{"id":909,"date":"2025-03-22T14:36:03","date_gmt":"2025-03-22T06:36:03","guid":{"rendered":"https:\/\/eve2333.top\/?p=909"},"modified":"2025-03-22T14:36:04","modified_gmt":"2025-03-22T06:36:04","slug":"mysql%e6%95%b0%e6%8d%ae%e5%ba%93%e5%85%a5%e9%97%a8%e5%88%b0%e5%a4%a7%e8%9b%87%e5%b0%9a%e7%a1%85%e8%b0%b7%e5%ae%8b%e7%ba%a2%e5%ba%b7%e8%80%81%e5%b8%88%e7%ac%94%e8%ae%b0-%e9%ab%98%e7%ba%a7%e7%af%87-pa-9","status":"publish","type":"post","link":"https:\/\/eve2333.top\/?p=909","title":{"rendered":"MySQL\u6570\u636e\u5e93\u5165\u95e8\u5230\u5927\u86c7\u5c1a\u7845\u8c37\u5b8b\u7ea2\u5eb7\u8001\u5e08\u7b14\u8bb0 \u9ad8\u7ea7\u7bc7 part 9"},"content":{"rendered":"\n<h1 class=\"wp-block-heading\">\u7b2c09\u7ae0_\u6027\u80fd\u5206\u6790\u5de5\u5177\u7684\u4f7f\u7528<\/h1>\n\n\n\n<h2 class=\"wp-block-heading\">1.\u6570\u636e\u5e93\u670d\u52a1\u5668\u7684\u4f18\u5316\u6b65\u9aa4<\/h2>\n\n\n\n<p>\u5f53\u6211\u4eec\u9047\u5230\u6570\u636e\u5e93\u8c03\u4f18\u95ee\u9898\u7684\u65f6\u5019\uff0c\u8be5\u5982\u4f55\u601d\u8003\u5462\uff1f\u8fd9\u91cc\u628a\u601d\u8003\u7684\u6d41\u7a0b\u6574\u7406\u6210\u4e0b\u9762\u8fd9\u5f20\u56fe\u3002<br>\u6574\u4e2a\u6d41\u7a0b\u5212\u5206\u6210\u4e86\u89c2\u5bdf\uff08Showstatus\uff09\u548c\u884c\u52a8\uff08Action\uff09\u4e24\u4e2a\u90e8\u5206\u3002\u5b57\u6bcdS\u7684\u90e8\u5206\u4ee3\u8868\u89c2\u5bdf\uff08\u4f1a\u4f7f\u7528\u76f8\u5e94\u7684\u5206\u6790\u5de5\u5177\uff09\uff0c\u5b57\u6bcdA\u4ee3\u8868\u7684\u90e8\u5206\u662f\u884c\u52a8\uff08\u5bf9\u5e94\u5206\u6790\u53ef\u4ee5\u91c7\u53d6\u7684\u884c\u52a8\uff09\u3002<\/p>\n\n\n\n<p><img decoding=\"async\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/b378be56454e4b518344b6316bea37fe.png\" alt=\"\"><\/p>\n\n\n\n<p>show profiling \u6211\u4eec\u53ef\u4ee5\u53bb\u67e5\u627e\u6bcf\u4e00\u4e2a\u6b65\u9aa4\u7684\u65f6\u95f4\u6210\u672c<\/p>\n\n\n\n<p>\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u89c2\u5bdf\u4e86\u89e3\u6570\u636e\u5e93\u6574\u4f53\u7684\u8fd0\u884c\u72b6\u6001\uff0c\u901a\u8fc7\u6027\u80fd\u5206\u6790\u5de5\u5177\u53ef\u4ee5\u8ba9\u6211\u4eec\u4e86\u89e3\u6267\u884c\u6162\u7684SQL\u90fd\u6709\u54ea\u4e9b\uff0c\u67e5\u770b\u5177\u4f53\u7684SQL\u6267\u884c\u8ba1\u5212\uff0c\u751a\u81f3\u662fSQL\u6267\u884c\u4e2d\u7684\u6bcf\u4e00\u6b65\u7684\u6210\u672c\u4ee3\u4ef7\uff0c\u8fd9\u6837\u624d\u80fd\u5b9a\u4f4d\u95ee\u9898\u6240\u5728\uff0c\u627e\u5230\u4e86\u95ee\u9898\uff0c\u518d\u91c7\u53d6\u76f8\u5e94\u7684\u884c\u52a8\u3002<\/p>\n\n\n\n<p>\u8be6\u7ec6\u89e3\u91ca\u4e00\u4e0b\u8fd9\u5f20\u56fe\uff1a<br>\u9996\u5148\u5728S1\u90e8\u5206\uff0c\u6211\u4eec\u9700\u8981\u89c2\u5bdf\u670d\u52a1\u5668\u7684\u72b6\u6001\u662f\u5426\u5b58\u5728\u5468\u671f\u6027\u7684\u6ce2\u52a8\u3002\u5982\u679c\u5b58\u5728\u5468\u671f\u6027\u6ce2\u52a8\uff0c\u6709\u53ef\u80fd\u662f\u5468\u671f\u6027\u8282\u70b9\u7684\u539f\u56e0\uff0c\u6bd4\u5982\u53cc\u5341\u4e00\u3001\u4fc3\u9500\u6d3b\u52a8\u7b49\u3002\u8fd9\u6837\u7684\u8bdd\uff0c\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7A1\u8fd9\u4e00\u6b65\u9aa4\u89e3\u51b3\uff0c\u4e5f\u5c31\u662f\u52a0\u7f13\u5b58\uff0c\u6216\u8005\u66f4\u6539\u7f13\u5b58\u5931\u6548\u7b56\u7565\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u7f13\u5b58\u7b56\u7565\u6ca1\u6709\u89e3\u51b3\uff0c\u6216\u8005\u4e0d\u662f\u5468\u671f\u6027\u6ce2\u52a8\u7684\u539f\u56e0\uff0c\u6211\u4eec\u5c31\u9700\u8981\u8fdb\u4e00\u6b65\u5206\u6790\u67e5\u8be2\u5ef6\u8fdf\u548c\u5361\u987f\u7684\u539f\u56e0\u3002\u63a5\u4e0b\u6765\u8fdb\u5165S2\u8fd9\u4e00\u6b65\uff0c\u6211\u4eec\u9700\u8981\u5f00\u542f\u6162\u67e5\u8be2\u3002\u6162\u67e5\u8be2\u53ef\u4ee5\u5e2e\u6211\u4eec\u5b9a\u4f4d\u6267\u884c\u6162\u7684SQL\u8bed\u53e5\u3002\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7\u8bbe\u7f6elong-query_time\u53c2\u6570\u5b9a\u4e49\u201c\u6162\"\u7684\u9608\u503c\uff0c\u5982\u679csQL\u6267\u884c\u65f6\u95f4\u8d85\u8fc7\u4e86long_query_time\uff0c\u5219\u4f1a\u8ba4\u4e3a\u662f\u6162\u67e5\u8be2\u3002\u5f53\u6536\u96c6\u4e0a\u6765\u8fd9\u4e9b\u6162\u67e5\u8be2\u4e4b\u540e\uff0c\u6211\u4eec\u5c31\u53ef\u4ee5\u901a\u8fc7\u5206\u6790\u5de5\u5177\u5bf9\u6162\u67e5\u8be2\u65e5\u5fd7\u8fdb\u884c\u5206\u6790\u3002<\/p>\n\n\n\n<p>\u5728S3\u8fd9\u4e00\u6b65\u9aa4\u4e2d\uff0c\u6211\u4eec\u5c31\u77e5\u9053\u4e86\u6267\u884c\u6162\u7684SQL\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u9488\u5bf9\u6027\u5730\u7528EXPLAIN\u67e5\u770b\u5bf9\u5e94SQL\u8bed\u53e5\u7684\u6267\u884c\u8ba1\u5212\uff0c\u6216\u8005\u4f7f\u7528showprofile\u67e5\u770bSQL\u4e2d\u6bcf\u4e00\u4e2a\u6b65\u9aa4\u7684\u65f6\u95f4\u6210\u672c\u3002\u8fd9\u6837\u6211\u4eec\u5c31\u53ef\u4ee5\u4e86\u89e3SQL\u67e5\u8be2\u6162\u662f\u56e0\u4e3a\u6267\u884c\u65f6\u95f4\u957f\uff0c\u8fd8\u662f\u7b49\u5f85\u65f6\u95f4\u957f\u3002<\/p>\n\n\n\n<p>\u5982\u679c\u662fSQL\u7b49\u5f85\u65f6\u95f4\u957f\uff0c\u6211\u4eec\u8fdb\u5165A2\u6b65\u9aa4\u3002\u5728\u8fd9\u4e00\u6b65\u9aa4\u4e2d\uff0c\u6211\u4eec\u53ef\u4ee5\u8c03\u4f18\u670d\u52a1\u5668\u7684\u53c2\u6570\uff0c\u6bd4\u5982\u9002\u5f53\u589e\u52a0\u6570\u636e\u5e93\u7f13\u51b2\u6c60\u7b49\u3002\u5982\u679c\u662fSQL\u6267\u884c\u65f6\u95f4\u957f\uff0c\u5c31\u8fdb\u5165A3\u6b65\u9aa4\uff0c\u8fd9\u4e00\u6b65\u4e2d\u6211\u4eec\u9700\u8981\u8003\u8651\u662f\u7d22\u5f15\u8bbe\u8ba1\u7684\u95ee\u9898\uff1f\u8fd8\u662f\u67e5\u8be2\u5173\u8054\u7684\u6570\u636e\u8868\u8fc7\u591a\uff1f\u7136\u540e\u5728\u8fd9\u4e0a\u8fdb\u884c\u5bf9\u5e94\u7684\u8c03\u6574<\/p>\n\n\n\n<p>\u5982\u679cA2\u548cA3\u90fd\u4e0d\u80fd\u89e3\u51b3\u95ee\u9898\uff0c\u6211\u4eec\u9700\u8981\u8003\u8651\u6570\u636e\u5e93\u81ea\u8eab\u7684SQL\u67e5\u8be2\u6027\u80fd\u662f\u5426\u5df2\u7ecf\u8fbe\u5230\u4e86\u74f6\u9888\uff0c\u5982\u679c\u786e\u8ba4\u6ca1\u6709\u8fbe\u5230\u6027\u80fd\u74f6\u9888\uff0c\u5c31\u9700\u8981\u91cd\u65b0\u68c0\u67e5\uff0c\u91cd\u590d\u4ee5\u4e0a\u7684\u6b65\u9aa4\u3002\u5982\u679c\u5df2\u7ecf\u8fbe\u5230\u4e86\u6027\u80fd\u74f6\u9888\uff0c\u8fdb\u5165A4\u9636\u6bb5\uff0c\u9700\u8981\u8003\u8651\u589e\u52a0\u670d\u52a1\u5668\uff0c\u91c7\u7528\u8bfb\u5199\u5206\u79bb\u7684\u67b6\u6784\uff0c\u6216\u8005\u8003\u8651\u5bf9\u6570\u636e\u5e93\u8fdb\u884c\u5206\u5e93\u5206\u8868\uff0c\u6bd4\u5982\u5782\u76f4\u5206\u5e93\u3001\u5782\u76f4\u5206\u8868\u548c\u6c34\u5e73\u5206\u8868\u7b49\u3002<\/p>\n\n\n\n<p>\u4ee5\u4e0a\u5c31\u662f\u6570\u636e\u5e93\u8c03\u4f18\u7684\u6d41\u7a0b\u601d\u8def\u3002\u5982\u679c\u6211\u4eec\u53d1\u73b0\u6267\u884cSQL\u65f6\u5b58\u5728\u4e0d\u89c4\u5219\u5ef6\u8fdf\u6216\u5361\u987f\u7684\u65f6\u5019\uff0c\u5c31\u53ef\u4ee5\u91c7\u7528\u5206\u6790\u5de5\u5177\u5e2e\u6211\u4eec\u5b9a\u4f4d\u6709\u95ee\u9898\u7684SQL\uff0c\u8fd9\u4e09\u79cd\u5206\u6790\u5de5\u5177\u4f60\u53ef\u4ee5\u7406\u89e3\u662fSQL\u8c03\u4f18\u7684\u4e09\u4e2a\u6b65\u9aa4\uff1a\u6162\u67e5\u8be2\u3001EXPLAIN\u548cSHOW&nbsp; PROFILING\u3002<\/p>\n\n\n\n<p>\u00a0<img loading=\"lazy\" decoding=\"async\" height=\"250\" width=\"405\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/508811886d4040dc882251c615e00d0e.png\" alt=\"\"><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">2.\u67e5\u770b\u7cfb\u7edf\u6027\u80fd\u53c2\u6570<\/h2>\n\n\n\n<p>\u5728MySQL\u4e2d\uff0c\u53ef\u4ee5\u4f7f\u7528SHOWSTATUS\u8bed\u53e5\u67e5\u8be2\u4e00\u4e9bMySQL\u6570\u636e\u5e93\u670d\u52a1\u5668\u7684\u6027\u80fd\u53c2\u6570\u3001\u6267\u884c\u9891\u7387\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SHOWSTATUS\u8bed\u53e5\u8bed\u6cd5\u5982\u4e0b\uff1a\nSHOW &#91;GLOBALISESSION] STATUS LIKE '\u53c2\u6570';<\/code><\/pre>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"240\" width=\"288\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/4685e2e0d94c4132aa5c62203750a842.png\" alt=\"\"><\/p>\n\n\n\n<p>InnoDB\u5f15\u64ce\u7684\u7edf\u8ba1\u6307\u6807<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Connections\uff1a\u8fde\u63a5MySQL\u670d\u52a1\u5668\u7684\u6b21\u6570\u3002<\/li>\n\n\n\n<li>Uptime\uff1aMySQL\u670d\u52a1\u5668\u7684\u4e0a\u7ebf\u65f6\u95f4\u3002<\/li>\n\n\n\n<li>Slow_queries\uff1a\u6162\u67e5\u8be2\u7684\u6b21\u6570\u3002<\/li>\n\n\n\n<li><strong>Innodb_rows_read<\/strong>: SELECT\u67e5\u8be2\u8fd4\u56de\u7684\u884c\u6570\u3002<\/li>\n\n\n\n<li><strong>Innodb_rows_inserted<\/strong>: \u6267\u884cINSERT\u64cd\u4f5c\u63d2\u5165\u7684\u884c\u6570\u3002<\/li>\n\n\n\n<li><strong>Innodb_rows_updated<\/strong>: \u6267\u884cUPDATE\u64cd\u4f5c\u66f4\u65b0\u7684\u884c\u6570\u3002<\/li>\n\n\n\n<li><strong>Innodb_rows_deleted<\/strong>: \u6267\u884cDELETE\u64cd\u4f5c\u5220\u9664\u7684\u884c\u6570\u3002<\/li>\n\n\n\n<li><strong>Com_select<\/strong>: \u67e5\u8be2\u64cd\u4f5c\u7684\u6b21\u6570\u3002<\/li>\n\n\n\n<li><strong>Com_insert<\/strong>: \u63d2\u5165\u64cd\u4f5c\u7684\u6b21\u6570\u3002\u5bf9\u4e8e\u6279\u91cf\u63d2\u5165\u7684INSERT\u64cd\u4f5c\uff0c\u53ea\u7d2f\u52a0\u4e00\u6b21\u3002<\/li>\n\n\n\n<li><strong>Com_update<\/strong>: \u66f4\u65b0\u64cd\u4f5c\u7684\u6b21\u6570\u3002<\/li>\n\n\n\n<li><strong>Com_delete<\/strong>: \u5220\u9664\u64cd\u4f5c\u7684\u6b21\u6570\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u67e5\u8be2MySQL\u670d\u52a1\u5668\u72b6\u6001<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>\u8fde\u63a5\u6b21\u6570<\/strong>: \u4f7f\u7528<code>SHOW STATUS LIKE 'Connections';<\/code>\u67e5\u8be2\u3002<\/li>\n\n\n\n<li><strong>\u670d\u52a1\u5668\u5de5\u4f5c\u65f6\u95f4<\/strong>: \u4f7f\u7528<code>SHOW STATUS LIKE 'Uptime';<\/code>\u67e5\u8be2\u3002<\/li>\n\n\n\n<li><strong>\u6162\u67e5\u8be2\u6b21\u6570<\/strong>: \u4f7f\u7528<code>SHOW STATUS LIKE 'Slow_queries';<\/code>\u67e5\u8be2\u3002<\/li>\n<\/ul>\n\n\n\n<p>\u6162\u67e5\u8be2\u6b21\u6570\u53c2\u6570\u53ef\u4ee5\u7ed3\u5408\u6162\u67e5\u8be2\u65e5\u5fd7\u627e\u51fa\u6162\u67e5\u8be2\u8bed\u53e5\uff0c\u7136\u540e\u9488\u5bf9\u6162\u67e5\u8be2\u8bed\u53e5\u8fdb\u884c\u8868\u7ed3\u6784\u4f18\u5316\u6216\u8005\u67e5\u8be2\u8bed\u53e5\u4f18\u5316\u3002<\/p>\n\n\n\n<p>\u67e5\u770b\u76f8\u5173\u6307\u4ee4\u60c5\u51b5<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u4f7f\u7528<code>SHOW STATUS LIKE 'Innodb_rows_%';<\/code>\u53ef\u4ee5\u67e5\u770b\u4e0eInnoDB\u5f15\u64ce\u76f8\u5173\u7684\u884c\u64cd\u4f5c\u7edf\u8ba1\u3002<\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">&nbsp;&nbsp;3. \u7edf\u8ba1SQL\u7684\u67e5\u8be2\u6210\u672c\uff1alast_query_cost<\/h2>\n\n\n\n<p>\u5982\u679c\u6211\u4eec\u60f3\u8981\u67e5\u770b\u67d0\u6761SQL\u8bed\u53e5\u7684\u67e5\u8be2\u6210\u672c\uff0c\u53ef\u4ee5\u5728\u6267\u884c\u5b8c\u8fd9\u6761SQL\u8bed\u53e5\u4e4b\u540e\uff0c\u901a\u8fc7\u67e5\u770b\u5f53\u524d\u4f1a\u8bdd\u4e2d\u7684last_query_cost\u53d8\u91cf\u503c\u6765\u5f97\u5230\u5f53\u524d\u67e5\u8be2\u7684\u6210\u672c\u3002\u5b83\u901a\u5e38\u4e5f\u662f\u6211\u4eec\u8bc4\u4ef7\u4e00\u4e2a\u67e5\u8be2\u7684\u6267\u884c\u6548\u7387\u7684\u4e00\u4e2a\u5e38\u7528\u6307\u6807\u3002\u8fd9\u4e2a\u67e5\u8be2\u6210\u672c\u5bf9\u5e94\u7684\u662fSQL\u8bed\u53e5\u6240\u9700\u8981\u8bfb\u53d6\u7684\u9875\u7684\u6570\u91cf\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u4f9d\u7136\u4f7f\u7528\u7b2c8\u7ae0\u7684student_info\u8868\u4e3a\u4f8b\uff1a<\/p>\n\n\n\n<p>&nbsp;\u4f60\u80fd\u770b\u5230\u9875\u7684\u6570\u91cf\u662f\u521a\u624d\u768420\u500d\uff0c\u4f46\u662f\u67e5\u8be2\u7684\u6548\u7387\u5e76\u6ca1\u6709\u660e\u663e\u7684\u53d8\u5316\uff0c\u5b9e\u9645\u4e0a\u8fd9\u4e24\u4e2aSQL\u67e5\u8be2\u7684\u65f6\u95f4\u57fa\u672c\u4e0a\u4e00\u6837\uff0c\u5c31\u662f\u56e0\u4e3a\u91c7\u7528\u4e86\u987a\u5e8f\u8bfb\u53d6\u7684\u65b9\u5f0f\u5c06\u9875\u9762\u4e00\u6b21\u6027\u52a0\u8f7d\u5230\u7f13\u51b2\u6c60\u4e2d\uff0c\u7136\u540e\u518d\u8fdb\u884c\u67e5\u627e\u3002\u867d\u7136\u9875\u6570\u91cf\uff08last_query_cost\uff09\u589e\u52a0\u4e86\u4e0d\u5c11\uff0c\u4f46\u662f\u901a\u8fc7\u7f13\u51b2\u6c60\u7684\u673a\u5236\uff0c\u5e76\u6ca1\u6709\u589e\u52a0\u591a\u5c11\u67e5\u8be2\u65f6\u95f4\u3002<\/p>\n\n\n\n<p>\u4f7f\u7528\u573a\u666f\uff1a\u5b83\u5bf9\u4e8e\u6bd4\u8f83\u5f00\u9500\u662f\u975e\u5e38\u6709\u7528\u7684\uff0c\u7279\u522b\u662f\u6211\u4eec\u6709\u597d\u51e0\u79cd\u67e5\u8be2\u65b9\u5f0f\u53ef\u9009\u7684\u65f6\u5019\u3002<br>SQL\u67e5\u8be2\u662f\u4e00\u4e2a\u52a8\u6001\u7684\u8fc7\u7a0b\uff0c\u4ece\u9875\u52a0\u8f7d\u7684\u89d2\u5ea6\u6765\u770b\uff0c\u6211\u4eec\u53ef\u4ee5\u5f97\u5230\u4ee5\u4e0b\u4e24\u70b9\u7ed3\u8bba\uff1a<br>1.\u4f4d\u7f6e\u51b3\u5b9a\u6548\u7387\u3002\u5982\u679c\u9875\u5c31\u5728\u6570\u636e\u5e93\u7f13\u51b2\u6c60\u4e2d\uff0c\u90a3\u4e48\u6548\u7387\u662f\u6700\u9ad8\u7684\uff0c\u5426\u5219\u8fd8\u9700\u8981\u4ece\u5185\u5b58\u6216\u8005\u78c1\u76d8\u4e2d\u8fdb\u884c\u8bfb\u53d6\uff0c\u5f53\u7136\u9488\u5bf9\u5355\u4e2a\u9875\u7684\u8bfb\u53d6\u6765\u8bf4\uff0c\u5982\u679c\u9875\u5b58\u5728\u4e8e\u5185\u5b58\u4e2d\uff0c\u4f1a\u6bd4\u5728\u78c1\u76d8\u4e2d\u8bfb\u53d6\u6548\u7387\u9ad8\u5f88\u591a\u3002<br>2.\u6279\u91cf\u51b3\u5b9a\u6548\u7387\u3002\u5982\u679c\u6211\u4eec\u4ece\u78c1\u76d8\u4e2d\u5bf9\u5355\u4e00\u9875\u8fdb\u884c\u968f\u673a\u8bfb\uff0c\u90a3\u4e48\u6548\u7387\u662f\u5f88\u4f4e\u7684\uff08\u5dee\u4e0d\u591a10ms\uff09\uff0c\u800c\u91c7\u7528\u987a\u5e8f\u8bfb\u53d6\u7684\u65b9\u5f0f\uff0c\u6279\u91cf\u5bf9\u9875\u8fdb\u884c\u8bfb\u53d6\uff0c\u5e73\u5747\u4e00\u9875\u7684\u8bfb\u53d6\u6548\u7387\u5c31\u4f1a\u63d0\u5347\u5f88\u591a\uff0c\u751a\u81f3\u8981\u5feb\u4e8e\u5355\u4e2a\u9875\u9762\u5728\u5185\u5b58\u4e2d\u7684\u968f\u673a\u8bfb\u53d6\u3002<\/p>\n\n\n\n<p>\u6240\u4ee5\u8bf4\uff0c\u9047\u5230io\u5e76\u4e0d\u7528\u62c5\u5fc3\uff0c\u65b9\u6cd5\u627e\u5bf9\u4e86\uff0c\u6548\u7387\u8fd8\u662f\u5f88\u9ad8\u7684\u3002\u6211\u4eec\u9996\u5148\u8981\u8003\u8651\u6570\u636e\u5b58\u653e\u7684\u4f4d\u7f6e\uff0c\u5982\u679c\u662f\u7ecf\u5e38\u4f7f\u7528\u7684\u6570\u636e\u5c31\u8981\u5c3d\u91cf\u653e\u5230\u7f13\u51b2\u6c60\u4e2d\uff0c\u5176\u6b21\u6211\u4eec\u53ef\u4ee5\u5145\u5206\u5229\u7528\u78c1\u76d8\u7684\u541e\u5410\u80fd\u529b\uff0c\u4e00\u6b21\u6027\u6279\u91cf\u8bfb\u53d6\u6570\u636e\uff0c\u8fd9\u6837\u5355\u4e2a\u9875\u7684\u8bfb\u53d6\u6548\u7387\u4e5f\u5c31\u5f97\u5230\u4e86\u63d0\u5347\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">4.\u5b9a\u4f4d\u6267\u884c\u6162\u7684SQL\uff1a\u6162\u67e5\u8be2\u65e5\u5fd7<\/h2>\n\n\n\n<p>MySQL\u7684\u6162\u67e5\u8be2\u65e5\u5fd7\uff0c<strong>\u7528\u6765\u8bb0\u5f55\u5728MySQL\u4e2d\u54cd\u5e94\u65f6\u95f4\u8d85\u8fc7\u9600\u503c\u7684\u8bed\u53e5\uff0c\u5177\u4f53\u6307\u8fd0\u884c\u65f6\u95f4\u8d85\u8fc7long-query_time\u503c\u7684SQL\uff0c<\/strong>\u5219\u4f1a\u88ab\u8bb0\u5f55\u5230\u6162\u67e5\u8be2\u65e5\u5fd7\u4e2d\u3002<strong>long_query_time\u7684\u9ed8\u8ba4\u503c\u4e3a10<\/strong>\uff0c\u610f\u601d\u662f\u8fd0\u884c10\u79d2\u4ee5\u4e0a\uff08\u4e0d\u542b10\u79d2\uff09\u7684\u8bed\u53e5\uff0c\u8ba4\u4e3a\u662f\u8d85\u51fa\u4e86\u6211\u4eec\u7684\u6700\u5927\u5fcd\u8010\u65f6\u95f4\u503c\u3002<\/p>\n\n\n\n<p>\u9ed8\u8ba4\u60c5\u51b5\u4e0b\uff0cMySQL\u6570\u636e\u5e93\u6ca1\u6709\u5f00\u542f\u6162\u67e5\u8be2\u65e5\u5fd7\uff0c\u9700\u8981\u6211\u4eec\u624b\u52a8\u6765\u8bbe\u7f6e\u8fd9\u4e2a\u53c2\u6570\u3002\u5982\u679c\u4e0d\u662f\u8c03\u4f18\u9700\u8981\u7684\u8bdd\uff0c\u4e00\u822c\u4e0d\u5efa\u8bae\u542f\u52a8\u8be5\u53c2\u6570\uff0c\u56e0\u4e3a\u5f00\u542f\u6162\u67e5\u8be2\u65e5\u5fd7\u4f1a\u6216\u591a\u6216\u5c11\u5e26\u6765\u4e00\u5b9a\u7684\u6027\u80fd\u5f71\u54cd\u3002<br>\u6162\u67e5\u8be2\u65e5\u5fd7\u652f\u6301\u5c06\u65e5\u5fd7\u8bb0\u5f55\u5199\u5165\u6587\u4ef6\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>set slow_query_log = on;\n\n\nmysql&gt; show variables like %slow_query_log%;\n+-----------------------+----------------------------------------+\n|     Variable_name     |         Value                          |\n+-----------------------+----------------------------------------+\n|     slow_query_log    |          ON                            |\n|  slow_query_log_file  |    \/var\/lib\/mysql\/atguigu05-slow.log   |\n+----------------------------------------------------------------+<\/code><\/pre>\n\n\n\n<p>\u63a5\u4e0b\u6765\u6211\u4eec\u6765\u770b\u4e0b\u6162\u67e5\u8be2\u7684\u65f6\u95f4\u9614\u503c\u8bbe\u7f6e\uff0c\u4f7f\u7528\u5982\u4e0b\u547d\u4ee4\uff1a<br>mysql &gt; show variables like '%long-query_time%';<br>\u57fa\u672c\u4e0a\u90fd\u662f10s\u5de6\u53f3\uff0c\u5927\u6982\u3002<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"487\" width=\"683\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/d0d34472305b43e496c974f45fdfd942.png\" alt=\"\"><img loading=\"lazy\" decoding=\"async\" height=\"168\" width=\"678\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/2b9b3322d54a4f5bacdcfb562bbd01d5.png\" alt=\"\"><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4.2 \u67e5\u770b\u6162\u67e5\u8be2\u6570\u76ee<\/h3>\n\n\n\n<p>\u67e5\u8be2\u5f53\u524d\u7cfb\u7edf\u4e2d\u6709\u591a\u5c11\u6761\u6162\u67e5\u8be2\u8bb0\u5f55<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SHOW GLOBAL STATUS LIKE '%Slow_queries%;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">4.3 \u6848\u4f8b\u6f14\u793a<\/h3>\n\n\n\n<h5 class=\"wp-block-heading\">\u6b65\u9aa41\uff1a\u5efa\u8868<\/h5>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE `student` (\n  `id` INT(11) NOT NULL AUTO_INCREMENT,\n  `stuno` INT NOT NULL,\n  `name` VARCHAR(20) DEFAULT NULL,\n  `age` INT(3) DEFAULT NULL,\n  `classid` INT(11) DEFAULT NULL,\n  PRIMARY KEY (`id`)\n) ENGINE=INNODB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8;<\/code><\/pre>\n\n\n\n<h5 class=\"wp-block-heading\">\u6b65\u9aa42\uff1a\u8bbe\u7f6e\u53c2\u6570&nbsp;<code>log_bin_trust_function_creators<\/code><\/h5>\n\n\n\n<p>\u5728\u521b\u5efa\u51fd\u6570\u65f6\uff0c\u5982\u679c\u9047\u5230\u9519\u8bef\u63d0\u793a\uff1a<\/p>\n\n\n\n<p><code>This function has none of DETERMINISTIC......