{"id":10008054,"date":"2023-07-07T14:59:21","date_gmt":"2023-07-07T06:59:21","guid":{"rendered":"https:\/\/ityet.com\/?p=10008054"},"modified":"2023-07-07T14:59:21","modified_gmt":"2023-07-07T06:59:21","slug":"mysql%e8%87%aa%e6%b2%bb%e5%b9%b3%e5%8f%b0%e5%bb%ba%e8%ae%be%e7%9a%84%e5%86%85%e6%a0%b8%e5%8e%9f%e7%90%86%e5%8f%8a%e5%ae%9e%e8%b7%b5%ef%bc%88%e4%b8%8b%ef%bc%89","status":"publish","type":"post","link":"https:\/\/itmax.cn\/?p=10008054","title":{"rendered":"MySQL\u81ea\u6cbb\u5e73\u53f0\u5efa\u8bbe\u7684\u5185\u6838\u539f\u7406\u53ca\u5b9e\u8df5\uff08\u4e0b\uff09"},"content":{"rendered":"<h2>0 \u524d\u6587\u56de\u987e<\/h2>\n<p>\u5728\u300a<a href=\"https:\/\/link.segmentfault.com\/?enc=gCI0xSuFdYUOscfpPjpEtw%3D%3D.ddY43VUCmZZPAk1c6elBAAMeD1AGpFXi47eKW7gxT0FnZgBLMcYduFXJyPJOG9QLOZvzpZFNu8SpQlb8Y8KO%2BZDxttj27U%2FjROTmCysj05k%3D\" rel=\"nofollow\">MySQL\u81ea\u6cbb\u5e73\u53f0\u5efa\u8bbe\u7684\u5185\u6838\u539f\u7406\u53ca\u5b9e\u8df5\uff08\u4e0a\uff09<\/a>\u300b\u4e00\u6587\u4e2d\uff0c\u6211\u4eec\u4e3b\u8981\u4ecb\u7ecd\u4e86\u6570\u636e\u5e93\u7684\u5f02\u5e38\u53d1\u73b0\u4e0e\u8bca\u65ad\u65b9\u9762\u7684\u5185\u5bb9\uff0c\u5728\u8bca\u65ad\u65b9\u9762\u7ecf\u5e38\u4f1a\u78b0\u5230\u4e00\u4e9b\u96be\u4ee5\u627e\u51fa\u6839\u56e0\u7684Case\u3002\u9488\u5bf9\u8fd9\u4e9b\u7591\u96be\u6742\u75c7Case\uff0c\u901a\u8fc7\u672c\u7bc7\u53ef\u4ee5\u4e86\u89e3\u5230\uff0c\u5982\u4f55\u901a\u8fc7\u5185\u6838\u53ef\u89c2\u6d4b\u6027\u4ee5\u53ca\u5168\u91cfSQL\u6765\u89e3\u51b3\u8fd9\u4e9b\u95ee\u9898\u3002\u9664\u6b64\u4e4b\u5916\uff0c\u5728\u5f97\u51fa\u6839\u56e0\u540e\uff0c\u5982\u4f55\u5904\u7406\u5f02\u5e38\uff0c\u5982\u4f55\u5bf9SQL\u8fdb\u884c\u4f18\u5316\uff0c\u4ee5\u53ca\u5982\u4f55\u8fdb\u884cSQL\u6cbb\u7406\u7b49\u76f8\u5173\u65b9\u9762\u95ee\u9898\uff0c\u4e5f\u5c06\u5728\u672c\u7bc7\u4e2d\u7ed9\u4e88\u89e3\u7b54\u3002<\/p>\n<h2>1 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\u89e3\u51b3\u601d\u8def<\/h4>\n<p>\u5982\u679c\u4f7f\u7528\u7684\u662f\u793e\u533a\u7248\u672c\u7684MySQL\uff0c\u57fa\u672c\u4e0a\u90fd\u4f1a\u9762\u4e34\u4e0a\u9762\u4e24\u5927\u95ee\u9898\u3002\u6211\u4eec\u5148\u4ece\u5185\u6838\u7684\u89d2\u5ea6\u5206\u6790\u4e00\u4e0b\u8fd9\u4e24\u4e2a\u6311\u6218\uff0c\u5bf9\u4e8e\u7b2c\u4e00\u4e2a\u6311\u6218\uff0c\u4e3b\u8981\u662f\u5bf9MySQL\u5728\u5185\u6838\u5c42\u9762\u6267\u884c\u7ec6\u8282\u4e0d\u591f\u4e86\u89e3\uff0c\u6bd4\u5982\u4e00\u6761SQL\u6267\u884c\u4e8610s\uff0c\u800c\u4ece\u5185\u6838\u5c42\u9762\u6765\u770b\u7684\u8bdd\uff0c\u8fd9\u5341\u79d2\u7684\u65f6\u95f4\u53ef\u80fd\u4f1a\u6709\u51e0\u767e\u4e2a\u6b65\u9aa4\u7ec4\u6210\uff0c\u68c0\u67e5\u540e\u53ef\u80fd\u53d1\u73b0row\u6216\u8005MDL\u9501\u7b49\u5f85\u65f6\u95f4\u52a0\u8d77\u6765\u53ea\u67091\u79d2\uff0c\u90a3\u4e48\u5176\u4ed6\u76849\u79d2\u7684\u8017\u65f6\u5728\u54ea\u91cc\u5462\uff1f\u53ef\u80fd\u53d1\u751f\u5728\u8fd9\u51e0\u767e\u4e2a\u6b65\u9aa4\u4e2d\u7684\u4efb\u4f55\u4e00\u4e2a\u6216\u8005\u591a\u4e2a\uff0c\u6240\u4ee5\u5982\u679c\u6ca1\u6709\u8fd9\u51e0\u767e\u4e2a\u6b65\u9aa4\u7684\u660e\u7ec6\u6570\u636e\uff0c\u5c31\u65e0\u6cd5\u8bca\u65ad\u51fa\u7a81\u7136\u51fa\u73b0\u7684\u6027\u80fd\u95ee\u9898\u7684\u6839\u56e0\u3002<\/p>\n<p>\u7b2c\u4e8c\u4e2a\u95ee\u9898\u8ddf\u7b2c\u4e00\u4e2a\u95ee\u9898\u4ece\u672c\u8d28\u4e0a\u6765\u8bf4\u662f\u4e00\u6837\u7684\u3002\u7531\u4e8e\u91c7\u96c6\u7684\u6570\u636e\u662f\u67d0\u4e2a\u65f6\u95f4\u70b9\u7684\u5feb\u7167\u6570\u636e\uff08\u901a\u8fc7\u6d3b\u8dc3\u4f1a\u8bdd\uff09\uff0c\u6216\u8005\u53ea\u662f\u90e8\u5206\u6307\u6807\u7684\u6570\u636e\uff08\u901a\u8fc7\u6162\u67e5\u8be2\u65e5\u5fd7\uff09\uff0c\u6240\u4ee5\u6211\u4eec\u770b\u5230\u7684\u53ea\u662f\u7247\u9762\u7684\u4fe1\u606f\uff0c\u800c\u6ca1\u6709\u529e\u6cd5\u83b7\u53d6\u5230\u6574\u4e2aSQL\u7684\u5b8c\u6574\u7684\u8017\u65f6\u5206\u5e03\u4fe1\u606f\u3002<\/p>\n<h4>1.1.3 Wait\u8017\u65f6\u91cf\u5316\u5206\u6790\u6cd5<\/h4>\n<p>\u5728\u5206\u6790\u5b8c\u539f\u56e0\u4e4b\u540e\uff0c\u6211\u4eec\u53c2\u8003\u4e86<a href=\"https:\/\/link.segmentfault.com\/?enc=ayvFqL6PhWsIWB2cxgc29w%3D%3D.y8YK63JbfCgMknzx4I2bivDtp4R7RbYI7myaTp9%2F5yo6k%2F2Aj2%2F%2F1zcfsybH0oYw\" rel=\"nofollow\">TSA<\/a>\u7684\u601d\u60f3\uff0c\u540c\u65f6\u7ed3\u5408MySQL\u81ea\u8eab\u7684\u7279\u70b9\u6765\u505a\u57fa\u4e8eWait\u7684\u5185\u6838\u53ef\u89c2\u6d4b\u6027\u7684\u5efa\u8bbe\u3002\u4eceTSA\u53ef\u4ee5\u770b\u51fa\uff0cSQL\u6267\u884c\u7684\u603b\u8017\u65f6\u65e0\u975e\u5c31\u662f\u7531Off-CPU\u8ddfON-CPU\u4e24\u5927\u90e8\u5206\u7ec4\u6210\uff0c\u5982\u679cSQL\u6709\u8017\u65f6\u957f\u7684\u95ee\u9898\uff0c\u9996\u5148\u8981\u786e\u8ba4\u662f\u5728OnCPU\u8fd8\u662f\u5728OffCPU\u4e0a\u8017\u65f6\u591a\u3002\u5982\u679c\u662f\u524d\u8005\uff0c\u90a3\u4e48\u8bf4\u660eSQL\u672c\u8eab\u6709\u95ee\u9898\uff0c\u6bd4\u5982\u6d88\u8017\u8d44\u6e90\u592a\u591a\uff08\u6bd4\u5982\u65e0\u6548\u7d22\u5f15\u9020\u6210\u626b\u63cf\u884c\u6570\u8fc7\u591a\uff09\uff1b\u5982\u679c\u662f\u540e\u8005\uff0c\u90a3\u4e48\u8bf4\u660eSQL\u672c\u8eab\u6ca1\u6709\u95ee\u9898\uff0c\u800c\u662f\u53d7\u5230\u5e72\u6270\u6216\u8005\u7cfb\u7edf\u8d44\u6e90\u4e0d\u8db3\uff0c\u8fdb\u800c\u9020\u6210OffCPU\u5c42\u9762\u8017\u65f6\u8fc7\u591a\u3002<\/p>\n<p>\u65e0\u8bba\u662f\u4f55\u79cd\u60c5\u51b5\uff0c\u6211\u4eec\u90fd\u9700\u8981\u628aOnCPU\u8ddfOffCPU\u7684\u8017\u65f6\u505a\u8fdb\u4e00\u6b65\u7684\u62c6\u5206\uff0c\u4ece\u800c\u6765\u67e5\u770b\u8017\u65f6\u74f6\u9888\u70b9\u5230\u5e95\u5728\u54ea\u91cc\uff0c\u5e76\u4e14\u5bf9\u8017\u65f6\u6bd4\u8f83\u591a\u7684\u5173\u952e\u4ee3\u7801\u8def\u5f84\u4ea4\u7531\u5185\u6838\u56e2\u961f\u6765\u8fdb\u884c\u57cb\u70b9\uff1b\u76f8\u5bf9MySQL performance_schema\u5e93\u4e2d\u7edf\u8ba1\u7684Wait\u4fe1\u606f\uff0c\u5b9e\u73b0\u975e\u5e38\u8f7b\u91cf\uff0c\u6240\u4ee5\u5bf9\u603b\u4f53\u7684\u6027\u80fd\u7684\u5f71\u54cd\u5f88\u5c0f\uff0c\u5e76\u4e14\u8017\u65f6\u6307\u6807\u90fd\u662fSQL\u660e\u7ec6\u7c92\u5ea6\u7684\uff0c\u800c\u4e0d\u662f\u7c7b\u4f3cperformance_schema\u4e2d\u7684SQL\u6a21\u7248\u7ea7\u522b\u7684\u805a\u5408\u6570\u636e\u3002<\/p>\n<p><strong>\u8017\u65f6\u5728OnCPU<\/strong><\/p>\n<p>\u5728\u5206\u6790\u4e00\u6761SQL\u6267\u884c\u8017\u65f6\uff0c\u5982\u679c\u53d1\u73b0\u50cf\u4e0b\u56fe\u4e00\u6837\uff0c\u8017\u65f6\u5206\u5e03\u5927\u90e8\u5206\u90fd\u5728OnCPU\uff0c\u8fd9\u8bf4\u660eSQL\u672c\u8eab\u6709\u4e25\u91cd\u7684\u6027\u80fd\u95ee\u9898\uff08\u5168\u8868\u626b\u63cf\u3001\u8fc7\u6ee4\u6548\u679c\u4e0d\u4f73\u6216\u8005\u67e5\u8be2\u4f18\u5316\u5668\u7684bug\u7b49\u539f\u56e0\uff09\uff0c\u6211\u4eec\u53ef\u4ee5\u628a\u8bca\u65ad\u7684\u65b9\u5411\u96c6\u4e2d\u5728\u5982\u4f55\u4f18\u5316SQL\u672c\u8eab\u5c31\u53ef\u4ee5\u4e86\uff0c\u800c\u4e0d\u9700\u8981\u53bb\u5173\u6ce8\u5176\u4ed6\u7684\u65b9\u9762\uff0c\u5982\u9501\u963b\u585e\u3001\u78c1\u76d8\u6216\u8005\u7f51\u7edc\u5ef6\u8fdf\u7b49OffCPU\u65b9\u9762\u7684\u95ee\u9898\u3002\u901a\u8fc7\u4f7f\u7528<a href=\"https:\/\/link.segmentfault.com\/?enc=t6ZzIv1rzi%2BPH2YdIrKvkg%3D%3D.rNwB4bFIVtNYx62kWq%2BOkAPawdBTKHZ09T2OvdSDiaigDtW8Y0EskxFU35Fsf6q3\" rel=\"nofollow\">getrusage<\/a>\u65b9\u6cd5\u6765\u83b7\u53d6\u67d0\u6761SQL\u7684OnCPU\u8017\u65f6\u65f6\u957f\uff0c\u6bd4\u5982\u5728SQL\u6267\u884c\u524d\uff0c\u83b7\u53d6\u5f53\u524d\u7ebf\u7a0b\u7684ru_utime\u3001ru_stime\u65f6\u95f4\uff0c\u7136\u540e\u5728SQL\u6267\u884c\u5b8c\u6bd5\u65f6\u518d\u6b21\u83b7\u53d6ru_utime\u3001ru_stime\u503c\uff0c\u5c31\u53ef\u4ee5\u5f97\u5230SQL\u6267\u884c\u7684CPU Time\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982389\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p><strong>\u8017\u65f6\u5728OffCPU<\/strong><\/p>\n<p>\u5982\u679c\u53d1\u73b0OnCPU\u7684\u8017\u65f6\u5360\u603b\u8017\u65f6\u7684\u6bd4\u7387\u6bd4\u8f83\u4f4e\uff0c\u901a\u8fc7OffCPU\u7684\u76f8\u5173\u6307\u6807\u53d1\u73b0\u5176\u5360\u603b\u8017\u65f6\u7684\u6bd4\u7387\u6bd4\u8f83\u9ad8\uff0c\u8bf4\u660eSQL\u672c\u8eab\u6ca1\u6709\u95ee\u9898\uff0c\u53ef\u80fd\u662f\u88ab\u9501\u4f4f\u4e86\u3001\u786c\u4ef6\u8d44\u6e90\u4e0d\u8db3\u6216\u8005\u662f\u88ab\u5185\u6838\u5c42\u9762\u67d0\u4e2a\u5185\u6838\u9501\u7ed9\u5361\u4f4f\u4e86\u3002\u6211\u4eec\u5c31\u9700\u8981\u67e5\u770b\u5230\u5e95\u662fOffCPU\u76f8\u5173\u7684\u54ea\u4e2a\uff0c\u6216\u8005\u54ea\u4e9b\u6307\u6807\u8017\u65f6\u6bd4\u8f83\u9ad8\uff0c\u9700\u8981\u5728\u5185\u6838\u5c42\u9762\u5bf9\u6267\u884c\u8fc7\u7a0b\u4e2d\u7684\u53ef\u80fd\u7684\u3001\u8017\u65f6\u6bd4\u8f83\u957f\u7684\u6267\u884c\u4ee3\u7801\u8def\u5f84\u8fdb\u884c\u57cb\u70b9\uff0c\u53ea\u6709\u83b7\u53d6\u5230\u4e86\u8ddf\u6027\u80fd\u76f8\u5173\u7684\u5173\u952e\u7684\u6570\u636e\uff0c\u624d\u80fd\u505a\u51fa\u51c6\u786e\u7684\u5224\u65ad\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982390\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>\u5982\u4f55\u9009\u62e9\u5408\u9002\u800c\u5168\u9762\u7684OffCPU\u76f8\u5173\u7684\u4ee3\u7801\u8def\u5f84\u8fdb\u884c\u57cb\u70b9\uff1f\u7ecf\u8fc7\u63a2\u7d22\uff0c\u8fd9\u91cc\u63d0\u4f9b\u4e86\u5982\u4e0b\u51e0\u4e2a\u65b9\u5f0f\uff1a<\/p>\n<ol>\n<li>\u5206\u6790setup_instruments\u8868\u4e2d\u5305\u542b\u7684\u5173\u952e\u57cb\u70b9\u4fe1\u606f\uff0c\u5927\u81f4\u77e5\u9053\u6709\u54ea\u4e9b\u5173\u952e\u7684\u6307\u6807\u53ef\u4ee5\u57cb\u70b9\uff0c\u6bd4\u5982wait\/IO\u3001Mutex\u7c7b\u7b49\uff0c\u518d\u7ed3\u5408\u81ea\u8eab\u7684\u7ecf\u9a8c\u6765\u5224\u65ad\u54ea\u4e9b\u6307\u6807\u53ef\u80fd\u6709\u6027\u80fd\u74f6\u9888\u7684\u95ee\u9898\u3002<\/li>\n<li>\u6839\u636e\u5b9e\u9645\u7591\u96becase\u6765\u5224\u65ad\u9009\u62e9\u54ea\u4e9bWait\u6307\u6807\uff0c\u6bd4\u5982\u770b\u5230&#8221;Thread