{"id":176525,"date":"2024-11-08T12:04:17","date_gmt":"2024-11-08T04:04:17","guid":{"rendered":"https:\/\/server.hk\/cnblog\/176525\/"},"modified":"2024-11-08T12:04:17","modified_gmt":"2024-11-08T04:04:17","slug":"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9mysql%e9%8c%af%e8%aa%a4-select%e5%b0%87%e6%aa%a2%e6%9f%a5%e8%b6%85%e9%81%8emax_join_size%e8%a1%8c","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/176525\/","title":{"rendered":"\u5982\u4f55\u4fee\u5fa9MySQL\u932f\u8aa4 &#8211; SELECT\u5c07\u6aa2\u67e5\u8d85\u904eMAX_JOIN_SIZE\u884c"},"content":{"rendered":"<h1 id=\"%e5%a6%82%e4%bd%95%e4%bf%ae%e5%be%a9mysql%e9%8c%af%e8%aa%a4-select%e5%b0%87%e6%aa%a2%e6%9f%a5%e8%b6%85%e9%81%8emax_join_size%e8%a1%8c-xOEKASGTen\">\u5982\u4f55\u4fee\u5fa9MySQL\u932f\u8aa4 &#8211; SELECT\u5c07\u6aa2\u67e5\u8d85\u904eMAX_JOIN_SIZE\u884c<\/h1>\n<p>\u5728\u4f7f\u7528MySQL\u6578\u64da\u5eab\u6642\uff0c\u958b\u767c\u8005\u53ef\u80fd\u6703\u9047\u5230\u5404\u7a2e\u932f\u8aa4\uff0c\u5176\u4e2d\u4e4b\u4e00\u662f\u300cSELECT\u5c07\u6aa2\u67e5\u8d85\u904eMAX_JOIN_SIZE\u884c\u300d\u3002\u9019\u500b\u932f\u8aa4\u901a\u5e38\u51fa\u73fe\u5728\u57f7\u884c\u8907\u96dc\u67e5\u8a62\u6642\uff0c\u7279\u5225\u662f\u7576\u6d89\u53ca\u591a\u500b\u8868\u7684\u806f\u63a5\u6642\u3002\u672c\u6587\u5c07\u63a2\u8a0e\u9019\u500b\u932f\u8aa4\u7684\u539f\u56e0\u53ca\u5176\u89e3\u6c7a\u65b9\u6848\u3002<\/p>\n<h2 id=\"%e9%8c%af%e8%aa%a4%e5%8e%9f%e5%9b%a0-xOEKASGTen\">\u932f\u8aa4\u539f\u56e0<\/h2>\n<p>MySQL\u7684MAX_JOIN_SIZE\u662f\u4e00\u500b\u7cfb\u7d71\u8b8a\u91cf\uff0c\u7528\u65bc\u9650\u5236\u67e5\u8a62\u4e2d\u53ef\u4ee5\u8655\u7406\u7684\u884c\u6578\u3002\u7576\u67e5\u8a62\u7684\u7d50\u679c\u96c6\u8d85\u904e\u9019\u500b\u9650\u5236\u6642\uff0cMySQL\u6703\u8fd4\u56de\u932f\u8aa4\uff0c\u9019\u662f\u70ba\u4e86\u9632\u6b62\u904e\u5ea6\u6d88\u8017\u7cfb\u7d71\u8cc7\u6e90\u3002\u9019\u500b\u9650\u5236\u7684\u8a2d\u7f6e\u662f\u70ba\u4e86\u4fdd\u8b77\u6578\u64da\u5eab\u7684\u6027\u80fd\uff0c\u7279\u5225\u662f\u5728\u8655\u7406\u5927\u578b\u6578\u64da\u96c6\u6642\u3002<\/p>\n<h2 id=\"%e5%a6%82%e4%bd%95%e6%aa%a2%e6%9f%a5max_join_size%e7%9a%84%e7%95%b6%e5%89%8d%e8%a8%ad%e7%bd%ae-xOEKASGTen\">\u5982\u4f55\u6aa2\u67e5MAX_JOIN_SIZE\u7684\u7576\u524d\u8a2d\u7f6e<\/h2>\n<p>\u8981\u6aa2\u67e5\u7576\u524d\u7684MAX_JOIN_SIZE\u8a2d\u7f6e\uff0c\u53ef\u4ee5\u4f7f\u7528\u4ee5\u4e0bSQL\u67e5\u8a62\uff1a<\/p>\n<pre><code>SHOW VARIABLES LIKE 'max_join_size';<\/code><\/pre>\n<p>\u9019\u5c07\u986f\u793a\u7576\u524d\u7684MAX_JOIN_SIZE\u503c\u3002\u5982\u679c\u9700\u8981\uff0c\u53ef\u4ee5\u6839\u64da\u5177\u9ad4\u9700\u6c42\u9032\u884c\u8abf\u6574\u3002<\/p>\n<h2 