{"id":21519,"date":"2024-01-02T10:44:26","date_gmt":"2024-01-02T10:44:26","guid":{"rendered":"https:\/\/server.hk\/blog\/21519\/"},"modified":"2024-11-14T10:31:24","modified_gmt":"2024-11-14T02:31:24","slug":"mongodb-glossary-read-preference","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/21519\/","title":{"rendered":"MongoDB \u8a5e\u5f59\u8868 &#8211; \u8b80\u53d6\u512a\u5148\u7d1a"},"content":{"rendered":"<h1 id=\"mongodb-glossary-read-preference-JVDSDiwtXT\">MongoDB \u8a5e\u5f59\u8868 &#8211; \u8b80\u53d6\u512a\u5148\u7d1a<\/h1>\n<p>\u5728\u8cc7\u6599\u5eab\u7684\u4e16\u754c\u4e2d\uff0cMongoDB \u56e0\u5176\u9748\u6d3b\u6027\u3001\u53ef\u64f4\u5c55\u6027\u548c\u6548\u80fd\u800c\u5099\u53d7\u9752\u775e\u3002\u4f5c\u70ba\u4e00\u500b NoSQL \u8cc7\u6599\u5eab\uff0cMongoDB \u63d0\u4f9b\u4e86\u591a\u7a2e\u529f\u80fd\uff0c\u4f7f\u5176\u6210\u70ba\u8a31\u591a\u958b\u767c\u8005\u548c\u4f01\u696d\u7684\u9996\u9078\u3002\u5176\u4e2d\u4e00\u500b\u91cd\u8981\u529f\u80fd\u662f\u300c\u8b80\u53d6\u512a\u5148\u7d1a\u300d\uff08Read Preference\uff09\uff0c\u5141\u8a31\u4f7f\u7528\u8005\u63a7\u5236 MongoDB \u5982\u4f55\u5728\u8907\u88fd\u96c6\uff08Replica Sets\uff09\u4e2d\u5206\u914d\u8b80\u53d6\u64cd\u4f5c\u3002<\/p>\n<h2 id=\"understanding-replica-sets-JVDSDiwtXT\">\u4e86\u89e3\u8907\u88fd\u96c6<\/h2>\n<p>\u5728\u6df1\u5165\u8a0e\u8ad6\u8b80\u53d6\u512a\u5148\u7d1a\u4e4b\u524d\uff0c\u5148\u4e86\u89e3 MongoDB \u4e2d\u7684\u8907\u88fd\u96c6\u6982\u5ff5\u662f\u975e\u5e38\u91cd\u8981\u7684\u3002\u8907\u88fd\u96c6\u662f MongoDB \u5be6\u4f8b\u7684\u4e00\u7d44\u96c6\u5408\uff0c\u5132\u5b58\u76f8\u540c\u7684\u6578\u64da\uff0c\u63d0\u4f9b\u5197\u9918\u548c\u9ad8\u53ef\u7528\u6027\u3002\u5b83\u7531\u4e00\u500b\u4e3b\u8981\u7bc0\u9ede\uff08Primary Node\uff09\u8ca0\u8cac\u8655\u7406\u6240\u6709\u5beb\u5165\u64cd\u4f5c\uff0c\u4ee5\u53ca\u591a\u500b\u6b21\u8981\u7bc0\u9ede\uff08Secondary Nodes\uff09\u8907\u88fd\u4e3b\u8981\u7bc0\u9ede\u7684\u6578\u64da\u3002<\/p>\n<p>\u8907\u88fd\u96c6\u78ba\u4fdd\u4e86\u6578\u64da\u7684\u6301\u4e45\u6027\u548c\u5bb9\u932f\u80fd\u529b\u3002\u5982\u679c\u4e3b\u8981\u7bc0\u9ede\u767c\u751f\u6545\u969c\uff0c\u6b21\u8981\u7bc0\u9ede\u4e4b\u4e00\u5c07\u81ea\u52d5\u5347\u7d1a\u70ba\u65b0\u7684\u4e3b\u8981\u7bc0\u9ede\uff0c\u78ba\u4fdd\u670d\u52d9\u4e0d\u4e2d\u65b7\u3002<\/p>\n<h2 