{"id":77078,"date":"2024-10-16T10:23:16","date_gmt":"2024-10-16T02:23:16","guid":{"rendered":"https:\/\/server.hk\/cnblog\/77078\/"},"modified":"2024-10-16T10:23:16","modified_gmt":"2024-10-16T02:23:16","slug":"mysql%e6%80%a7%e8%83%bd%e5%88%86%e6%9e%90%e5%8f%8aexplain%e7%9a%84%e4%bd%bf%e7%94%a8","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/77078\/","title":{"rendered":"MySQL\u6027\u80fd\u5206\u6790\u53caexplain\u7684\u4f7f\u7528"},"content":{"rendered":"<h1 id=\"mysql%e6%80%a7%e8%83%bd%e5%88%86%e6%9e%90%e5%8f%8aexplain%e7%9a%84%e4%bd%bf%e7%94%a8-gduEkPdmFI\">MySQL\u6027\u80fd\u5206\u6790\u53caEXPLAIN\u7684\u4f7f\u7528<\/h1>\n<p>\u5728\u7576\u4eca\u7684\u6578\u64da\u9a45\u52d5\u6642\u4ee3\uff0c\u6578\u64da\u5eab\u7684\u6027\u80fd\u5c0d\u65bc\u61c9\u7528\u7a0b\u5e8f\u7684\u6574\u9ad4\u6548\u80fd\u81f3\u95dc\u91cd\u8981\u3002MySQL\u4f5c\u70ba\u4e00\u500b\u6d41\u884c\u7684\u958b\u6e90\u6578\u64da\u5eab\u7ba1\u7406\u7cfb\u7d71\uff0c\u63d0\u4f9b\u4e86\u591a\u7a2e\u5de5\u5177\u4f86\u5e6b\u52a9\u958b\u767c\u8005\u548c\u6578\u64da\u5eab\u7ba1\u7406\u54e1\u5206\u6790\u548c\u512a\u5316\u67e5\u8a62\u6027\u80fd\u3002\u5176\u4e2d\uff0cEXPLAIN\u8a9e\u53e5\u662f\u4e00\u500b\u5f37\u5927\u7684\u5de5\u5177\uff0c\u53ef\u4ee5\u5e6b\u52a9\u6211\u5011\u7406\u89e3\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\uff0c\u5f9e\u800c\u9032\u884c\u76f8\u61c9\u7684\u512a\u5316\u3002<\/p>\n<h2 id=\"%e4%bb%80%e9%ba%bc%e6%98%afexplain%ef%bc%9f-gduEkPdmFI\">\u4ec0\u9ebc\u662fEXPLAIN\uff1f<\/h2>\n<p>EXPLAIN\u662f\u4e00\u500bMySQL\u547d\u4ee4\uff0c\u7528\u65bc\u986f\u793a\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\u3002\u901a\u904e\u4f7f\u7528EXPLAIN\uff0c\u6211\u5011\u53ef\u4ee5\u7372\u5f97\u6709\u95dc\u67e5\u8a62\u5982\u4f55\u88ab\u57f7\u884c\u7684\u8a73\u7d30\u4fe1\u606f\uff0c\u5305\u62ec\u4f7f\u7528\u7684\u7d22\u5f15\u3001\u8868\u7684\u8a2a\u554f\u9806\u5e8f\u3001\u4ee5\u53ca\u6bcf\u500b\u6b65\u9a5f\u7684\u9810\u4f30\u884c\u6578\u7b49\u3002\u9019\u4e9b\u4fe1\u606f\u5c0d\u65bc\u6027\u80fd\u8abf\u512a\u81f3\u95dc\u91cd\u8981\u3002<\/p>\n<h2 id=\"%e5%a6%82%e4%bd%95%e4%bd%bf%e7%94%a8explain-gduEkPdmFI\">\u5982\u4f55\u4f7f\u7528EXPLAIN<\/h2>\n<p>\u4f7f\u7528EXPLAIN\u975e\u5e38\u7c21\u55ae\uff0c\u53ea\u9700\u5728\u67e5\u8a62\u524d\u52a0\u4e0aEXPLAIN\u95dc\u9375\u5b57\u5373\u53ef\u3002\u4f8b\u5982\uff1a<\/p>\n<pre><code>EXPLAIN SELECT * FROM users WHERE age &gt; 