id=\"%e8%a7%a3%e6%b1%ba%e6%96%b9%e6%a1%88-xOEKASGTen\">\u89e3\u6c7a\u65b9\u6848<\/h2>\n<h3 id=\"1-%e8%aa%bf%e6%95%b4max_join_size-xOEKASGTen\">1. \u8abf\u6574MAX_JOIN_SIZE<\/h3>\n<p>\u5982\u679c\u78ba\u5b9a\u67e5\u8a62\u7684\u8a2d\u8a08\u662f\u6b63\u78ba\u7684\uff0c\u4e26\u4e14\u9700\u8981\u8655\u7406\u7684\u6578\u64da\u91cf\u662f\u5408\u7406\u7684\uff0c\u53ef\u4ee5\u8003\u616e\u8abf\u6574MAX_JOIN_SIZE\u7684\u503c\u3002\u9019\u53ef\u4ee5\u901a\u904e\u4ee5\u4e0bSQL\u547d\u4ee4\u4f86\u5b8c\u6210\uff1a<\/p>\n<pre><code>SET GLOBAL max_join_size = 1000000000;<\/code><\/pre>\n<p>\u9019\u88e1\u7684\u6578\u5b57\u53ef\u4ee5\u6839\u64da\u5be6\u969b\u9700\u6c42\u9032\u884c\u8abf\u6574\u3002\u8acb\u6ce8\u610f\uff0c\u9019\u500b\u8a2d\u7f6e\u6703\u5f71\u97ff\u6574\u500b\u6578\u64da\u5eab\uff0c\u56e0\u6b64\u5728\u4fee\u6539\u4e4b\u524d\u61c9\u8a72\u8b39\u614e\u8003\u616e\u3002<\/p>\n<h3 id=\"2-%e5%84%aa%e5%8c%96%e6%9f%a5%e8%a9%a2-xOEKASGTen\">2. \u512a\u5316\u67e5\u8a62<\/h3>\n<p>\u53e6\u4e00\u7a2e\u89e3\u6c7a\u65b9\u6848\u662f\u512a\u5316\u67e5\u8a62\u672c\u8eab\u3002\u9019\u53ef\u4ee5\u901a\u904e\u4ee5\u4e0b\u5e7e\u7a2e\u65b9\u5f0f\u4f86\u5be6\u73fe\uff1a<\/p>\n<ul>\n<li><strong>\u4f7f\u7528\u7d22\u5f15\uff1a<\/strong>\u78ba\u4fdd\u5728\u806f\u63a5\u7684\u5217\u4e0a\u6709\u9069\u7576\u7684\u7d22\u5f15\uff0c\u9019\u6a23\u53ef\u4ee5\u52a0\u5feb\u67e5\u8a62\u901f\u5ea6\uff0c\u6e1b\u5c11\u9700\u8981\u6aa2\u67e5\u7684\u884c\u6578\u3002<\/li>\n<li><strong>\u7c21\u5316\u67e5\u8a62\uff1a<\/strong>\u5982\u679c\u53ef\u80fd\uff0c\u5c07\u8907\u96dc\u7684\u67e5\u8a62\u62c6\u5206\u70ba\u591a\u500b\u7c21\u55ae\u7684\u67e5\u8a62\uff0c\u7136\u5f8c\u5728\u61c9\u7528\u5c64\u9032\u884c\u5408\u4f75\u3002<\/li>\n<li><strong>\u9650\u5236\u7d50\u679c\u96c6\uff1a<\/strong>\u4f7f\u7528LIMIT\u5b50\u53e5\u4f86\u9650\u5236\u67e5\u8a62\u8fd4\u56de\u7684\u884c\u6578\uff0c\u9019\u6a23\u53ef\u4ee5\u907f\u514d\u8d85\u904eMAX_JOIN_SIZE\u7684\u9650\u5236\u3002<\/li>\n<\/ul>\n<h3 id=\"3-%e6%aa%a2%e6%9f%a5%e6%95%b8%e6%93%9a%e5%ba%ab%e8%a8%ad%e8%a8%88-xOEKASGTen\">3. \u6aa2\u67e5\u6578\u64da\u5eab\u8a2d\u8a08<\/h3>\n<p>\u6709\u6642\u5019\uff0c\u932f\u8aa4\u7684\u6578\u64da\u5eab\u8a2d\u8a08\u6703\u5c0e\u81f4\u67e5\u8a62\u6548\u7387\u4f4e\u4e0b\u3002\u6aa2\u67e5\u6578\u64da\u5eab\u7684\u7d50\u69cb\uff0c\u78ba\u4fdd\u8868\u4e4b\u9593\u7684\u95dc\u4fc2\u662f\u5408\u7406\u7684\uff0c\u4e26\u4e14\u6c92\u6709\u4e0d\u5fc5\u8981\u7684\u5197\u9918\u6578\u64da\u3002<\/p>\n<h2 