xxx has waited at trx0trx.cc line 1193 for 241.00 seconds the semaphore: xxxxx mutex REDO_RSEG created trx0rseg.cc:211, lock var 1&#8243;\uff0c\u5219\u5bf9mutex REDO_RSEG\u8fdb\u884c\u57cb\u70b9\uff0c\u770b\u5230&#8221;Thread xxx has waited at dict0dict.cc line 1239 for 245.00 seconds the semaphore: xxxxxx Mutex DICT_SYS created dict0dict.cc:1173, lock var 1&#8243;\u5219\u5bf9 Mutex DICT_SYS\u8fdb\u884c\u57cb\u70b9\u3002<\/li>\n<li>\u6e90\u7801\u5206\u6790\uff0c\u5728\u5185\u6838\u5c42\u9762\u5bf9SQL\u7684\u6267\u884c\u8fc7\u7a0b\u8fdb\u884c\u9010\u6b65\u7684Debug\uff0c\u6839\u636e\u7ecf\u9a8c\u5206\u6790\u53ef\u80fd\u7684\u74f6\u9888\u70b9\u6765\u57cb\u70b9\uff1b\u4e0b\u9762\u4e3e\u4e24\u4e2a\u4f8b\u5b50\u5206\u522b\u5c31\u7eaf\u6e90\u7801\u7684\u89d2\u5ea6\u6765\u5206\u6790\uff0cSQL\u5728\u8bfb\u3001\u5199\u8fc7\u7a0b\u4e2d\u54ea\u4e9b\u5730\u65b9\u53ef\u80fd\u4f1a\u9020\u6210\u6027\u80fd\u6296\u52a8\u5e76\u505a\u57cb\u70b9\u3002<\/li>\n<\/ol>\n<p>\u4f8b\u5b501\uff0c\u5728SQL\u8bfb\u64cd\u4f5c\u7684\u6267\u884c\u8fc7\u7a0b\u4e2d\uff0c\u9700\u8981\u4ecebuffer pool\u4e2d\u8bf7\u6c42\u5185\u5b58\u8d44\u6e90\uff0c\u5982\u679c\u4e00\u76f4\u6ee1\u8db3\u4e0d\u4e86\u5185\u5b58\u8d44\u6e90\u7684\u8bf7\u6c42\u5219\u4e00\u76f4\u4f1a\u5faa\u73af\u5c1d\u8bd5\u83b7\u53d6\uff0c\u5982\u679c\u57282000ms\u5185\u8fd8\u662f\u6ca1\u6709\u4eceBuffer pool\u4e2d\u8bf7\u6c42\u5230\u9700\u8981\u7684\u5185\u5b58\uff0c\u4f1a\u6253\u5370\u65e5\u5fd7\u201cDifficult to find free blocks in the buffer pool&#8230;&#8230;\u201d\uff0c\u6765\u8868\u660e\u5185\u5b58\u5f88\u7d27\u5f20\uff1b\u8fd9\u79cd\u957f\u65f6\u95f4\u7b49\u5f85\u5185\u5b58\u8d44\u6e90\u7684\u83b7\u53d6\u4f1a\u751f\u4ea7\u4e86\u6027\u80fd\u6296\u52a8\uff0c\u8fd9\u4e2a\u65f6\u5019\u5c31\u9700\u8981\u5728\u5bf9\u5e94\u7684\u5185\u6838\u4ee3\u7801\u5904\u8fdb\u884c\u57cb\u70b9\u83b7\u53d6BP\u5185\u5b58\u8d44\u6e90\u7b49\u5f85\u65f6\u95f4\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982391\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>\u4f8b\u5b502\uff0c\u5728SQL\u5199\u64cd\u4f5c\u7684\u6267\u884c\u8fc7\u7a0b\u4e2d\u662f\u9700\u8981\u5199redo log\u7684\uff0c\u5982\u679credo log\u7a7a\u95f4\u4e0d\u591f\uff0c\u5219\u9700\u8981\u5237\u76d8redo log\u8ddfBP\u4e2d\u7684\u810f\u9875\uff0c\u800c\u5237\u810f\u9875\u53ef\u80fd\u662f\u4e2a\u5f88\u8017\u65f6\u7684\u64cd\u4f5c\uff0c\u5e76\u4f1a\u5f15\u8d77\u5305\u62ec\u6d3b\u8dc3\u4f1a\u8bdd\u7a81\u589e\u3001\u6162\u67e5\u8be2\u7b49\u6027\u80fd\u6296\u52a8\u95ee\u9898\u3002\u8fd9\u4e2a\u573a\u666f\u8ddf\u4e0a\u9762\u7684\u7c7b\u4f3c\uff0c\u4e5f\u9700\u8981\u5bf9\u6e90\u7801\u8fdb\u884c\u5206\u6790\uff0c\u5e76\u4e14\u5728\u5173\u952e\u7684\u4f4d\u7f6e\u8fdb\u884c\u57cb\u70b9\u6765\u7edf\u8ba1\u5237\u810f\u7684\u8017\u65f6\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982392\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>1.1.4 Wait\u6307\u6807\u5c42\u6b21\u56fe<\/h4>\n<p>\u901a\u8fc7\u4e0a\u9762\u7684\u4e09\u79cd\u65b9\u5f0f\u6211\u4eec\u4e0d\u65ad\u5730\u8fed\u4ee3\u7d2f\u8ba1\u7684\u5173\u952e\u8017\u65f6\u6307\u6807\uff0c\u6574\u7406\u6210\u5982\u4e0b\u7684OffCPU\u8ddfOnCPU\u4e24\u5927\u7c7b\u7684\u5206\u5c42\u67b6\u6784\u56fe\u3002\u622a\u6b62\u76ee\u524d\u4e3a\u6b62\uff0c\u6211\u4eec\u5185\u6838\u56e2\u961f\u5728\u5185\u6838\u5c42\u9762\u57cb\u70b9\u4e86100\u591a\u4e2a\u5173\u952e\u6307\u6807\u6765\u8f85\u52a9\u8bca\u65ad\uff0c\u6307\u6807\u5206\u4e3aStatement\u8ddfWait\u4e24\u5927\u5c42\u7ea7\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982393\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p><strong>Statement<\/strong><\/p>\n<p>SQL\u8bed\u53e5\u7ea7\u522b\u7684\u6307\u6807\uff0c\u5982QUERY_TIME\u3001 Row_time\u884c\u9501\u65f6\u95f4\u3001ROWS_EXAMINED\u3001ROWS_SENT\u3001Bytes_sent\u3001NO_INDEX_USED\u3001Full_SCAN\u7b49\uff0c\u4f46\u662f\u8fd9\u4e2a\u5c42\u9762\u7684\u6570\u636e\u4e0d\u8db3\u4e8e\u5224\u65ad\u51faSQL\u6027\u80fd\u95ee\u9898\u7684\u6839\u56e0\uff0c\u6bd4\u5982QUERY_TIME\u5f88\u957f\uff0c\u4f46\u662fROWS_EXAMINED\u3001ROWS_SENT\u90fd\u5f88\u5c0f\uff0c\u5c31\u9700\u8981\u8fdb\u5165\u4e0b\u4e00\u4e2aWait\u7ea7\u522b\u7684\u6307\u6807\u8fdb\u884c\u8fdb\u4e00\u6b65\u7684\u5206\u6790\u3002<\/p>\n<p><strong>Wait<\/strong><\/p>\n<p>Wait\u5c42\u9762\u4e3b\u8981\u662fMySQL\u5185\u6838\u5c42\u9762\u7684\u6307\u6807\uff0c\u6bd4\u5982Latch\uff08Mutex\u3001rw_lock\u3001sx_lock\u3001cond\uff09\u7684\u6307\u6807\uff0c\u8fd9\u91cc\u9700\u8981\u8bf4\u660e\u7684\u662f\u4e0a\u9762\u7684\u5206\u5c42\u56fe\u8ddfMySQL\u81ea\u5e26\u7684performance_schema\u4e2d\u7684wait type\u5206\u5c42\u56fe\u770b\u4e0a\u53bb\u5f88\u50cf\uff0c\u90a3\u4e3a\u4ec0\u4e48\u4e0d\u76f4\u63a5\u4f7f\u7528\u800c\u9700\u8981\u81ea\u7814\u5462\uff1f\u8fd9\u91cc\u4e3b\u8981\u4ece\u5982\u4e0b\u51e0\u4e2a\u539f\u56e0\u4e14\u5185\u6838\u56e2\u961f\u90fd\u5f88\u597d\u7684\u89e3\u51b3\u4e86\uff1a<\/p>\n<ol>\n<li>performance_schema\u76f8\u5173\u7684\u7edf\u8ba1\u4fe1\u606f\u662f\u81ea\u5b9e\u4f8b\u542f\u52a8\u540e\u603b\u4f53\u7684wait\u65f6\u95f4\u7684\u805a\u5408\u6570\u636e\uff0c\u800c\u66f4\u9700\u8981\u7684\u662f\u4efb\u4f55\u65f6\u95f4\u6bb5\u3001\u5355SQL\u4f8b\u5b50\u7684\u660e\u7ec6\u6570\u636e\uff0c\u56e0\u4e3a\u8bca\u65ad\u7684\u5f80\u5f80\u662f\u67d0\u4e2a\u65f6\u95f4\u70b9\u6216\u8005\u65f6\u95f4\u6bb5\u7684\u5f02\u5e38SQL\u95ee\u9898\u3002<\/li>\n<li>performance_schema\u4e2d\u5176\u6709\u4e0d\u5c11Bug\uff0c\u9664\u6b64\u4e4b\u5916\uff0c\u5b83\u53ea\u652f\u6301OffCPU\u7c7b\u578b\u7684\u6307\u6807\uff0cOnCPU\u8017\u65f6\u7684\u7edf\u8ba1\u4e0d\u652f\u6301\uff0c\u751a\u81f3\u6709\u4e9b\u975e\u5e38\u91cd\u8981OffCPU\u7684\u6307\u6807\uff0c\u6bd4\u5982row lock\u7684wait\u7edf\u8ba1\u4fe1\u606f\u90fd\u4e0d\u652f\u6301\u3002<\/li>\n<li>\u5f00\u542fperformance_schema\u76f8\u5173\u7684wait\u540e\uff0c\u5bf9\u603b\u4f53\u7684\u6027\u80fd\u5f71\u54cd\u6bd4\u8f83\u5927\uff0c\u800c\u57fa\u4e8e\u5185\u6838\u57cb\u70b9\u7684\u5b9e\u73b0\u65b9\u5f0f\u5f88\u8f7b\u91cf\u7ea7\uff0c\u5bf9\u6570\u636e\u5e93\u6574\u4f53\u6027\u80fd\u5f71\u54cd\u5f88\u5c0f\u3002<\/li>\n<\/ol>\n<h2>2 \u5168\u91cfSQL<\/h2>\n<p>\u5168\u91cfSQL\uff0c\u6307\u7684\u662f\u628a\u5e94\u7528\u7a0b\u5e8f\u6216\u8005\u7528\u6237\u8bbf\u95eeDB\u7684\u6240\u6709SQL\u96c6\u5408\uff0c\u9700\u8981\u6355\u83b7\u5230\u8fd9\u4e9bSQL\u5e76\u4e14\u53d1\u81f3\u540e\u7aef\u8fdb\u884c\u5206\u6790\u3002\u5728\u5185\u6838\u53ef\u89c2\u6d4b\u6027\u5efa\u8bbe\u4e4b\u524d\uff0c\u539f\u6765\u91c7\u7528\u7684\u65b9\u5f0f\u662f\u6839\u636eMySQL\u7684\u534f\u8bae\uff0c\u6765\u89e3\u6790TCP\u62a5\u6587\u6765\u63d0\u53d6\u51faSQL\u3002\u6b64\u79cd\u5b9e\u73b0\u65b9\u5f0f\u7684\u7f3a\u9677\u4e5f\u5f88\u660e\u663e\uff0c\u5c31\u662f\u9664\u4e86SQL\u6587\u672c\u5916\uff0c\u5176\u4ed6\u7684\u80fd\u83b7\u53d6\u5230\u7684\u5173\u952eSQL\u6307\u6807\u4fe1\u606f\u975e\u5e38\u5c11\uff0c\u8fd9\u6837\u505a\u6570\u636e\u5e93\u7684\u6545\u969c\u8bca\u65ad\u8ddfSQL\u6027\u80fd\u5206\u6790\uff0c\u4f1a\u56e0\u4e3a\u7f3a\u5c11\u5173\u952e\u6307\u6807\u800c\u5e26\u6765\u6311\u6218\u3002<\/p>\n<p>\u9488\u5bf9\u6b64\u6311\u6218\uff0c\u6211\u4eec\u7684\u89e3\u51b3\u65b9\u6848\u662f\uff1a\u6539\u9020\u4e3a\u76f4\u63a5\u4eceMySQL\u5185\u6838\u5410\u6570\u636e\uff0c\u6765\u4f5c\u4e3a\u5168\u91cfSQL\u7684\u6570\u636e\u6765\u6e90\uff08\u524d\u9762\u7684\u5185\u6838\u53ef\u89c2\u6d4b\u6027\u5206\u6790\u4ecb\u7ecd\u53ef\u77e5\uff0c\u5355\u6761SQL\u7ef4\u5ea6\u4e0a\u80fd\u4ece\u5185\u6838\u5c42\u9762\u8f93\u51fa100\u591a\u4e2a\u5173\u952e\u6307\u6807\uff0c\u5305\u542b\u6545\u969c\u8bca\u65ad\u8ddfSQL\u6027\u80fd\u5206\u6790\u9700\u8981\u7684\u91cd\u8981\u6307\u6807\uff09\u3002<\/p>\n<h3>2.1 \u5b9e\u73b0\u65b9\u5f0f<\/h3>\n<p>\u5168\u91cfSQL\u5176\u5b9e\u6709\u597d\u51e0\u4e2a\u5b9e\u73b0\u65b9\u5f0f\uff0c\u521d\u7248\u4f7f\u7528\u4e86\u6293TCP\u5305\u7684\u65b9\u5f0f\uff0c\u73b0\u5728\u9010\u6b65\u4eceTCP\u6293\u5305\u8fc7\u6e21\u5230\u4e86\u57fa\u4e8e\u5185\u6838\u8f93\u51faSQL\u6587\u672c\u8ddf\u5173\u952e\u6307\u6807\u7684\u65b9\u6848\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982394\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h3>2.2 \u5185\u6838\u5b9e\u73b0\u65b9\u5f0f<\/h3>\n<p>\u4ece\u5185\u6838\u5c42\u9762\u6765\u8bf4\uff0cMySQL\u5bf9\u4e8e\u7528\u6237\u7684\u94fe\u63a5\u5c06\u521b\u5efa\u72ec\u7acb\u7684thd\u7ed3\u6784\u4f53\uff0c\u6240\u4ee5\u91c7\u96c6\u7684\u5168\u91cfSQL\u5bf9\u5e94\u7684SQL\u6587\u672c\u8ddf\u5173\u952e\u6307\u6807\u6570\u636e\uff0c\u53ef\u4ee5\u5b58\u4e8ethd\u7ed3\u6784\u4f53\u4e2d\u3002\u7136\u540e\u7528\u6237\u7ebf\u7a0b\u5c06thd\u4fdd\u5b58\u7684\u6307\u6807\u6570\u636e\uff0c\u590d\u5236\u5230\u4e00\u4e2a\u81ea\u5b9a\u4e49\u5185\u5b58\u6c60\u4e2d\uff08\u65e0\u9501\u961f\u5217\uff09\uff1b\u8f93\u51fa\u6a21\u5757\u6709\u4e00\u4e2a\u7ebf\u7a0b\u4ece\u5185\u5b58\u6c60\u4e2d\u4f9d\u6b21\u83b7\u53d6\u4fdd\u5b58\u7684\u4fe1\u606f\u540e\uff0c\u5199\u5165\u5168\u91cfSQL\u6587\u4ef6\u3002\u5177\u4f53\u6d41\u7a0b\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982395\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h3>2.3 \u5168\u91cfSQL\u603b\u4f53\u67b6\u6784<\/h3>\n<p>\u5982\u4f55\u628a\u6d77\u91cf\u4fe1\u606f\uff08\u65e5\u5747PB\u7ea7\u522b\uff09\u4e0a\u62a5\u5230\u540e\u7aef\u7cfb\u7edf\uff0c\u6765\u8d4b\u80fd\u6545\u969c\u8bca\u65ad\u3001SQL\u5ba1\u6838\u3001\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7b49\u573a\u666f\u662f\u4e00\u4e2a\u8f83\u5927\u7684\u6311\u6218\u3002\u6211\u4eec\u9996\u5148\u901a\u8fc7\u6570\u636e\u91c7\u96c6\u5668\uff08rds-agent\uff09\u8bfb\u53d6Full SQL File\u6587\u4ef6\u5185\u7684\u5185\u5bb9\uff0c\u518d\u5f80\u540e\u7aef\u4f20\u8f93\u3002<\/p>\n<p>\u4f46\u662f\u7531\u4e8e\u6570\u636e\u91cf\u7279\u522b\u5927\uff0c\u4e3a\u4e86\u8282\u7701\u5b58\u50a8\u8d44\u6e90\uff0c\u5206\u6790\u540e\u9009\u7528Snappy\u538b\u7f29\u7b97\u6cd5\u8fdb\u884c\u538b\u7f29\uff0c\u9ed8\u8ba4\u60c5\u51b5\u4e0b\u538b\u7f29\u6548\u679c\u53ea\u67091\uff5e2\u500d\uff0c\u4e3a\u6b64\u5206\u6790\u4e86Snappy\u7684\u6e90\u7801\uff0c\u53d1\u73b0\u5982\u679c\u8ba9\u76f8\u4f3c\u7684SQL\u6587\u672c\u805a\u5408\u5728\u4e00\u8d77\uff0c\u90a3\u4e48\u538b\u7f29\u6548\u679c\u4f1a\u6709\u5f88\u5927\u7684\u63d0\u9ad8\uff0c\u6240\u4ee5\u6309\u7167SQL\u6587\u672c\u7684\u524dN\u4e2a\u5b57\u7b26\uff08N\u53d650\uff0c\u53ef\u4ee5\u6839\u636eSQL\u6587\u672c\u7684\u5b9e\u9645\u60c5\u51b5\u505a\u8c03\u6574\uff09\u8fdb\u884c\u4e86\u6392\u5e8f\u540e\u518d\u538b\u7f29\uff0c\u53d1\u73b0\u538b\u7f29\u6bd4\u63d0\u9ad8\u5230\u4e867\uff5e8\u500d\u3002\u540e\u7aef\u7684SQL\u5b58\u50a8\u5206\u6210\u4e86\u4e24\u79cd\u5f62\u5f0f\uff0c\u4e00\u79cd\u662f\u5b58\u660e\u7ec6SQL\uff0c\u53e6\u4e00\u79cd\u662f\u5b58\u805a\u5408\u540e\u7684SQL\u6a21\u7248\u4fe1\u606f\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982396\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p><strong>\u4ea7\u54c1\u5c55\u793a<\/strong><\/p>\n<p>\u91c7\u96c6\u5230\u7684\u5168\u91cfSQL\u65e2\u53ef\u4ee5\u6a21\u7248\u5316\u5c55\u793a\uff0c\u70b9\u51fb\u6a21\u7248\u540e\u4e5f\u53ef\u4ee5\u770b\u5230\u660e\u7ec6\u7684SQL\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982397\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h2>3 \u5f02\u5e38\u5904\u7406<\/h2>\n<p>\u6839\u56e0\u5206\u6790\u540e\uff0c\u5c31\u9700\u8981\u6839\u636e\u5177\u4f53\u6839\u56e0\u6765\u8fdb\u884c\u76f8\u5e94\u7684\u5904\u7406\uff0c\u4f46\u662f\u5982\u4f55\u5b89\u5168\u3001\u53ef\u9760\u7684\u8fdb\u884c\u5904\u7406\u5176\u5b9e\u662f\u4e00\u4e2a\u5f88\u5927\u7684\u6311\u6218\u3002\u5177\u4f53\u7684\u7b56\u7565\u662f\u6839\u636e\u5176\u64cd\u4f5c\u662f\u201c\u65e0\u635f\u201d\u8fd8\u662f\u201c\u6709\u635f\u201d\u6765\u91c7\u53d6\u4e0d\u540c\u7684\u5904\u7406\u7b56\u7565\u3002<\/p>\n<p>\u5982\u679c\u662f\u5bf9\u4e1a\u52a1\u201c\u65e0\u635f\u201d\u7684\u64cd\u4f5c\uff0c\u6bd4\u5982\u78c1\u76d8\u7a7a\u95f4\u6e05\u7406\u3001\u53c2\u6570\u503c\u8c03\u6574\u3001\u7f3a\u5931\u7d22\u5f15\u6dfb\u52a0\u7b49\uff0c\u76ee\u6807\u662f\u8ba9\u64cd\u4f5c\u5c3d\u91cf\u7684\u81ea\u52a8\u5316\u3002\u5982\u679c\u662f\u5bf9\u4e1a\u52a1\u662f\u201c\u6709\u635f\u201d\u7684\u64cd\u4f5c\uff0c\u6bd4\u5982\u9700\u8981Kill\u6216\u8005\u9650\u6d41\uff0c\u628a\u76f8\u5173\u64cd\u4f5c\u8fdb\u884c\u5305\u88c5\uff0c\u53d1\u9001\u76f8\u5173\u7684\u804a\u5929\u7fa4\u8ba9DBA\u6216\u8005\u7528\u6237\u786e\u8ba4\u540e\u518d\u8fdb\u884c\u76f8\u5173\u7684\u64cd\u4f5c\u3002<\/p>\n<p>\u5bf9\u4e8eMySQL Hang\u7684\u60c5\u51b5\uff0c\u9ad8\u53ef\u7528\u56e2\u961f\u4f1a\u8fdb\u884c\u5468\u671f\u6027\u63a2\u6d4b\uff0c\u5982\u679c\u53d1\u73b0\u4e3b\u5e93MySQL Hang\u4e86\uff0c\u5219\u4f1a\u81ea\u52a8\u8fdb\u884c\u4e3b\u4ece\u5207\u6362\uff0c\u5982\u679c\u53d1\u73b0\u4ece\u5e93MySQL Hang\u4e86\u5219\u4f1a\u8fdb\u884c\u76f8\u5e94\u7684MySQL\u5b9e\u4f8b\u4e0b\u7ebf\u66ff\u6362\u52a8\u4f5c\u3002<\/p>\n<h3>3.1\u7cfb\u7edf\u67b6\u6784<\/h3>\n<p>\u6574\u4e2a\u5f02\u5e38\u5904\u7406\u7684\u7cfb\u7edf\u67b6\u6784\u56fe\u5982\u4e0b\uff0c\u7531\u201c\u5f02\u5e38\u53d1\u73b0\u4e0e\u5206\u6790\u201d\u7cfb\u7edf\u4ee5\u53caDBA\u56e2\u961f\u5f00\u53d1\u7684\u201c\u9884\u6848\u670d\u52a1\u201d\u7cfb\u7edf\u7ec4\u6210\uff0c\u524d\u8005\u63d0\u4f9b\u7cbe\u786e\u7684\u6545\u969c\u6839\u56e0\uff0c\u540e\u8005\u6839\u636e\u5177\u4f53\u7684\u6839\u56e0\u6765\u5b89\u5168\u3001\u53ef\u9760\u7684\u6267\u884c\u5bf9\u5e94\u7684\u9884\u6848\uff0c\u4f7f\u6545\u969c\u5feb\u901f\u6062\u590d\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982398\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h3>3.2 \u4ea7\u54c1\u5c55\u793a<\/h3>\n<p>\u4e0b\u56fe\u662f\u4e24\u4e2a\u5f02\u5e38\u53d1\u73b0\u3001\u5206\u6790\u3001\u7ed9\u51fa\u5efa\u8bae\u4ee5\u53ca\u5904\u7406\u7684\u4f8b\u5b50\uff1a1\uff09\u5f02\u5e38\u53d1\u73b0\u3001\u786e\u8ba4\u6839\u56e0\u540e\uff0c\u53d1\u73b0\u7f3a\u7d22\u5f15\uff0c\u7cfb\u7edf\u4f1a\u81ea\u52a8\u8c03\u7528\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7cfb\u7edf\u7ed9\u51fa\u5efa\u8bae\uff0c\u7528\u6237\u53ef\u4e00\u952e\u6dfb\u52a0\u7d22\u5f15\uff1b2\uff09\u5bf9\u4e8e\u6162\u67e5\u8be2\u6216\u8005\u4e3b\u4ece\u5ef6\u8fdf\u95ee\u9898\uff0c\u5206\u6790\u6839\u56e0\u540e\u63d0\u4f9b\u7528\u6237\u8fdb\u884c\u9650\u6d41\u3001Kill\u3001\u53c2\u6570\u8c03\u4f18\u7b49\u64cd\u4f5c\u7684\u5efa\u8bae\uff0c\u907f\u514d\u5f02\u5e38\u88ab\u8fdb\u4e00\u6b65\u653e\u5927\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982399\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h2>4 \u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u4e0e\u6cbb\u7406<\/h2>\n<p>\u4f17\u6240\u5468\u77e5\uff0c\u5f88\u5927\u4e00\u90e8\u5206\u7684\u6570\u636e\u5e93\u7684\u5f02\u5e38\u90fd\u662f\u8ddfSQL\u6027\u80fd\u6709\u5173\u3002\u5f88\u663e\u7136\uff0c\u65e5\u5e38\u7684SQL\u6027\u80fd\u95ee\u9898\u7684\u6cbb\u7406\u5c31\u5f88\u6709\u5fc5\u8981\uff0c\u4e00\u4e2a\u4f4e\u6210\u672c\u4f46\u6548\u679c\u663e\u8457\u7684SQL\u6027\u80fd\u4f18\u5316\u65b9\u6848\u662f\u63d0\u4f9b\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\uff0c\u5e76\u4e14\u53ef\u4ee5\u5c06\u8fd9\u79cd\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7684\u80fd\u529b\u5e94\u7528\u4e8eSQL\u751f\u547d\u5468\u671f\u7684\u4e09\u4e2a\u9636\u6bb5\uff0c\u8fd9\u4e09\u4e2a\u9636\u6bb5\u4e0b\u6587\u4f1a\u8fdb\u4e00\u6b65\u9610\u8ff0\u3002<\/p>\n<ol>\n<li>\u5e94\u7528\u7a0b\u5e8f\u201c\u53d1\u5e03\u524d\u201d\u7684\u6027\u80fd\u95ee\u9898SQL\u5ba1\u6838\uff08\u4e8b\u524d\uff09\uff1b<\/li>\n<li>SQL\u6267\u884c\u8fc7\u7a0b\u4e2d\u7684\u5b9e\u65f6\u6027\u80fd\u95ee\u9898SQL\u53d1\u73b0\uff08\u4e8b\u4e2d\uff09\uff1b<\/li>\n<li>SQL\u201c\u6267\u884c\u5b8c\u6bd5\u201d\u540e\u6279\u91cf\u7684SQL\u6cbb\u7406\uff08\u4e8b\u540e\uff09\u3002<\/li>\n<\/ol>\n<h3>4.1 \u7d22\u5f15\u4f18\u5316\u5efa\u8bae<\/h3>\n<p>\u5efa\u7acb\u9002\u5408\u7684\u7d22\u5f15\u5bf9SQL\u7684\u6027\u80fd\u63d0\u5347\u6548\u679c\u5f88\u660e\u663e\uff0c\u5982\u4f55\u6dfb\u52a0\u9002\u5408\u7684\u7d22\u5f15\u662f\u4e00\u4e2a\u6709\u6311\u6218\u6027\u7684\u4efb\u52a1\u3002\u7d22\u5f15\u7684\u6dfb\u52a0\u4e0d\u80fd\u5149\u51ed\u7ecf\u9a8c\uff0c\u56e0\u4e3a\u7d22\u5f15\u662f\u5426\u88ab\u7528\u5230\u4e0d\u4f46\u8ddf\u8868\u7684\u6570\u636e\u7684\u5206\u5e03\u6709\u5173\uff0c\u8fd8\u8ddfMySQL\u67e5\u8be2\u4f18\u5316\u5668\u7684Cost\u903b\u8f91\u6709\u5173\u7cfb\uff0c\u6240\u4ee5\u201c\u4eba\u8089\u201d\u8fdb\u884c\u7d22\u5f15\u5efa\u8bae\u7684\u8bc4\u4f30\u5e76\u4e0d\u662f\u4e00\u4e2a\u597d\u7684\u65b9\u6848\u3002<\/p>\n<p>\u89e3\u51b3\u65b9\u5f0f\u662f\u5c3d\u91cf\u8981\u57fa\u4e8eMySQL\u7684Cost\u6a21\u578b\uff0c\u5229\u7528MySQL\u81ea\u8eab\u63d0\u4f9b\u7684\u67e5\u8be2\u4f18\u5316\u5668\u7684\u80fd\u529b\uff0c\u6765\u7ed9\u51fa\u6700\u4f73\u7684\u7d22\u5f15\uff1b\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7684\u5efa\u8bbe\u4e00\u822c\u5206\u4e3a\u4e09\u4e2a\u9636\u6bb5\uff1a1\uff09\u5355SQL\u7ef4\u5ea6\u7684\u4f18\u5316\u5efa\u8bae\uff1b2\uff09\u57fa\u4e8eworkload\u7684\u6574\u4f53\u4f18\u5316\u5efa\u8bae\uff1b3\uff09\u7d22\u5f15\u81ea\u7ef4\u62a4\u3002\u8fd9\u51e0\u4e2a\u9636\u6bb5\u7684\u5efa\u8bbe\u9700\u8981\u6309\u987a\u5e8f\u6765\u8fdb\u884c\uff0c\u5e76\u4e14\u4e0d\u53ef\u8df3\u8dc3\u3002\u4e0b\u9762\u6211\u4eec\u5c06\u5206\u522b\u8fdb\u884c\u9610\u8ff0\u3002<\/p>\n<h3>4.2 \u5355SQL\u7d22\u5f15\u4f18\u5316\u5efa\u8bae<\/h3>\n<h4>4.2.1 \u5b9e\u73b0\u601d\u8def<\/h4>\n<p>\u5355SQL\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\uff0c\u5c31\u662f\u6307\u8f93\u5165\u4e00\u6761SQL\u8bed\u53e5\u540e\uff0c\u4f18\u5316\u5efa\u8bae\u7cfb\u7edf\u7ed9\u51fa\u4e00\u4e2a\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7684\u8fc7\u7a0b\u3002\u60f3\u8981\u5229\u7528\u67e5\u8be2\u4f18\u5316\u5668\u672c\u8eab\u7684\u80fd\u529b\u6765\u5b9e\u73b0\u7d22\u5f15\u5efa\u8bae\u7684\u76ee\u6807\uff0c\u5c31\u5fc5\u987b\u5148\u8981\u4e86\u89e3MySQL\u7684\u67e5\u8be2\u4f18\u5316\u5668\u662f\u5982\u4f55\u5de5\u4f5c\u7684\u3002<\/p>\n<p>\u8fd9\u91cc\u4e3e\u4e2a\u7b80\u5355\u7684\u5355\u8868SQL\u67e5\u8be2\u7684\u4f8b\u5b50\uff0c\u5e2e\u52a9\u6211\u4eec\u6765\u521d\u6b65\u4e86\u89e3\u5176\u5de5\u4f5c\u539f\u7406\u3002\u6211\u4eec\u5148\u4e86\u89e3\u67e5\u8be2\u4f18\u5316\u5668\u662f\u5982\u4f55\u4ece\u4f17\u591a\u7684\u5019\u9009\u6267\u884c\u8ba1\u5212\u4e2d\u9009\u62e9\u6700\u7ec8\u7684\u6267\u884c\u8ba1\u5212\u7684\uff1b\u5728\u6709\u4e86\u8fd9\u4e2a\u57fa\u7840\u4e4b\u540e\uff0c\u518d\u6765\u8bb2\u662f\u5982\u4f55\u5229\u7528\u67e5\u8be2\u4f18\u5316\u5668\u81ea\u8eab\u7684\u80fd\u529b\u6765\u505a\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u3002<\/p>\n<p>\u6bd4\u5982\u6709SQL\u8bed\u53e5\u201cselect * from test_db.table1 where c2=3 and c3=4 and