id=\"what-is-read-preference-JVDSDiwtXT\">\u4ec0\u9ebc\u662f\u8b80\u53d6\u512a\u5148\u7d1a\uff1f<\/h2>\n<p>\u8b80\u53d6\u512a\u5148\u7d1a\u6c7a\u5b9a\u4e86 MongoDB \u5982\u4f55\u5c07\u8b80\u53d6\u64cd\u4f5c\u6307\u5f15\u5230\u8907\u88fd\u96c6\u7684\u6210\u54e1\u3002\u9810\u8a2d\u60c5\u6cc1\u4e0b\uff0cMongoDB \u5c07\u6240\u6709\u8b80\u53d6\u64cd\u4f5c\u6307\u5411\u4e3b\u8981\u7bc0\u9ede\u3002\u7136\u800c\uff0c\u5728\u67d0\u4e9b\u60c5\u6cc1\u4e0b\uff0c\u5c07\u8b80\u53d6\u64cd\u4f5c\u5206\u914d\u7d66\u6b21\u8981\u7bc0\u9ede\u53ef\u80fd\u66f4\u6709\u5229\u3002<\/p>\n<p>\u8b80\u53d6\u512a\u5148\u7d1a\u53ef\u4ee5\u5728\u4e0d\u540c\u5c64\u7d1a\u8a2d\u7f6e\uff0c\u5305\u62ec\uff1a<\/p>\n<ul>\n<li><strong>Primary\uff1a<\/strong>\u6240\u6709\u8b80\u53d6\u64cd\u4f5c\u90fd\u6307\u5411\u4e3b\u8981\u7bc0\u9ede\u3002\u9019\u662f\u9810\u8a2d\u7684\u8b80\u53d6\u512a\u5148\u7d1a\u3002<\/li>\n<li><strong>PrimaryPreferred\uff1a<\/strong>\u8b80\u53d6\u64cd\u4f5c\u512a\u5148\u6307\u5411\u4e3b\u8981\u7bc0\u9ede\uff0c\u5982\u679c\u4e3b\u8981\u7bc0\u9ede\u4e0d\u53ef\u7528\uff0c\u5247\u8f49\u5411\u6b21\u8981\u7bc0\u9ede\u3002<\/li>\n<li><strong>Secondary\uff1a<\/strong>\u8b80\u53d6\u64cd\u4f5c\u50c5\u6307\u5411\u6b21\u8981\u7bc0\u9ede\u3002<\/li>\n<li><strong>SecondaryPreferred\uff1a<\/strong>\u8b80\u53d6\u64cd\u4f5c\u512a\u5148\u6307\u5411\u6b21\u8981\u7bc0\u9ede\uff0c\u5982\u679c\u6240\u6709\u6b21\u8981\u7bc0\u9ede\u4e0d\u53ef\u7528\uff0c\u5247\u8f49\u5411\u4e3b\u8981\u7bc0\u9ede\u3002<\/li>\n<li><strong>Nearest\uff1a<\/strong>\u8b80\u53d6\u64cd\u4f5c\u6307\u5411\u8ddd\u96e2\u6700\u8fd1\u7684\u8907\u88fd\u96c6\u6210\u54e1\uff0c\u4e0d\u8ad6\u662f\u4e3b\u8981\u7bc0\u9ede\u9084\u662f\u6b21\u8981\u7bc0\u9ede\u3002<\/li>\n<\/ul>\n<h2 id=\"choosing-the-right-read-preference-JVDSDiwtXT\">\u9078\u64c7\u5408\u9069\u7684\u8b80\u53d6\u512a\u5148\u7d1a<\/h2>\n<p>\u9078\u64c7\u9069\u7576\u7684\u8b80\u53d6\u512a\u5148\u7d1a\u53d6\u6c7a\u65bc\u60a8\u7684\u61c9\u7528\u7a0b\u5f0f\u7684\u5177\u9ad4\u9700\u6c42\u3002\u8b93\u6211\u5011\u4f86\u770b\u770b\u4e0d\u540c\u60c5\u5883\u4e0b\uff0c\u54ea\u4e9b\u8b80\u53d6\u512a\u5148\u7d1a\u53ef\u80fd\u66f4\u6709\u5229\uff1a<\/p>\n<h3 