id=\"%e7%a4%ba%e4%be%8b-xOEKASGTen\">\u793a\u4f8b<\/h2>\n<p>\u5047\u8a2d\u6709\u5169\u500b\u8868\uff1a<code>orders<\/code>\u548c<code>customers<\/code>\uff0c\u6211\u5011\u5e0c\u671b\u67e5\u8a62\u6240\u6709\u5ba2\u6236\u7684\u8a02\u55ae\u4fe1\u606f\u3002\u5982\u679c\u67e5\u8a62\u5982\u4e0b\uff1a<\/p>\n<pre><code>SELECT * FROM orders JOIN customers ON orders.customer_id = customers.id;<\/code><\/pre>\n<p>\u5982\u679c\u9019\u500b\u67e5\u8a62\u8fd4\u56de\u7684\u884c\u6578\u8d85\u904e\u4e86MAX_JOIN_SIZE\u7684\u9650\u5236\uff0c\u5247\u6703\u51fa\u73fe\u932f\u8aa4\u3002\u53ef\u4ee5\u8003\u616e\u512a\u5316\u67e5\u8a62\uff0c\u4f8b\u5982\uff1a<\/p>\n<pre><code>SELECT orders.id, customers.name FROM orders JOIN customers ON orders.customer_id = customers.id LIMIT 100;<\/code><\/pre>\n<p>\u9019\u6a23\u53ef\u4ee5\u6709\u6548\u5730\u9650\u5236\u8fd4\u56de\u7684\u884c\u6578\uff0c\u907f\u514d\u8d85\u904eMAX_JOIN_SIZE\u7684\u9650\u5236\u3002<\/p>\n<h2 id=\"%e7%b8%bd%e7%b5%90-xOEKASGTen\">\u7e3d\u7d50<\/h2>\n<p>\u5728MySQL\u4e2d\u9047\u5230\u300cSELECT\u5c07\u6aa2\u67e5\u8d85\u904eMAX_JOIN_SIZE\u884c\u300d\u7684\u932f\u8aa4\u6642\uff0c\u9996\u5148\u61c9\u8a72\u6aa2\u67e5\u7576\u524d\u7684MAX_JOIN_SIZE\u8a2d\u7f6e\uff0c\u7136\u5f8c\u8003\u616e\u8abf\u6574\u8a72\u503c\u6216\u512a\u5316\u67e5\u8a62\u3002\u901a\u904e\u5408\u7406\u7684\u6578\u64da\u5eab\u8a2d\u8a08\u548c\u67e5\u8a62\u512a\u5316\uff0c\u53ef\u4ee5\u6709\u6548\u5730\u907f\u514d\u6b64\u985e\u554f\u984c\u7684\u767c\u751f\u3002\u5c0d\u65bc\u9700\u8981\u9ad8\u6548\u6578\u64da\u8655\u7406\u7684\u7528\u6236\uff0c\u9078\u64c7\u5408\u9069\u7684 <a href=\"https:\/\/server.hk\">VPS<\/a> \u89e3\u6c7a\u65b9\u6848\u4e5f\u662f\u81f3\u95dc\u91cd\u8981\u7684\uff0c\u9019\u6a23\u53ef\u4ee5\u78ba\u4fdd\u6578\u64da\u5eab\u7684\u6027\u80fd\u548c\u7a69\u5b9a\u6027\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u5b78\u7fd2\u5982\u4f55\u4fee\u5fa9MySQL\u932f\u8aa4\uff1aSELECT\u5c07\u6aa2\u67e5\u8d85\u904eMAX_JOIN_SIZE\u884c\uff0c\u4e26\u512a\u5316\u67e5\u8a62\u4ee5\u63d0\u9ad8\u6027\u80fd\u548c\u907f\u514d\u932f\u8aa4\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-176525","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/176525","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=176525"}],"version-history":[{"count":1,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/176525\/revisions"}],"predecessor-version":[{"id":176526,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/176525\/revisions\/176526"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=176525"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=176525"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=176525"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}