30;<\/code><\/pre>\n<p>\u57f7\u884c\u4e0a\u8ff0\u547d\u4ee4\u5f8c\uff0cMySQL\u5c07\u8fd4\u56de\u4e00\u500b\u8868\u683c\uff0c\u986f\u793a\u67e5\u8a62\u7684\u57f7\u884c\u8a08\u5283\u3002\u4ee5\u4e0b\u662f\u4e00\u4e9b\u91cd\u8981\u7684\u5217\uff1a<\/p>\n<ul>\n<li><strong>id\uff1a<\/strong>\u67e5\u8a62\u7684\u552f\u4e00\u6a19\u8b58\u7b26\u3002<\/li>\n<li><strong>select_type\uff1a<\/strong>\u67e5\u8a62\u7684\u985e\u578b\uff0c\u4f8b\u5982\u7c21\u55ae\u67e5\u8a62\u3001\u806f\u63a5\u67e5\u8a62\u7b49\u3002<\/li>\n<li><strong>table\uff1a<\/strong>\u6b63\u5728\u8a2a\u554f\u7684\u8868\u540d\u3002<\/li>\n<li><strong>type\uff1a<\/strong>\u8a2a\u554f\u985e\u578b\uff0c\u986f\u793a\u67e5\u8a62\u7684\u6548\u7387\uff0c\u5f9e\u6700\u512a\u7684\u201cconst\u201d\u5230\u6700\u5dee\u7684\u201cALL\u201d\u3002<\/li>\n<li><strong>possible_keys\uff1a<\/strong>\u53ef\u80fd\u4f7f\u7528\u7684\u7d22\u5f15\u3002<\/li>\n<li><strong>key\uff1a<\/strong>\u5be6\u969b\u4f7f\u7528\u7684\u7d22\u5f15\u3002<\/li>\n<li><strong>rows\uff1a<\/strong>\u9810\u4f30\u9700\u8981\u6383\u63cf\u7684\u884c\u6578\u3002<\/li>\n<li><strong>Extra\uff1a<\/strong>\u5176\u4ed6\u4fe1\u606f\uff0c\u4f8b\u5982\u662f\u5426\u4f7f\u7528\u4e86\u81e8\u6642\u8868\u6216\u6587\u4ef6\u6392\u5e8f\u3002<\/li>\n<\/ul>\n<h2 id=\"%e6%80%a7%e8%83%bd%e5%88%86%e6%9e%90%e7%9a%84%e6%ad%a5%e9%a9%9f-gduEkPdmFI\">\u6027\u80fd\u5206\u6790\u7684\u6b65\u9a5f<\/h2>\n<p>\u9032\u884cMySQL\u6027\u80fd\u5206\u6790\u6642\uff0c\u53ef\u4ee5\u9075\u5faa\u4ee5\u4e0b\u6b65\u9a5f\uff1a<\/p>\n<ol>\n<li><strong>\u8b58\u5225\u6162\u67e5\u8a62\uff1a<\/strong>\u4f7f\u7528\u6162\u67e5\u8a62\u65e5\u8a8c\u4f86\u8b58\u5225\u57f7\u884c\u6642\u9593\u8f03\u9577\u7684\u67e5\u8a62\u3002<\/li>\n<li><strong>\u4f7f\u7528EXPLAIN\u5206\u6790\u67e5\u8a62\uff1a<\/strong>\u5c0d\u65bc\u8b58\u5225\u51fa\u7684\u6162\u67e5\u8a62\uff0c\u4f7f\u7528EXPLAIN\u4f86\u67e5\u770b\u5176\u57f7\u884c\u8a08\u5283\u3002<\/li>\n<li><strong>\u6aa2\u67e5\u7d22\u5f15\uff1a<\/strong>\u78ba\u4fdd\u67e5\u8a62\u4e2d\u4f7f\u7528\u4e86\u9069\u7576\u7684\u7d22\u5f15\uff0c\u4e26\u8003\u616e\u6dfb\u52a0\u7f3a\u5931\u7684\u7d22\u5f15\u3002<\/li>\n<li><strong>\u512a\u5316\u67e5\u8a62\uff1a<\/strong>\u6839\u64daEXPLAIN\u7684\u7d50\u679c\uff0c\u91cd\u5beb\u67e5\u8a62\u4ee5\u63d0\u9ad8\u6027\u80fd\u3002<\/li>\n<li><strong>\u6e2c\u8a66\u548c\u9a57\u8b49\uff1a<\/strong>\u5728\u9032\u884c\u4efb\u4f55\u66f4\u6539\u5f8c\uff0c\u91cd\u65b0\u6e2c\u8a66\u67e5\u8a62\u4ee5\u78ba\u4fdd\u6027\u80fd\u6709\u6240\u6539\u5584\u3002<\/li>\n<\/ol>\n<h2 id=\"explain%e7%9a%84%e9%80%b2%e9%9a%8e%e7%94%a8%e6%b3%95-gduEkPdmFI\">EXPLAIN\u7684\u9032\u968e\u7528\u6cd5<\/h2>\n<p>\u9664\u4e86\u57fa\u672c\u7684EXPLAIN\u7528\u6cd5\u5916\uff0cMySQL\u9084\u63d0\u4f9b\u4e86EXPLAIN