{"id":8794,"date":"2023-06-08T17:47:48","date_gmt":"2023-06-08T09:47:48","guid":{"rendered":"\/?p=8794"},"modified":"2023-06-08T17:47:48","modified_gmt":"2023-06-08T09:47:48","slug":"mysql%e9%9d%a2%e8%af%95%e7%bb%8f","status":"publish","type":"post","link":"\/?p=8794","title":{"rendered":"mysql\u9762\u8bd5\u7ecf"},"content":{"rendered":"<h3>1\u3001\u4e09\u5927\u8303\u5f0f<\/h3>\n<p>1NF(\u7b2c\u4e00\u8303\u5f0f)\uff1a\u5c5e\u6027\uff08\u5bf9\u5e94\u4e8e\u8868\u4e2d\u7684\u5b57\u6bb5\uff09\u4e0d\u80fd\u518d\u88ab\u5206\u5272\uff0c\u4e5f\u5c31\u662f\u8fd9\u4e2a\u5b57\u6bb5\u53ea\u80fd\u662f\u4e00\u4e2a\u503c\uff0c\u4e0d\u80fd\u518d\u5206\u4e3a\u591a\u4e2a\u5176\u4ed6\u7684\u5b57\u6bb5\u4e86\u3002<strong>1NF \u662f\u6240\u6709\u5173\u7cfb\u578b\u6570\u636e\u5e93\u7684\u6700\u57fa\u672c\u8981\u6c42<\/strong> \uff0c\u4e5f\u5c31\u662f\u8bf4\u5173\u7cfb\u578b\u6570\u636e\u5e93\u4e2d\u521b\u5efa\u7684\u8868\u4e00\u5b9a\u6ee1\u8db3\u7b2c\u4e00\u8303\u5f0f\u3002<\/p>\n<p>2NF(\u7b2c\u4e8c\u8303\u5f0f)\uff1a2NF \u8981\u6c42\u6570\u636e\u5e93\u8868\u4e2d\u7684\u6bcf\u4e2a\u5b9e\u4f8b\u6216\u884c\u5fc5\u987b<strong>\u53ef\u4ee5\u88ab\u60df\u4e00\u5730\u533a\u5206<\/strong>\uff0c2NF \u5728 1NF \u7684\u57fa\u7840\u4e0a\u589e\u52a0\u4e86\u4e00\u4e2a\u5217\uff0c\u8fd9\u4e2a\u5217\u79f0\u4e3a\u4e3b\u952e\uff0c\u975e\u4e3b\u5c5e\u6027\u90fd\u4f9d\u8d56\u4e8e\u4e3b\u952e\u3002<\/p>\n<p>3NF(\u7b2c\u4e09\u8303\u5f0f)\uff1a3NF \u5728 2NF \u7684\u57fa\u7840\u4e4b\u4e0a\uff0c\u8981\u6c42\u6bcf\u5217\u90fd\u548c\u4e3b\u952e\u5217\u76f4\u63a5\u76f8\u5173\uff0c\u800c\u4e0d\u662f\u95f4\u63a5\u76f8\u5173\uff0c\u5373\u4e0d\u5b58\u5728\u5176\u4ed6\u8868\u7684\u975e\u4e3b\u952e\u4fe1\u606f\u3002<\/p>\n<p>\u5728\u5f00\u53d1\u8fc7\u7a0b\u4e2d\uff0c\u5e76\u4e0d\u4e00\u5b9a\u8981\u6ee1\u8db3\u4e09\u5927\u8303\u5f0f\uff0c\u6709\u65f6\u5019\u4e3a\u4e86\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\uff0c\u53ef\u4ee5\u5728\u8868\u4e2d\u5197\u4f59\u5176\u4ed6\u8868\u7684\u5b57\u6bb5\u3002<\/p>\n<h3>2\u3001DML \u8bed\u53e5\u548c DDL \u8bed\u53e5\u533a\u522b<\/h3>\n<ul>\n<li>DML \u662f\u6570\u636e\u5e93\u64cd\u4f5c\u8bed\u8a00\uff08Data Manipulation Language\uff09\u7684\u7f29\u5199\uff0c\u662f\u6307\u5bf9\u6570\u636e\u5e93\u4e2d\u8868\u8bb0\u5f55\u7684\u64cd\u4f5c\uff0c\u4e3b\u8981\u5305\u62ec\u8868\u8bb0\u5f55\u7684\u63d2\u5165\u3001\u66f4\u65b0\u3001\u5220\u9664\u548c\u67e5\u8be2\uff0c\u662f\u5f00\u53d1\u4eba\u5458\u65e5\u5e38\u4f7f\u7528\u6700\u9891\u7e41\u7684\u64cd\u4f5c\u3002<\/li>\n<li>DDL \uff08Data Definition Language\uff09\u662f\u6570\u636e\u5b9a\u4e49\u8bed\u8a00\u7684\u7f29\u5199\uff0c\u7b80\u5355\u6765\u8bf4\uff0c\u5c31\u662f\u5bf9\u6570\u636e\u5e93\u5185\u90e8\u7684\u5bf9\u8c61\u8fdb\u884c\u521b\u5efa\u3001\u5220\u9664\u3001\u4fee\u6539\u7684\u64cd\u4f5c\u8bed\u8a00\u3002\u5b83\u548c DML \u8bed\u8a00\u7684\u6700\u5927\u533a\u522b\u662f DML \u53ea\u662f\u5bf9\u8868\u5185\u90e8\u6570\u636e\u7684\u64cd\u4f5c\uff0c\u800c\u4e0d\u6d89\u53ca\u5230\u8868\u7684\u5b9a\u4e49\u3001\u7ed3\u6784\u7684\u4fee\u6539\uff0c\u66f4\u4e0d\u4f1a\u6d89\u53ca\u5230\u5176\u4ed6\u5bf9\u8c61\u3002DDL \u8bed\u53e5\u66f4\u591a\u7684\u88ab\u6570\u636e\u5e93\u7ba1\u7406\u5458\uff08DBA\uff09\u6240\u4f7f\u7528\uff0c\u4e00\u822c\u7684\u5f00\u53d1\u4eba\u5458\u5f88\u5c11\u4f7f\u7528\u3002<\/li>\n<\/ul>\n<h3>3\u3001\u4e3b\u952e\u548c\u5916\u952e\u7684\u533a\u522b<\/h3>\n<ul>\n<li><strong>\u4e3b\u952e<\/strong>\uff1a\u7528\u4e8e\u552f\u4e00\u6807\u8bc6\u4e00\u884c\u6570\u636e\uff0c\u4e0d\u80fd\u6709\u91cd\u590d\uff0c\u4e0d\u5141\u8bb8\u4e3a\u7a7a\uff0c\u4e14\u4e00\u4e2a\u8868\u53ea\u80fd\u6709\u4e00\u4e2a\u4e3b\u952e\uff1b<\/li>\n<li><strong>\u5916\u952e<\/strong>\uff1a\u7528\u6765\u548c\u5176\u4ed6\u8868\u5efa\u7acb\u8054\u7cfb\uff0c\u5916\u952e\u662f\u53e6\u4e00\u8868\u7684\u4e3b\u952e\uff0c\u5916\u952e\u662f\u53ef\u4ee5\u6709\u91cd\u590d\u7684\uff0c\u53ef\u4ee5\u662f\u7a7a\u503c\u3002\u4e00\u4e2a\u8868\u53ef\u4ee5\u6709\u591a\u4e2a\u5916\u952e\uff1b<\/li>\n<\/ul>\n<h3>4\u3001drop\u3001delete\u3001truncate \u533a\u522b<\/h3>\n<p>\uff081\uff09\u7528\u6cd5\u4e0d\u540c<\/p>\n<ul>\n<li><code>drop<\/code>(\u4e22\u5f03\u6570\u636e): <code>drop table \u8868\u540d<\/code> \uff0c\u76f4\u63a5\u5c06\u8868\u7ed3\u6784\u90fd\u5220\u9664\u6389\uff0c\u5728\u5220\u9664\u8868\u7684\u65f6\u5019\u4f7f\u7528\u3002<\/li>\n<li><code>truncate<\/code> (\u6e05\u7a7a\u6570\u636e) : <code>truncate table \u8868\u540d<\/code> \uff0c\u53ea\u5220\u9664\u8868\u4e2d\u7684\u6570\u636e\uff0c\u518d\u63d2\u5165\u6570\u636e\u7684\u65f6\u5019\u81ea\u589e\u957f id \u53c8\u4ece 1 \u5f00\u59cb\uff0c\u5728\u6e05\u7a7a\u8868\u4e2d\u6570\u636e\u7684\u65f6\u5019\u4f7f\u7528\u3002<\/li>\n<li><code>delete<\/code>\uff08\u5220\u9664\u6570\u636e\uff09 : <code>delete from \u8868\u540d where \u5217\u540d=\u503c<\/code>\uff0c\u5220\u9664\u67d0\u4e00\u884c\u7684\u6570\u636e\uff0c\u5982\u679c\u4e0d\u52a0 <code>where<\/code> \u5b50\u53e5\u548c<code>truncate table \u8868\u540d<\/code>\u4f5c\u7528\u7c7b\u4f3c\u3002<\/li>\n<\/ul>\n<p>\uff082\uff09\u5c5e\u4e8e\u4e0d\u540c\u7684\u6570\u636e\u5e93\u8bed\u8a00<\/p>\n<ul>\n<li><code>truncate<\/code> \u548c <code>drop<\/code> \u5c5e\u4e8e DDL(\u6570\u636e\u5b9a\u4e49\u8bed\u8a00)\u8bed\u53e5\uff0c\u64cd\u4f5c\u7acb\u5373\u751f\u6548\uff0c\u539f\u6570\u636e\u4e0d\u653e\u5230 rollback segment \u4e2d\uff0c\u4e0d\u80fd\u56de\u6eda\uff0c\u64cd\u4f5c\u4e0d\u89e6\u53d1 trigger\u3002<\/li>\n<li><code>delete<\/code> \u8bed\u53e5\u662f DML (\u6570\u636e\u5e93\u64cd\u4f5c\u8bed\u8a00)\u8bed\u53e5\uff0c\u8fd9\u4e2a\u64cd\u4f5c\u4f1a\u653e\u5230 rollback segment \u4e2d\uff0c\u4e8b\u52a1\u63d0\u4ea4\u4e4b\u540e\u624d\u751f\u6548\u3002<\/li>\n<\/ul>\n<p>\uff083\uff09\u6267\u884c\u901f\u5ea6\u4e0d\u540c<\/p>\n<ul>\n<li><code>delete<\/code>\u547d\u4ee4\u6267\u884c\u7684\u65f6\u5019\u4f1a\u4ea7\u751f\u6570\u636e\u5e93\u7684<code>binlog<\/code>\u65e5\u5fd7\uff0c\u800c\u65e5\u5fd7\u8bb0\u5f55\u662f\u9700\u8981\u6d88\u8017\u65f6\u95f4\u7684\uff0c\u4f46\u662f\u4e5f\u6709\u4e2a\u597d\u5904\u65b9\u4fbf\u6570\u636e\u56de\u6eda\u6062\u590d\u3002<\/li>\n<li><code>truncate<\/code>\u547d\u4ee4\u6267\u884c\u7684\u65f6\u5019\u4e0d\u4f1a\u4ea7\u751f\u6570\u636e\u5e93\u65e5\u5fd7\uff0c\u56e0\u6b64\u6bd4<code>delete<\/code>\u8981\u5feb\u3002\u9664\u6b64\u4e4b\u5916\uff0c\u8fd8\u4f1a\u628a\u8868\u7684\u81ea\u589e\u503c\u91cd\u7f6e\u548c\u7d22\u5f15\u6062\u590d\u5230\u521d\u59cb\u5927\u5c0f\u7b49\u3002<\/li>\n<li><code>drop<\/code>\u547d\u4ee4\u4f1a\u628a\u8868\u5360\u7528\u7684\u7a7a\u95f4\u5168\u90e8\u91ca\u653e\u6389\u3002<\/li>\n<\/ul>\n<p>\u6ce8\u610f\uff1a<code>truncate<\/code>\u5728pgsql\u4e2d\u662f\u65e0\u6cd5\u5220\u9664\u81ea\u589e\u7684\uff0c\u5e8f\u5217\u8fd8\u662f\u9700\u8981\u81ea\u884c\u4fee\u6539<\/p>\n<p>\u4e00\u822c\u6765\u8bf4\uff1a<code>drop<\/code> &gt; <code>truncate<\/code> &gt; <code>delete<\/code><\/p>\n<h3>5\u3001\u57fa\u7840\u67b6\u6784<\/h3>\n<p>\u4e0b\u56fe\u662f MySQL \u7684\u4e00\u4e2a\u7b80\u8981\u67b6\u6784\u56fe\uff0c\u4ece\u4e0b\u56fe\u4f60\u53ef\u4ee5\u5f88\u6e05\u6670\u7684\u770b\u5230\u5ba2\u6237\u7aef\u7684\u4e00\u6761 SQL \u8bed\u53e5\u5728 MySQL \u5185\u90e8\u662f\u5982\u4f55\u6267\u884c\u7684\u3002<\/p>\n<p><img src=\"https:\/\/lemon-guess.oss-cn-hangzhou.aliyuncs.com\/img\/640.png\" alt=\"\u56fe\u7247\" \/>img<\/p>\n<ul>\n<li><strong>\u8fde\u63a5\u5668\uff1a<\/strong> \u8eab\u4efd\u8ba4\u8bc1\u548c\u6743\u9650\u76f8\u5173(\u767b\u5f55 MySQL \u7684\u65f6\u5019)\u3002<\/li>\n<li><strong>\u67e5\u8be2\u7f13\u5b58\uff1a<\/strong> \u6267\u884c\u67e5\u8be2\u8bed\u53e5\u7684\u65f6\u5019\uff0c\u4f1a\u5148\u67e5\u8be2\u7f13\u5b58\uff08MySQL 8.0 \u7248\u672c\u540e\u79fb\u9664\uff0c\u56e0\u4e3a\u8fd9\u4e2a\u529f\u80fd\u4e0d\u592a\u5b9e\u7528\uff09\u3002<\/li>\n<li><strong>\u5206\u6790\u5668\uff1a<\/strong> \u6ca1\u6709\u547d\u4e2d\u7f13\u5b58\u7684\u8bdd\uff0cSQL \u8bed\u53e5\u5c31\u4f1a\u7ecf\u8fc7\u5206\u6790\u5668\uff0c\u5206\u6790\u5668\u8bf4\u767d\u4e86\u5c31\u662f\u8981\u5148\u770b\u4f60\u7684 SQL \u8bed\u53e5\u8981\u5e72\u561b\uff0c\u518d\u68c0\u67e5\u4f60\u7684 SQL \u8bed\u53e5\u8bed\u6cd5\u662f\u5426\u6b63\u786e\u3002<\/li>\n<li><strong>\u4f18\u5316\u5668\uff1a<\/strong> \u6309\u7167 MySQL \u8ba4\u4e3a\u6700\u4f18\u7684\u65b9\u6848\u53bb\u6267\u884c\u3002<\/li>\n<li><strong>\u6267\u884c\u5668\uff1a<\/strong> \u6267\u884c\u8bed\u53e5\uff0c\u7136\u540e\u4ece\u5b58\u50a8\u5f15\u64ce\u8fd4\u56de\u6570\u636e\u3002\u6267\u884c\u8bed\u53e5\u4e4b\u524d\u4f1a\u5148\u5224\u65ad\u662f\u5426\u6709\u6743\u9650\uff0c\u5982\u679c\u6ca1\u6709\u6743\u9650\u7684\u8bdd\uff0c\u5c31\u4f1a\u62a5\u9519\u3002<\/li>\n<li><strong>\u63d2\u4ef6\u5f0f\u5b58\u50a8\u5f15\u64ce<\/strong>\uff1a\u4e3b\u8981\u8d1f\u8d23\u6570\u636e\u7684\u5b58\u50a8\u548c\u8bfb\u53d6\uff0c\u91c7\u7528\u7684\u662f\u63d2\u4ef6\u5f0f\u67b6\u6784\uff0c\u652f\u6301 InnoDB\u3001MyISAM\u3001Memory \u7b49\u591a\u79cd\u5b58\u50a8\u5f15\u64ce\u3002<\/li>\n<\/ul>\n<h3>6\u3001MyISAM \u548c InnoDB \u6709\u4ec0\u4e48\u533a\u522b\uff1f<\/h3>\n<p>MySQL 5.5 \u4e4b\u524d\uff0cMyISAM \u5f15\u64ce\u662f MySQL \u7684\u9ed8\u8ba4\u5b58\u50a8\u5f15\u64ce\uff0cMySQL 5.5 \u7248\u672c\u4e4b\u540e\uff0cInnoDB \u662f MySQL \u7684\u9ed8\u8ba4\u5b58\u50a8\u5f15\u64ce\u3002<\/p>\n<p><strong>\uff081\uff09\u662f\u5426\u652f\u6301\u884c\u7ea7\u9501<\/strong><\/p>\n<p>MyISAM \u53ea\u6709\u8868\u7ea7\u9501\uff0c\u800c InnoDB \u652f\u6301\u884c\u7ea7\u9501\u548c\u8868\u7ea7\u9501\uff0c\u9ed8\u8ba4\u4e3a\u884c\u7ea7\u9501\u3002<\/p>\n<p>\u5177\u4f53\u7684\u9501\u8be6\u60c5\u8bf7\u53c2\u8003\u963fQ\u7684\u6b64\u7bc7\u6587\u7ae0\uff1a<a href=\"https:\/\/mp.weixin.qq.com\/s?__biz=MzI5MDg2NjEzNA==&amp;mid=2247484201&amp;idx=1&amp;sn=57f339e7126a815fbbbfc7398090f6be&amp;scene=21#wechat_redirect\">\u9762\u8bd5\u5fc5\u5907\u5e38\u89c1\u5b58\u50a8\u5f15\u64ce\u4e0e\u9501\u7684\u5206\u7c7b\uff0c\u8bf7\u67e5\u6536<\/a><\/p>\n<p><strong>\uff082\uff09\u662f\u5426\u652f\u6301\u4e8b\u52a1<\/strong><\/p>\n<p>MyISAM \u4e0d\u63d0\u4f9b\u4e8b\u52a1\u652f\u6301\uff0cInnoDB \u63d0\u4f9b\u4e8b\u52a1\u652f\u6301\uff0c\u5b9e\u73b0\u4e86 SQL \u6807\u51c6\u5b9a\u4e49\u7684\u56db\u4e2a\u9694\u79bb\u7ea7\u522b\uff0c\u5177\u6709\u63d0\u4ea4\u548c\u56de\u6eda\u4e8b\u52a1\u7684\u80fd\u529b\u3002<\/p>\n<p>InnoDB \u9ed8\u8ba4\u4f7f\u7528\u7684 REPEATABLE-READ\uff08\u53ef\u91cd\u8bfb\uff09\u9694\u79bb\u7ea7\u522b\u662f\u53ef\u4ee5\u89e3\u51b3\u5e7b\u8bfb\u95ee\u9898\u53d1\u751f\u7684\uff08\u57fa\u4e8e MVCC \u548c Next-Key Lock\uff09\u3002<\/p>\n<p>\u5173\u4e8e MySQL \u4e8b\u52a1\u4ee5\u53ca\u89e3\u51b3\u5e7b\u8bfb\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u53ef\u4ee5\u770b\u770b\u963fQ\u5199\u7684\u8fd9\u7bc7\u6587\u7ae0\uff1a<a href=\"https:\/\/mp.weixin.qq.com\/s?__biz=MzI5MDg2NjEzNA==&amp;mid=2247484182&amp;idx=1&amp;sn=09489278900940ff1ef90cd7c0c14f98&amp;scene=21#wechat_redirect\">InnoDB \u89e3\u51b3\u5e7b\u8bfb\u7684\u65b9\u6848--LBCC&amp;MVCC<\/a><\/p>\n<p><strong>\uff083\uff09\u662f\u5426\u652f\u6301\u5916\u952e<\/strong><\/p>\n<p>MyISAM \u4e0d\u652f\u6301\uff0c\u800c InnoDB \u652f\u6301\u3002<\/p>\n<p><strong>\uff084\uff09\u662f\u5426\u652f\u6301\u6570\u636e\u5e93\u5f02\u5e38\u5d29\u6e83\u540e\u7684\u5b89\u5168\u6062\u590d<\/strong><\/p>\n<p>MyISAM \u4e0d\u652f\u6301\uff0c\u800c InnoDB \u652f\u6301\u3002\u4f7f\u7528 InnoDB \u7684\u6570\u636e\u5e93\u5728\u5f02\u5e38\u5d29\u6e83\u540e\uff0c\u6570\u636e\u5e93\u91cd\u65b0\u542f\u52a8\u7684\u65f6\u5019\u4f1a\u4fdd\u8bc1\u6570\u636e\u5e93\u6062\u590d\u5230\u5d29\u6e83\u524d\u7684\u72b6\u6001\u3002\u8fd9\u4e2a\u6062\u590d\u7684\u8fc7\u7a0b\u4f9d\u8d56\u4e8e <code>redo log<\/code> \u3002<\/p>\n<p><strong>\uff085\uff09\u662f\u5426\u652f\u6301 MVCC<\/strong><\/p>\n<p>MyISAM \u4e0d\u652f\u6301\uff0c\u800c InnoDB \u652f\u6301\u3002<\/p>\n<p><strong>\uff086\uff09\u7d22\u5f15\u5b9e\u73b0<\/strong><\/p>\n<p>\u867d\u7136 MyISAM \u5f15\u64ce\u548c InnoDB \u5f15\u64ce\u90fd\u662f\u4f7f\u7528 B+Tree \u4f5c\u4e3a\u7d22\u5f15\u7ed3\u6784\uff0c\u4f46\u662f\u4e24\u8005\u7684\u5b9e\u73b0\u65b9\u5f0f\u4e0d\u592a\u4e00\u6837\u3002<\/p>\n<ul>\n<li>InnoDB \u5f15\u64ce\u4e2d\uff0c\u5176\u6570\u636e\u6587\u4ef6\u672c\u8eab\u5c31\u662f\u7d22\u5f15\u6587\u4ef6\u3002\u5176\u8868\u6570\u636e\u6587\u4ef6\u672c\u8eab\u5c31\u662f\u6309 B+Tree \u7ec4\u7ec7\u7684\u4e00\u4e2a\u7d22\u5f15\u7ed3\u6784\uff0c\u6811\u7684\u53f6\u5b50\u8282\u70b9 data \u57df\u4fdd\u5b58\u4e86\u5b8c\u6574\u7684\u6570\u636e\u8bb0\u5f55\u3002<\/li>\n<li>MyISAM \u7d22\u5f15\u6587\u4ef6\u548c\u6570\u636e\u6587\u4ef6\u662f\u5206\u79bb\u7684\uff0c\u7d22\u5f15\u4fdd\u5b58\u7684\u662f\u6570\u636e\u6587\u4ef6\u7684\u6307\u9488\u3002<\/li>\n<\/ul>\n<p><strong>\uff087\uff09\u6027\u80fd\u5dee\u522b<\/strong><\/p>\n<p>InnoDB \u7684\u6027\u80fd\u6bd4 MyISAM \u66f4\u5f3a\u5927\uff0c\u4e0d\u7ba1\u662f\u5728\u8bfb\u5199\u6df7\u5408\u6a21\u5f0f\u4e0b\u8fd8\u662f\u53ea\u8bfb\u6a21\u5f0f\u4e0b\uff0c\u968f\u7740 CPU \u6838\u6570\u7684\u589e\u52a0\uff0cInnoDB \u7684\u8bfb\u5199\u80fd\u529b\u5448\u7ebf\u6027\u589e\u957f\u3002MyISAM \u56e0\u4e3a\u8bfb\u5199\u4e0d\u80fd\u5e76\u53d1\uff0c\u5b83\u7684\u5904\u7406\u80fd\u529b\u8ddf\u6838\u6570\u6ca1\u5173\u7cfb\u3002<\/p>\n<p><img src=\"mysql%E9%9D%A2%E8%AF%95.assets\/640-1686215019035-1.png\" alt=\"\u56fe\u7247\" \/>InnoDB \u548c MyISAM \u6027\u80fd\u5bf9\u6bd4<\/p>\n<h3>7\u3001\u63a8\u8350\u81ea\u589eid\u4f5c\u4e3a\u4e3b\u952e\u95ee\u9898<\/h3>\n<ul>\n<li>\u666e\u901a\u7d22\u5f15\u7684 B+ \u6811\u4e0a\u5b58\u653e\u7684\u662f\u4e3b\u952e\u7d22\u5f15\u7684\u503c\uff0c\u5982\u679c\u8be5\u503c\u8f83\u5927\uff0c\u4f1a<strong>\u300c\u5bfc\u81f4\u666e\u901a\u7d22\u5f15\u7684\u5b58\u50a8\u7a7a\u95f4\u8f83\u5927\u300d<\/strong><\/li>\n<li>\u4f7f\u7528\u81ea\u589e id \u505a\u4e3b\u952e\u7d22\u5f15\u65b0\u63d2\u5165\u6570\u636e\u53ea\u8981\u653e\u5728\u8be5\u9875\u7684\u6700\u5c3e\u7aef\u5c31\u53ef\u4ee5\uff0c\u76f4\u63a5<strong>\u300c\u6309\u7167\u987a\u5e8f\u63d2\u5165\u300d<\/strong>\uff0c\u4e0d\u7528\u523b\u610f\u7ef4\u62a4<\/li>\n<li>\u9875\u5206\u88c2\u5bb9\u6613\u7ef4\u62a4\uff0c\u5f53\u63d2\u5165\u6570\u636e\u7684\u5f53\u524d\u9875\u5feb\u6ee1\u65f6\uff0c\u4f1a\u53d1\u751f\u9875\u5206\u88c2\u7684\u73b0\u8c61\uff0c\u5982\u679c\u4e3b\u952e\u7d22\u5f15\u4e0d\u4e3a\u81ea\u589e id\uff0c\u90a3\u4e48\u6570\u636e\u5c31\u53ef\u80fd\u4ece\u9875\u7684\u4e2d\u95f4\u63d2\u5165\uff0c\u9875\u7684\u6570\u636e\u4f1a\u9891\u7e41\u7684\u53d8\u52a8\uff0c<strong>\u300c\u5bfc\u81f4\u9875\u5206\u88c2\u7ef4\u62a4\u6210\u672c\u8f83\u9ad8\u300d<\/strong><\/li>\n<\/ul>\n<h3>8\u3001\u4e3a\u4ec0\u4e48 MySQL \u7684\u81ea\u589e\u4e3b\u952e\u4e0d\u8fde\u7eed<\/h3>\n<ul>\n<li>\u5728MySQL 5.7\u53ca\u4e4b\u524d\u7684\u7248\u672c\uff0c\u81ea\u589e\u503c\u4fdd\u5b58\u5728\u5185\u5b58\u91cc\uff0c\u5e76\u6ca1\u6709\u6301\u4e45\u5316\uff1b<\/li>\n<li>\u552f\u4e00\u952e\u51b2\u7a81\uff1a\u63d2\u5165\u6570\u636e\u65f6\u5148\u5c06\u81ea\u589e\u4e3b\u952e+1\uff0c\u7136\u540e\u63d2\u5165\u6570\u636e\u65f6\u552f\u4e00\u952e\u51b2\u7a81\uff0c\u63d2\u5165\u6570\u636e\u5931\u8d25\uff0c\u4f46\u662f\u672a\u5c06\u81ea\u589e\u4e3b\u952e\u6539\u56de\uff1b<\/li>\n<li>\u4e8b\u52a1\u56de\u6eda\uff1a\u548c\u552f\u4e00\u952e\u51b2\u7a81\u7c7b\u4f3c\uff0c\u56de\u6eda\u64cd\u4f5c\u65f6\u81ea\u589e\u503c\u4e5f\u4e0d\u56de\u9000\uff0c\u4e8b\u5b9e\u4e0a\uff0c\u8fd9\u4e48\u505a\u7684\u4e3b\u8981\u539f\u56e0\u662f\u4e3a\u4e86\u63d0\u9ad8\u6027\u80fd\u3002<\/li>\n<\/ul>\n<p><strong>\u603b\u7ed3\uff1a<\/strong>mysql\u548cpgsql\u90fd\u5b58\u5728\u81ea\u589e\u4e3b\u952e\u4e0d\u8fde\u7eed\u7684\u60c5\u51b5\uff0c\u6211\u5b9e\u6d4b\u7684\u662f\uff0c\u5728\u8bbe\u7f6eunique\u552f\u4e00\u952e\uff0c\u62a5\u9519<code>ERROR: duplicate key value ...<\/code>\u9519\u8bef\u540e\uff0c\u518d\u6210\u529f\u63d2\u5165\uff0c\u8fd9\u4e2a\u81ea\u589eid\u5c31\u4f1a\u88ab\u8df3\u8fc7\u3002\u5f53\u7136\uff0c\u5220\u9664\u4e86\uff0c\u518d\u589e\u52a0\uff0c\u540e\u7eed\u6570\u636e\u7684\u4e3b\u952eid\u4e5f\u56de\u4e0d\u6765\u4e86\u3002<\/p>\n<p>\u4e3a\u907f\u514dMySQL \u7684\u81ea\u589e\u4e3b\u952e\u4e0d\u8fde\u7eed\uff0c\u53ef\u4ee5\u91c7\u53d6\u4ee5\u4e0b\u63aa\u65bd\uff1a<\/p>\n<ol>\n<li>\n<p>\u907f\u514d\u4f7f\u7528DELETE\u8bed\u53e5\u5220\u9664\u884c\uff0c\u800c\u662f\u4f7f\u7528UPDATE\u8bed\u53e5\u5c06\u884c\u6807\u8bb0\u4e3a\u5220\u9664\u72b6\u6001\u3002\u8fd9\u6837\uff0c\u81ea\u589e\u4e3b\u952e\u5c06\u4fdd\u6301\u8fde\u7eed\uff0c\u4f46\u662f\u9700\u8981\u5728\u67e5\u8be2\u65f6\u8fc7\u6ee4\u6389\u6807\u8bb0\u4e3a\u5220\u9664\u7684\u884c\u3002<\/p>\n<\/li>\n<li>\n<p>\u4f7f\u7528\u4e8b\u52a1\u6765\u786e\u4fdd\u63d2\u5165\u65b0\u884c\u65f6\u4e0d\u4f1a\u53d1\u751f\u56de\u6eda\u3002\u5982\u679c\u53d1\u751f\u56de\u6eda\uff0c\u53ef\u4ee5\u901a\u8fc7\u91cd\u65b0\u63d2\u5165\u884c\u6765\u4fdd\u6301\u81ea\u589e\u4e3b\u952e\u7684\u8fde\u7eed\u6027\u