c4&lt;&#8216;3&#8217;\u201d\uff0c\u5206\u522b\u5728\u5b57\u6bb5id\u3001c2\u3001c3\u4ee5\u53cac4\u4e0a\u9762\u5efa\u7acb\u4e86\u4e3b\u5065\u7d22\u5f15Primary\u4ee5\u53ca\u4e09\u4e2a\u4e8c\u7ea7\u7d22\u5f15idx_c2\u3001idx_c3\u53cadx_c4\u3002\u5047\u8bbe\u6700\u7ec8\u67e5\u8be2\u4f18\u5316\u5668\u4ece\u591a\u4e2a\u5019\u9009\u6267\u884c\u8ba1\u5212\u4e2d\u9009\u62e9\u4e86\u201c\u6267\u884c\u8ba1\u52122\u201d\uff08\u901a\u8fc7\u7d22\u5f15idx_c2\u505aindex seek\u64cd\u4f5c\u6765\u6267\u884cSQL\uff09\uff0c\u95ee\u9898\u662f\u6b64SQL\u7684\u5019\u9009\u6267\u884c\u8ba1\u5212\u6709\u591a\u4e2a\uff0c\u4e3a\u4ec0\u4e48\u6700\u540e\u9009\u4e2d\u4e86\u901a\u8fc7\u7d22\u5f15idx_c2\u800c\u4e0d\u662f\u5176\u4ed6\u7684\u7d22\u5f15\u505aindex seek\u64cd\u4f5c\u7684\u6267\u884c\u8ba1\u5212\u5462\uff1f\u603b\u7684\u6765\u8bf4\uff0c\u9009\u62e9idx_c2\u4e3a\u7d22\u5f15\u7684\u6267\u884c\u8ba1\u5212\uff0c\u662f\u56e0\u4e3a\u76f8\u6bd4\u4e8e\u9009\u62e9\u5176\u4ed6\u7d22\u5f15\u751f\u6210\u7684\u6267\u884c\u8ba1\u5212\u7684Cost\u66f4\u5c0f\u3002<\/p>\n<p>\u5177\u4f53\u6765\u8bf4\uff0c\u9488\u5bf9SQL\u7684\u4e24\u7c7b\u8868\u8bbf\u95ee\u65b9\u5f0f\uff1a1\uff09\u57fa\u4e8e\u5168\u8868\u626b\u63cf\u7684\u8bbf\u95ee\u65b9\u5f0f\uff1b2\uff09\u975e\u5168\u8868\u626b\u63cf\u7684\u65b9\u5f0f\uff08\u6bd4\u5982Index_scan\u3001ref\u7c7b\u578b\u6216\u8005range_access\u7b49\uff09\uff0c\u4e0b\u56fe\u662f\u8fd9\u4e9b\u8bbf\u95ee\u65b9\u5f0fCost\u8ba1\u7b97\u8fc7\u7a0b\u4e2d\u6d89\u53ca\u5230\u7684\u67e5\u8be2\u4f18\u5316\u5668\u8ddf\u5b58\u50a8\u5f15\u64ce\u7684\u5173\u952e\u51fd\u6570\uff0c\u76ee\u6807\u662f\u5047\u8bbe\u67d0\u4e2a\u7d22\u5f15\u5b58\u5728\u7684\u60c5\u51b5\u4e0b\uff0c\u4fee\u6539\u8fd9\u4e9b\u51fd\u6570\u6765\u6a21\u62dfCost\u7684\u8ba1\u7b97\u8fc7\u7a0b\uff0c\u6765\u53d1\u73b0\u54ea\u4e2a\u7d22\u5f15\u5b58\u5728\u7684\u60c5\u51b5\u4e0b\u5bf9\u5e94\u7684Cost\u503c\u6700\u5c0f\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982400\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>\u6d41\u7a0b\u4e2d\u7684\u5404\u79cd\u6570\u636e\u8bbf\u95ee\u65b9\u5f0f\uff0c\u5bf9\u5176Cost\u8ba1\u7b97\u65b9\u5f0f\u9010\u4e2a\u5206\u6790\u3002<\/p>\n<p>1\uff09Table scan\u8bbf\u95ee\u65b9\u5f0f<\/p>\n<p>\u4ece<a href=\"https:\/\/link.segmentfault.com\/?enc=oCFANJH413YF0Af3JAs9eQ%3D%3D.Mv3zPxyEWAQ0BPUZBc2S9jhqke9aG5LTL7FnoY8ikFWy49%2BYUmN9QEUQ3p2SiRjYBr%2BSiFRdE08N%2BP9UKo9IXK0t25iHcnb%2Bd99f%2BMf6pa8xnvZXn1VcK%2FSE8DjoQ0HZ\" rel=\"nofollow\">\u5168\u8868\u626b\u63cfcost\u8ba1\u7b97<\/a>\u516c\u5f0f\u53ef\u4ee5\u77e5\u9053Table scan\u7684Cost\u5206\u4e3aIO\u7684Cost\u8ddfCPU Cost\u4e24\u4e2a\u90e8\u5206\u4e4b\u548c\uff0c\u5927\u81f4\u7684\u516c\u5f0f\u4e3a\uff1aIO-cost:#pages in table <em> IO_BLOCK_READ_COST + CPU cost:#records <\/em> ROW_EVALUATE_COST\uff0c\u5176\u4e2dIO-cost\u662f\u901a\u8fc7<a href=\"https:\/\/link.segmentfault.com\/?enc=Z1G6wN%2BAEdrCjTysyyFKKg%3D%3D.GlNTlsKj%2BBONNc1g%2FsrTplHQ6yWZVbmbytwHy%2FN4%2B6LiSK0B01n91RRuaXqrghRN12Pqh5JZgQdG52Jc%2BDEgFKrrawKXqlbZyLcaRiTUla46JC9cRhx3RmURBHxECIE8\" rel=\"nofollow\">table_scan_cost<\/a>\u6765\u8ba1\u7b97\u7684\u3002<\/p>\n<p>\u8fd9\u91cc\u6709\u4e24\u4e2a\u5173\u952e\u7684\u53d8\u91cfrecords\u8ddfpages in table\uff0c\u5206\u522b\u8868\u793a\u8fd9\u4e2a\u8868\u6709\u591a\u5c11\u884c\u8ddf\u591a\u5c11page\uff0c\u8fd9\u4e24\u4e2a\u53d8\u91cf\u7684\u503c\u662f\u600e\u4e48\u6765\u7684\u5462\uff1f\u5982\u679c\u4f7f\u7528\u7684\u662finnodb\uff0c\u90a3\u4e48\u524d\u8005\u6765\u81ea\u4e8e<a href=\"https:\/\/link.segmentfault.com\/?enc=HUx8xzAMnW414L1E4wI6QA%3D%3D.hwjloNpPykiKCQ1o0cAHivdKBohg1al9zPqRCeT2dkk533%2FQa4C%2BPUqtOAWGDhrR17f8gvQ2BkeBi5V%2Fd27Gu1NdJbqISqOdJ4KnOIpa2j0zMvK3FmFtHdeXD6%2FhGS6wRnKZ7kezV1mgph51Ew7RQg%3D%3D\" rel=\"nofollow\">ha_innobase::info_low<\/a>\uff08ha_innobase::info\uff09\uff0c\u540e\u8005\u6765\u81ea\u4e8e<a href=\"https:\/\/link.segmentfault.com\/?enc=Fukmoes674RwQTh2vNBZYw%3D%3D.x54yxYUwLEvgWDU7BnYfxR%2B18Kvb0j0PtL3YNPN4eook3LYi6UdzyZu8EJmXWH6CJHobR4PJ%2FeOD%2B8TWiT%2F%2BEkJX%2BAPsbrNbq78B6Hhgbw5Syn5ZHblFl1k9%2FgPE8r%2FfqRCvC%2FUnm51uOSlz1SM%2Fvw%3D%3D\" rel=\"nofollow\">ha_innobase::scan_time()<\/a>\uff08\u800c\u8fd9\u4e24\u4e2a\u51fd\u6570\u90fd\u662fSQL\u5c42<a href=\"https:\/\/link.segmentfault.com\/?enc=DVRpKK8W%2BTK0%2FK%2F9rhzgWA%3D%3D.o0jekHARKri5%2BJfUj8S3W3RTKfzQ9aHA9Y7Pv9iEs6LJiMbOnEtp%2FVc1HMg6mB0Weyqw4DM2lXKwd2MrpuoaoHc8nushWqyVhQt7bxiPbIo%3D\" rel=\"nofollow\">handler.h<\/a>\u5b9a\u4e49\u7684\u865a\u51fd\u6570\uff0c\u4e0d\u540c\u7684\u5b58\u50a8\u5f15\u64ce\u5206\u522b\u5b9e\u73b0\u4e4b\uff09\uff0c\u77e5\u9053\u4e86\u8fd9\u4e24\u4e2a\u53d8\u91cf\u7684\u503c\uff0c\u5c31\u77e5\u9053\u5177\u4f53\u7684Cost\u503c\u4e86\u3002<\/p>\n<p>2\uff09Index scan\u8bbf\u95ee\u65b9\u5f0f<\/p>\n<p>\u8986\u76d6\u7d22\u5f15\u7684\u626b\u63cf\uff0c\u4ece<a href=\"https:\/\/link.segmentfault.com\/?enc=alMmYWof8RPNfr7UFyKxQA%3D%3D.JezFspHTt%2F0I8Pwt2d5s2IV6Vd5MsQKmjMhrwHUXUjKk%2BI5%2Bm2GYEJTA936SDjZwPMTKQfmE8wxSTIqaK74OknkCfDobbmL24syLoMyP%2BY9gkbh06nt3Q8PNfB4blQNZ\" rel=\"nofollow\">index_scan_cost<\/a>\u5f97\u77e5Index scan\u7684Cost\u4e3a\uff1aO-cost:#(records\/keys_per_block)  <em> IO_BLOCK_READ_COST+ CPU cost:#records <\/em> ROW_EVALUATE_COST\uff0c\u7531\u4e8eIO_BLOCK_READ_COST\u8ddfROW_EVALUATE_COST\u90fd\u662f\u5e38\u91cf\uff0c\u6240\u4ee5\u9700\u8981\u5173\u6ce8\u662fkeys_per_block\uff08keys_per_block\u7684\u8ba1\u7b97\u8ddfblock_size\u7b49\u6709\u5173\uff09\u8ddfrecords\u8fd9\u4e24\u4e2a\u53d8\u91cf\uff0c\u4e5f\u5c31\u662f\u8bf4\u5982\u679c\u77e5\u9053\u4e86\u8fd9\u4e24\u4e2a\u53d8\u91cf\u7684\u503c\uff0c\u5c31\u77e5\u9053\u4e86\u5177\u4f53\u7684Cost\u503c\u4e86\u3002<\/p>\n<p>3\uff09range access\u8bbf\u95ee\u65b9\u5f0f<\/p>\n<p>\u4ece<a href=\"https:\/\/link.segmentfault.com\/?enc=hbJ7Pmq%2F0vkf1cSlXf%2BbJg%3D%3D.PgRpGX7qYH68T5ayzm075t4FBHPJ0V1IgMYxLovD1BHXtNjkQCkJHiThHCmZ4YXShsg96DKF%2B10E%2FOK0ZC6usSOJrmMZBwSk3PJt4VGN%2BlieIB9d8L1fJHLvFwOK5DJo\" rel=\"nofollow\">multi_range_read_info_const<\/a>\u5f97\u77e5range access\u7684Cost\u4e3a\uff1aIO-cost:#records_in_range <em> IO_BLOCK_READ_COST + CPU cost:2<\/em>#records_in_range* ROW_EVALUATE_COST\uff0c\u7531\u4e8eIO_BLOCK_READ_COST\u8ddfROW_EVALUATE_COST\u90fd\u662f\u5e38\u91cf\uff0c\u6240\u4ee5\u53ea\u9700\u8981\u77e5\u9053records_in_range\u8fd9\u4e2a\u53d8\u91cf\u7684\u503c\uff0c\u5c31\u80fd\u8ba1\u7b97\u5176Cost\u4e86\u3002<\/p>\n<p>4\uff09ref\u8bbf\u95ee\u65b9\u5f0f<\/p>\n<p>\u4ece<a href=\"https:\/\/link.segmentfault.com\/?enc=ey5LEnMy2%2FMH4kGNCyMd%2Bg%3D%3D.N5mScJyULE1hVepp2XEeRYPD7kZUSWiU8j2uEAc1vq6Jb8a7n8MtgRMbZ72%2Bg7KDV0dqCRVL3gn6EXf5ilbvxYB5J1jKfkb3irOS%2FT2kupHKVxXOlh%2BmGzTHkcNPP9hi\" rel=\"nofollow\">find_best_ref<\/a>\u5f97\u77e5ref\u8bbf\u95ee\u65b9\u5f0f\u7684Cost\u5927\u81f4\u4e3a\uff1aIO-cost:#prefix_rowcount <em> IO_BLOCK_READ_COST + CPU cost:#prefix_rowcount <\/em> cur_fanout <em> ROW_EVALUATE_COST\uff0c\u9700\u8981\u5b9e\u73b0cur_fanout\u8fd9\u4e2a\u53d8\u91cf\uff0c\u800c\u8fd9\u4e2a\u53d8\u91cf\u8ddfinfo\u4e2d\u7684 <a href=\"https:\/\/link.segmentfault.com\/?enc=9SPZ1OELJc5QwQIi3eTtlw%3D%3D.iDZv4n7IdSOmBEKBhTpbuAGIz8kZHniRzOoCfe1KrLTdzwMq%2FLumurDp4Js1ybCH3nfGqJXIk%2BlKk5v1ASpY6dAeZPu0BXA9aSYNo58xa97bZ4MMEuBnQj7IZ1BautfsYYzJGHY5z6yIzWQsBIYyHQ%3D%3D\" rel=\"nofollow\">rec_per_key<\/a>\uff08rec_per_key\u7684\u610f\u601d\u662f\uff0c\u6bd4\u5982\u5bf9\u4e8eselect <\/em> from test_db.table1 where c2=3\uff0ctable1\u4e2d\u6709\u591a\u5c11\u884c\u6570\u636e\u6ee1\u8db3c2=3\uff09\u6709\u5173\u7cfb\uff0c\u6240\u4ee5\u5b9e\u73b0rec_per_key\u7b97\u6cd5\u540e\u5c31\u53ef\u4ee5\u77e5\u9053\u5176Cost\u503c\u4e86\u3002<\/p>\n<h4>4.2.2 What_If\u7d22\u5f15\u5efa\u8bae\u7b56\u7565<\/h4>\n<p>\u5982\u4f55\u628a\u4e0a\u9762\u7684Cost\u8ba1\u7b97\u65b9\u5f0f\u7684\u7406\u8bba\u5206\u6790\u5e94\u7528\u5230\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u4e2d\uff1f\u5047\u8bbe\u8868table1\u9664\u4e86\u4e3b\u952e\u5916\u6ca1\u6709\u4efb\u4f55\u7d22\u5f15\uff0c\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u5de5\u5177\u6700\u540e\u600e\u4e48\u80fd\u7ed9\u7528\u6237\u63a8\u8350\u51fa\u7d22\u5f15idx_2\u5462\uff1f\u5173\u4e8e\u8fd9\u4e2a\u95ee\u9898\u53ef\u4ee5\u7528\u5230\u4e00\u79cd\u79f0\u4e4b\u4e3aWhat_If\u7684\u7b56\u7565\uff08\u5728\u5fae\u8f6f\u7684<a href=\"https:\/\/link.segmentfault.com\/?enc=4C7rPOi9yg%2Bpk%2BXlot1g8g%3D%3D.21jr3W8AJJpzuwdVnctIpKrkDtonp%2F5OWEJG93gpS%2FfhGKqz1FvWSRt7qDtcRsLt\" rel=\"nofollow\">AutoAdmin \u201cwhat-if\u201d index analysis utility<\/a>\u4e2d\u63d0\u51fa\uff09\uff0c\u601d\u8def\u5c31\u662f\u5047\u8bbe\u7d22\u5f15idx_2\u5b58\u5728\u5e76\u4e14\u80fd\u8ba1\u7b97\u51fa\u5728\u7d22\u5f15idx_2\u5b58\u5728\u7684\u60c5\u51b5\u4e0b\uff0c\u6b64\u6267\u884c\u8ba1\u5212\u7684Cost\u503c\uff0c\u5982\u679c\u53d1\u73b0\u5176Cost\u53ea\u8981\u6bd4\u5f53\u524d\u5b58\u5728\u7684\u5176\u4ed6\u6267\u884c\u8ba1\u5212\u7684Cost\u503c\u66f4\u5c0f\uff0c\u5c31\u63a8\u8350\u8fd9\u4e2a\u7d22\u5f15\u3002<\/p>\n<p>\u4f46\u662fMySQL\u8ba1\u7b97Cost\u7684\u65f6\u5019\uff0c\u8981\u6c42\u7d22\u5f15\u662f\u771f\u5b9e\u5b58\u5728\u7684\uff0c\u4e3a\u4e86\u7ed9\u51fa\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u5728\u751f\u4ea7\u73af\u5883\u5b9e\u9645\u53bb\u521b\u5efa\u5404\u79cd\u7d22\u5f15\u662f\u4e0d\u53ef\u80fd\u7684\u3002\u89e3\u51b3\u7684\u7b56\u7565\u5c31\u662f\u5728\u975e\u751f\u4ea7\u73af\u5883\u7684\u6570\u636e\u5e93\u5b9e\u4f8b\u4e0a\u521b\u5efa\u4e00\u4e2a\u7a7a\u8868\uff0c\u5e76\u4e14\u6dfb\u52a0\u6240\u6709\u53ef\u80fd\u88ab\u7528\u5230\u7684\u7d22\u5f15\uff08\u53ea\u662f\u4e00\u4e2a\u5143\u6570\u636e\u7684create