id=\"1-high-availability-JVDSDiwtXT\">1. \u9ad8\u53ef\u7528\u6027<\/h3>\n<p>\u5982\u679c\u60a8\u7684\u61c9\u7528\u7a0b\u5f0f\u9700\u8981\u9ad8\u53ef\u7528\u6027\u548c\u5373\u6642\u4e00\u81f4\u6027\uff0c\u5c07\u6240\u6709\u8b80\u53d6\u64cd\u4f5c\u6307\u5411\u4e3b\u8981\u7bc0\u9ede\uff08Primary \u8b80\u53d6\u512a\u5148\u7d1a\uff09\u53ef\u78ba\u4fdd\u60a8\u59cb\u7d42\u8b80\u53d6\u6700\u65b0\u6578\u64da\u3002\u7136\u800c\uff0c\u9019\u53ef\u80fd\u6703\u589e\u52a0\u4e3b\u8981\u7bc0\u9ede\u7684\u8ca0\u64d4\uff0c\u4e26\u53ef\u80fd\u5f71\u97ff\u5beb\u5165\u6548\u80fd\u3002<\/p>\n<h3 id=\"2-read-scalability-JVDSDiwtXT\">2. \u8b80\u53d6\u53ef\u64f4\u5c55\u6027<\/h3>\n<p>\u5728\u9700\u8981\u8b80\u53d6\u53ef\u64f4\u5c55\u6027\u7684\u60c5\u5883\u4e0b\uff0c\u5c07\u8b80\u53d6\u64cd\u4f5c\u5206\u6563\u5230\u6b21\u8981\u7bc0\u9ede\uff08Secondary \u8b80\u53d6\u512a\u5148\u7d1a\uff09\u53ef\u4ee5\u6e1b\u8f15\u4e3b\u8981\u7bc0\u9ede\u7684\u8ca0\u64d4\u4e26\u63d0\u5347\u6574\u9ad4\u8b80\u53d6\u6548\u80fd\u3002\u9019\u5c0d\u65bc\u8b80\u53d6\u5de5\u4f5c\u8ca0\u8f09\u8f03\u91cd\u7684\u61c9\u7528\u7a0b\u5f0f\u5c24\u70ba\u6709\u7528\u3002<\/p>\n<h3 id=\"3-eventual-consistency-JVDSDiwtXT\">3. \u6700\u7d42\u4e00\u81f4\u6027<\/h3>\n<p>\u5982\u679c\u60a8\u7684\u61c9\u7528\u7a0b\u5f0f\u53ef\u4ee5\u5bb9\u5fcd\u6700\u7d42\u4e00\u81f4\u6027\u4e26\u512a\u5148\u8003\u616e\u4f4e\u5ef6\u9072\uff0c\u4f7f\u7528 Nearest \u8b80\u53d6\u512a\u5148\u7d1a\u53ef\u8b93\u60a8\u5f9e\u6700\u8fd1\u7684\u8907\u88fd\u96c6\u6210\u54e1\u8b80\u53d6\u8cc7\u6599\uff0c\u9019\u53ef\u4ee5\u6e1b\u5c11\u7db2\u7d61\u5ef6\u9072\u4e26\u63d0\u5347\u6574\u9ad4\u56de\u61c9\u6642\u9593\u3002<\/p>\n<h2 id=\"setting-read-preference-in-mongodb-JVDSDiwtXT\">\u5728 MongoDB \u4e2d\u8a2d\u7f6e\u8b80\u53d6\u512a\u5148\u7d1a<\/h2>\n<p>\u5728 MongoDB \u4e2d\u8a2d\u7f6e\u8b80\u53d6\u512a\u5148\u7d1a\u975e\u5e38\u7c21\u55ae\u3002\u5b83\u53ef\u4ee5\u5728\u9023\u7dda\u5c64\u7d1a\u6216\u55ae\u6b21\u67e5\u8a62\u4e2d\u5b9a\u7fa9\u3002<\/p>\n<p>\u8981\u5728\u9023\u7dda\u5c64\u7d1a\u8a2d\u7f6e\u8b80\u53d6\u512a\u5148\u7d1a\uff0c\u60a8\u53ef\u4ee5\u4f7f\u7528 MongoDB \u9a45\u52d5\u7a0b\u5e8f\u7684\u914d\u7f6e\u9078\u9805\u3002\u4f8b\u5982\uff0c\u5728 Node.js \u4e2d\uff1a<\/p>\n<pre><code>const MongoClient = require('mongodb').MongoClient;\r\nconst uri = 'mongodb:\/\/localhost:27017\/mydb?readPreference=secondary';\r\nconst client = new