<\/code><\/p>\n\n\n\n<p>\u53ef\u4ee5\u901a\u8fc7\u8bbe\u7f6e\u53c2\u6570 <code>log_bin_trust_function_creators<\/code> \u6765\u89e3\u51b3\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SET GLOBAL log_bin_trust_function_creators = 1;<\/code><\/pre>\n\n\n\n<p>\u6ce8\u610f\uff1a\u5982\u679c\u4e0d\u52a0 <code>GLOBAL<\/code>\uff0c\u8bbe\u7f6e\u53ea\u5728\u5f53\u524d\u7a97\u53e3\u6709\u6548\u3002<\/p>\n\n\n\n<h5 class=\"wp-block-heading\">\u6b65\u9aa43\uff1a\u521b\u5efa\u51fd\u6570<\/h5>\n\n\n\n<p>\u521b\u5efa\u4e00\u4e2a\u51fd\u6570\u6765\u968f\u673a\u751f\u6210\u5b57\u7b26\u4e32\u3002\uff08\u5177\u4f53\u5b9e\u73b0\u53ef\u4ee5\u53c2\u8003\u4e0a\u4e00\u7ae0\uff09<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>DELIMITER \/\/\nCREATE FUNCTION rand_string(n INT)\nRETURNS VARCHAR(255)  -- \u8be5\u51fd\u6570\u4f1a\u8fd4\u56de\u4e00\u4e2a\u5b57\u7b26\u4e32\nBEGIN\n  DECLARE chars_str VARCHAR(100) DEFAULT 'abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';\n  DECLARE return_str VARCHAR(255) DEFAULT '';\n  DECLARE i INT DEFAULT 0;\n  WHILE i &lt; n DO\n    SET return_str = CONCAT(return_str, SUBSTRING(chars_str, FLOOR(1+RAND()*52), 1));\n    SET i = i + 1;\n  END WHILE;\n  RETURN return_str;\nEND \/\/\nDELIMITER ;\n\n#\u6d4b\u8bd5\nSELECT rand_string(10);<\/code><\/pre>\n\n\n\n<h5 class=\"wp-block-heading\">\u6b65\u9aa44\uff1a\u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b<\/h5>\n\n\n\n<pre class=\"wp-block-code\"><code>DELIMITER \/\/\nCREATE PROCEDURE insert_stu1(START INT, max_num INT)\nBEGIN\n  DECLARE i INT DEFAULT 0;\n  SET autocommit = 0;  -- \u8bbe\u7f6e\u624b\u52a8\u63d0\u4ea4\u4e8b\u52a1\n  REPEAT  -- \u5faa\u73af\n    SET i = i + 1;  -- \u8d4b\u503c\n    INSERT INTO student (stuno, name, age, classId) VALUES\n    ((START + i), rand_string(6), rand_num(10, 100), rand_num(18, 1000));\n  UNTIL i = max_num\n  END REPEAT;\n  COMMIT;  -- \u63d0\u4ea4\u4e8b\u52a1\nEND \/\/\nDELIMITER ;<\/code><\/pre>\n\n\n\n<h5 class=\"wp-block-heading\">\u6b65\u9aa45\uff1a\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b<\/h5>\n\n\n\n<p>\u8c03\u7528\u521a\u521a\u521b\u5efa\u7684\u5b58\u50a8\u8fc7\u7a0b <code>insert_stu1<\/code>\uff0c\u4ece <code>100001<\/code> \u53f7\u5f00\u59cb\u63d2\u5165 <code>4000000<\/code> \u6761\u8bb0\u5f55\u3002\uff08\u9700\u89813-7\u5206\u949f\uff09<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>CALL insert_stu1(100001, 4000000);<\/code><\/pre>\n\n\n\n<p>\u00a0<img loading=\"lazy\" decoding=\"async\" height=\"406\" width=\"496\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/578d347bb48044f8bcc59fed9de06c0e.png\" alt=\"\"><\/p>\n\n\n\n<p>\u672c\u6b21\u5b9e\u9a8c\u4e2d\u628a1s\u4ee5\u5916\u7684\u5b9a\u4e49\u4e3a\u6162\u67e5\u8be2\uff0c\u5b9e\u9645\u4e0a\u9664\u4e86\u4e0a\u8ff0\u53d8\u91cf\uff0c\u63a7\u5236\u6162\u67e5\u8be2\u65e5\u5fd7\u7684\u8fd8\u6709\u4e00\u4e2a\u7cfb\u7edf\u53d8\u91cf\uff1amin_examined_row_limit\u3002\u8fd9\u4e2a\u53d8\u91cf\u7684\u610f\u601d\u662f\uff0c\u67e5\u8be2\u626b\u63cf\u8fc7\u7684\u6700\u5c11\u8bb0\u5f55\u6570\u3002\u8fd9\u4e2a\u53d8\u91cf\u548c\u67e5\u8be2\u6267\u884c\u65f6\u95f4\uff0c\u5171\u540c\u7ec4\u6210\u4e86\u5224\u522b\u4e00\u4e2a\u67e5\u8be2\u662f\u5426\u662f\u6162\u67e5\u8be2\u7684\u6761\u4ef6\u3002\u5982\u679c\u67e5\u8be2\u626b\u63cf\u8fc7\u7684\u8bb0\u5f55\u6570\u5927\u4e8e\u7b49\u4e8e\u8fd9\u4e2a\u53d8\u91cf\u7684\u503c\uff0c\u5e76\u4e14\u67e5\u8be2\u6267\u884c\u65f6\u95f4\u8d85\u8fc7long_query_time\u7684\u503c\uff0c\u90a3\u4e48\uff0c\u8fd9\u4e2a\u67e5\u8be2\u5c31\u88ab\u8bb0\u5f55\u5230\u6162\u67e5\u8be2\u65e5\u5fd7\u4e2d\uff1b\u53cd\u4e4b\uff0c\u5219\u4e0d\u88ab\u8bb0\u5f55\u5230\u6162\u67e5\u8be2\u65e5\u5fd7\u4e2d\u3002<\/p>\n\n\n\n<p>\u8fd9\u4e2a\u503c\u9ed8\u8ba4\u662f0\u3002\u4e0elong_queryLime=10\u5408\u5728\u4e00\u8d77\uff0c\u8868\u793a\u53ea\u8981\u67e5\u8be2\u7684\u6267\u884c\u65f6\u95f4\u8d85\u8fc710\u79d2\u949f\uff0c\u54ea\u6015\u4e00\u4e2a\u8bb0\u5f55\u4e5f\u6ca1\u6709\u626b\u63cf\u8fc7\uff0c\u90fd\u8981\u88ab\u8bb0\u5f55\u5230\u6162\u67e5\u8be2\u65e5\u5fd7\u4e2d\u3002\u4f60\u4e5f\u53ef\u4ee5\u6839\u636e\u9700\u8981\uff0c\u901a\u8fc7\u4fee\u6539\u201cmy.ini\"\u6587\u4ef6\uff0c\u6765\u4fee\u6539\u67e5\u8be2\u65f6\u957f\uff0c\u6216\u8005\u901a\u8fc7SET\u6307\u4ee4\uff0c\u7528SQL\u8bed\u53e5\u4fee\u6539\u201cmin_examined_row_limit\"\u7684\u503c\u3002<\/p>\n\n\n\n<p>\u6ce8\u610f\u8fd9\u4e2a\u4e0d\u662f\u5728mysql\u7684\u547d\u4ee4\u6bb5\u4e0b\u6267\u884c\uff0c\u800c\u662f\u5728root\u4e0b\u6267\u884c\u8fd9\u4e2a\u811a\u672c\u6587\u4ef6\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>systemctl restart mysqld;\nmysqldumpslow -help<\/code><\/pre>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"516\" width=\"653\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/ce327e8715bc4046a8b32ae1d53a50a9.png\" alt=\"\"><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">4.7\u5220\u9664\u6162\u67e5\u8be2\u65e5\u5fd7<\/h3>\n\n\n\n<p>\u4f7f\u7528SHOW\u8bed\u53e5\u663e\u793a\u6162\u67e5\u8be2\u65e5\u5fd7\u4fe1\u606f\uff0c\u5177\u4f53SQL\u8bed\u53e5\u5982\u4e0b\u3002<br>SHOW VARIABLES LIKE 'slow_query_log%';<\/p>\n\n\n\n<p>\u4ece\u6267\u884c\u7ed3\u679c\u53ef\u4ee5\u770b\u51fa\uff0c\u6162\u67e5\u8be2\u65e5\u5fd7\u7684\u76ee\u5f55\u9ed8\u8ba4\u4e3aMySQL\u7684\u6570\u636e\u76ee\u5f55\uff0c\u5728\u8be5\u76ee\u5f55\u4e0b\u624b\u52a8\u5220\u9664\u6162\u67e5\u8be2\u65e5\u5fd7\u6587\u4ef6\u5373\u53ef\u3002<\/p>\n\n\n\n<p>\u4f7f\u7528\u547d\u4ee4mysqladminflush-logs\u6765\u91cd\u65b0\u751f\u6210\u67e5\u8be2\u65e5\u5fd7\u6587\u4ef6\uff0c\u5177\u4f53\u547d\u4ee4\u5982\u4e0b\uff0c\u6267\u884c\u5b8c\u6bd5\u4f1a\u5728\u6570\u636e\u76ee\u5f55\u4e0b\u91cd\u65b0\u751f\u6210\u6162\u67e5\u8be2\u65e5\u5fd7\u6587\u4ef6\u3002<br>mysqladmin -uroot -p flush-logs slow<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">5. \u67e5\u770bSQL\u6267\u884c\u6210\u672c\uff1aSHOW PROFILE<\/h2>\n\n\n\n<p>showprofile\u5728\u300a\u903b\u8f91\u67b6\u6784\u300b\u7ae0\u8282\u4e2d\u8bb2\u8fc7\uff0c\u8fd9\u91cc\u4f5c\u4e3a\u590d\u4e60\u3002<br>ShowProfile\u662fMySQL\u63d0\u4f9b\u7684\u53ef\u4ee5\u7528\u6765\u5206\u6790\u5f53\u524d\u4f1a\u8bdd\u4e2dSQL\u90fd\u505a\u4e86\u4ec0\u4e48\u3001\u6267\u884c\u7684\u8d44\u6e90\u6d88\u8017\u60c5\u51b5\u7684\u5de5\u5177\uff0c\u53ef\u7528\u4e8esql\u8c03\u4f18\u7684\u6d4b\u91cf\u3002\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u5904\u4e8e\u5173\u95ed\u72b6\u6001\uff0c\u5e76\u4fdd\u5b58\u6700\u8fd115\u6b21\u7684\u8fd0\u884c\u7ed3\u679c\u3002<\/p>\n\n\n\n<p>\u6211\u4eec\u53ef\u4ee5\u5728\u4f1a\u8bdd\u7ea7\u522b\u5f00\u542f\u8fd9\u4e2a\u529f\u80fd<br>mysql &gt; show variables like 'profiling';<\/p>\n\n\n\n<p>\u901a\u8fc7\u8bbe\u7f6eprofiling='ON'\u6765\u5f00\u542fshow profile\uff1a<br>mysql &gt; set profiling = \u2018ON';<\/p>\n\n\n\n<p>\u7136\u540e\u6267\u884c\u76f8\u5173\u7684\u67e5\u8be2\u8bed\u53e5\u3002\u63a5\u7740\u770b\u4e0b\u5f53\u524d\u4f1a\u8bdd\u90fd\u6709\u54ea\u4e9bprofiles\uff0c\u4f7f\u7528\u4e0b\u9762\u8fd9\u6761\u547d\u4ee4\uff1a<br>mysql > show profiles;<br><img loading=\"lazy\" decoding=\"async\" height=\"336\" width=\"330\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/1d187d6fe4c2462f83c1c9bcdc631321.png\" alt=\"\"><\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"307\" width=\"673\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/4ee12ad1fb5f430aafeedcc8042d6e87.png\" alt=\"\"><\/p>\n\n\n\n<p>\u6211\u4eec\u5c31\u53ef\u4ee5\u5224\u65ad\u51fa\u91c7SQL\u5230\u5e95\u6162\u5728\u54ea\u91cc\u3002<\/p>\n\n\n\n<p>showprofile\u7684\u5e38\u7528\u67e5\u8be2\u53c2\u6570\uff1a<\/p>\n\n\n\n<ol class=\"wp-block-list\">\n<li>\u00a0ALL\uff1a\u663e\u793a\u6240\u6709\u7684\u5f00\u9500\u4fe1\u606f\u3002<\/li>\n\n\n\n<li>\u00a0BLOCKIO\uff1a\u663e\u793a\u5757IO\u5f00\u9500\u3002<\/li>\n\n\n\n<li>\u00a0CONTEXTSWITCHES:\u4e0a\u4e0b\u6587\u5207\u6362\u5f00\u9500\u3002<\/li>\n\n\n\n<li>\u00a0CPU\uff1a\u663e\u793aCPU\u5f00\u9500\u4fe1\u606f\u3002<\/li>\n\n\n\n<li>\u00a0IPC\uff1a\u663e\u793a\u53d1\u9001\u548c\u63a5\u6536\u5f00\u9500\u4fe1\u606f\u3002<\/li>\n\n\n\n<li>MEMORY\uff1a\u663e\u793a\u5185\u5b58\u5f00\u9500\u4fe1\u606f\u3002<\/li>\n\n\n\n<li>PAGEFAULTS\uff1a\u663e\u793a\u9875\u9762\u9519\u8bef\u5f00\u9500\u4fe1\u606f\u3002<\/li>\n\n\n\n<li>SOURCE\uff1a\u663e\u793a\u548cSource_function\uff0cSource_file\uff0cSource_line\u76f8\u5173\u7684\u5f00\u9500\u4fe1\u606f\u3002<\/li>\n\n\n\n<li>SWAPS\uff1a\u663e\u793a\u4ea4\u6362\u6b21\u6570\u5f00\u9500\u4fe1\u606f\u3002<\/li>\n<\/ol>\n\n\n\n<p>\u65e5\u5e38\u5f00\u53d1\u9700\u6ce8\u610f\u7684\u7ed3\u8bba\uff1a<br>\u2460converting