index\u64cd\u4f5c\u800c\u4e0d\u53bb\u771f\u6b63\u7684\u5411\u8868\u5185\u6dfb\u52a0\u6570\u636e\uff09\uff0c\u6700\u540e\u8ba9\u4f18\u5316\u5668\u53bb\u81ea\u5df1\u9009\u62e9\u6700\u4f73\u7684\u7d22\u5f15\u6765\u751f\u6210\u6267\u884c\u8ba1\u5212\uff0c\u8fd9\u5c31\u662f\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u603b\u4f53\u601d\u8def\u3002<\/p>\n<p>\u90a3\u4e48\u95ee\u9898\u6765\u4e86\uff0c\u5728\u975e\u751f\u4ea7\u73af\u5883\u4e0b\u521b\u5efa\u7684\u7d22\u5f15\u53ea\u662f\u4e00\u4e2a\u5143\u6570\u636e\uff0c\u4e0d\u5305\u542b\u4efb\u4f55\u6570\u636e\uff0c\u5982\u679c\u5c31\u8fd9\u6837\u8ba9\u67e5\u8be2\u4f18\u5316\u5668\u53bb\u8ba1\u7b97Cost\u80af\u5b9a\u662f\u884c\u4e0d\u901a\u3002\u4e3b\u8981\u539f\u56e0\u662f\u7f3a\u4e4f\u4e0a\u9762\u7684\u5206\u6790\u7684\u5404\u4e2a\u8bbf\u95ee\u65b9\u5f0f\u7684\u5173\u952e\u53d8\u91cf\u503c\uff0c\u6240\u4ee5\u6700\u5173\u952e\u7684\u5982\u4f55\u83b7\u53d6\u5230\u90a3\u4e9b\u5f71\u54cdcost\u8ba1\u7b97\u7684\u5173\u952e\u7684\u53d8\u91cf\u4fe1\u606f\u3002<\/p>\n<p>\u4ece\u4e0a\u9762\u7684\u201c\u5b9e\u73b0\u601d\u8def\u201d\u5206\u6790\u53ef\u77e5\uff0c\u5728\u8ba1\u7b97Table scan\u3001Index scan\u3001range access\u6216\u8005ref\u7684cost\u7684\u65f6\u5019\uff0c\u4e3b\u8981\u662f\u4ecescan_time()\u3001records_in_range()\u3001info()\u8fd9\u4e9b\u5728innodb\u5b58\u50a8\u5f15\u64ce\u91cc\u5b9e\u73b0\u7684\u65b9\u6cd5\u83b7\u53d6\u76f8\u5173\u7edf\u8ba1\u4fe1\u606f\uff0c\u6765\u8ba1\u7b97Cost\u5927\u5c0f\u3002\u800c\u7d22\u5f15\u6ca1\u6709\u771f\u5b9e\u7684\u6570\u636e\uff0c\u6240\u4ee5\u5fc5\u987b\u8981\u4fee\u6539\u5b58\u50a8\u5f15\u64ce\u91ccscan_time()\u3001records_in_range()\u3001info()\u8fd9\u4e9b\u8ddf\u8ba1\u7b97Cost\u76f8\u5173\u7684\u65b9\u6cd5\u7684\u5b9e\u73b0\u4ee3\u7801\uff0c\u8ba9\u5176\u5728\u7d22\u5f15\u6570\u636e\u4e0d\u5b58\u5728\u7684\u60c5\u51b5\u4e0b\uff0c\u4e5f\u80fd\u6bd4\u8f83\u771f\u5b9e\u5730\u83b7\u53d6\u5230\u8ddf\u8ba1\u7b97Cost\u503c\u76f8\u5173\u7684\u7edf\u8ba1\u6570\u636e\u3002<\/p>\n<p>\u6bd4\u5982\uff0c\u4e0a\u9762\u63d0\u5230\u7684records\u3001keys_per_block\u3001pages in table\u3001records_in_range\u3001cur_fanout\u7b49\u8fd9\u4e9b\u53d8\u91cf\uff0c\u5c31\u9700\u8981\u81ea\u5df1\u53bb\u8ba1\u7b97\uff1b\u6bd4\u5982records\u8fd9\u4e2a\u53d8\u91cf\uff0c\u53d1\u73b0\u5176\u662f\u5728Innodb\u4e2dinfo()\u7684\u5b9e\u73b0\uff0c\u901a\u8fc7<a href=\"https:\/\/link.segmentfault.com\/?enc=Ts8Ufqo5eIBXZ%2FuSS825kQ%3D%3D.VXZMQNhGJuEXIPN5CaPytzRxYnoD4eAFgSdtNC1fBstwkg3BwctnYX%2BX%2B81att%2B8O5NCDtSas4iVO1%2FO%2B5tr13gU9cWerpVcy9sQGofq57Tzm6Jb5A94TseSF9Xre1x1dDhRM63QGN3wOQgFtXs6Sw%3D%3D\" rel=\"nofollow\">n_rows\uff08records\uff09<\/a>\u8d4b\u503c\u7ed9records\uff0c\u6240\u4ee5\u53ea\u9700\u8981\u5728info()\u4e2d\u4ece\u751f\u4ea7\u73af\u5883\u7684\u8868\u91cc\u83b7\u53d6\u5230\u771f\u5b9e\u7684\u884c\u6570\uff0c\u8d4b\u503c\u7ed9records\u5c31\u53ef\u4ee5\u4e86\uff0c\u5176\u5b9e\u5c31\u662f\u4e00\u4e2a\u5143\u6570\u636e\u7684\u67e5\u8be2\u800c\u5df2\u3002<\/p>\n<p>\u518d\u770b\u4e00\u4e0bref\u7c7b\u578b\u8bbf\u95ee\u65b9\u5f0f\u7684Cost\u8ba1\u7b97\u8fc7\u7a0b\u4e2d\u7528\u5230\u7684cur_fanout\u53d8\u91cf\uff0c\u800c\u8fd9\u4e2a\u503c\u662f\u6765\u81eainfo()\u4e2d<a href=\"https:\/\/link.segmentfault.com\/?enc=8EJAuTgVXkSQRCxauLxL4g%3D%3D.p2ShToL%2F1k9eJRBIiCq3NYPgek2kLwKYcnmwZKoTDIaaSPAw%2BHLl3RirjoifVCcE%2FLUTa5uaUk7oWpoycu6n%2FQNFqdfHWCauYYYvDP4PWifweFJ59VsvfcU1g%2FriYSQ7q0QQJdQIMUxJ3BTiHpGdSQ%3D%3D\" rel=\"nofollow\">innodb_rec_per_key<\/a>\u7684\u503c\uff0c\u5b83\u8868\u793a\u6709\u591a\u5c11\u4e2a\u503c\u6ee1\u8db3\u7b49\u503c\u6761\u4ef6\uff0c\u53ea\u9700\u8981\u5728info()\u4e2d\u5b9e\u73b0innodb_rec_per_key\u7684\u8ba1\u7b97\u5c31\u53ef\u4ee5\u4e86\u3002<\/p>\n<p>\u90a3\u4e48innodb_rec_per_key\u53c8\u600e\u4e48\u8ba1\u7b97\u5462\uff1f\u6211\u4eec\u53ef\u4ee5\u5bf9\u8868\u8fdb\u884c\u4e86\u91c7\u6837\uff08\u91c7\u6837\u7684\u65b9\u6848\u53ef\u4ee5\u53c2\u8003\u8fd9\u7bc7\u300a<a href=\"https:\/\/link.segmentfault.com\/?enc=6s13BhJB2K1jJTQv%2FbYaNw%3D%3D.5YaqyY9rSm3hS6AGAvnn%2FbI7iommicO5T1s3HFNiRVxSksucj5ODORlGTFhBu7gmqRmXWO%2FT63Bv3WsHPjlFiE9cIM3b%2Fkuvkw8m8Ai40B7TeyXXB8OOusI0MX%2Bd%2FmaPbq9hrmNeeOz18Uzt41Xcl9IN4PEOD%2B7XZU9d5g%2Fhrf8%3D\" rel=\"nofollow\">Random Sampling for Histogram Construction: How Much is Enough?<\/a>\u300b\u8bba\u6587\uff09\uff0c\u91c7\u6837\u540e\u7684\u6570\u636e\u5bf9\u67d0\u5217\u7edf\u8ba1\u6709\u591a\u5c11\u4e2a\u4e0d\u540c\u7684\u503c\uff0c\u4e4b\u540e\u4f7f\u7528\u91c7\u96c6\u5230\u7684\u603b\u884c\u6570\/\u4e0d\u540c\u503c\u7684\u4e2a\u6570\u6765\u83b7\u53d6\u5230innodb_rec_per_key\u503c\u3002<\/p>\n<p>\u8fd9\u91cc\u8fd8\u6709\u4e00\u4e2a\u975e\u5e38\u91cd\u8981\u7684\u95ee\u9898\uff0c\u4e0a\u9762\u7684\u65b9\u6848\u662f\u9700\u8981\u4fee\u6539\u5bf9\u5e94\u5b58\u50a8\u5f15\u64ce\u7684scan_time()\u3001records_in_range()\u3001info()\u8fd9\u4e9b\u5173\u952e\u7684\u65b9\u6cd5\uff0c\u4f46\u662finnodb\u5b58\u50a8\u5f15\u64ce\u7684\u4ee3\u7801\u592a\u590d\u6742\u4e86\uff0c\u4fee\u6539\u7684\u96be\u5ea6\u6bd4\u8f83\u5927\uff0c\u4e00\u4e2a\u6bd4\u8f83\u597d\u7684\u65b9\u6848\u662f\u53bb\u4fee\u6539federated\u5b58\u50a8\u5f15\u64ce\u91cc\u7684scan_time()\u3001records_in_range()\u3001info()\u8fd9\u4e9b\u65b9\u6cd5\uff0c\u53bb\u83b7\u53d6\u4e0a\u9762\u4e0d\u540c\u8bbf\u95ee\u65b9\u5f0f\u4e2d\u9700\u8981\u7528\u5230\u7684\u5173\u952e\u53d8\u91cf\uff0c\u56e0\u4e3a\u5176\u5b9e\u73b0\u4ee3\u7801\u6bd4\u8f83\u7b80\u5355\u3002<\/p>\n<h4>4.2.3 \u7d22\u5f15\u5efa\u8bae\u6574\u4f53\u6d41\u7a0b\u56fe<\/h4>\n<p>\u628a\u4e4b\u524d\u7684\u6b65\u9aa4\u6574\u7406\u540e\u7684\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7684\u6d41\u7a0b\u56fe\u5982\u4e0b\uff1a<\/p>\n<ol>\n<li>\u4ece\u5f85\u4f18\u5316\u7684SQL\u7684\u5173\u952e\u4f4d\u7f6e\uff0c\u6bd4\u5982Where\u3001On\u3001Ordr By\u7b49\u4f4d\u7f6e\u63d0\u53d6\u5173\u952e\u5b57\u6bb5\u4fe1\u606f\uff0c\u5229\u7528\u63d0\u53d6\u5230\u7684\u5b57\u6bb5\u4fe1\u606f\u751f\u6210\u5019\u9009\u7d22\u5f15\uff1b<\/li>\n<li>\u901a\u8fc7\u5bf9\u6d89\u53ca\u5230\u7684\u8868\u7684\u6570\u636e\u8fdb\u884c\u91c7\u6837\u6765\u83b7\u53d6\u67e5\u8be2\u4f18\u5316\u5668\u8ba1\u7b97Cost\u65f6\u9700\u8981\u7528\u5230\u7684\u7edf\u8ba1\u4fe1\u606f\uff0c\u4e4b\u540e\u521b\u5efa\u4e0d\u5305\u542b\u4efb\u4f55\u6570\u636e\u7684\u7d22\u5f15\uff1b<\/li>\n<li>\u4fee\u6539\u5b58\u50a8\u5f15\u64ce\u7684\u4ee3\u7801\u91cd\u65b0\u5b9e\u73b0\u7684scan_time()\u3001records_in_range()\u3001info()\u8fd9\u4e9b\u51fd\u6570\uff0c\u4f7f\u5f97\u67e5\u8be2\u4f18\u5316\u5668\u80fd\u5229\u7528\u6570\u636e\u91c7\u6837\u540e\u8ba1\u7b97\u51fa\u6765\u7684\u7edf\u8ba1\u4fe1\u606f\u6765\u6bd4\u8f83\u771f\u5b9e\u7684\u83b7\u53d6Cost\u503c\uff1b<\/li>\n<li>\u9009\u62e9\u4e00\u4e2aCost\u4ee3\u4ef7\u6700\u5c0f\u7684\u6267\u884c\u8ba1\u5212\uff0c\u800c\u6b64\u6267\u884c\u8ba1\u5212\u80cc\u540e\u7684\u7d22\u5f15\u5c31\u662f\u4f18\u5316\u5efa\u8bae\u5de5\u5177\u63a8\u8350\u7684\u7d22\u5f15\uff0c\u6574\u4f53\u601d\u8def\u5c31\u662f\u8fd9\u6837\u3002<\/li>\n<\/ol>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982401\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>4.2.4 \u9a8c\u8bc1\u4e0e\u8ddf\u8e2a<\/h4>\n<p>\u901a\u8fc7\u5168\u91cfSQL\u7b49\u7cfb\u7edf\u83b7\u53d6\u5f85\u4f18\u5316\u7684SQL\u8bed\u53e5\u540e\uff0c\u8f93\u5165\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7cfb\u7edf\uff0c\u5728\u7ed9\u771f\u5b9e\u7684\u751f\u4ea7\u73af\u5883\u6dfb\u52a0\u8fd9\u4e9b\u7d22\u5f15\u4e4b\u524d\uff0c\u9700\u8981\u5728\u975e\u751f\u4ea7\u73af\u5883\u8fdb\u884c\u9a8c\u8bc1\uff0c\u770b\u4e00\u4e0b\u6dfb\u52a0\u4e86\u76f8\u5173\u7684\u7d22\u5f15\u540e\u6027\u80fd\u662f\u5426\u771f\u7684\u6709\u63d0\u5347\u3002\u5982\u679c\u6709\u63d0\u5347\uff0c\u90a3\u4e48\u628a\u7d22\u5f15\u5728\u751f\u4ea7\u73af\u5883\u6dfb\u52a0\u540e\uff08\u6bd4\u5982\u901a\u8fc7\u5f00\u6e90\u7684\u6539\u8868\u5de5\u5177Ghost\u7b49\uff09\uff0c\u9700\u8981\u901a\u8fc7\u8ddf\u8e2a\u88ab\u5f71\u54cdSQL\u7684\u6027\u80fd\uff0c\u6765\u67e5\u770b\u5176\u6267\u884c\u65f6\u95f4\u6027\u80fd\u662f\u5426\u771f\u7684\u6709\u6240\u63d0\u9ad8\u3002\u5982\u679c\u6709\u6027\u80fd\u6709\u56de\u9000\uff0c\u9700\u8981\u53ca\u65f6\u8fdb\u884c\u544a\u8b66\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982402\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>4.2.5 \u4ea7\u54c1\u5c55\u793a<\/h4>\n<p>\u4e0b\u9762\u7684\u4e09\u4e2a\u56fe\u5206\u522b\u5c55\u793a\u4e86\u63d0\u4f9b\u7ed9\u7528\u6237\u7684\u7d22\u5f15\u5efa\u8bae\uff0c\u4ee5\u53ca\u7d22\u5f15\u6dfb\u52a0\u524d\u540e\u7684\u6267\u884c\u65f6\u95f4\u6548\u679c\u6570\u636e\u5bf9\u6bd4\u56fe\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982403\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h3>4.3 \u57fa\u4e8eWorkload\u7684\u7d22\u5f15\u4f18\u5316\u5efa\u8bae<\/h3>\n<p>\u5177\u5907\u4e86\u5355SQL\u7684\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u80fd\u529b\u540e\uff0c\u90a3\u4e48\u5728\u6709\u9650\u7684\u5b58\u50a8\u7a7a\u95f4\u7684\u9650\u5236\u4e0b\uff08\u6bd4\u5982\u67d0\u4e2a\u5b9e\u4f8b\u6700\u591a\u53ea\u80fd\u6dfb\u52a0100G\u7a7a\u95f4\u7684\u7d22\u5f15\uff09\uff0c\u5982\u679c\u60f3\u7ed9\u67d0\u4e2aDB\u6216\u8005\u5b9e\u4f8b\u6dfb\u52a0\u7d22\u5f15\uff0c\u6dfb\u52a0\u54ea\u4e9b\u7d22\u5f15\u624d\u80fd\u4f7f\u6574\u4e2a\u6570\u636e\u5e93\u7684\u6027\u80fd\u63d0\u5347\u8fbe\u5230\u6700\u5927\u5316\u5462\uff1f\u601d\u8def\u4e3b\u8981\u662f\u53c2\u8003\u4e86\u5fae\u8f6f\u5728\u57fa\u4e8eWorkload\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u65b9\u9762\u7684\u4e00\u5e8f\u5217\u76f8\u5173\u5de5\u4f5c\u3002<\/p>\n<h4>4.3.1 \u603b\u4f53\u67b6\u6784<\/h4>\n<p>\u57fa\u4e8eWorkload\u7684\u7d22\u5f15\u4f18\u5316\u603b\u4f53\u67b6\u6784\u5982\u4e0b\uff0c\u603b\u5171\u67096\u5927\u6b65\u9aa4\u7ec4\u6210\uff0c\u6bcf\u4e2a\u6b65\u9aa4\u5bf9\u5e94\u7740\u4e00\u4e2a\u6838\u5fc3\u7ec4\u4ef6\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982404\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>1\uff09COLUMN GROUP RESTRICTION\u7ec4\u4ef6<\/p>\n<p>\u5982\u679c\u4e00\u4e2aworkload\uff08\u5178\u578b\u4e1a\u52a1\u5468\u671f\u5185\u5305\u542b\u7684\u6240\u6709SQL\u603b\u548c\u79f0\u4e4b\u4e3aworkload\uff09\u5305\u542b\u5927\u91cf\u7684SQL\u6a21\u7248\uff0c\u90a3\u4e48\u6f5c\u5728\u7684\u7d22\u5f15\u7ec4\u5408\u7684\u6570\u91cf\u662f\u6781\u5176\u5e9e\u5927\u7684\uff0c\u4ece\u4e2d\u6311\u9009\u51fa\u8ba9\u7cfb\u7edf\u6027\u80fd\u63d0\u5347\u6700\u5927\u7684\u7d22\u5f15\u7ec4\u5408\u662f\u4e00\u4e2a\u975e\u5e38\u56f0\u96be\u5e76\u4e14\u8017\u65f6\u7684\u8fc7\u7a0b\u3002\u6240\u4ee5\uff0c\u6211\u4eec\u9700\u8981\u4e00\u79cd\u79f0\u4e3a\u5217\u7ec4\u5408\u9650\u5236(COLUMN GROUP RESTRICTION)\u7684\u6280\u672f\uff0c\u5b83\u7684\u76ee\u7684\u662f\u6d88\u9664\u5927\u91cf\u53ef\u80fd\u7ec4\u6210\u7d22\u5f15\u7684\u5217\u7ec4\uff0c\u56e0\u4e3a\u8fd9\u4e9b\u5217\u7ec4\u6700\u591a\u53ea\u80fd\u5bf9\u6700\u7ec8\u63a8\u8350\u7684\u8d28\u91cf\u4ea7\u751f\u5f88\u5c0f\u7684\u8fb9\u9645\u5f71\u54cd\uff08\u5c31\u662f\u8bf4\u5c31\u7b97\u63a8\u8350\u4e86\u7d22\u5f15\uff0c\u6700\u540e\u5bf9\u6570\u636e\u5e93\u6574\u4f53\u7684\u6027\u80fd\u7684\u63d0\u5347\u5f88\u6709\u9650\uff0c\u6bd4\u5982\u67d0\u4e2aSQL\u53ea\u6267\u884c\u4e86\u4e00\u6b21\uff0c\u90a3\u4e48\u7ed9\u4e4b\u5bf9\u5e94\u7684\u8868\u52a0\u7d22\u5f15\u5c31\u6ca1\u610f\u4e49\u4e86\uff09\uff0c\u6240\u4ee5\u672c\u6b65\u9aa4\u7684\u8f93\u51fa\u662fworkload\u7684\u4e00\u7ec4\u201c\u6709\u8da3\u201d\u7684\u3001\u5bf9\u6574\u4f53\u6027\u80fd\u63d0\u5347\u53ef\u80fd\u6709\u6700\u5927\u63d0\u5347\u7684\u5217\u7ec4\u3002<\/p>\n<p>\u90a3\u4e48\uff0c\u600e\u4e48\u6837\u9009\u51fa\u8fd9\u4e2a\u201c\u6709\u8da3\u201d\u5217\u7ec4\u5462\uff1f\u6211\u4eec\u9700\u8981\u5b9a\u4e49\u4e00\u4e2a\u53ebCG-Cost (g) \u7684\u51fd\u6570\uff0c\u5176\u503c\u4e3a\u5f15\u7528\u5217\u7ec4\u5408g\u7684workload\u4e2d\u6240\u6709\u67e5\u8be2SQL\u7684Cost\u7684\u67d0\u4e2a\u5206\u6570\u503c\uff0c\u67e5\u8be2SQL\u7684Cost\u53ef\u4ee5\u901a\u8fc7\u4f18\u5316\u5668\u4f30\u8ba1\u7684\u6210\u672c\uff08MySQL\u4e2dexplain\u7ed9\u51fa\u7684Cost\uff09\u6765\u83b7\u53d6\u3002\u5982\u679cCG-Cost(g) \u2265 f \uff0c\u5217\u7ec4g\u9700\u8981\u4fdd\u7559\u4e0b\u6765\uff08\u5176\u4e2d\u76840 \u2264 f \u2264 1\u662f\u9884\u5148\u786e\u5b9a\u7684\u9608\u503c\uff09\uff0c\u5426\u5219\u53ef\u4ee5\u4e22\u5931\u8fd9\u4e2a\u5217\u7ec4g\u3002\u770b\u4e00\u4e2a\u5177\u4f53\u7684\u4f8b\u5b50\uff1a\u8003\u8651\u4e0b\u9762\u7684\u8868T (A,B,C,D) \u7684workload\u7531\u201cQ1\uff0c&#8230; Q10\u201d\u7b4910\u4e2aSQL\u7ec4\u6210\u3002\u5982\u679c\u67e5\u8be2\u5f15\u7528\u8be5\u5217\uff0c\u5219\u4e0a\u8ff0\u77e9\u9635\u4e2d\u7684\u5355\u5143\u683c\u5305\u542b1\uff0c\u5426\u5219\u5305\u542b0\u3002\u4e3a\u4e86\u7b80\u5355\u8d77\u89c1\uff0c\u5047\u8bbe\u6240\u6709\u67e5\u8be2\u7684\u6210\u672c\u5747\u4e3a1\u4e2a\u5355\u4f4d\u3002 <\/p>\n<p>\u5047\u8bbe\u6307\u5b9a\u7684\u9608\u503cf = 0.2\uff0c\u90a3\u4e48\u5de5\u4f5c\u8d1f\u8f7d\u7684\u6709\u8da3\u5217\u7ec4\u662f{A}\u3001{B}\u3001{C}\u3001{A,B}\u3001{A,C}\u3001{B,C} \u548c {A,B,C} \uff0c\u4ee5\u53ca\u5404\u7ec4\u7684 CG-Cost(g)\u4e3a1.0\u30010.3\u30010.9\u30010.3\u30010.9\u30010.2\u30010.2\uff0c\u800cD\u76f8\u5173\u7684\u5217\u56e0\u4e3aCG-Cost (g) \u503c\u5c0f\u4e8e0.2\u800c\u4e0d\u88ab\u8003\u8651\uff0c\u8fd9\u6837\u5c31\u53ef\u4ee5\u5728\u5e9e\u5927\u7684\u5217\u7ec4\u5408\u7684\u60c5\u51b5\u4e0b\u6392\u9664\u6389\u5927\u90e8\u5206\u5217\u7ec4\u5408\uff0c\u52a0\u5feb\u6574\u4e2a\u7d22\u5f15\u9009\u62e9\u7684\u8fed\u4ee3\u4f18\u5316\u7684\u8fc7\u7a0b\u3002 <\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982405\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>2\uff09Candidate index selection\u7ec4\u4ef6<\/p>\n<p>\u5355\u5217\u7d22\u5f15\uff08\u5047\u8bbe\u7d22\u5f15\uff09\u7684\u5efa\u7acb\uff0c\u5982\u679c\u8003\u8651workload\u7684\u6bcf\u4e00\u4e2a\u53ef\u80fd\u7684\u7d22\u5f15\u96c6\uff0c\u90a3\u4e48\u5c31\u4f1a\u6709\u592a\u591a\u7684what_if\u7d22\u5f15\u9700\u8981\u8003\u8651\uff0c\u8fd9\u6837\u6574\u4f53\u7684\u4f18\u5316\u8fc7\u7a0b\u4f1a\u975e\u5e38\u7f13\u6162\u3002<\/p>\n<p>\u4e00\u4e2a\u6bd4\u8f83\u597d\u7684\u601d\u8def\u662f\u4e3a\u6bcf\u4e2aQuery\u72ec\u7acb\u786e\u5b9a\u6700\u4f73\u7684\u7d22\u5f15\u96c6\uff0c\u5e76\u5c06\u5c5e\u4e8e\u8fd9\u4e9b\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u4e2d\u7684\u4e00\u4e2a\u6216\u591a\u4e2a\u7d22\u5f15\u89c6\u4e3a\u5019\u9009\u7d22\u5f15\u96c6\u3002\u8be5\u7b97\u6cd5\u80cc\u540e\u7684\u76f4\u89c9\u662f\uff0c\u5982\u679c\u5bf9\u4e8eworkload\u4e2d\u7684\u5355\u4e2a\u67e5\u8be2\uff0c\u8be5\u7d22\u5f15\u4e0d\u662f\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u7684\u4e00\u90e8\u5206\uff0c\u4e5f\u4e0d\u53ef\u80fd\u662f\u6574\u4e2aworkload\u7684\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u7684\u4e00\u90e8\u5206\u3002 <\/p>\n<p>\u8fd9\u4e2a\u7b97\u6cd5\u7684\u6311\u6218\u5728\u4e8e\u5982\u4f55\u4e3aworkload\u4e2d\u7684\u6bcf\u4e2a\u67e5\u8be2Q\u786e\u5b9a\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u5462\uff1f\u5176\u5b9e\u9488\u5bf9\u5355\u4e2a\u67e5\u8be2\u6765\u786e\u5b9a\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u8fd9\u4e2a\u95ee\u9898\u4e0e\u6839\u636e\u6574\u4f53\u7684\u57fa\u4e8eworkload\u6765\u9009\u62e9\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u8fd9\u4e2a\u95ee\u9898\uff0c\u4e24\u8005\u6ca1\u6709\u672c\u8d28\u7684\u4e0d\u540c\u3002\u6240\u4ee5\u53ef\u4ee5\u8bbe\u8ba1\u4e00\u4e2a\u7279\u6b8a\u7684workload\uff0c\u800c\u8fd9\u4e2aworkload\u53ea\u5305\u542b\u4e00\u4e2a\u67e5\u8be2\uff0c\u4e4b\u540e\u53ef\u4ee5\u901a\u8fc7\u4e0a\u9762\u5df2\u7ecf\u5b9e\u73b0\u7684\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u5de5\u5177\u672c\u8eab\uff0c\u6765\u4e3a\u5355\u4e2aQuery\u83b7\u53d6\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u3002<\/p>\n<p>\u5355\u67e5\u8be2\u83b7\u53d6\u6700\u4f73\u7684\u7d22\u5f15\u96c6\uff0c\u5982\u4f55\u4e3a\u5355\u4e2aSQL\uff08SQL\u6a21\u7248\uff09\u83b7\u53d6\u6700\u4f73\u7684\u7d22\u5f15\u96c6\u5462\uff1f\u4e00\u4e2a\u65b9\u6cd5\u662f\u5355\u4e2aSQL\u6a21\u7248\u8fdb\u884c\u89e3\u6790\uff0c\u5728SQL\u5173\u952e\u7684\u4f4d\u7f6e\u6bd4\u5982where\u3001on\u3001order by\u3001group by\u3001select\u7b49\u7684\u53d6\u51fa\u5173\u952e\u7684\u5217\u5148\u521b\u5efa\u5355\u4e2a\u5217\u4f5c\u4e3a\u5019\u9009\u7d22\u5f15\u5217\uff0c\u518d\u7ed3\u5408\u4e0b\u9762\u7684\u4ece\u201cMulti-column Index Generation\u7ec4\u4ef6\u201d\u90a3\u8282\u521b\u5efa\u51fa\u6765\u7684\u591a\u5217\u5019\u9009\u7d22\u5f15\uff0c\u8ba9\u67e5\u8be2\u4f18\u5316\u5668\u81ea\u5df1\u53bb\u9009\u62e9\u6700\u597d\u7684\u7d22\u5f15\u3002\u540c\u65f6\u8fd9\u4e2a\u6b65\u9aa4\u4f9d\u9760\u4f18\u5316\u5668\u9009\u51fa\u6765\u7684\u7d22\u5f15\uff0c\u4f5c\u4e3a\u4e0b\u4e00\u8f6e\u7b97\u6cd5\uff08\u7d22\u5f15\u5408\u5e76\uff09\u7684\u8f93\u5165\u3002<\/p>\n<p>3\uff09Index merging\u7ec4\u4ef6<\/p>\n<p>\u4e0a\u9762\u7684\u201cCANDIDATE SELECTION\u201d\u7ec4\u5efa\u9009\u51fa\u6765\u7684\u7d22\u5f15\u662f\u4e13\u95e8\u9488\u5bf9\u5355SQL\u4f18\u5316\u7684\u7d22\u5f15\u96c6\uff0c\u4f46\u662f\u5bf9\u4e8e\u6574\u4f53workload\u6765\u8bf4\uff0c\u8fd9\u4e2a\u65b9\u6cd5\u4f1a\u5bfc\u81f4\u8f83\u5927\u7684\u5b58\u50a8\u548c\u7d22\u5f15\u7ef4\u62a4\u6210\u672c\u3002\u6bd4\u5982\uff0c\u9488\u5bf9\u5355SQL\u9009\u51fa\u7684\u7d22\u5f15\u90fd\u662f\u6700\u4f73\u7684\uff0c\u4f46\u662f\u8fd9\u4e9b\u7d22\u5f15\u52a0\u8d77\u6765\u540e\u7684\u5b58\u50a8\u5927\u5c0f\u5df2\u7ecf\u8d85\u51fa\u4e86\u5141\u8bb8\u7684\u8303\u56f4\uff0c\u9700\u8981\u8fdb\u884c\u4e00\u4e9b\u7d22\u5f15\u7684\u5408\u5e76\u3002<\/p>\n<p>\u5982\u679c\u4e24\u4e2a\u7d22\u5f15\u7684\u5217\u5b58\u5728\u90e8\u5206\u91cd\u53e0\uff0c\u5219\u53ef\u80fd\u53ef\u4ee5\u5408\u5e76\uff0c\u6bd4\u5982\u5305\u62ec\u5173\u7cfb\u7684\u7d22\u5f15[a,b,c] \u8ddf[a,b] \u4ee5\u53ca\u6709\u90e8\u5206\u91cd\u53e0\u7684\u7d22\u5f15[a,b,c] \u8ddf[c,d}] \u7684\u5408\u5e76\uff0c\u5f53\u7136[a,b] \u8ddf[c,d}]\u662f\u4e0d\u80fd\u5408\u5e76\u7684\u3002\u7d22\u5f15\u5408\u5e76\u7684\u4e3b\u8981\u601d\u60f3\u5c31\u662f\u91c7\u7528\u73b0\u6709\u7684\u4e00\u7ec4\u7d22\u5f15\u751f\u6210\u4e00\u7ec4\u5177\u6709\u66f4\u4f4e\u5b58\u50a8\u548c\u7ef4\u62a4\u5f00\u9500\u7684\u65b0\u7d22\u5f15\uff0c\u540c\u65f6\u7d22\u5f15\u88ab\u5408\u5e76\u7684\u60c5\u51b5\u4e0b\uff0cSQL\u67e5\u8be2\u7684\u6027\u80fd\u80fd\u4fdd\u6301\u4e0d\u53d8\u6216\u8005\u5f71\u54cd\u6bd4\u8f83\u5c0f\uff0c\u7d22\u5f15\u5408\u5e76\u7684\u67b6\u6784\u5982\u4e0b\uff1a<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982406\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>4\uff09Configuration