ANALYZE\u547d\u4ee4\uff0c\u9019\u662f\u4e00\u500b\u66f4\u70ba\u8a73\u7d30\u7684\u5206\u6790\u5de5\u5177\u3002\u5b83\u4e0d\u50c5\u986f\u793a\u57f7\u884c\u8a08\u5283\uff0c\u9084\u5be6\u969b\u57f7\u884c\u67e5\u8a62\u4e26\u63d0\u4f9b\u5be6\u969b\u7684\u57f7\u884c\u6642\u9593\u548c\u884c\u6578\u3002\u4f7f\u7528\u65b9\u6cd5\u5982\u4e0b\uff1a<\/p>\n<pre><code>EXPLAIN ANALYZE SELECT * FROM users WHERE age &gt; 30;<\/code><\/pre>\n<p>\u9019\u6a23\u53ef\u4ee5\u66f4\u7cbe\u78ba\u5730\u4e86\u89e3\u67e5\u8a62\u7684\u6027\u80fd\u74f6\u9838\uff0c\u4e26\u9032\u884c\u91dd\u5c0d\u6027\u7684\u512a\u5316\u3002<\/p>\n<h2 id=\"%e7%b5%90%e8%ab%96-gduEkPdmFI\">\u7d50\u8ad6<\/h2>\n<p>MySQL\u7684\u6027\u80fd\u5206\u6790\u662f\u4e00\u500b\u6301\u7e8c\u7684\u904e\u7a0b\uff0c\u4f7f\u7528EXPLAIN\u548cEXPLAIN ANALYZE\u53ef\u4ee5\u5e6b\u52a9\u958b\u767c\u8005\u6df1\u5165\u4e86\u89e3\u67e5\u8a62\u7684\u57f7\u884c\u904e\u7a0b\uff0c\u5f9e\u800c\u9032\u884c\u6709\u6548\u7684\u512a\u5316\u3002\u901a\u904e\u5408\u7406\u7684\u7d22\u5f15\u8a2d\u8a08\u548c\u67e5\u8a62\u91cd\u5beb\uff0c\u53ef\u4ee5\u986f\u8457\u63d0\u9ad8\u6578\u64da\u5eab\u7684\u6027\u80fd\uff0c\u78ba\u4fdd\u61c9\u7528\u7a0b\u5e8f\u7684\u9ad8\u6548\u904b\u884c\u3002<\/p>\n<p>\u5982\u9700\u4e86\u89e3\u66f4\u591a\u6709\u95dc<code><a href=\"https:\/\/server.hk\">VPS<\/a><\/code>\u548c<code><a href=\"https:\/\/server.hk\">\u9999\u6e2f\u4f3a\u670d\u5668<\/a><\/code>\u7684\u8cc7\u8a0a\uff0c\u8acb\u8a2a\u554f\u6211\u5011\u7684\u7db2\u7ad9\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u6df1\u5165\u63a2\u8ba8MySQL\u6027\u80fd\u5206\u6790\u6280\u5de7\uff0c\u5b66\u4e60\u5982\u4f55\u6709\u6548\u4f7f\u7528EXPLAIN\u547d\u4ee4\u4f18\u5316\u67e5\u8be2\uff0c\u63d0\u5347\u6570\u636e\u5e93\u6027\u80fd\u3002<\/p>\n","protected":false},"author":0,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-77078","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77078","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"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=77078"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77078\/revisions"}],"predecessor-version":[{"id":77079,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/77078\/revisions\/77079"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=77078"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=77078"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=77078"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}