HEAP to MyISAM\uff1a\u67e5\u8be2\u7ed3\u679c\u592a\u5927\uff0c\u5185\u5b58\u4e0d\u591f\uff0c\u6570\u636e\u5f80\u78c1\u76d8\u4e0a\u642c\u4e86\u3002<br>\u2461Creatingtmptable\uff1a\u521b\u5efa\u4e34\u65f6\u8868\u3002\u5148\u62f7\u8d1d\u6570\u636e\u5230\u4e34\u65f6\u8868\uff0c\u7528\u5b8c\u540e\u518d\u5220\u9664\u4e34\u65f6\u8868\u3002<br>\u2462Copyingtotmptableondisk\uff1a\u628a\u5185\u5b58\u4e2dl\u4e34\u65f6\u8868\u590d\u5236\u5230\u78c1\u76d8\u4e0a\uff0c\u8b66\u60d5\uff01<br>\u2463locked\u3002<br>\u5982\u679c\u5728showprofile\u8bca\u65ad\u7ed3\u679c\u4e2d\u51fa\u73b0\u4e86\u4ee5\u4e0a4\u6761\u7ed3\u679c\u4e2d\u7684\u4efb\u4f55\u4e00\u6761\uff0c\u5219sql\u8bed\u53e5\u9700\u8981\u4f18\u5316<\/p>\n\n\n\n<p>\u6ce8\u610f\uff1a\u4e0d\u8fc7SHOW&nbsp; PROFILE\u547d\u4ee4\u5c06\u88ab\u5f03\u7528\uff0c\u6211\u4eec\u53ef\u4ee5\u4eceinformation_schema\u4e2d\u7684profiling\u6570\u636e\u8868\u8fdb\u884c\u67e5\u770b\u3002<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">6.\u5206\u6790\u67e5\u8be2\u8bed\u53e5\uff1aEXPLAIN<\/h2>\n\n\n\n<p>\u5b9a\u4f4d\u4e86\u67e5\u8be2\u6162\u7684SQL\u4e4b\u540e\uff0c\u6211\u4eec\u5c31\u53ef\u4ee5\u4f7f\u7528EXPLAIN\u6216DESCRIBE\u5de5\u5177\u505a\u9488\u5bf9\u6027\u7684\u5206\u6790\u67e5\u8be2\u8bed\u53e5\u3002DESCRIBE\u8bed\u53e5\u7684\u4f7f\u7528\u65b9\u6cd5\u4e0eEXPLAIN\u8bed\u53e5\u662f\u4e00\u6837\u7684\uff0c\u5e76\u4e14\u5206\u6790\u7ed3\u679c\u4e5f\u662f\u4e00\u6837\u7684\u3002<br>MySQL\u4e2d\u6709\u4e13\u95e8\u8d1f\u8d23\u4f18\u5316SELECT\u8bed\u53e5\u7684\u4f18\u5316\u5668\u6a21\u5757\uff0c\u4e3b\u8981\u529f\u80fd\uff1a\u901a\u8fc7\u8ba1\u7b97\u5206\u6790\u7cfb\u7edf\u4e2d\u6536\u96c6\u5230\u7684\u7edf\u8ba1\u4fe1\u606f\uff0c\u4e3a\u5ba2\u6237\u7aef\u8bf7\u6c42\u7684Query\u63d0\u4f9b\u5b83\u8ba4\u4e3a\u6700\u4f18\u7684\u6267\u884c\u8ba1\u5212\uff08\u4ed6\u8ba4\u4e3a\u6700\u4f18\u7684\u6570\u636e\u68c0\u7d22\u65b9\u5f0f\uff0c\u4f46\u4e0d\u89c1\u5f97\u662fDBA\u8ba4\u4e3a\u662f\u6700\u4f18\u7684\uff0c\u8fd9\u90e8\u5206\u6700\u8017\u8d39\u65f6\u95f4\uff09\u3002<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">&nbsp;1.\u80fd\u505a\u4ec0\u4e48\uff1f<\/h4>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u00b7\u8868\u7684\u8bfb\u53d6\u987a\u5e8f<\/li>\n\n\n\n<li>\u00b7\u6570\u636e\u8bfb\u53d6\u64cd\u4f5c\u7684\u64cd\u4f5c\u7c7b\u578b<\/li>\n\n\n\n<li>\u00b7\u54ea\u4e9b\u7d22\u5f15\u53ef\u4ee5\u4f7f\u7528<\/li>\n\n\n\n<li>\u00b7\u54ea\u4e9b\u7d22\u5f15\u88ab\u5b9e\u9645\u4f7f\u7528<\/li>\n\n\n\n<li>\u00b7\u8868\u4e4b\u95f4\u7684\u5f15\u7528<\/li>\n\n\n\n<li>\u00b7&lt;fontcolor='red'>\u6bcf\u5f20\u8868\u6709\u591a\u5c11\u884c\u88ab\u4f18\u5316\u5668\u67e5\u8be2&lt;\/font><\/li>\n<\/ul>\n\n\n\n<h4 class=\"wp-block-heading\">2.\u5b98\u7f51\u4ecb\u7ecd<\/h4>\n\n\n\n<p>https:\/\/dev.mysql.com\/doc\/refman\/5.7\/en\/explain-output.html<br>https:\/\/dev.mysql.com\/doc\/refman\/8.0\/en\/explain-output.html<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">&nbsp;6.2\u57fa\u672c\u8bed\u6cd5<\/h3>\n\n\n\n<p>EXPLAIN\u6216DESCRIBE\u8bed\u53e5\u7684\u8bed\u6cd5\u5f62\u5f0f\u5982\u4e0b\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>EXPLAIN SELECT select_options\n\u6216\u8005\nDESCRIBE SELECT select_options\n\n\u5982\u679c\u6211\u4eec\u60f3\u770b\u770b\u67d0\u4e2a\u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212\u7684\u8bdd\uff0c\u53ef\u4ee5\u5728\u5177\u4f53\u7684\u67e5\u8be2\u8bed\u53e5\u524d\u8fb9\u52a0\u4e00\u4e2aEXPLAIN\uff0c\u5c31\u50cf\u8fd9\u6837\uff1a\nmysql&gt; EXPLAIN SELECT ;<\/code><\/pre>\n\n\n\n<h3 class=\"wp-block-heading\">&nbsp;6.3 \u6570\u636e\u51c6\u5907<\/h3>\n\n\n\n<figure class=\"wp-block-table\"><table class=\"has-fixed-layout\"><thead><tr><th>\u5217\u540d<\/th><th>\u63cf\u8ff0<\/th><\/tr><\/thead><tbody><tr><td>id<\/td><td>\u5728\u4e00\u4e2a\u5927\u7684\u67e5\u8be2\u8bed\u53e5\u4e2d\u6bcf\u4e2aSELECT\u5173\u952e\u5b57\u90fd\u5bf9\u5e94\u4e00\u4e2a\u552f\u4e00\u7684id<\/td><\/tr><tr><td>select_type<\/td><td>SELECT\u5173\u952e\u5b57\u5bf9\u5e94\u7684\u90a3\u4e2a\u67e5\u8be2\u7684\u7c7b\u578b<\/td><\/tr><tr><td>table<\/td><td>\u8868\u540d<\/td><\/tr><tr><td>partitions<\/td><td>\u5339\u914d\u7684\u5206\u533a\u4fe1\u606f<\/td><\/tr><tr><td>type<\/td><td>\u9488\u5bf9\u5355\u8868\u7684\u8bbf\u95ee\u65b9\u6cd5<\/td><\/tr><tr><td>possible_keys<\/td><td>\u53ef\u80fd\u7528\u5230\u7684\u7d22\u5f15<\/td><\/tr><tr><td>key<\/td><td>\u5b9e\u9645\u4e0a\u4f7f\u7528\u7684\u7d22\u5f15<\/td><\/tr><tr><td>key_len<\/td><td>\u5b9e\u9645\u4f7f\u7528\u5230\u7684\u7d22\u5f15\u957f\u5ea6<\/td><\/tr><tr><td>ref<\/td><td>\u5f53\u4f7f\u7528\u7d22\u5f15\u5217\u7b49\u503c\u67e5\u8be2\u65f6\uff0c\u4e0e\u7d22\u5f15\u5217\u8fdb\u884c\u7b49\u503c\u5339\u914d\u7684\u5bf9\u8c61\u4fe1\u606f<\/td><\/tr><tr><td>rows<\/td><td>\u9884\u4f30\u7684\u9700\u8981\u8bfb\u53d6\u7684\u8bb0\u5f55\u6761\u6570<\/td><\/tr><tr><td>filtered<\/td><td>\u67d0\u4e2a\u8868\u7ecf\u8fc7\u641c\u7d22\u6761\u4ef6\u8fc7\u6ee4\u540e\u5269\u4f59\u8bb0\u5f55\u6761\u6570\u7684\u767e\u5206\u6bd4<\/td><\/tr><tr><td>Extra<\/td><td>\u4e00\u4e9b\u989d\u5916\u7684\u4fe1\u606f<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<pre class=\"wp-block-code\"><code>CREATE TABLE s1 (\n  id INT AUTO_INCREMENT,\n  key1 VARCHAR(100),\n  key2 INT,\n  key3 VARCHAR(100),\n  key_part1 VARCHAR(100),\n  key_part2 VARCHAR(100),\n  key_part3 VARCHAR(100),\n  common_field VARCHAR(100),\n  PRIMARY KEY (id),\n  INDEX idx_key1 (key1),\n  UNIQUE INDEX idx_key2 (key2),\n  INDEX idx_key3 (key3),\n  INDEX idx_key_part (key_part1, key_part2, key_part3)  #key123\u6784\u5efa\u8054\u5408\u7d22\u5f15\n) ENGINE=INNODB CHARSET=utf8;\n\nCREATE TABLE s2 (\n    id INT AUTO_INCREMENT,\n    key1 VARCHAR(100),\n    key2 INT,\n    key3 VARCHAR(100),\n    key_part1 VARCHAR(100),\n    key_part2 VARCHAR(100),\n    key_part3 VARCHAR(100),\n    common_field VARCHAR(100),\n    PRIMARY KEY (id),\n    INDEX idx_key1 (key1),\n    UNIQUE INDEX idx_key2 (key2),\n    INDEX idx_key3 (key3),\n    INDEX idx_key_part(key_part1, key_part2, key_part3)\n) ENGINE=INNODB CHARSET=utf8;\n<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>2.\u8bbe\u7f6e\u53c2\u6570log_bin_trust_function_creators\n\n\u521b\u5efa\u51fd\u6570\uff0c\u5047\u5982\u62a5\u9519\uff0c\u9700\u5f00\u542f\u5982\u4e0b\u547d\u4ee4\uff1a\u5141\u8bb8\u521b\u5efa\u51fd\u6570\u8bbe\u7f6e\uff1a\nset global log_bin_trust_function_creators=1;    #\u4e0d\u52a0global\u53ea\u662f\u5f53\u524d\u7a97\u53e3\u6709\u6548\u3002<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>#\u521b\u5efa\u5b58\u50a8\u51fd\u6570\uff1a\nDELIMITER \/\/\nCREATE FUNCTION rand_string1(n INT) \n\tRETURNS VARCHAR(255) #\u8be5\u51fd\u6570\u4f1a\u8fd4\u56de\u4e00\u4e2a\u5b57\u7b26\u4e32\nBEGIN \n\tDECLARE chars_str VARCHAR(100) DEFAULT 'abcdefghijklmnopqrstuvwxyzABCDEFJHIJKLMNOPQRSTUVWXYZ';\n\tDECLARE return_str VARCHAR(255) DEFAULT '';\n\tDECLARE i INT DEFAULT 0;\n\tWHILE i &lt; n DO\n\t\tSET return_str =CONCAT(return_str,SUBSTRING(chars_str,FLOOR(1+RAND()*52),1));\n\t\tSET i = i + 1;\n\tEND WHILE;\n\tRETURN return_str;\nEND \/\/\nDELIMITER ;\n\nSET GLOBAL log_bin_trust_function_creators=1; <\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>#\u521b\u5efa\u5b58\u50a8\u8fc7\u7a0b\uff1a\nDELIMITER \/\/\nCREATE PROCEDURE insert_s1 (IN min_num INT (10),IN max_num INT (10))\nBEGIN\n\tDECLARE i INT DEFAULT 0;\n\tSET autocommit = 0;\n\tREPEAT\n\tSET i = i + 1;\n\tINSERT INTO s1 VALUES(\n    (min_num + i),\n    rand_string1(6),\n    (min_num + 30 * i + 5),\n    rand_string1(6),\n    rand_string1(10),\n    rand_string1(5),\n    rand_string1(10),\n    rand_string1(10));\n\tUNTIL i = max_num\n\tEND REPEAT;\n\tCOMMIT;\nEND \/\/\nDELIMITER ;\n\n\nDELIMITER \/\/\nCREATE PROCEDURE insert_s2 (IN min_num INT (10),IN max_num INT (10))\nBEGIN\n\tDECLARE i INT DEFAULT 0;\n\tSET autocommit = 0;\n\tREPEAT\n\tSET i = i + 1;\n\tINSERT INTO s2 VALUES(\n        (min_num + i),\n\t\trand_string1(6),\n\t\t(min_num + 30 * i + 5),\n\t\trand_string1(6),\n\t\trand_string1(10),\n\t\trand_string1(5),\n\t\trand_string1(10),\n\t\trand_string1(10));\n\tUNTIL i = max_num\n\tEND REPEAT;\n\tCOMMIT;\nEND \/\/\nDELIMITER ;<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>#\u8c03\u7528\u5b58\u50a8\u8fc7\u7a0b\nCALL insert_s1(10001,10000);\n\nCALL insert_s2(10001,10000);\n\nSELECT