Enumeration\u7ec4\u4ef6<\/p>\n<p>\u5982\u679c\u57fa\u4e8eworkload\u7684\u7d22\u5f15\u96c6\u6709n\u4e2a\u5019\u9009\u7d22\u5f15\uff0c\u4f46\u662f\u56e0\u4e3a\u5b58\u50a8\u5927\u5c0f\u9650\u5236\uff0c\u8981\u6c42workload\u5de5\u5177\u6700\u591a\u53ea\u80fd\u9009\u62e9k\u4e2a\u7d22\u5f15\uff08\u4e00\u822c\u662f\u53d7\u5230\u4e86\u5b58\u50a8\u5927\u5c0f\u8ddfCost\u5927\u5c0f\u7684\u9650\u5236\uff09\uff0c\u90a3\u4e48\u5e94\u8be5\u5982\u4f55\u9009\u62e9\u8fd9\u4e2ak\u4e2a\u7d22\u5f15\u5462\uff1f\u4e00\u822c\u6765\u8bf4\uff0c\u539f\u59cb\u7684\u66b4\u529b\u679a\u4e3e\u7b97\u6cd5\u5c06\u679a\u4e3e\u5927\u5c0f\u4e3ak\u6216\u66f4\u5c0f\u7684\u5019\u9009\u7d22\u5f15\u7684\u6240\u6709\u5b50\u96c6\uff0c\u5e76\u9009\u62e9\u603b\u6210\u672c\u6700\u4f4e\u7684\u4e00\u4e2a\u7d22\u5f15\u96c6\uff0c\u8fd9\u4e2a\u679a\u4e3e\u7b97\u6cd5\u786e\u5b9e\u4fdd\u8bc1\u4e86\u6700\u4f18\u89e3\u3002<\/p>\n<p>\u7136\u800c\uff0c\u8fd9\u5728\u5de5\u7a0b\u4e0a\u4e0d\u5207\u5b9e\u9645\u7684\u3002\u56e0\u4e3a\u5bf9\u4e8en=40\u548ck=10\u7684\u60c5\u51b5\uff0c\u679a\u4e3e\u7684\u7d22\u5f15\u96c6\u7684\u6570\u91cf\u5b9e\u5728\u592a\u5e9e\u5927\uff0c\u65e0\u6cd5\u8fdb\u884c\u8be6\u5c3d\u7684\u679a\u4e3e\uff0c\u6240\u4ee5\u9700\u8981\u4e00\u4e2a\u6027\u80fd\u66f4\u597d\u7684\u7b97\u6cd5\u7684\u201c\u8d2a\u5fc3\u7b97\u6cd5\u201d\uff0c\u5176\u601d\u60f3\u662f\u5047\u8bbe\u6709n\u4e2aSQL\uff08\u4e00\u822c\u662f\u5b9e\u65bd\u7684\u65f6\u5019\uff0c\u662fn\u4e2aSQL\u6a21\u7248\u6765\u66ff\u4ee3n\u4e2aSQL\u5b9e\u4f8b\uff09\uff0c\u6574\u4e2aworkload W\u8868\u793a\u4e3a {Q1, .., Qn}\u3002<\/p>\n<p>\u65b9\u6848\u662f\u5229\u7528\u66b4\u529b\u8ddf\u8d2a\u5fc3\u7b97\u6cd5\u7684\u7ec4\u5408\uff0c\u8fd0\u884cGreedy(m, k)\u7b97\u6cd5\u679a\u4e3e\u7d22\u5f15\u96c6\u5408\uff08m\u4e3a\u901a\u8fc7\u66b4\u529b\u7b97\u6cd5\u9009\u62e9\u7684m\u4e2a\u6700\u4f73\u7d22\u5f15\uff0ck\u4e3a\u9009\u62e9\u7684\u7d22\u5f15\u7684\u603b\u5927\u5c0f\uff09\uff0c\u9009\u62e9\u4e00\u7ec4\u7d22\u5f15\uff0c\u76f4\u5230\u9009\u51fa\u6240\u9700\u6570\u91cf\u7684\u7d22\u5f15\u6216\u603bCost\u65e0\u6cd5\u8fdb\u4e00\u6b65\u964d\u4f4e\uff0c\u8be5\u7b97\u6cd5\u9009\u62e9\u5927\u5c0f\u4e3am\uff08\u5176\u4e2dm &lt;= k\uff09\u7684\u6700\u4f73\u7d22\u5f15\u96c6\u4f5c\u4e3a\u201c\u79cd\u5b50\u201d\uff0c\u7136\u540e\u4ee5\u8d2a\u5fc3\u7b97\u6cd5\u6269\u5c55\u8fd9\u4e2a\u79cd\u5b50\uff0c\u76f4\u5230\u9009\u62e9\u4e86\u6240\u6709k\u4e2a\u7d22\u5f15\uff0c\u63a2\u7d22\u7b97\u6cd5\u5c31\u662f\u4ece\u6240\u6709\u7684\u5019\u9009\u7d22\u5f15\u4e2d\u9009\u62e9\u4e00\u4e2a\u7d22\u5f15\uff0c\u4f7f\u5f97\u52a0\u4e86\u8fd9\u4e2a\u7d22\u5f15\u540e\uff0c\u6574\u4f53SQL\u7684\u6027\u80fd\u63d0\u5347\u6548\u679c\u6700\u5927\u5316\uff0c\u867d\u7136\u4ece\u5168\u5c40\u89d2\u5ea6\u770b\u672a\u5fc5\u662f\u63d0\u5347\u6700\u5927\u5316\u7684\u3002<\/p>\n<p>5\uff09Multi-column Index Generation\u7ec4\u4ef6<\/p>\n<p>\u591a\u5217\u7d22\u5f15\u7684\u9009\u62e9\u6709\u4e00\u4e2a\u6bd4\u8f83\u5927\u7684\u6311\u6218\uff0c\u5c31\u662f\u5019\u9009\u7d22\u5f15\u5b9e\u5728\u592a\u591a\uff0c\u6bd4\u5982\u5bf9\u4e8e\u8868\u4e2d\u7ed9\u5b9a\u7684\u4e00\u7ec4k\u5217\uff0c\u6700\u591a\u53ef\u80fd\u6709k!\u591a\u5217\u7d22\u5f15\uff0c\u8003\u8651\u6240\u6709\u6392\u5217\u7ec4\u5408\u5c06\u4f1a\u663e\u8457\u589e\u52a0Configuration\uff08\u7d22\u5f15\uff09\u7a7a\u95f4\uff0c\u6240\u4ee5\u9700\u8981\u51cf\u5c11\u5217\u7ec4\u5408\u7684\u641c\u7d22\u7a7a\u95f4\u3002\u91c7\u7528\u8fed\u4ee3\u65b9\u6cd5\u6765\u8003\u8651\u591a\u5217\u7d22\u5f15\u7684\u5bbd\u5ea6\uff08\u5217\u7684\u4e2a\u6570\uff09\u3002\u5728\u7b2c\u4e00\u6b21\u8fed\u4ee3\u4e2d\uff0c\u53ea\u8003\u8651\u5355\u5217\u7d22\u5f15\uff0c\u57fa\u4e8e\u5728\u7b2c\u4e00\u6b21\u8fed\u4ee3\u4e2d\u9009\u62e9\u7684\u5355\u5217\u7d22\u5f15\uff0c\u5728\u5f80\u540e\u7684\u8fed\u4ee3\u4e2d\u9009\u62e9\u4e00\u7ec4\u53ef\u63a5\u53d7\u7684\u53cc\u5217\u7d22\u5f15\u3002\u8fd9\u7ec4\u201c\u4e24\u5217\u7d22\u5f15\u201d\u4e0e\u5355\u5217\u7d22\u5f15\u4e00\u8d77\u6210\u4e3a\u7b2c\u4e8c\u6b21\u8fed\u4ee3\u7684\u8f93\u5165\u3002 <\/p>\n<p>\u90a3\u4e48\uff0c\u5177\u4f53\u662f\u5982\u4f55\u5728\u5355\u5217\u7684\u57fa\u7840\u4e0a\u9009\u62e9\u5176\u4ed6\u7684\u5217\u7ec4\u6210\u591a\u5217\u7d22\u5f15\u5462\uff1f\u8fd9\u91cc\u6709\u591a\u79cd\u7b97\u6cd5\uff0c\u5148\u4f7f\u7528\u7b26\u53f7M (a, b) \u6765\u8868\u793a\u5217a\u548cb\u4e0a\u7684\u53cc\u5217\u7d22\u5f15\uff0c\u5176\u4e2da\u662f\u53cc\u5217\u7d22\u5f15\u7684\u524d\u5bfc\u5217\u3002\u591a\u5217\u7d22\u5f15\u9009\u62e9\u4e00\u822c\u6709MC_LEAD\u3001MC_ALL\u3001MC_BASIC\u4e09\u79cd\u7b97\u6cd5\uff0c\u8fd9\u51e0\u79cd\u7b97\u6cd5\u5728\u5b9e\u73b0\u7684\u65f6\u5019\u4e00\u822c\u4f1a\u91c7\u7528MC_LEAD\u7b97\u6cd5 \uff0c\u56e0\u4e3a\u88ab\u8bc1\u660e\u6548\u679c\u6700\u597d\u3002<\/p>\n<ul>\n<li><strong>MC_LEAD<\/strong>\uff1a\u4eceCANDIDATE SELECTION\u88ab\u4f18\u5316\u5668\u9009\u62e9\u7684\u7d22\u5f15\uff0c\u518d\u52a0\u4e0a\u67d0\u4e2a\u201cindexable column\u201d \u5217\uff0c\u8fd9\u4e2a\u201cindexable column\u201d \u5217\u5bf9\u5e94\u7684\u7d22\u5f15\u4e0d\u4e00\u5b9a\u5728\u7b2c\u4e00\u8f6e\u8fed\u4ee3\u4e2d\u88ab\u9009\u62e9\uff1b<\/li>\n<li><strong>MC_ALL<\/strong>\uff1a\u4eceCANDIDATE SELECTION\u88ab\u4f18\u5316\u5668\u9009\u62e9\u7684\u7d22\u5f15\uff0c\u518d\u52a0\u4e0a\u67d0\u4e2a\u201cindexable column\u201d \u5217\uff0c\u8fd9\u4e2a\u201cindexable column\u201d \u5217\u5bf9\u5e94\u7684\u7d22\u5f15\u4e00\u5b9a\u5728\u7b2c\u4e00\u8f6e\u8fed\u4ee3\u4e2d\u88ab\u9009\u62e9\uff0c\u8fd9\u79cd\u6761\u4ef6\u6bd4\u8f83\u82db\u523b\uff0c\u4e1a\u754c\u76f8\u5173\u7684\u6d4b\u8bd5\u8868\u660e\u6548\u679c\u660e\u786e\u4e0d\u5982MC_LEAD\u8ddfMC_BASIC\uff0c\u867d\u7136\u591a\u5217\u7d22\u5f15\u7684\u641c\u7d22\u7a7a\u95f4\u660e\u663e\u51cf\u5c11\uff0c\u63d0\u5347\u4e86\u603b\u4f53\u6027\u80fd\uff1b<\/li>\n<li><strong>MC_BASIC<\/strong>\uff1a\u5219\u662f\u628a\u5355\u5217\u8ddf\u591a\u5217\u7d22\u5f15\u6df7\u5728\u4e00\u4e2a\u8fed\u4ee3\u5468\u671f\u91cc\u5efa\u7acb\uff0c\u800c\u4e0d\u662f\u5148\u6839\u636e\u5355\u5217\u5efa\u8bae\u4e00\u4e2a\u7d22\u5f15\uff0c\u7136\u540e\u518d\u901a\u8fc7\u8fed\u4ee3\u7684\u65b9\u5f0f\u5728\u5355\u5217\u7684\u57fa\u7840\u4e0a\u9010\u6e10\u589e\u52a0\u7d22\u5f15\u7684\u5bbd\u5ea6\u3002<\/li>\n<\/ul>\n<p>6\uff09Final Indexes\u7ec4\u4ef6<\/p>\n<p>\u7ecf\u8fc7\u51e0\u8f6e\u8fed\u4ee3\uff0c\u5f53\u540c\u65f6\u6ee1\u8db3Cost\u8ddfStorage Size\u7684\u8981\u6c42\u540e\u9000\u51fa\u8fed\u4ee3\u4f18\u5316\u8fc7\u7a0b\uff0c\u8f93\u51fa\u4e00\u7ec4\u6700\u4f18\u7684\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u96c6\u5408\u3002<\/p>\n<h3>4.4 SQL\u6cbb\u7406<\/h3>\n<p>\u5177\u5907\u4e86SQL\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7684\u80fd\u529b\u540e\uff0c\u5c31\u53ef\u4ee5\u5bf9\u6709\u6027\u80fd\u95ee\u9898\u7684SQL\u8fdb\u884c\u4e09\u4e2a\u9636\u6bb5\u7684\u6cbb\u7406\uff0c1\uff09SQL\u53d1\u5e03\u751f\u4ea7\u73af\u5883\u524d\uff0c\u8d77\u5230\u9632\u60a3\u4e8e\u672a\u7136\u3001\u628a\u95ee\u9898\u627c\u6740\u5728\u6447\u7bee\u4e2d\u7684\u4f5c\u7528\uff1b2\uff09SQL\u751f\u4ea7\u73af\u5883\u6267\u884c\u8fc7\u7a0b\u4e2d\uff0c\u8d77\u5230\u5b9e\u65f6\u76d1\u63a7\u53d1\u73b0\u6b63\u5728\u6267\u884c\u7684\u95ee\u9898SQL\uff0c\u5feb\u901f\u6b62\u635f\uff0c\u6bd4\u5982\u8bef\u5220\u7d22\u5f15\u7684\u4f5c\u7528\uff1b3\uff09SQL\u751f\u4ea7\u73af\u5883\u6267\u884c\u8fc7\u540e\uff0c\u5bf9\u4e8e\u6267\u884c\u8fc7\u7684SQL\uff0c\u57fa\u4e8e\u6574\u4f53\u7684Workload\u4f18\u5316\u7b56\u7565\uff0c\u901a\u8fc7\u79bb\u7ebf\u7684\u65b9\u5f0f\u8fdb\u884c\u6279\u91cf\u7684\u98ce\u9669SQL\u6cbb\u7406\u3002\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982407\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>4.4.1 \u98ce\u9669SQL\u5ba1\u6838\uff08\u4e8b\u524d\uff09<\/h4>\n<p>\u6b64\u9636\u6bb5\u662f\u7a0b\u5e8f\u53d1\u5e03\u524d\u5bf9\u6f5c\u5728\u7684\u98ce\u9669SQL\u8fdb\u884c\u5361\u70b9\uff0c\u5728\u516c\u53f8\u7684CI\/CD\u5e73\u53f0\u96c6\u6210\u6d41\u6c34\u7ebf\u91cc\u589e\u8bbeSQL\u5ba1\u6838\u5361\u63a7\u70b9\uff0c\u5c3d\u91cf\u9632\u6b62\u98ce\u9669SQL\u88ab\u5e26\u5230\u751f\u4ea7\u73af\u5883\u5f15\u53d1\u6545\u969c\uff0c\u8d77\u9632\u60a3\u4e8e\u672a\u7136\u7684\u4f5c\u7528\u3002<\/p>\n<p>\u5177\u4f53\u6765\u8bf4\uff0c\u6307\u5b9a\u4e86\u4e00\u5e8f\u5217\u7684\u89c4\u5219\uff0c\u53d1\u73b0\u98ce\u9669SQL\u540e\u53ef\u4ee5\u6682\u505c\u53d1\u5e03\uff0c\u5e76\u4e14\u7ed9\u51fa\u76f8\u5e94\u7684\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u6765\u4f18\u5316SQL\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982408\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>4.4.2 \u4ea7\u54c1\u5c55\u793a<\/h4>\n<p>\u6839\u636e\u5ba1\u6838\u89c4\u5219\uff0c\u5c55\u793a\u5ba1\u6838\u7ed3\u679c\u4e0e\u5efa\u8bae\uff0c\u5305\u62ec\u98ce\u9669\u63d0\u793a\u8ddfSQL\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7b49\u5185\u5bb9\uff0c\u5ba1\u6838\u7684\u89c4\u5219\u5305\u62ec\u662f\u5426\u5168\u8868\u626b\u63cf\u3001\u626b\u63cf\u884c\u6570\u8fc7\u591a\u7b49\u5185\u5bb9\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982409\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>4.4.3 \u6027\u80fd\u95ee\u9898SQL\u5b9e\u65f6\u53d1\u73b0\uff08\u4e8b\u4e2d\uff09<\/h4>\n<p>\u6b64\u9636\u6bb5\u662f\u98ce\u9669SQL\u7684\u5b9e\u65f6\u53d1\u73b0\u529f\u80fd\uff0c\u4e3b\u8981\u9488\u5bf9\u5728SQL\u8fd0\u884c\u8fc7\u7a0b\u4e2d\u56e0\u4e3a\u8868\u7ed3\u6784\u7684\u66f4\u6539\uff08\u5982\u7d22\u5f15\u8bef\u5220\u9664\uff09\u3001\u4e8b\u524d\u5ba1\u8ba1\u9636\u6bb5\u9057\u6f0f\u6389\u7684\u6027\u80fd\u95ee\u9898SQL\u7b49\u573a\u666f\uff0c\u5b9e\u65f6\u5730\u53d1\u73b0\u6709\u6027\u80fd\u95ee\u9898\u7684SQL\uff0c\u5e76\u4e14\u7ed9\u51fa\u4f18\u5316\u5efa\u8bae\u3002\u5bf9\u4e8e\u5b9e\u65f6\u7684\u6027\u80fd\u95ee\u9898SQL\u53d1\u73b0\u4f7f\u7528\u4e86\u4e24\u79cd\u53d1\u73b0\u7b56\u7565\uff0c\u4e00\u79cd\u662f\u57fa\u4e8e\u89c4\u5219\u7684\u53d1\u73b0\u7b56\u7565\uff0c\u53e6\u4e00\u79cd\u901a\u8fc7\u6570\u636e\u5efa\u6a21\u7684\u65b9\u5f0f\u6765\u53d1\u73b0\u7b56\u7565\u3002<\/p>\n<p>\u57fa\u4e8e\u89c4\u5219\u7684\u98ce\u9669\u53d1\u73b0\u7b56\u7565\uff0c\u5176\u4e2d\u7684\u89c4\u5219\u5305\u62ec\u5355\u4f4d\u65f6\u95f4\u5185\u7684\u6162\u67e5\u8be2\u6570\u91cf\u3001SQL\u6267\u884c\u65f6\u95f4\u3001\u626b\u63cf\u884c\u6570\u7b49\u5185\u5bb9\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982410\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>\u57fa\u4e8e\u6570\u636e\u5efa\u6a21\u7684\u98ce\u9669\u53d1\u73b0\u7b56\u7565\uff0c\u662f\u901a\u8fc7\u5168\u91cfSQL\u83b7\u53d6SQL\u7684\u5386\u53f2\u6267\u884c\u65f6\u957f\u6765\u5efa\u6a21\uff0c\u518d\u901a\u8fc7Process