ed9\u6bcf\u4e2adoReduceTask)\u3002doReduce\u5408\u5e76\u8fd9\u4e9b\u6587\u4ef6\u4e2dkey\u76f8\u540c\u7684\uff0ckey\u6709\u591a\u5c11\u4e2a\u4e0d\u540c\u7684\u5c31\u8c03\u7528\u591a\u5c11\u6b21reduceF(key string,\u00a0 values []string) string\u3002\u6bcf\u4e2areduceF\u8fd4\u56de\u8fd9\u4e00\u4e2akey\u7684\u5bf9\u5e94\u7684\u6700\u7ec8\u7ed3\u679c\u503c\u3002doReduceTask\u6700\u7ec8\u5f97\u5230\u6240\u6709\u4e0d\u540ckey\u53ca\u5176\u5bf9\u5e94\u7684\u6700\u7ec8\u7ed3\u679c\u503c\u3002———\u6ce8\u610f\uff1adoReduceTask\u5f97\u5230\u7684\u8fd9\u4e9b<Key, Value>\u4e2d\u7684key\u662fmapF\u8fd4\u56de\u7684key<\/li>\n
  5. 5.\u6240\u6709doReduceTask\u7684\u7ed3\u679c\u518d\u6b21\u5408\u5e76\u3002<\/li>\n<\/ol>\n

    \u6709\u4ee5\u4e0b\u89c4\u5f8b\uff1a<\/p>\n

      \n
    1. \u4e00\u4e2a\u8f93\u5165\u6587\u4ef6\u5bf9\u5e94\u4e00\u4e2adoMap\uff0cdoMap\u5bf9\u5e94r\u4e2a\u8f93\u51fa\u6587\u4ef6\u7ed9r\u4e2adoReduceTask\uff0cdoReduceTask\u6709m\u4e2a\u8f93\u5165\u6587\u4ef6\u6765\u81eam\u4e2adoMap\u3002<\/li>\n
    2. 2. \u8f93\u5165\u6587\u4ef6\u88ab\u5747\u5206\u6210m\u4e2a\uff0c\u6bcf\u4e2adoMap\u7684\u7ed3\u679c\u88ab\u5747\u5206\u7ed9r\u4e2adoReduceTask\uff0c\u6bcf\u4e2adoReduceTask\u4f7f\u7528\u6765\u81ea\u6bcf\u4e00\u4e2adoMapTask\u7684\u8f93\u51fa\u3002<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"

      1.\u914d\u7f6em\u4e2aworker\u6765map\uff0cr\u4e2aworker\u6765reduce\u3002 2.\u5c06\u6df7\u5408\u5747\u5300\u7684\u8f93\u5165\u6587\u4ef6\u5206\u6210m\u4e2a\u8f93\u5165\u6587\u4ef6\uff0c […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[36],"tags":[70,69],"class_list":["post-1351","post","type-post","status-publish","format-standard","hentry","category-36","tag-mapreduce","tag-69"],"_links":{"self":[{"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=\/wp\/v2\/posts\/1351","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1351"}],"version-history":[{"count":8,"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=\/wp\/v2\/posts\/1351\/revisions"}],"predecessor-version":[{"id":1359,"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=\/wp\/v2\/posts\/1351\/revisions\/1359"}],"wp:attachment":[{"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1351"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1351"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/bloo.heing.fun\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1351"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}