COUNT(*) FROM s1;\n\nSELECT COUNT(*) FROM s2;<\/code><\/pre>\n\n\n\n<p>\u201c \u8d44\u6599 \u201d\u6587\u4ef6\u5939\u4e2d\u6709\u4e00\u4e2aEXPLAIN\u4f7f\u7528.sql\u6587\u4ef6&nbsp; P136\u768422.00 \u5927\u6982tts\u76f8\u5173\u7684\u5185\u5bb9<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#1. table\uff1a\u8868\u540d\n#\u67e5\u8be2\u7684\u6bcf\u4e00\u884c\u8bb0\u5f55\u90fd\u5bf9\u5e94\u7740\u4e00\u4e2a\u5355\u8868\nEXPLAIN SELECT * FROM s1;\n\n#s1:\u9a71\u52a8\u8868  s2:\u88ab\u9a71\u52a8\u8868\nEXPLAIN SELECT * FROM s1 INNER JOIN s2;\n\n#2. id\uff1a\u5728\u4e00\u4e2a\u5927\u7684\u67e5\u8be2\u8bed\u53e5\u4e2d\u6bcf\u4e2aSELECT\u5173\u952e\u5b57\u90fd\u5bf9\u5e94\u4e00\u4e2a\u552f\u4e00\u7684id\n SELECT * FROM s1 WHERE key1 = 'a';\n\n\n SELECT * FROM s1 INNER JOIN s2\n ON s1.key1 = s2.key1\n WHERE s1.common_field = 'a';\n\n\n SELECT * FROM s1 \n WHERE key1 IN (SELECT key3 FROM s2);\n\n\n SELECT * FROM s1 UNION SELECT * FROM s2;\n\n\n EXPLAIN SELECT * FROM s1 WHERE key1 = 'a';\n \n \n EXPLAIN SELECT * FROM s1 INNER JOIN s2;\n \n \n EXPLAIN SELECT * FROM s1 WHERE key1 IN (SELECT key1 FROM s2) OR key3 = 'a';<\/code><\/pre>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"57\" width=\"663\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/0d43764ab5954751a3117255c5cb2b65.png\" alt=\"\"><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>######\u67e5\u8be2\u4f18\u5316\u5668\u53ef\u80fd\u5bf9\u6d89\u53ca\u5b50\u67e5\u8be2\u7684\u67e5\u8be2\u8bed\u53e5\u8fdb\u884c\u91cd\u5199,\u8f6c\u53d8\u4e3a\u591a\u8868\u67e5\u8be2\u7684\u64cd\u4f5c########\n EXPLAIN SELECT * FROM s1 WHERE key1 IN (SELECT key2 FROM s2 WHERE common_field = 'a');\n \n #Union\u53bb\u91cd \u5b9e\u9645\u4e0a\u662f\u53d6\u5e76\u96c6\u7684\u64cd\u4f5c\uff0c\u56e0\u6b64\u4f1a\u591a\u4e00\u4e2a\n EXPLAIN SELECT * FROM s1 UNION SELECT * FROM s2;<\/code><\/pre>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"73\" width=\"677\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/d1eb01dc47814991ab7f5aadded5ef1f.png\" alt=\"\"><\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>\u00a0id\u5982\u679c\u76f8\u540c\uff0c\u53ef\u4ee5\u8ba4\u4e3a\u662f\u4e00\u7ec4\uff0c\u4ece\u4e0a\u5f80\u4e0b\u987a\u5e8f\u6267\u884c<\/li>\n\n\n\n<li>\u5728\u6240\u6709\u7ec4\u4e2d\uff0cid\u503c\u8d8a\u5927\uff0c\u4f18\u5148\u7ea7\u8d8a\u9ad8\uff0c\u8d8a\u5148\u6267\u884c<\/li>\n\n\n\n<li>\u5173\u6ce8\u70b9\uff1aid\u53f7\u6bcf\u4e2a\u53f7\u7801\uff0c\u8868\u793a\u4e00\u8d9f\u72ec\u7acb\u7684\u67e5\u8be2\uff0c\u4e00\u4e2asql\u7684\u67e5\u8be2\u8d9f\u6570\u8d8a\u5c11\u8d8a\u597d\uff0c\u591a\u4e86\u5d4c\u5957\u5c31\u6210\u4e86\u6307\u6570\u589e\u957f\u3002<\/li>\n<\/ul>\n\n\n\n<p>3. select_type<\/p>\n\n\n\n<p>\u4e00\u6761\u5927\u7684\u67e5\u8be2\u8bed\u53e5\u91cc\u8fb9\u53ef\u4ee5\u5305\u542b\u82e5\u5e72\u4e2aSELECT\u5173\u952e\u5b57\uff0c\u6bcf\u4e2aSELECT\u5173\u952e\u5b57\u4ee3\u8868\u7740\u4e00\u4e2a\u5c0f\u7684\u67e5\u8be2\u8bed\u53e5\uff0c\u800c\u6bcf\u4e2aSELECT\u5173\u952e\u5b57\u7684FROM\u5b50\u53e5\u4e2d\u90fd\u53ef\u4ee5\u5305\u542b\u82e5\u5e72\u5f20\u8868\uff08\u8fd9\u4e9b\u8868\u7528\u6765\u505a\u8fde\u63a5\u67e5\u8be2\uff09\uff0c\u6bcf\u4e00\u5f20\u8868\u90fd\u5bf9\u5e94\u7740\u6267\u884c\u8ba1\u5212\u8f93\u51fa\u4e2d\u7684\u4e00\u6761\u8bb0\u5f55\uff0c\u5bf9\u4e8e\u5728\u540c\u4e00\u4e2aSELECT\u5173\u952e\u5b57\u4e2d\u7684\u8868\u6765\u8bf4\uff0c\u5b83\u4eec\u7684id\u503c\u662f\u76f8\u540c\u7684\u3002<\/p>\n\n\n\n<p><strong>MySQL\u4e3a\u6bcf\u4e00\u4e2aSELECT\u5173\u952e\u5b57\u4ee3\u8868\u7684\u5c0f\u67e5\u8be2\u90fd\u5b9a\u4e49\u4e86\u4e00\u4e2a\u79f0\u4e4b\u4e3aselect_type\u7684\u5c5e\u6027\uff0c\u610f\u601d\u662f\u6211\u4eec\u53ea\u8981\u77e5\u9053\u4e86\u67d0\u4e2a\u5c0f\u67e5\u8be2\u7684select_type\u5c5e\u6027\uff0c\u5c31\u77e5\u9053\u4e86\u8fd9\u4e2a\u5c0f\u67e5\u8be2\u5728\u6574\u4e2a\u5927\u67e5\u8be2\u4e2d\u626e\u6f14\u4e86\u4e00\u4e2a\u4ec0\u4e48\u89d2\u8272\uff0c\u6211\u4eec\u770b\u4e00\u4e0bselect_type\u90fd\u80fd\u53d6\u54ea\u4e9b\u503c\uff0c\u8bf7\u770b\u5b98\u65b9\u6587\u6863\uff1a<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code> #3. select_type\uff1aSELECT\u5173\u952e\u5b57\u5bf9\u5e94\u7684\u90a3\u4e2a\u67e5\u8be2\u7684\u7c7b\u578b,\u786e\u5b9a\u5c0f\u67e5\u8be2\u5728\u6574\u4e2a\u5927\u67e5\u8be2\u4e2d\u626e\u6f14\u4e86\u4e00\u4e2a\u4ec0\u4e48\u89d2\u8272\n \n # \u67e5\u8be2\u8bed\u53e5\u4e2d\u4e0d\u5305\u542b`UNION`\u6216\u8005\u5b50\u67e5\u8be2\u7684\u67e5\u8be2\u90fd\u7b97\u4f5c\u662f`SIMPLE`\u7c7b\u578b\n EXPLAIN SELECT * FROM s1;\n \n \n #\u8fde\u63a5\u67e5\u8be2\u4e5f\u7b97\u662f`SIMPLE`\u7c7b\u578b\n EXPLAIN SELECT * FROM s1 INNER JOIN s2;\n \n \n #\u5bf9\u4e8e\u5305\u542b`UNION`\u6216\u8005`UNION ALL`\u6216\u8005\u5b50\u67e5\u8be2\u7684\u5927\u67e5\u8be2\u6765\u8bf4\uff0c\u5b83\u662f\u7531\u51e0\u4e2a\u5c0f\u67e5\u8be2\u7ec4\u6210\u7684\uff0c\u5176\u4e2d\u6700\u5de6\u8fb9\u7684\u90a3\u4e2a\n #\u67e5\u8be2\u7684`select_type`\u503c\u5c31\u662f`PRIMARY`\n \n \n #\u5bf9\u4e8e\u5305\u542b`UNION`\u6216\u8005`UNION ALL`\u7684\u5927\u67e5\u8be2\u6765\u8bf4\uff0c\u5b83\u662f\u7531\u51e0\u4e2a\u5c0f\u67e5\u8be2\u7ec4\u6210\u7684\uff0c\u5176\u4e2d\u9664\u4e86\u6700\u5de6\u8fb9\u7684\u90a3\u4e2a\u5c0f\u67e5\u8be2\n #\u4ee5\u5916\uff0c\u5176\u4f59\u7684\u5c0f\u67e5\u8be2\u7684`select_type`\u503c\u5c31\u662f`UNION`\n \n #`MySQL`\u9009\u62e9\u4f7f\u7528\u4e34\u65f6\u8868\u6765\u5b8c\u6210`UNION`\u67e5\u8be2\u7684\u53bb\u91cd\u5de5\u4f5c\uff0c\u9488\u5bf9\u8be5\u4e34\u65f6\u8868\u7684\u67e5\u8be2\u7684`select_type`\u5c31\u662f\n #`UNION RESULT`\n EXPLAIN SELECT * FROM s1 UNION SELECT * FROM s2;\n \n EXPLAIN SELECT * FROM s1 UNION ALL SELECT * FROM s2;<\/code><\/pre>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"55\" width=\"671\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/d108c8153dcd40d38db86cbf541e1dbe.png\" alt=\"\"><img loading=\"lazy\" decoding=\"async\" height=\"66\" width=\"676\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/fb64b8c2f032424785c0bf7a4197dfb2.png\" alt=\"\"><\/p>\n\n\n\n<p>\u5de6\u8fb9\u7684\u5217\u8868\u5c31\u662fprimary\uff0c\u53f3\u8fb9union\u3002<\/p>\n\n\n\n<p>&nbsp;\u7136\u540e\u8fd9\u4e2a\u6570\u636e\u7ed3\u679c\u4f5c\u4e3a\u4e3b\u67e5\u8be2\u7684\u6761 \u4ef6\u8fdb\u884c\u6267\u884c\uff0c\u90a3\u4e48\u8fd9\u6837\u7684\u5b50\u67e5\u8be2\u53eb\u505a\u4e0d\u76f8\u5173\u5b50\u67e5\u8be2\u3002<br>\u6bcf\u6b21\u90fd\u4f20\u5165\u5b50\u67e5\u8be2\u8fdb\u884c\u67e5 \u8be2\uff0c\u7136\u540e\u518d\u5c06\u7ed3\u679c\u53cd\u9988\u7ed9\u5916\u90e8\uff0c\u8fd9\u79cd\u5d4c\u5957\u7684\u6267\u884c\u65b9\u5f0f\u5c31\u79f0\u4e3a\u76f8\u5173\u5b50\u67e5\u8be2\u3002<br>\u5982\u679c\u5b50\u67e5\u8be2\u9700\u8981\u6267\u884c\u591a\u6b21\uff0c\u5373\u91c7\u7528\u5faa\u73af\u7684\u65b9\u5f0f\uff0c\u5148\u4ece\u5916\u90e8\u67e5\u8be2\u5f00\u59cb\uff0c<br>\u5b50\u67e5\u8be2\u4ece\u6570\u636e\u8868\u4e2d\u67e5\u8be2\u4e86\u6570\u636e\u7ed3\u679c\uff0c\u5982\u679c\u8fd9\u4e2a\u6570\u636e\u7ed3\u679c\u53ea\u6267\u884c\u4e00\u6b21\uff0c\u7136<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#\u5b50\u67e5\u8be2\uff1a\n #\u5982\u679c\u5305\u542b\u5b50\u67e5\u8be2\u7684\u67e5\u8be2\u8bed\u53e5\u4e0d\u80fd\u591f\u8f6c\u4e3a\u5bf9\u5e94\u7684`semi-join`\u7684\u5f62\u5f0f\uff0c\u5e76\u4e14\u8be5\u5b50\u67e5\u8be2\u662f\u4e0d\u76f8\u5173\u5b50\u67e5\u8be2\u3002\n #\u8be5\u5b50\u67e5\u8be2\u7684\u7b2c\u4e00\u4e2a`SELECT`\u5173\u952e\u5b57\u4ee3\u8868\u7684\u90a3\u4e2a\u67e5\u8be2\u7684`select_type`\u5c31\u662f`SUBQUERY`\n EXPLAIN SELECT * FROM s1 WHERE key1 IN (SELECT key1 FROM s2) OR key3 = 'a';\n \n \n #\u5982\u679c\u5305\u542b\u5b50\u67e5\u8be2\u7684\u67e5\u8be2\u8bed\u53e5\u4e0d\u80fd\u591f\u8f6c\u4e3a\u5bf9\u5e94\u7684`semi-join`\u7684\u5f62\u5f0f\uff0c\u5e76\u4e14\u8be5\u5b50\u67e5\u8be2\u662f\u76f8\u5173\u5b50\u67e5\u8be2\uff0c\n #\u5219\u8be5\u5b50\u67e5\u8be2\u7684\u7b2c\u4e00\u4e2a`SELECT`\u5173\u952e\u5b57\u4ee3\u8868\u7684\u90a3\u4e2a\u67e5\u8be2\u7684`select_type`\u5c31\u662f`DEPENDENT SUBQUERY`\n EXPLAIN SELECT * FROM s1 \n WHERE key1 IN (SELECT key1 FROM s2 WHERE s1.key2 = s2.key2) OR key3 = 'a';\n #\u6ce8\u610f\u7684\u662f\uff0cselect_type\u4e3a`DEPENDENT SUBQUERY`\u7684\u67e5\u8be2\u53ef\u80fd\u4f1a\u88ab\u6267\u884c\u591a\u6b21\u3002\n \n \n #\u5728\u5305\u542b`UNION`\u6216\u8005`UNION ALL`\u7684\u5927\u67e5\u8be2\u4e2d\uff0c\u5982\u679c\u5404\u4e2a\u5c0f\u67e5\u8be2\u90fd\u4f9d\u8d56\u4e8e\u5916\u5c42\u67e5\u8be2\u7684\u8bdd\uff0c\u90a3\u9664\u4e86\n #\u6700\u5de6\u8fb9\u7684\u90a3\u4e2a\u5c0f\u67e5\u8be2\u4e4b\u5916\uff0c\u5176\u4f59\u7684\u5c0f\u67e5\u8be2\u7684`select_type`\u7684\u503c\u5c31\u662f`DEPENDENT UNION`\u3002\n EXPLAIN SELECT * FROM s1 \n WHERE