List\u7b49\u6570\u636e\u6e90\uff0c\u628a\u5f53\u524d\u6b63\u5728\u6267\u884cSQL\u7684\u6267\u884c\u65f6\u95f4\u8f93\u5165\u6a21\u578b\uff0c\u4ece\u6267\u884c\u65f6\u95f4\u7684\u89d2\u5ea6\u6765\u5224\u65ad\u662f\u5426\u6709\u5f02\u5e38\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982411\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>4.4.4 \u6279\u91cfSQL\u6cbb\u7406\uff08\u4e8b\u540e\uff09<\/h4>\n<p>\u6b64\u9636\u6bb5\u662f\u901a\u8fc7\u5bf9SQL\u6267\u884c\u7684\u5386\u53f2\u8bb0\u5f55\u8fdb\u884c\u6279\u91cf\u5206\u6790\uff0c\u4ece\u5168\u5c40\u7684\u89d2\u5ea6\u3001\u5229\u7528workload\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\u7684\u601d\u60f3\u63d0\u4f9b\u6700\u4f73SQL\u7d22\u5f15\u4f18\u5316\u5efa\u8bae\uff0c\u6279\u91cf\u63a8\u9001\u4f18\u5316\u5efa\u8bae\u7ed9\u7528\u6237\u8fdb\u884c\u98ce\u9669SQL\u7684\u6cbb\u7406\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982412\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h4>4.4.5 \u4ea7\u54c1\u5c55\u793a<\/h4>\n<p>\u5bf9\u4e8e\u6279\u91cf\u7684SQL\u4f18\u5316\u5efa\u8bae\uff0c\u8fd9\u91cc\u63d0\u4f9b\u4e86\u4e00\u952e\u5ba1\u6279\u7d22\u5f15\u6dfb\u52a0\u7684\u529f\u80fd\uff0c\u53ef\u4ee5\u66f4\u5feb\u7684\u8ba9\u88ab\u5efa\u8bae\u7684\u7d22\u5f15\u6dfb\u52a0\u5230\u751f\u4ea7\u73af\u5883\u4e0a\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000043982413\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<h2>5 \u672c\u6587\u4f5c\u8005<\/h2>\n<p>\u88d5\u950b\uff0c\u6765\u81ea\u7f8e\u56e2\u57fa\u7840\u7814\u53d1\u5e73\u53f0-\u57fa\u7840\u6280\u672f\u90e8\uff0c\u8d1f\u8d23\u7f8e\u56e2\u6570\u636e\u5e93\u81ea\u6cbb\u5e73\u53f0\u7684\u76f8\u5173\u5de5\u4f5c\u3002<\/p>\n<h2>6 \u53c2\u8003<\/h2>\n<ul>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=jl2WJotNQuZBUHEixJtmnQ%3D%3D.jZ%2FqdprhOIReOoxFtQoTc9DYLoScblMqGmt1Q1T%2BVLIxRE8N4kVxSIg8oxkbmyDy\" rel=\"nofollow\">https:\/\/github.com\/shenyufengdb\/sql<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=PSxo7NvAlRaxva6blQyp3A%3D%3D.xsJ1x1fw%2ByuBnzMU%2FNYSkQcSLoYLpKKObT7gUrSOlqzs1rfA1%2F438wCrUr%2FM4MEUEak9c9TChtrIrxxqsx1yv6tzyaZ48eEkfb4KpbR1Ti4%3D\" rel=\"nofollow\">https:\/\/github.com\/percona\/percona-server\/blob\/release-5.7.41-44<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=27C1lpVO6BOwMdknbXPlpw%3D%3D.wayF70PslxbuzH6OK8Y1CWE7xzPGHSLke7Ap5AOPvsRM7SJKVlUMx21XUCO2qC%2BNW75K31VdqaMvBWGrsH4QVS3PLipPRywp1AlPcY%2FOTOUuOLLNNPIuwsu%2FBks%2F%2Bp2egurgcI0X2eMRYR9rj8e4h3SchWDM9iuaAjmbc3L%2BZrs%3D\" rel=\"nofollow\">An Efficient, Cost-Driven Index Selection Tool for Microsoft SQL Server<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=YRxYXdmJ3ix1lug3jYKyGA%3D%3D.POcd5bTww0PLg9YSzyv9mcFOQsRF6EZ2D6Wk%2BZPysCYs1dBxizK5c6vdzAMl4ul4YxIRW%2BZKKe1OdWBIMeksHjuwbrygzKzaGhkMfRNDXCo%2FK%2F3j1myOfAORWivBomWKgFnoQCKHopJkdt7XUpBK2w%3D%3D\" rel=\"nofollow\">plan-stitch-harnessing-the-best-of-many-plans-2<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=N0BTNg%2B01o2ZLYOgutRU5Q%3D%3D.cN4%2Fw1bkHGU9T%2FPPEzNqArwiiHSNJW%2BGRTBAvpqtcOI8WesWqP3xOXyD9Djp9md4khlPSAC7O0OKa8geqXaKTdkwwn6gQzjQl7d%2FseTkfRGNYkKn%2FLkqIG8AbY13%2FeIJ69q1YmblJKB0dVkHB%2F6hnPgu%2Fu08hQSNc9KQbu9CYA8%3D\" rel=\"nofollow\">Random Sampling for Histogram Construction: How Much is Enough?<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=Q0M7Thl27HeMYhUjDog68g%3D%3D.mspZ6aXzZr28Lf%2FP3Sg610E0fPgIXt6jki9iZ0WwuF%2FyU%2Fq1eCWPJQYQKNUnbZPt\" rel=\"nofollow\">AutoAdmin \u201cwhat-if\u201d index analysis utility<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=U5kBJxDjNmxq6TfNwaIYtg%3D%3D.8oFVKhd2%2FVFRGQ3sdKECk%2Bm45dMv7xWDXGQVt%2BOE9fTSDku2Hcc5JSwB52svA96lTEq5u4mIEGne26PQs7l1aZ8nrGrXJGB8wXyPYTINjMqdq31f0KP3c4WJa2JyZvE3aj1Oiwu2wD10p6IJLlJNyw%3D%3D\" rel=\"nofollow\">What is a Self-Driving Database Management System?<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=ulHKg6UYIMhjKWYdw89Umw%3D%3D.NZqqYPWbB0fG7RxwR%2FdzH%2FRfeGWOEFIIiAfDDG4OI62gUz6dvgxMvHCdgwXPRKGDrTua3sOBmRNCu0NKWixaBQYGT668v5bxTb%2FtJMAvbThfiZUV9cMO9nC%2BfP3mEzSm7z712tGaBKQd5IE%2FYDUO3w%3D%3D\" rel=\"nofollow\">https:\/\/www.microsoft.com\/en-us\/research\/publication\/self-tuning-database-systems-a-decade-of-progress\/<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=JvFiuYuC3oOkYBIz70xS0Q%3D%3D.DSSvHpO%2FsfuGjty7PQknbUd6QgicQ2cernISVRyujpfuqkSozdQTfCTVAJCDG5cpRZ5hLFmUC4AIwQ%2FBHs91jA%3D%3D\" rel=\"nofollow\">Automatic Database Management System Tuning Through Large-scale Machine Learning<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=HlC5nFAVsqqyNMJGiSIdTw%3D%3D.YviTRkl7uGXM6GQQF3YroFL1vAGUe5XfPjGuGKtHbChWY9GTRuMWCtKQEth35KHyfZoAwqqrODqhJ80kIlMTFA%3D%3D\" rel=\"nofollow\">Query-based Workload Forecasting for Self-Driving Database Management Systems<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=9fp5C5i%2BuubD9ONz%2FfvfxQ%3D%3D.axDnEfg%2FXJmq9BmegJKuxCsk9yJB%2FJcoYvHOgRuq7FdXHRddHB%2FrQ2WTCJslMogy\" rel=\"nofollow\">The TSA Method<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=eRPa9DZMcLePQQ%2B2IDBGPw%3D%3D.EnGXwdzTl46WIGOrpHjHfYjlimT1CrzUaDeR8YicpNlC0X%2Bc0tjoCI6cjEYDMaQD\" rel=\"nofollow\">https:\/\/blog.langchain.dev\/langchain-chat\/<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=7XmEFHg2XyfVMaTd%2Bj%2Bwyw%3D%3D.oHfODJD1KWB9xVHH36xOah6SMZU8%2BfVfxFimrEUjers2Pz0m1CtOTTLHvUIocyta\" rel=\"nofollow\">https:\/\/github.com\/hwchase17\/langchain<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=TQqThtNk%2Fo%2BUq9QRQvWi6Q%3D%3D.BytgIVfegT49Tj1t3NLJbkDt84UT%2FSautar38GdQdogZP0wFur4C05e5oAo6Hts1\" rel=\"nofollow\">REAC T: SYNERGIZING REASONING AND ACTING IN LANGUAGE MODELS<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=X0qAyXmYOuI4XkvNCUu%2BBQ%3D%3D.fydZOQj1Vu8Q90NdFLq%2BEY%2FI6VQu7Z18NtKtRUM94qK%2FmlUTvD3j%2BetC2jw9SwzI\" rel=\"nofollow\">Evaluating the Text-to-SQL Capabilities of Large Language Models<\/a><\/li>\n<li><a href=\"https:\/\/link.segmentfault.com\/?enc=JLF0zywNi9EPIgEXek0ayw%3D%3D.NBmVCHxA%2BwMMkwl%2Ftq5Rn6GPSd1U%2BfcikyKrk6ZoVUcMBJBgv377ullJenUmPr98\" rel=\"nofollow\">SQL-PALM: IMPROVED LARGE LANGUAGE MODEL ADAPTATION FOR TEXT-TO-SQL<\/a><\/li>\n<\/ul>\n<h2>\u9605\u8bfb\u66f4\u591a<\/h2>\n<p><strong>|<\/strong>  \u5728\u7f8e\u56e2\u516c\u4f17\u53f7\u83dc\u5355\u680f\u5bf9\u8bdd\u6846\u56de\u590d\u30102022\u5e74\u8d27\u3011\u3001\u30102021\u5e74\u8d27\u3011\u3001\u30102020\u5e74\u8d27\u3011\u3001\u30102019\u5e74\u8d27\u3011\u3001\u30102018\u5e74\u8d27\u3011\u3001\u30102017\u5e74\u8d27\u3011\u7b49\u5173\u952e\u8bcd\uff0c\u53ef\u67e5\u770b\u7f8e\u56e2\u6280\u672f\u56e2\u961f\u5386\u5e74\u6280\u672f\u6587\u7ae0\u5408\u96c6\u3002<\/p>\n<p><img decoding=\"async\" referrerpolicy=\"no-referrer\" src=\"https:\/\/segmentfault.com\/img\/remote\/1460000042283403\" alt=\"\" title=\"\" loading=\"lazy\"><\/p>\n<p>| \u672c\u6587\u7cfb\u7f8e\u56e2\u6280\u672f\u56e2\u961f\u51fa\u54c1\uff0c\u8457\u4f5c\u6743\u5f52\u5c5e\u7f8e\u56e2\u3002\u6b22\u8fce\u51fa\u4e8e\u5206\u4eab\u548c\u4ea4\u6d41\u7b49\u975e\u5546\u4e1a\u76ee\u7684\u8f6c\u8f7d\u6216\u4f7f\u7528\u672c\u6587\u5185\u5bb9\uff0c\u656c\u8bf7\u6ce8\u660e\u201c\u5185\u5bb9\u8f6c\u8f7d\u81ea\u7f8e\u56e2\u6280\u672f\u56e2\u961f\u201d\u3002\u672c\u6587\u672a\u7ecf\u8bb8\u53ef\uff0c\u4e0d\u5f97\u8fdb\u884c\u5546\u4e1a\u6027\u8f6c\u8f7d\u6216\u8005\u4f7f\u7528\u3002\u4efb\u4f55\u5546\u7528\u884c\u4e3a\uff0c\u8bf7\u53d1\u9001\u90ae\u4ef6\u81f3<a href=\"https:\/\/segmentfault.com\/a\/mailto:tech@meituan.com\">tech@meituan.com<\/a>\u7533\u8bf7\u6388\u6743\u3002<\/p>\n<p><a href=\"https:\/\/segmentfault.com\/a\/1190000043982387\">https:\/\/segmentfault.com\/a\/1190000043982387<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"<p>0 \u524d\u6587\u56de\u987e \u5728\u300aMySQL\u81ea\u6cbb\u5e73\u53f0\u5efa\u8bbe\u7684\u5185\u6838\u539f\u7406\u53ca\u5b9e\u8df5\uff08\u4e0a\uff09\u300b\u4e00\u6587\u4e2d\uff0c\u6211\u4eec\u4e3b\u8981\u4ecb\u7ecd\u4e86\u6570\u636e\u5e93\u7684\u5f02\u5e38\u53d1\u73b0\u4e0e\u8bca\u65ad\u65b9 [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":""},"categories":[4],"tags":[],"class_list":["post-10008054","post","type-post","status-publish","format-standard","hentry","category-share"],"jetpack_sharing_enabled":true,"jetpack_featured_media_url":"","_links":{"self":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008054","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=10008054"}],"version-history":[{"count":0,"href":"https:\/\/itmax.cn\/index.php?rest_route=\/wp\/v2\/posts\/10008054\/revisions"}],"wp:attachment":[{"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=10008054"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=10008054"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/itmax.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=10008054"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}