MongoClient(uri, { useNewUrlParser: true });\r\n<\/code><\/pre>\n<p>\u6216\u8005\uff0c\u60a8\u53ef\u4ee5\u5728\u55ae\u6b21\u67e5\u8a62\u4e2d\u4f7f\u7528 `readPreference` \u9078\u9805\u8a2d\u7f6e\u8b80\u53d6\u512a\u5148\u7d1a\uff1a<\/p>\n<pre><code>db.collection('mycollection').find({}).readPreference('secondary').toArray();\r\n<\/code><\/pre>\n<h2 id=\"conclusion-JVDSDiwtXT\">\u7d50\u8ad6<\/h2>\n<p>\u4e86\u89e3 MongoDB \u4e2d\u7684\u8b80\u53d6\u512a\u5148\u7d1a\u5c0d\u65bc\u512a\u5316\u61c9\u7528\u7a0b\u5f0f\u7684\u6548\u80fd\u548c\u53ef\u64f4\u5c55\u6027\u81f3\u95dc\u91cd\u8981\u3002\u901a\u904e\u9078\u64c7\u9069\u7576\u7684\u8b80\u53d6\u512a\u5148\u7d1a\uff0c\u60a8\u53ef\u4ee5\u5e73\u8861\u8ca0\u8f09\u3001\u63d0\u5347\u56de\u61c9\u901f\u5ea6\u4e26\u78ba\u4fdd\u9ad8\u53ef\u7528\u6027\u3002\u7121\u8ad6\u60a8\u512a\u5148\u8003\u616e\u5373\u6642\u4e00\u81f4\u6027\u3001\u8b80\u53d6\u53ef\u64f4\u5c55\u6027\u9084\u662f\u4f4e\u5ef6\u9072\uff0cMongoDB \u7684\u8b80\u53d6\u512a\u5148\u7d1a\u9078\u9805\u90fd\u80fd\u63d0\u4f9b\u9748\u6d3b\u6027\uff0c\u4ee5\u6eff\u8db3\u60a8\u7684\u5177\u9ad4\u9700\u6c42\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u6709\u95dc MongoDB \u53ca\u5176\u529f\u80fd\uff0c\u8acb\u8003\u616e\u63a2\u7d22 <a href=\"https:\/\/server.hk\">Server.HK<\/a>\uff0c\u9019\u662f\u4e00\u5bb6\u9818\u5148\u7684 VPS \u8a17\u7ba1\u516c\u53f8\uff0c\u63d0\u4f9b\u53ef\u9760\u4e14\u9ad8\u6548\u80fd\u7684 MongoDB \u8a17\u7ba1\u89e3\u6c7a\u65b9\u6848\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>MongoDB \u8a5e\u5f59\u8868 &#038;#82&#46;&#46;&#46;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[4925],"tags":[],"class_list":["post-21519","post","type-post","status-publish","format-standard","hentry","category-4925"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/21519","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=21519"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/21519\/revisions"}],"predecessor-version":[{"id":23944,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/21519\/revisions\/23944"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=21519"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=21519"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=21519"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}