key1 IN (SELECT key1 FROM s2 WHERE key1 = 'a' UNION SELECT key1 FROM s1 WHERE key1 = 'b');<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code> #\u5bf9\u4e8e\u5305\u542b`\u6d3e\u751f\u8868`\u7684\u67e5\u8be2\uff0c\u8be5\u6d3e\u751f\u8868\u5bf9\u5e94\u7684\u5b50\u67e5\u8be2\u7684`select_type`\u5c31\u662f`DERIVED`\n EXPLAIN SELECT * \n FROM (SELECT key1, COUNT(*) AS c FROM s1 GROUP BY key1) AS derived_s1 WHERE c &gt; 1;\n \n \n #\u5f53\u67e5\u8be2\u4f18\u5316\u5668\u5728\u6267\u884c\u5305\u542b\u5b50\u67e5\u8be2\u7684\u8bed\u53e5\u65f6\uff0c\u9009\u62e9\u5c06\u5b50\u67e5\u8be2\u7269\u5316\u4e4b\u540e\u4e0e\u5916\u5c42\u67e5\u8be2\u8fdb\u884c\u8fde\u63a5\u67e5\u8be2\u65f6\uff0c\n #\u8be5\u5b50\u67e5\u8be2\u5bf9\u5e94\u7684`select_type`\u5c5e\u6027\u5c31\u662f`MATERIALIZED`\n EXPLAIN SELECT * FROM s1 WHERE key1 IN (SELECT key1 FROM s2); #\u5b50\u67e5\u8be2\u88ab\u8f6c\u4e3a\u4e86\u7269\u5316\u8868<\/code><\/pre>\n\n\n\n<p>\u8bb2\u89e3\u8bb2\u7684\u592a\u957f\u4e86\uff0c<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">7 EXPLAIN<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">7.1 EXPLAIN\u56db\u79cd\u8f93\u51fa\u683c\u5f0f<\/h3>\n\n\n\n<p>\u8fd9\u91cc\u8c08\u8c08EXPLAIN\u7684\u8f93\u51fa\u683c\u5f0f\u3002EXPLAIN\u53ef\u4ee5\u8f93\u51fa\u56db\u79cd\u683c\u5f0f\uff1a\u4f20\u7edf\u683c\u5f0f\uff0cJSON\u683c\u5f0f\uff0cTREE\u683c\u5f0f\u4ee5\u53ca\u53ef\u89c6\u5316\u8f93\u51fa\u3002<br>\u7528\u6237\u53ef\u4ee5\u6839\u636e\u9700\u8981\u9009\u62e9\u9002\u7528\u4e8e\u81ea\u5df1\u7684\u683c\u5f0f\u3002<\/p>\n\n\n\n<p>1. \u4f20\u7edf\u683c\u5f0f<br>\u4f20\u7edf\u683c\u5f0f\u7b80\u5355\u660e\u4e86\uff0c\u8f93\u51fa\u662f\u4e00\u4e2a\u8868\u683c\u5f62\u5f0f\uff0c\u6982\u8981\u8bf4\u660e\u67e5\u8be2\u8ba1\u5212\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>mysql&gt; EXPLAIN SELECT s1.key1, s2.key1 FROM s1 LEFT JOIN s2 ON s1.key1 = s2.key1 WHERE s2.common_field IS NOT NULL;\n+----+-------------+-------+--------+------------+-------+-------+------------+---------+----------+-------------+\n| id | select_type | table | partitions | type | possible_keys | key | key_len | ref | rows | filtered | Extra |\n+----+-------------+-------+--------+------------+-------+-------+------------+---------+----------+-------------+\n| 1 | SIMPLE | s2 | NULL | ALL | idx_key1 | NULL | NULL | NULL | 9954 | 90.00 | Using where |\n| 1 | SIMPLE | s1 | NULL | ref | idx_key1 | idx_key1 | 303 | xiaohaizi.s2.key1 | 1 | 100.00 | Using index |\n+----+-------------+-------+--------+------------+-------+-------+------------+---------+----------+-------------+\n2 rows in set, 1 warning (0.00 sec)<\/code><\/pre>\n\n\n\n<p>2. JSON\u683c\u5f0f<br>\u7b2c1\u79cd\u683c\u5f0f\u4e2d\u4ecb\u7ecd\u7684EXPLAIN\u8bed\u53e5\u8f93\u51fa\u4e2d\u7f3a\u5c11\u4e86\u4e00\u4e2a\u8861\u91cf\u6267\u884c\u8ba1\u5212\u597d\u574f\u7684\u91cd\u8981\u5c5e\u6027\u2014\u2014\u6210\u672c\u3002\u800cJSON\u683c\u5f0f\u662f\u56db\u79cd\u683c\u5f0f\u91cc\u9762\u8f93\u51fa\u4fe1\u606f\u6700\u8be6\u5c3d\u7684\u683c\u5f0f\uff0c\u91cc\u9762\u5305\u542b\u4e86\u6267\u884c\u7684\u6210\u672c\u4fe1\u606f\u3002<\/p>\n\n\n\n<p>- JSON\u683c\u5f0f\uff1a\u5728EXPLAIN\u5355\u8bcd\u548c\u771f\u6b63\u7684\u67e5\u8be2\u8bed\u53e5\u4e2d\u95f4\u52a0\u4e0aFORMAT=JSON\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>EXPLAIN FORMAT=JSON SELECT ...<\/code><\/pre>\n\n\n\n<p>- EXPLAIN\u7684Column\u4e0eJSON\u7684\u5bf9\u5e94\u5173\u7cfb\uff1a\uff08\u6765\u6e90\u4e8eMySQL 5.7\u6587\u6863\uff09<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"505\" width=\"681\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/0f90786f92f34fb7a12658c2a5770056.png\" alt=\"\"><img loading=\"lazy\" decoding=\"async\" height=\"15\" width=\"15\" src=\"blob:https:\/\/eve2333.top\/62ecc3eb-214f-4cf1-9e8e-12f18bb17ecc\"><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#json\u683c\u5f0f\u7684explain\nEXPLAIN FORMAT=JSON SELECT * FROM s1 INNER JOIN s2 ON s1.key1 = s2.key2 \nWHERE s1.common_field = 'a';<\/code><\/pre>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"318\" width=\"680\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/1214b9c3fe324ec5b6894ed11d6fe4de.png\" alt=\"\"><\/p>\n\n\n\n<p>\u6211\u4eec\u4f7f\u7528#\u540e\u8fb9\u8ddf\u968f\u6ce8\u91ca\u7684\u5f62\u5f0f\u4e3a\u5927\u5bb6\u89e3\u91ca\u4e86EXPLAIN FORMAT=JSON\u8bed\u53e5\u7684\u8f93\u51fa\u5185\u5bb9\uff0c\u4f46\u662f\u5927\u5bb6\u53ef\u80fd\u6709\u7591\u95ee\u201ccost_info\u201d\u91cc\u8fb9\u7684\u6210\u672c\u770b\u7740\u602a\u602a\u7684\uff0c\u5b83\u4eec\u662f\u600e\u4e48\u8ba1\u7b97\u51fa\u6765\u7684\uff1f\u5148\u770bs1\u8868\u7684\u201ccost_info\u201d\u90e8\u5206\uff1a<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>\"cost_info\": {\n&nbsp; &nbsp; \"read_cost\": \"1840.84\",\n&nbsp; &nbsp; \"eval_cost\": \"193.76\",\n&nbsp; &nbsp; \"prefix_cost\": \"2034.60\",\n&nbsp; &nbsp; \"data_read_per_join\": \"1M\"\n}\n\n- read_cost \u662f\u7531\u4e0b\u8fb9\u8fd9\u4e24\u90e8\u5206\u7ec4\u6210\u7684\uff1a\n&nbsp; - IO \u6210\u672c\n&nbsp; - \u68c0\u6d4b rows \u00d7 (1 - filter) \u6761\u8bb0\u5f55\u7684CPU\u6210\u672c<\/code><\/pre>\n\n\n\n<p>\u5c0f\u8d34\u58eb\uff1arows\u548cfilter\u90fd\u662f\u6211\u4eec\u524d\u8fb9\u4ecb\u7ecd\u6267\u884c\u8ba1\u5212\u7684\u8f93\u51fa\u5217\uff0c\u5728JSON\u683c\u5f0f\u7684\u6267\u884c\u8ba1\u5212\u4e2d\uff0crows\u76f8\u5f53\u4e8erows_examined_per_scan\uff0cfiltered\u540d\u79f0\u4e0d\u53d8\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>- eval_cost \u662f\u8fd9\u6837\u8ba1\u7b97\u7684\uff1a\n  \u68c0\u6d4b rows \u00d7 filter \u6761\u8bb0\u5f55\u7684\u6210\u672c\u3002\n- prefix_cost \u5c31\u662f\u5355\u72ec\u67e5\u8be2 s1 \u8868\u7684\u6210\u672c\uff0c\u4e5f\u5c31\u662f\uff1a\n  read_cost + eval_cost\n- data_read_per_join \u8868\u793a\u5728\u6b64\u6b21\u67e5\u8be2\u4e2d\u9700\u8981\u8bfb\u53d6\u7684\u6570\u636e\u91cf\u3002\n\n\u5bf9\u4e8e s2 \u8868\u7684 \"cost_info\" \u90e8\u5206\u662f\u8fd9\u6837\u7684\uff1a\n\n\"cost_info\": {\n    \"read_cost\": \"968.80\",\n    \"eval_cost\": \"193.76\",\n    \"prefix_cost\": \"3197.16\",\n    \"data_read_per_join\": \"1M\"\n}\n<\/code><\/pre>\n\n\n\n<p>\u7531\u4e8e s2 \u8868\u662f\u88ab\u9a71\u52a8\u8868\uff0c\u6240\u4ee5\u53ef\u80fd\u88ab\u8bfb\u53d6\u591a\u6b21\uff0c\u8fd9\u91cc\u7684 read_cost \u548c eval_cost \u662f\u8bbf\u95ee\u591a\u6b21 s2 \u8868\u540e\u7d2f\u52a0\u8d77\u6765\u7684\u503c\uff0c\u5927\u5bb6\u4e3b\u8981\u5173\u6ce8\u91cc\u8fb9\u513f\u7684 prefix_cost \u7684\u503c\u4ee3\u8868\u7684\u662f\u6574\u4e2a\u8fde\u63a5\u67e5\u8be2\u9884\u8ba1\u7684\u6210\u672c\uff0c\u4e5f\u5c31\u662f\u5355\u6b21\u67e5\u8be2 s1 \u8868\u548c\u591a\u6b21\u67e5\u8be2 s2 \u8868\u540e\u7684\u6210\u672c\u7684\u548c\uff0c\u4e5f\u5c31\u662f\uff1a<\/p>\n\n\n\n<p>968.80 + 193.76 + 2034.60 = 3197.16<\/p>\n\n\n\n<h4 class=\"wp-block-heading\">&nbsp;3.TREE\u683c\u5f0f<\/h4>\n\n\n\n<p>TREE\u683c\u5f0f\u662f8.0.16\u7248\u672c\u4e4b\u540e\u5f15\u5165\u7684\u65b0\u683c\u5f0f\uff0c\u4e3b\u8981\u6839\u636e\u67e5\u8be2\u7684\u5404\u4e2a\u90e8\u5206\u4e4b\u95f4\u7684\u5173\u7cfb\u548c\u5404\u90e8\u5206\u7684\u6267\u884c\u987a\u5e8f\u6765\u63cf\u8ff0\u5982\u4f55\u67e5\u8be2\u3002<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"161\" width=\"673\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/0895cb8f836240abbb8cdc0b59802bfb.png\" alt=\"\"><\/p>\n\n\n\n<h4 class=\"wp-block-heading\">&nbsp;4.\u53ef\u89c6\u5316\u8f93\u51fa<\/h4>\n\n\n\n<p>\u53ef\u89c6\u5316\u8f93\u51fa\uff0c\u53ef\u4ee5\u901a\u8fc7MySQL Workbench\u53ef\u89c6\u5316\u67e5\u770bMySQL\u7684\u6267\u884c\u8ba1\u5212\u3002\u901a\u8fc7\u70b9\u51fbWorkbench\u7684\u653e\u5927\u955c\u56fe\u6807\uff0c\u5373\u53ef\u751f\u6210\u53ef\u89c6\u5316\u7684\u67e5\u8be2\u8ba1\u5212\u3002<img loading=\"lazy\" decoding=\"async\" height=\"392\" width=\"683\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/a74879363d734a9f82897f210cf242d2.png\" alt=\"\"><\/p>\n\n\n\n<h3 class=\"wp-block-heading\">7.2 SHOW WARNINGS\u7684\u4f7f\u7528&nbsp;<\/h3>\n\n\n\n<p>\u5728\u6211\u4eec\u4f7f\u7528EXPLAIN\u8bed\u53e5\u67e5\u770b\u4e86\u67d0\u4e2a\u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212\u540e\uff0c\u7d27\u63a5\u7740\u8fd8\u53ef\u4ee5\u4f7f\u7528SHOWWARNINGS\u8bed\u53e5\u67e5\u770b\u4e0e\u8fd9\u4e2a\u67e5\u8be2\u7684\u6267\u884c\u8ba1\u5212\u6709\u5173\u7684\u4e00\u4e9b\u6269\u5c55\u4fe1\u606f\uff0c\u6bd4\u5982\u8fd9\u6837\uff1a<img loading=\"lazy\" decoding=\"async\" height=\"343\" width=\"678\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/6dc920c05540444597390a0d29d6e508.png\" alt=\"\"><\/p>\n\n\n\n<p>message\u76f8\u5f53\u4e8e\u539f\u7ec4\u6362\u5f0f\u91cd\u5199\u4ee5\u540e\u7684\u7ed3\u6784<\/p>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"123\" width=\"1029\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/7b2d96de887a44b9a55fc9d1a946dc85.png\" alt=\"\"><img loading=\"lazy\" decoding=\"async\" height=\"120\" width=\"1249\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/6bf36dacf5da4a8a899968fc0134fcf0.png\" alt=\"\"><\/p>\n\n\n\n<p>&nbsp;<a href=\"https:\/\/www.bilibili.com\/video\/BV1iq4y1u7vj?t=1019.9&amp;p=139\" target=\"_blank\"  rel=\"nofollow\" >139-EXPLAIN\u76844\u79cd\u683c\u5f0f\u4e0e\u67e5\u770b\u4f18\u5316\u5668\u91cd\u5199SQL_\u54d4\u54e9\u54d4\u54e9_bilibili<\/a>\u5f00\u59cbtts<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">8.\u5206\u6790\u4f18\u5316\u5668\u6267\u884c\u8ba1\u5212\uff1atrace<\/h2>\n\n\n\n<p>OPTIMIZER_TRACE\u662fMySQL5.6\u5f15I\u5165\u7684\u4e00\u9879\u8ddf\u8e2a\u529f\u80fd\uff0c\u5b83\u53ef\u4ee5\u8ddf\u8e2a\u4f18\u5316\u5668\u505a\u51fa\u7684\u5404\u79cd\u51b3\u7b56\uff08\u6bd4\u5982\u8bbf\u95ee\u8868\u7684\u65b9\u6cd5\u3001\u5404\u79cd\u5f00\u9500\u8ba1\u7b97\u3001\u5404\u79cd\u8f6c\u6362\u7b49\uff09\uff0c\u5e76\u5c06\u8ddf\u8e2a\u7ed3\u679c\u8bb0\u5f55<strong>INFORMATION_SCHEMA.OPTIMIZER_TRACE\u8868\u4e2d\u3002<\/strong>\u6b64\u529f\u80fd\u9ed8\u8ba4\u5173\u95ed\u3002\u5f00\u542ftrace\uff0c\u5e76\u8bbe\u7f6e\u683c\u5f0f\u4e3aJSON\uff0c\u540c\u65f6\u8bbe\u7f6etrace\u6700\u5927\u80fd\u591f\u4f7f\u7528\u7684\u5185\u5b58\u5927\u5c0f\uff0c\u907f\u514d\u89e3\u6790\u8fc7\u7a0b\u4e2d\u56e0\u4e3a\u9ed8\u8ba4\u5185\u5b58\u8fc7\u5c0f\u800c\u4e0d\u80fd\u591f\u5b8c\u6574\u5c55\u793a\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>SET optimizer_trace=\"enabled=on\",end_markers_in_json=on;\nset optimizer_trace_max_mem_size=1000000;<\/code><\/pre>\n\n\n\n<pre class=\"wp-block-code\"><code>\u6d4b\u8bd5\uff1a\u6267\u884c\u5982\u4e0bSQL\u8bed\u53e5\nselect * from student whqre id &lt; 10;\n\u6700\u540e\uff0c\u67e5\u8be2information_schema.optimizer_trace\u5c31\u53ef\u4ee5\u77e5\u9053MySQL\u662f\u5982\u4f55\u6267\u884cSQL\u7684\uff1a\nselect * from information_schema.optimizer_trace\\G<\/code><\/pre>\n\n\n\n<p><img loading=\"lazy\" decoding=\"async\" height=\"314\" width=\"223\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/a3a5bb22ffe84c2c96dbd2deb38d3987.png\" alt=\"\"><img loading=\"lazy\" decoding=\"async\" height=\"316\" width=\"429\" src=\"https:\/\/i-blog.csdnimg.cn\/direct\/4c48271e8f6547a38fb5cf6f53f568c7.png\" alt=\"\"><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code> *************************** 1. row ***************************\n  \/\/\u7b2c1\u90e8\u5206\uff1a\u67e5\u8be2\u8bed\u53e5\n  QUERY: select * from student where id &lt; 10\n  \/\/\u7b2c2\u90e8\u5206\uff1aQUERY\u5b57\u6bb5\u5bf9\u5e94\u8bed\u53e5\u7684\u8ddf\u8e2a\u4fe1\u606f\n  TRACE: {\n  \"steps\": &#91;\n    {\n      \"join_preparation\": {  \/\/\u9884\u5907\u5de5\u4f5c\n        \"select#\": 1,\n        \"steps\": &#91;\n          {\n            \"expanded_query\": \"\/* select#1 *\/ select `student`.`id` AS \n`id`,`student`.`stuno` AS `stuno`,`student`.`name` AS `name`,`student`.`age` AS \n`age`,`student`.`classId` AS `classId` from `student` where (`student`.`id` &lt; 10)\"\n          }\n        ] \/* steps *\/\n      } \/* join_preparation *\/\n    },\n    {\n      \"join_optimization\": {  \/\/\u8fdb\u884c\u4f18\u5316\n        \"select#\": 1,\n        \"steps\": &#91;\n          {\n            \"condition_processing\": {   \/\/\u6761\u4ef6\u5904\u7406\n              \"condition\": \"WHERE\",\n              \"original_condition\": \"(`student`.`id` &lt; 10)\",\n              \"steps\": &#91;\n                {\n                  \"transformation\": \"equality_propagation\",\n                  \"resulting_condition\": \"(`student`.`id` &lt; 10)\"\n                },\n                {\n                  \"transformation\": \"constant_propagation\",\n                  \"resulting_condition\": \"(`student`.`id` &lt; 10)\"\n                },\n                {\n                  \"transformation\": \"trivial_condition_removal\",\n                  \"resulting_condition\": \"(`student`.`id` &lt; 10)\"\n                }\n              ] \/* steps *\/\n            } \/* condition_processing *\/\n          },\n          {\n            \"substitute_generated_columns\": {   \/\/\u66ff\u6362\u751f\u6210\u7684\u5217\n            } \/* substitute_generated_columns *\/\n          },\n          {\n            \"table_dependencies\": &#91;    \/\/\u8868\u7684\u4f9d\u8d56\u5173\u7cfb\n              {\n                \"table\": \"`student`\",\n                \"row_may_be_null\": false,\n                \"map_bit\": 0,\n                \"depends_on_map_bits\": &#91;\n                ] \/* depends_on_map_bits *\/\n              }\n            ] \/* table_dependencies *\/\n          },\n          {\n            \"ref_optimizer_key_uses\": &#91;    \/\/\u4f7f\u7528\u952e\n            ] \/* ref_optimizer_key_uses *\/\n          },\n          {\n            \"rows_estimation\": &#91;    \/\/\u884c\u5224\u65ad\n              {\n                \"table\": \"`student`\",\n                \"range_analysis\": {\n                  \"table_scan\": {\n                    \"rows\": 3973767,\n                    \"cost\": 408558\n                  } \/* table_scan *\/,     \/\/\u626b\u63cf\u8868\n                  \"potential_range_indexes\": &#91;     \/\/\u6f5c\u5728\u7684\u8303\u56f4\u7d22\u5f15\n                    {\n                      \"index\": \"PRIMARY\",\n                      \"usable\": true,\n                      \"key_parts\": &#91;\n                        \"id\"\n                      ] \/* key_parts *\/\n                    }\n                  ] \/* potential_range_indexes *\/,\n                  \"setup_range_conditions\": &#91;     \/\/\u8bbe\u7f6e\u8303\u56f4\u6761\u4ef6\n                  ] \/* setup_range_conditions *\/,\n                  \"group_index_range\": {\n                    \"chosen\": false,\n                    \"cause\": \"not_group_by_or_distinct\"\n                  } \/* group_index_range *\/,\n                  \"skip_scan_range\": {\n                    \"potential_skip_scan_indexes\": &#91;\n                      {\n                        \"index\": \"PRIMARY\",\n                        \"usable\": false,\n                        \"cause\": \"query_references_nonkey_column\"\n                      }\n                    ] \/* potential_skip_scan_indexes *\/\n                  } \/* skip_scan_range *\/,\n                  \"analyzing_range_alternatives\": {   \/\/\u5206\u6790\u8303\u56f4\u9009\u9879\n                    \"range_scan_alternatives\": &#91;\n                      {\n                        \"index\": \"PRIMARY\",\n                        \"ranges\": &#91;\n                          \"id &lt; 10\"\n                        ] \/* ranges *\/,\n                        \"index_dives_for_eq_ranges\": true,\n                        \"rowid_ordered\": true,\n                        \"using_mrr\": false,\n                        \"index_only\": false,\n                        \"rows\": 9,\n                        \"cost\": 1.91986,\n                        \"chosen\": true\n                      }\n                    ] \/* range_scan_alternatives *\/,\n                    \"analyzing_roworder_intersect\": {\n                      \"usable\": false,\n                      \"cause\": \"too_few_roworder_scans\"\n                    } \/* analyzing_roworder_intersect *\/\n                  } \/* analyzing_range_alternatives *\/,\n                  \"chosen_range_access_summary\": {    \/\/\u9009\u62e9\u8303\u56f4\u8bbf\u95ee\u6458\u8981\n                    \"range_access_plan\": {\n                      \"type\": \"range_scan\",\n                      \"index\": \"PRIMARY\",\n                      \"rows\": 9,\n                      \"ranges\": &#91;\n                        \"id &lt; 10\"\n                      ] \/* ranges *\/\n                    } \/* range_access_plan *\/,\n                    \"rows_for_plan\": 9,\n                    \"cost_for_plan\": 1.91986,\n                    \"chosen\": true\n                  } \/* chosen_range_access_summary *\/\n                } \/* range_analysis *\/\n              }\n            ] \/* rows_estimation *\/\n          },\n          {\n            \"considered_execution_plans\": &#91;   \/\/\u8003\u8651\u6267\u884c\u8ba1\u5212\n              {\n                \"plan_prefix\": &#91;\n                ] \/* plan_prefix *\/,\n                \"table\": \"`student`\",\n                \"best_access_path\": {   \/\/\u6700\u4f73\u8bbf\u95ee\u8def\u5f84\n                  \"considered_access_paths\": &#91;\n                    {\n                      \"rows_to_scan\": 9,\n                      \"access_type\": \"range\",\n                      \"range_details\": {\n                        \"used_index\": \"PRIMARY\"\n                      } \/* range_details *\/,\n                      \"resulting_rows\": 9,\n                      \"cost\": 2.81986,\n                      \"chosen\": true\n                    }\n                  ] \/* considered_access_paths *\/\n                } \/* best_access_path *\/,\n                \"condition_filtering_pct\": 100,   \/\/\u884c\u8fc7\u6ee4\u767e\u5206\u6bd4\n                \"rows_for_plan\": 9,\n                \"cost_for_plan\": 2.81986,\n                \"chosen\": true\n              }\n            ] \/* considered_execution_plans *\/\n          },\n          {\n            \"attaching_conditions_to_tables\": {   \/\/\u5c06\u6761\u4ef6\u9644\u52a0\u5230\u8868\u4e0a\n              \"original_condition\": \"(`student`.`id` &lt; 10)\",\n              \"attached_conditions_computation\": &#91;\n              ] \/* attached_conditions_computation *\/,\n              \"attached_conditions_summary\": &#91;   \/\/\u9644\u52a0\u6761\u4ef6\u6982\u8981\n                {\n                  \"table\": \"`student`\",\n                  \"attached\": \"(`student`.`id` &lt; 10)\"\n                }\n              ] \/* attached_conditions_summary *\/\n            } \/* attaching_conditions_to_tables *\/\n          },\n          {\n            \"finalizing_table_conditions\": &#91;\n              {\n                \"table\": \"`student`\",\n                \"original_table_condition\": \"(`student`.`id` &lt; 10)\",\n                \"final_table_condition   \": \"(`student`.`id` &lt; 10)\"\n              }\n            ] \/* finalizing_table_conditions *\/\n          },\n          {\n            \"refine_plan\": &#91;   \/\/\u7cbe\u7b80\u8ba1\u5212\n              {\n                \"table\": \"`student`\"\n              }\n            ] \/* refine_plan *\/\n          }\n        ] \/* steps *\/\n      } \/* join_optimization *\/\n    },\n    {\n      \"join_execution\": {    \/\/\u6267\u884c\n        \"select#\": 1,\n        \"steps\": &#91;\n        ] \/* steps *\/\n      } \/* join_execution *\/\n    }\n  ] \/* steps *\/\n }\n \/\/\u7b2c3\u90e8\u5206\uff1a\u8ddf\u8e2a\u4fe1\u606f\u8fc7\u957f\u65f6\uff0c\u88ab\u622a\u65ad\u7684\u8ddf\u8e2a\u4fe1\u606f\u7684\u5b57\u8282\u6570\u3002\nMISSING_BYTES_BEYOND_MAX_MEM_SIZE: 0   \/\/\u4e22\u5931\u7684\u8d85\u51fa\u6700\u5927\u5bb9\u91cf\u7684\u5b57\u8282\n\/\/\u7b2c4\u90e8\u5206\uff1a\u6267\u884c\u8ddf\u8e2a\u8bed\u53e5\u7684\u7528\u6237\u662f\u5426\u6709\u67e5\u770b\u5bf9\u8c61\u7684\u6743\u9650\u3002\u5f53\u4e0d\u5177\u6709\u6743\u9650\u65f6\uff0c\u8be5\u5217\u4fe1\u606f\u4e3a1\n\u4e14TRACE\u5b57\u6bb5\u4e3a\u7a7a\uff0c\u4e00\u822c\u5728\u8c03\u7528\u5e26\u6709SQL SECURITY DEFINER\u7684\u89c6\u56fe\u6216\u8005\u662f\u5b58\u50a8\u8fc7\u7a0b\u7684\u60c5\u51b5\u4e0b\uff0c\u4f1a\u51fa\u73b0\u6b64\u95ee\u9898\u3002\nINSUFFICIENT_PRIVILEGES: 0   \/\/\u7f3a\u5931\u6743\u9650\n1 row in set (0.00 sec)\n<\/code><\/pre>\n\n\n\n<p>03.28-----------tts&nbsp;<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">9. MySQL\u76d1\u63a7\u5206\u6790\u89c6\u56fe-sys schema&nbsp;<\/h2>\n\n\n\n<p>\u5173\u4e8eMySQL\u7684\u6027\u80fd\u76d1\u63a7\u548c\u95ee\u9898\u8bca\u65ad\uff0c\u6211\u4eec\u4e00\u822c\u90fd\u4eceperformance_schema\u4e2d\u53bb\u83b7\u53d6\u60f3\u8981\u7684\u6570\u636e\uff0c\u5728MySQL5.7.7\u7248\u672c\u4e2d\u65b0\u589esysschema\uff0c\u5b83\u5c06performance_schema\u548cinformation_schema\u4e2d\u7684\u6570\u636e\u4ee5\u66f4\u5bb9\u6613\u7406\u89e3\u7684\u65b9\u5f0f\u603b\u7ed3\u5f52\u7eb3\u4e3a\"\u89c6\u56fe\u201d\uff0c\u5176\u76ee\u7684\u5c31\u662f\u4e3a\u4e86\u964d\u4f4e\u67e5\u8be2performance_schema\u7684\u590d\u6742\u5ea6\uff0c\u8ba9DBA\u80fd\u591f\u5feb\u901f\u7684\u5b9a\u4f4d\u95ee\u9898\u3002\u4e0b\u9762\u770b\u770b\u8fd9\u4e9b\u5e93\u4e2d\u90fd\u6709\u54ea\u4e9b\u76d1\u63a7\u8868\u548c\u89c6\u56fe\uff0c\u638c\u63e1\u4e86\u8fd9\u4e9b\uff0c\u5728\u6211\u4eec\u5f00\u53d1\u548c\u8fd0\u7ef4\u7684\u8fc7\u7a0b\u4e2d\u5c31\u8d77\u5230\u4e86\u4e8b\u534a\u529f\u500d\u7684\u6548\u679c\u3002<\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#1.\u67e5\u8be2\u7a76\u4f59\u7d22\u5f15\nSELECT * FROM sys.schema_redundant_indexes;\n#2.\u67e5\u8be2\u672a\u4f7f\u7528\u8fc7\u7684\u7d22\u5f15\nSELECT * FROM sys.schema_unused_indexes;\n#3.\u67e5\u8be2\u7d22\u5f15\u7684\u4f7f\u7528\u60c5\u51b5\nSELECT index_name,rows_selected,rows_inserted,rows_updated,rows_deleted\nFROM sys.schema_index_statistics WHERE table_schema='dbname'<\/code><\/pre>\n\n\n\n<p>\u8fd9\u51e0\u6761\u90fd\u662f\u5bf9\u4e8e\u6574\u4e2a\u6570\u636e\u5e93\u7cfb\u7edf\u6765\u8bf4\u7684\uff0c\u5373sys\u4e2d\uff0c\u56e0\u6b64\u653e\u5230\u4efb\u610f\u6570\u636e\u5e93\u4e2d\u5747\u53ef\uff0c<a href=\"https:\/\/www.bilibili.com\/video\/BV1iq4y1u7vj?t=350.0&amp;p=140\" target=\"_blank\"  rel=\"nofollow\" >140-trace\u5206\u6790\u4f18\u5316\u5668\u6267\u884c\u8ba1\u5212\u4e0eSys schema\u89c6\u56fe\u7684\u4f7f\u7528_\u54d4\u54e9\u54d4\u54e9_bilibili<\/a><\/p>\n\n\n\n<pre class=\"wp-block-code\"><code>#1.\u67e5\u8be2\u8868\u7684\u8bbf\u95ee\u91cf\nSELEcT table_schema,table_name,SUM(io_read_requests+io_write_requests) AS io\nFROM sys.schema_table_statistics GRoUP BY table_schema,table_name ORDER BY io DESC;\n\n#2.\u67e5\u8be2\u5360\u7528bufferpool\u8f83\u591a\u7684\u8868\nSELECT object_schema,object_name,allocated,DATA\nFROM sys.innodb_buffer_stats_by_table ORDER BY allocated LIMIT 10;\n#3.\u67e5\u770b\u8868\u7684\u5168\u8868\u626b\u63cf\u60c5\u51b5\nSELECT * FROM sys.statements with full table scans WHERE db='dbname';\n\n\n#1.\u76d1\u63a7SQL\u6267\u884c\u7684\u9891\u7387\nSELECT db,exec_count,QUERY FROM sys.statement_analysis\nORDER BY eXeC_count DESC;\n#2.\u76d1\u63a7\u4f7f\u7528\u4e86\u6392\u5e8f\u7684SQL\nSELECT db,exec_count,first_seen,last_seen,QUERY\nFROM sys.statements_with_sorting LIMIT 1;\n#3.\u76d1\u63a7\u4f7f\u7528\u4e86\u4e34\u65f6\u8868\u6216\u8005\u78c1\u76d8\u4e34\u65f6\u8868\u7684SQL\nSELECT db,exec_count,tmp_tables,tmp_disk_tables,QUERY\nFROM sys.statement_analysis WHERE tmp_tables&gt;O OR tmp_disk_tables &gt;0\nORDER BY (tmp_tables+tmp_disk_tables)DESC;<\/code><\/pre>\n\n\n\n<p>IO\u76f8\u5173<\/p>\n\n\n\n<p>#1. \u67e5\u770b\u6d88\u8017\u78c1\u76d8IO\u7684\u6587\u4ef6<br>select file,avg_read,avg_write,avg_read+avg_write as avg_io<br>from sys.io_global_by_file_by_bytes order by avg_read limit 10;<\/p>\n\n\n\n<p>Innodb \u76f8\u5173<\/p>\n\n\n\n<p>#1. \u884c\u9501\u963b\u585e\u60c5\u51b5<br>select * from sys.innodb_lock_waits;<\/p>\n\n\n\n<p>\u98ce\u9669\u63d0\u793a\uff1a<br>\u901a\u8fc7sys\u5e93\u53bb\u67e5\u8be2\u65f6\uff0cMySQL\u4f1a\u6d88\u8017\u5927\u91cf\u8d44\u6e90\u53bb\u6536\u96c6\u76f8\u5173\u4fe1\u606f\uff0c\u4e25\u91cd\u7684\u53ef\u80fd\u4f1a\u5bfc\u81f4\u4e1a\u52a1\u8bf7\u6c42\u88ab\u963b\u585e\uff0c\u4ece\u800c\u5f15\u8d77\u6545\u969c\u3002\u5efa\u8bae\u751f\u4ea7\u4e0a\u4e0d\u8981\u9891\u7e41\u7684\u53bb\u67e5\u8be2sys\u6216\u8005performance_schema\u3001information_schema\u6765\u5b8c\u6210\u76d1\u63a7\u3001\u5de1\u68c0\u7b49\u5de5\u4f5c\u3002 \u200b<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u7b2c09\u7ae0_\u6027\u80fd\u5206\u6790\u5de5\u5177\u7684\u4f7f\u7528 1.\u6570\u636e\u5e93\u670d\u52a1\u5668\u7684\u4f18\u5316\u6b65\u9aa4 \u5f53\u6211\u4eec\u9047\u5230\u6570\u636e\u5e93\u8c03\u4f18\u95ee\u9898\u7684\u65f6\u5019\uff0c\u8be5\u5982\u4f55\u601d\u8003\u5462\uff1f\u8fd9\u91cc\u628a\u601d\u8003\u7684\u6d41\u7a0b\u6574\u7406\u6210\u4e0b\u9762 &#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"emotion":"","emotion_color":"","title_style":"","license":"","footnotes":""},"categories":[2],"tags":[16],"class_list":["post-909","post","type-post","status-publish","format-standard","hentry","category-2","tag-sql"],"_links":{"self":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/909","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=909"}],"version-history":[{"count":1,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/909\/revisions"}],"predecessor-version":[{"id":910,"href":"https:\/\/eve2333.top\/index.php?rest_route=\/wp\/v2\/posts\/909\/revisions\/910"}],"wp:attachment":[{"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=909"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=909"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/eve2333.top\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=909"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}