3002<\/p>\n<\/li>\n<li>\n<p>\u907f\u514d\u5728\u63d2\u5165\u65b0\u884c\u65f6\u624b\u52a8\u6307\u5b9a\u4e3b\u952e\u503c\uff0c\u800c\u662f\u8ba9MySQL\u81ea\u52a8\u751f\u6210\u4e3b\u952e\u503c\u3002\u8fd9\u6837\u53ef\u4ee5\u786e\u4fdd\u81ea\u589e\u4e3b\u952e\u7684\u8fde\u7eed\u6027\u3002<\/p>\n<\/li>\n<li>\n<p>\u5728\u8bbe\u8ba1\u8868\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528UUID\u6216\u5176\u4ed6\u552f\u4e00\u6807\u8bc6\u7b26\u4f5c\u4e3a\u4e3b\u952e\uff0c\u800c\u4e0d\u662f\u4f7f\u7528\u81ea\u589e\u4e3b\u952e\u3002\u8fd9\u6837\u53ef\u4ee5\u907f\u514d\u81ea\u589e\u4e3b\u952e\u4e0d\u8fde\u7eed\u7684\u95ee\u9898\uff0c\u4f46\u662f\u53ef\u80fd\u4f1a\u5f71\u54cd\u6027\u80fd\u3002<\/p>\n<\/li>\n<\/ol>\n<p><strong>\u603b\u7ed3\uff1a<\/strong>\u7b2c\u4e00\u4e2a\u65b9\u6cd5\u597d\uff0c\u5c31\u662f\u6709\u70b9\u6d6a\u8d39\u5b58\u50a8\u7a7a\u95f4\uff1b\u7b2c\u4e8c\u4e2a\u65b9\u6cd5\u4e5f\u53ea\u662f\u591atry;\u7b2c\u56db\u4e2a\u6709\u5f85\u5546\u69b7<\/p>\n<pre><code class=\"language-python\">import pymysql\n\ndef insert_user(username):\n    # \u8fde\u63a5MySQL\u6570\u636e\u5e93\n    conn = pymysql.connect(host=&#039;localhost&#039;, port=3306, user=&#039;root&#039;, password=&#039;123456&#039;, db=&#039;test&#039;)\n    cursor = conn.cursor()\n\n    try:\n        # \u5f00\u59cb\u4e8b\u52a1\n        conn.begin()\n\n        # \u63d2\u5165\u65b0\u884c\n        sql = &quot;INSERT INTO user (username) VALUES (%s)&quot;\n        cursor.execute(sql, (username,))\n        conn.commit()\n\n        # \u7ed3\u675f\u4e8b\u52a1\n        conn.close()\n\n    except Exception as e:\n        # \u53d1\u751f\u56de\u6eda\uff0c\u91cd\u65b0\u63d2\u5165\u884c\n        conn.rollback()\n        cursor.execute(sql, (username,))\n        conn.commit()\n\n        # \u7ed3\u675f\u4e8b\u52a1\n        conn.close()<\/code><\/pre>\n<h3>9\u3001redo log \u662f\u505a\u4ec0\u4e48\u7684?<\/h3>\n<p><code>redo log<\/code>\uff08\u91cd\u505a\u65e5\u5fd7\uff09\u662f<code>InnoDB<\/code>\u5b58\u50a8\u5f15\u64ce\u72ec\u6709\u7684\uff0c\u5b83\u8ba9<code>MySQL<\/code>\u62e5\u6709\u4e86\u5d29\u6e83\u6062\u590d\u80fd\u529b\u3002<\/p>\n<p>\u6bd4\u5982 <code>MySQL<\/code> \u5b9e\u4f8b\u6302\u4e86\u6216\u5b95\u673a\u4e86\uff0c\u91cd\u542f\u65f6\uff0c<code>InnoDB<\/code>\u5b58\u50a8\u5f15\u64ce\u4f1a\u4f7f\u7528<code>redo log<\/code>\u6062\u590d\u6570\u636e\uff0c\u4fdd\u8bc1\u6570\u636e\u7684\u6301\u4e45\u6027\u4e0e\u5b8c\u6574\u6027\u3002<\/p>\n<p>\u66f4\u65b0\u8868\u6570\u636e\u7684\u65f6\u5019\uff0c\u5982\u679c\u53d1\u73b0 <code>Buffer Pool<\/code> \u91cc\u5b58\u5728\u8981\u66f4\u65b0\u7684\u6570\u636e\uff0c\u5c31\u76f4\u63a5\u5728 <code>Buffer Pool<\/code> \u91cc\u66f4\u65b0\u3002\u7136\u540e\u4f1a\u628a\u201c\u5728\u67d0\u4e2a\u6570\u636e\u9875\u4e0a\u505a\u4e86\u4ec0\u4e48\u4fee\u6539\u201d\u8bb0\u5f55\u5230\u91cd\u505a\u65e5\u5fd7\u7f13\u5b58\uff08<code>redo log buffer<\/code>\uff09\u91cc\uff0c\u63a5\u7740\u5237\u76d8\u5230 <code>redo log<\/code> \u6587\u4ef6\u91cc\u3002<\/p>\n<h3>10\u3001redo log \u7684\u5237\u76d8\u65f6\u673a<\/h3>\n<p><img src=\"https:\/\/lemon-guess.oss-cn-hangzhou.aliyuncs.com\/img\/640-1686215019036-2.png\" alt=\"\u56fe\u7247\" \/><\/p>\n<ul>\n<li>\u7ea2\u8272\u90e8\u5206\u4e3a redo log buffer \u5c5e\u4e8e\u5185\u5b58<\/li>\n<li>\u9ec4\u8272\u90e8\u5206\u4e3a page cache \uff0c\u6b64\u65f6\u5df2\u7ecf\u5199\u5165\u78c1\u76d8\u4e86\uff0c\u4f46\u662f\u672a\u8fdb\u884c\u6301\u4e45\u5316<\/li>\n<li>\u7eff\u8272\u90e8\u5206\u662f\u786c\u76d8\uff0c\u5df2\u7ecf\u5b8c\u6210\u6301\u4e45\u5316<\/li>\n<\/ul>\n<p>InnoDB \u5b58\u50a8\u5f15\u64ce\u4e3a redo log \u7684\u5237\u76d8\u7b56\u7565\u63d0\u4f9b\u4e86 innodb_flush_log_at_trx_commit \u53c2\u6570\uff0c\u5b83\u652f\u6301<strong>\u4e09\u79cd\u7b56\u7565<\/strong><\/p>\n<ul>\n<li>\u8bbe\u7f6e\u4e3a0\u7684\u65f6\u5019\uff0c\u8868\u793a\u6bcf\u6b21\u4e8b\u52a1\u63d0\u4ea4\u65f6<strong>\u4e0d\u8fdb\u884c\u5237\u76d8<\/strong>\u64cd\u4f5c\uff0c\u53ea\u662f\u4fdd\u7559\u5728 redo log buffer\u4e2d\uff0cmysql \u5d29\u6e83\u4f1a\u4e22\u59311s\u7684\u6570\u636e\uff1b<\/li>\n<li>\u8bbe\u7f6e\u4e3a1\u7684\u65f6\u5019\uff0c\u8868\u793a\u6bcf\u6b21\u4e8b\u52a1\u63d0\u4ea4\u65f6<strong>\u90fd\u5c06\u8fdb\u884c<\/strong>\u5237\u76d8\u64cd\u4f5c\uff08\u9ed8\u8ba4\u503c\uff09\uff0c\u6301\u4e45\u5316\u5230\u78c1\u76d8\uff1b<\/li>\n<li>\u8bbe\u7f6e\u4e3a2\u7684\u65f6\u5019\uff0c\u8868\u793a\u6bcf\u6b21\u4e8b\u52a1\u63d0\u4ea4\u65f6\u90fd\u53ea\u628aredo log buffer\u5185\u5bb9\u5199\u5165<strong>page cache<\/strong>\uff0cOS\u5b95\u673a\u4f1a\u4e22\u59311s\u7684\u6570\u636e\uff0c\u56e0\u4e3a\u672a\u8fdb\u884c\u6301\u4e45\u5316\uff1b<\/li>\n<\/ul>\n<p>innodb_flush_log_at_trx_commit \u53c2\u6570\u9ed8\u8ba4\u4e3a 1 \uff0c\u4e5f\u5c31\u662f\u8bf4\u5f53\u4e8b\u52a1\u63d0\u4ea4\u65f6\u4f1a\u8c03\u7528 fsync(\u540c\u6b65\u64cd\u4f5c) \u5bf9 redo log \u8fdb\u884c\u5237\u76d8\u3002<\/p>\n<p>\u53e6\u5916 InnoDB \u5b58\u50a8\u5f15\u64ce\u6709\u4e00\u4e2a\u540e\u53f0<strong>\u7ebf\u7a0b<\/strong>\uff0c\u6bcf\u96941\u79d2\uff0c\u5c31\u4f1a\u628a redo log buffer \u4e2d\u7684\u5185\u5bb9\u5199\u5230\u6587\u4ef6\u7cfb\u7edf\u7f13\u5b58\uff08page cache\uff09\uff0c\u7136\u540e\u8c03\u7528 fsync \u5237\u76d8\u3002<\/p>\n<p>redo log buffer\u5360\u7528\u7684\u7a7a\u95f4\u5373\u5c06\u8fbe\u5230 innodb_log_buffer_size \u4e00\u534a\u7684\u65f6\u5019\uff0c\u540e\u53f0\u7ebf\u7a0b\u4f1a\u4e3b\u52a8\u5237\u76d8\u3002<\/p>\n<h3>11\u3001redo log \u662f\u600e\u4e48\u8bb0\u5f55\u65e5\u5fd7\u7684<\/h3>\n<p>\u786c\u76d8\u4e0a\u5b58\u50a8\u7684 <code>redo log<\/code> \u65e5\u5fd7\u6587\u4ef6\u4e0d\u53ea\u4e00\u4e2a\uff0c\u800c\u662f\u4ee5\u4e00\u4e2a<strong>\u65e5\u5fd7\u6587\u4ef6\u7ec4<\/strong>\u7684\u5f62\u5f0f\u51fa\u73b0\u7684\uff0c\u6bcf\u4e2a\u7684<code>redo<\/code>\u65e5\u5fd7\u6587\u4ef6\u5927\u5c0f\u90fd\u662f\u4e00\u6837\u7684\u3002<\/p>\n<p>\u6bd4\u5982\u53ef\u4ee5\u914d\u7f6e\u4e3a\u4e00\u7ec4<code>4<\/code>\u4e2a\u6587\u4ef6\uff0c\u6bcf\u4e2a\u6587\u4ef6\u7684\u5927\u5c0f\u662f <code>1GB<\/code>\uff0c\u6574\u4e2a <code>redo log<\/code> \u65e5\u5fd7\u6587\u4ef6\u7ec4\u53ef\u4ee5\u8bb0\u5f55<code>4G<\/code>\u7684\u5185\u5bb9\u3002<\/p>\n<p>\u5b83\u91c7\u7528\u7684\u662f\u73af\u5f62\u6570\u7ec4\u5f62\u5f0f\uff0c\u4ece\u5934\u5f00\u59cb\u5199\uff0c\u5199\u5230\u672b\u5c3e\u53c8\u56de\u5230\u5934\u5faa\u73af\u5199\uff0c\u5982\u4e0b\u56fe\u6240\u793a\u3002<\/p>\n<p><img src=\"https:\/\/lemon-guess.oss-cn-hangzhou.aliyuncs.com\/img\/640-1686215019036-3.png\" alt=\"\u56fe\u7247\" \/><\/p>\n<p>\u6240\u4ee5\uff0c\u5982\u679c\u6570\u636e\u5199\u6ee1\u4e86\u4f46\u662f\u8fd8\u6ca1\u6709\u6765\u5f97\u53ca\u5c06\u6570\u636e\u771f\u6b63\u7684\u5237\u5165\u78c1\u76d8\u5f53\u4e2d\uff0c\u90a3\u4e48\u5c31\u4f1a\u53d1\u751f<strong>\u300c\u5185\u5b58\u6296\u52a8\u300d<\/strong>\u73b0\u8c61\uff0c\u4ece\u8089\u773c\u7684\u89d2\u5ea6\u6765\u89c2\u5bdf\u4f1a\u53d1\u73b0 mysql \u4f1a\u5b95\u673a\u4e00\u4f1a\u513f\uff0c\u6b64\u65f6\u5c31\u662f\u6b63\u5728\u5237\u76d8\u4e86\u3002<\/p>\n<h3>12\u3001\u4ec0\u4e48\u662f binlog<\/h3>\n<p>binlog \u662f\u5f52\u6863\u65e5\u5fd7\uff0c\u5c5e\u4e8e Server \u5c42\u7684\u65e5\u5fd7\uff0c\u662f\u4e00\u4e2a\u4e8c\u8fdb\u5236\u683c\u5f0f\u7684\u6587\u4ef6\uff0c\u8bb0\u5f55\u5185\u5bb9\u662f\u8bed\u53e5\u7684\u539f\u59cb\u903b\u8f91\uff0c\u7c7b\u4f3c\u4e8e\u201c\u7ed9 ID=2 \u8fd9\u4e00\u884c\u7684 c \u5b57\u6bb5\u52a0 1\u201d\u3002<\/p>\n<p>\u4e0d\u7ba1\u7528\u4ec0\u4e48\u5b58\u50a8\u5f15\u64ce\uff0c\u53ea\u8981\u53d1\u751f\u4e86\u8868\u6570\u636e\u66f4\u65b0\uff0c\u90fd\u4f1a\u4ea7\u751f <code>binlog<\/code> \u65e5\u5fd7\u3002\u5b83\u7684\u4e3b\u8981\u4f5c\u7528\u5c31\u662f\u6570\u636e\u5907\u4efd\u3001\u4e3b\u4ece\u590d\u5236\u3002<\/p>\n<p><code>binlog<\/code>\u4f1a\u8bb0\u5f55\u6240\u6709\u6d89\u53ca\u66f4\u65b0\u6570\u636e\u7684\u903b\u8f91\u64cd\u4f5c\uff0c\u5c5e\u4e8e\u903b\u8f91\u65e5\u5fd7\uff0c\u5e76\u4e14\u662f\u987a\u5e8f\u5199\u3002<\/p>\n<h3>13\u3001binlog \u8bb0\u5f55\u683c\u5f0f<\/h3>\n<p><code>binlog<\/code> \u65e5\u5fd7\u6709\u4e09\u79cd\u683c\u5f0f\uff0c\u53ef\u4ee5\u901a\u8fc7<code>binlog_format<\/code>\u53c2\u6570\u6307\u5b9a\u3002<\/p>\n<ul>\n<li><strong>statement<\/strong> \uff1a\u8bb0\u5f55\u7684\u5185\u5bb9\u662f<code>SQL<\/code>\u8bed\u53e5\u539f\u6587\uff0c\u5b58\u5728\u6570\u636e\u4e00\u81f4\u6027\u95ee\u9898\uff1b<\/li>\n<li><strong>row<\/strong>\uff1a\u8bb0\u5f55\u5305\u542b\u64cd\u4f5c\u7684\u5177\u4f53\u6570\u636e\uff0c\u80fd\u4fdd\u8bc1\u540c\u6b65\u6570\u636e\u7684\u4e00\u81f4\u6027\uff1b<\/li>\n<li><strong>mixed<\/strong>\uff1a\u8bb0\u5f55\u7684\u5185\u5bb9\u662f\u524d\u4e24\u8005\u7684\u6df7\u5408\uff0c<code>MySQL<\/code>\u4f1a\u5224\u65ad\u8fd9\u6761<code>SQL<\/code>\u8bed\u53e5\u662f\u5426\u53ef\u80fd\u5f15\u8d77\u6570\u636e\u4e0d\u4e00\u81f4\uff1a\u5982\u679c\u662f\uff0c\u5c31\u7528<code>row<\/code>\u683c\u5f0f\uff0c\u5426\u5219\u5c31\u7528<code>statement<\/code>\u683c\u5f0f\u3002<\/li>\n<\/ul>\n<h3>14\u3001binlog \u5199\u5165\u673a\u5236<\/h3>\n<p>\u4e8b\u52a1\u6267\u884c\u8fc7\u7a0b\u4e2d\uff0c\u5148\u628a\u65e5\u5fd7\u5199\u5230<code>binlog cache<\/code>\uff0c\u4e8b\u52a1\u63d0\u4ea4\u7684\u65f6\u5019\uff0c\u518d\u628a<code>binlog cache<\/code>\u5199\u5230<code>binlog<\/code>\u6587\u4ef6\u4e2d\u3002<\/p>\n<p>\u56e0\u4e3a\u4e00\u4e2a\u4e8b\u52a1\u7684<code>binlog<\/code>\u4e0d\u80fd\u88ab\u62c6\u5f00\uff0c\u65e0\u8bba\u8fd9\u4e2a\u4e8b\u52a1\u591a\u5927\uff0c\u4e5f\u8981\u786e\u4fdd\u4e00\u6b21\u6027\u5199\u5165\uff0c\u6240\u4ee5\u7cfb\u7edf\u4f1a\u7ed9\u6bcf\u4e2a\u7ebf\u7a0b\u5206\u914d\u4e00\u4e2a\u5757\u5185\u5b58\u4f5c\u4e3a<code>binlog cache<\/code>\u3002<\/p>\n<p>\u6211\u4eec\u53ef\u4ee5\u901a\u8fc7<code>binlog_cache_size<\/code>\u53c2\u6570\u63a7\u5236\u5355\u4e2a\u7ebf\u7a0b binlog cache \u5927\u5c0f\uff0c\u5982\u679c\u5b58\u50a8\u5185\u5bb9\u8d85\u8fc7\u4e86\u8fd9\u4e2a\u53c2\u6570\uff0c\u5c31\u8981\u6682\u5b58\u5230\u78c1\u76d8\uff08<code>Swap<\/code>\uff09\u3002<\/p>\n<p>binlog \u4e5f\u63d0\u4f9b\u4e86 sync_binlog \u53c2\u6570\u6765\u63a7\u5236\u5199\u5165 page cache \u548c\u78c1\u76d8\u7684\u65f6\u673a\uff1a<\/p>\n<ul>\n<li>0\uff1a\u6bcf\u6b21\u63d0\u4ea4\u4e8b\u52a1\u90fd\u53ea\u5199\u5165\u5230\u6587\u4ef6\u7cfb\u7edf\u7684 page cache\uff0c\u7531\u7cfb\u7edf\u81ea\u884c\u5224\u65ad\u4ec0\u4e48\u65f6\u5019\u6267\u884c<code>fsync<\/code>\uff0c\u673a\u5668\u5b95\u673a\uff0c<code>page cache<\/code>\u91cc\u9762\u7684 binlog \u4f1a\u4e22\u5931\u3002<\/li>\n<li>1\uff1a\u6bcf\u6b21\u63d0\u4ea4\u4e8b\u52a1\u90fd\u4f1a\u6267\u884c<code>fsync<\/code>\uff0c\u5c31\u5982\u540c <strong>redo log \u65e5\u5fd7\u5237\u76d8\u6d41\u7a0b<\/strong> \u4e00\u6837\u3002<\/li>\n<li>N(N&gt;1)\uff1a\u6bcf\u6b21\u63d0\u4ea4\u4e8b\u52a1\u90fd\u5199\u5165\u5230\u6587\u4ef6\u7cfb\u7edf\u7684 page cache\uff0c\u4f46\u7d2f\u79ef<code>N<\/code>\u4e2a\u4e8b\u52a1\u540e\u624d<code>fsync<\/code>\u3002\u5982\u679c\u673a\u5668\u5b95\u673a\uff0c\u4f1a\u4e22\u5931\u6700\u8fd1<code>N<\/code>\u4e2a\u4e8b\u52a1\u7684<code>binlog<\/code>\u65e5\u5fd7\u3002<\/li>\n<\/ul>\n<h3>15\u3001redolog \u548c binlog \u7684\u533a\u522b\u662f\u4ec0\u4e48<\/h3>\n<ul>\n<li><strong>redolog<\/strong> \u662f <strong>Innodb<\/strong> \u72ec\u6709\u7684\u65e5\u5fd7\uff0c\u800c <strong>binlog<\/strong> \u662f <strong>server<\/strong> \u5c42\u7684\uff0c\u6240\u6709\u7684\u5b58\u50a8\u5f15\u64ce\u90fd\u6709\u4f7f\u7528\u5230\uff1b<\/li>\n<li><strong>redolog<\/strong> \u8bb0\u5f55\u4e86<strong>\u5177\u4f53\u7684\u6570\u503c<\/strong>\uff0c\u5bf9\u67d0\u4e2a\u9875\u505a\u4e86\u4ec0\u4e48\u4fee\u6539\uff0c<strong>binlog<\/strong> \u8bb0\u5f55\u7684<strong>\u64cd\u4f5c\u5185\u5bb9<\/strong>\uff1b<\/li>\n<li><strong>binlog<\/strong> \u5927\u5c0f\u8fbe\u5230\u4e0a\u9650\u6216\u8005 flush log <strong>\u4f1a\u751f\u6210\u4e00\u4e2a\u65b0\u7684\u6587\u4ef6<\/strong>\uff0c\u800c <strong>redolog<\/strong> \u6709\u56fa\u5b9a\u5927\u5c0f<strong>\u53ea\u80fd\u5faa\u73af\u5229\u7528<\/strong>\uff1b<\/li>\n<li><strong>binlog \u65e5\u5fd7\u6ca1\u6709 crash-safe \u7684\u80fd\u529b<\/strong>\uff0c\u53ea\u80fd\u7528\u4e8e\u5f52\u6863\uff0c\u800c redo log \u6709 crash-safe \u80fd\u529b\uff1b<\/li>\n<li><strong>redo log<\/strong> \u5728\u4e8b\u52a1\u6267\u884c\u8fc7\u7a0b\u4e2d\u53ef\u4ee5\u4e0d\u65ad\u5199\u5165\uff08\u5237\u76d8\u8bbe\u7f6e\u4e3a1\uff0c\u540e\u53f0\u7ebf\u7a0b1s\u6267\u884c\u4e00\u6b21\u6216\u8005 redo log buffer \u5360\u7528\u7684\u7a7a\u95f4\u5373\u5c06\u8fbe\u5230 innodb_log_buffer_size \u4e00\u534a\u7684\u65f6\u5019\uff09\uff0c\u800c binlog \u53ea\u6709\u5728\u63d0\u4ea4\u4e8b\u52a1\u65f6\u624d\u5199\u5165\u6587\u4ef6\u7f13\u5b58\u7cfb\u7edf\uff1b<\/li>\n<\/ul>\n<h3>16\u3001\u4e24\u9636\u6bb5\u63d0\u4ea4<\/h3>\n<p>\u5047\u8bbe\u6267\u884c sql \u8fc7\u7a0b\u4e2d\u5199\u5b8c redo log \u65e5\u5fd7\u540e\uff0cbinlog \u65e5\u5fd7\u5199\u671f\u95f4\u53d1\u751f\u4e86\u5f02\u5e38\uff0c\u4f1a\u51fa\u73b0\u4ec0\u4e48\u60c5\u51b5\u5462\uff1f<\/p>\n<p>\u7531\u4e8e binlog \u6ca1\u5199\u5b8c\u5c31\u5f02\u5e38\uff0c\u8fd9\u65f6\u5019 binlog \u91cc\u9762\u6ca1\u6709\u5bf9\u5e94\u7684\u4fee\u6539\u8bb0\u5f55\u3002\u56e0\u6b64\uff0c\u4e4b\u540e\u7528 binlog \u65e5\u5fd7\u6062\u590d\u6570\u636e\u65f6\uff0c\u5c31\u4f1a\u5c11\u8fd9\u4e00\u6b21\u66f4\u65b0\uff0c<strong>\u6700\u7ec8\u6570\u636e\u4e0d\u4e00\u81f4<\/strong>\u3002<\/p>\n<p>\u4e3a\u4e86\u89e3\u51b3\u4e24\u4efd\u65e5\u5fd7\u4e4b\u95f4\u7684\u903b\u8f91\u4e00\u81f4\u95ee\u9898\uff0cInnoDB \u5b58\u50a8\u5f15\u64ce\u4f7f\u7528<strong>\u4e24\u9636\u6bb5\u63d0\u4ea4<\/strong>\u65b9\u6848\u3002<\/p>\n<p>\u5c06 redo log \u7684\u5199\u5165\u62c6\u6210\u4e86\u4e24\u4e2a\u6b65\u9aa4 prepare \u548c commit\uff0c\u8fd9\u5c31\u662f\u4e24\u9636\u6bb5\u63d0\u4ea4\u3002\u4f7f\u7528\u4e24\u9636\u6bb5\u63d0\u4ea4\u540e\uff0c\u5199\u5165 binlog \u65f6\u53d1\u751f\u5f02\u5e38\u4e5f\u4e0d\u4f1a\u6709\u5f71\u54cd\uff0c\u56e0\u4e3a MySQL \u6839\u636e redo log\u65e5\u5fd7\u6062\u590d\u6570\u636e\u65f6\uff0c\u53d1\u73b0 redo log \u8fd8\u5904\u4e8e prepare \u9636\u6bb5\uff0c\u5e76\u4e14\u6ca1\u6709\u5bf9\u5e94 binlog \u65e5\u5fd7\uff0c\u5c31\u4f1a\u56de\u6eda\u8be5\u4e8b\u52a1\u3002<\/p>\n<p>\u518d\u770b\u4e00\u4e2a\u573a\u666f\uff0credo log \u8bbe\u7f6e commit \u9636\u6bb5\u53d1\u751f\u5f02\u5e38\uff0c\u90a3\u4f1a\u4e0d\u4f1a\u56de\u6eda\u4e8b\u52a1\u5462\uff1f<\/p>\n<p>\u5e76\u4e0d\u4f1a\u56de\u6eda\u4e8b\u52a1\uff0c\u867d\u7136 redo log \u662f\u5904\u4e8e prepare \u9636\u6bb5\uff0c\u4f46\u662f\u80fd\u901a\u8fc7\u4e8b\u52a1id\u627e\u5230\u5bf9\u5e94\u7684 binlog \u65e5\u5fd7\uff0c\u6240\u4ee5 MySQL \u8ba4\u4e3a\u662f\u5b8c\u6574\u7684\uff0c\u5c31\u4f1a\u63d0\u4ea4\u4e8b\u52a1\u6062\u590d\u6570\u636e\u3002<\/p>\n<h3>17\u3001\u4ec0\u4e48\u662f undo log.<\/h3>\n<p>\u6211\u4eec\u77e5\u9053\u5982\u679c\u60f3\u8981<strong>\u4fdd\u8bc1\u4e8b\u52a1\u7684\u539f\u5b50\u6027<\/strong>\uff0c\u5c31\u9700\u8981\u5728\u5f02\u5e38\u53d1\u751f\u65f6\uff0c\u5bf9\u5df2\u7ecf\u6267\u884c\u7684\u64cd\u4f5c\uff08INSERT\u3001DELETE\u3001UPDATE\uff09\u8fdb\u884c\u56de\u6eda\uff0c\u5728 MySQL \u4e2d\uff0c\u6062\u590d\u673a\u5236\u662f\u901a\u8fc7\u56de\u6eda\u65e5\u5fd7\uff08undo log\uff09 \u5b9e\u73b0\u7684\uff0c\u6240\u6709\u4e8b\u52a1\u8fdb\u884c\u7684\u4fee\u6539\u90fd\u4f1a\u5148\u8bb0\u5f55\u5230\u8fd9\u4e2a\u56de\u6eda\u65e5\u5fd7\u4e2d\uff0c\u7136\u540e\u518d\u6267\u884c\u76f8\u5173\u7684\u64cd\u4f5c\u3002<\/p>\n<p>\u6bcf\u6b21\u5bf9\u8bb0\u5f55\u8fdb\u884c\u6539\u52a8\u90fd\u4f1a\u8bb0\u5f55\u4e00\u6761 undo log\uff0c\u6bcf\u6761 undo log \u4e5f\u90fd\u6709\u4e00\u4e2a<code>DB_ROLL_PTR<\/code>\u5c5e\u6027\uff0c\u53ef\u4ee5\u5c06\u8fd9\u4e9b undo log \u90fd\u8fde\u8d77\u6765\uff0c\u4e32\u6210\u4e00\u4e2a\u94fe\u8868\uff0c\u5f62\u6210\u7248\u672c\u94fe\u3002<\/p>\n<p>\u7248\u672c\u94fe\u7684\u5934\u8282\u70b9\u5c31\u662f\u5f53\u524d\u8bb0\u5f55\u6700\u65b0\u7684\u503c\u3002<\/p>\n<p><img src=\"https:\/\/lemon-guess.oss-cn-hangzhou.aliyuncs.com\/img\/640-1686215019036-4.png\" alt=\"\u56fe\u7247\" \/><\/p>\n<h3>18\u3001\u4ec0\u4e48\u662f relaylog<\/h3>\n<p>relaylog \u662f\u4e2d\u7ee7\u65e5\u5fd7\uff0c<strong>\u5728\u4e3b\u4ece\u540c\u6b65\u7684\u65f6\u5019\u4f7f\u7528\u5230<\/strong>\uff0c\u5b83\u662f\u4e00\u4e2a\u4e2d\u4ecb\u4e34\u65f6\u7684\u65e5\u5fd7\u6587\u4ef6\uff0c\u7528\u4e8e\u5b58\u50a8\u4ece master \u8282\u70b9\u540c\u6b65\u8fc7\u6765\u7684 binlog \u65e5\u5fd7\u5185\u5bb9\u3002<\/p>\n<p>![\u56fe\u7247](data:image\/svg+xml,%3C%3Fxml version='1.0' encoding='UTF-8'%3F%3E%3Csvg width='1px' height='1px' viewBox='0 0 1 1' version='1.1' xmlns='<a href=\"http:\/\/www.w3.org\/2000\/svg\">http:\/\/www.w3.org\/2000\/svg<\/a>' xmlns:xlink='<a href=\"http:\/\/www.w3.org\/1999\/xlink&#039;%3E%3Ctitle%3E%3C\/title%3E%3Cg\">http:\/\/www.w3.org\/1999\/xlink'%3E%3Ctitle%3E%3C\/title%3E%3Cg<\/a> stroke='none' stroke-width='1' fill='none' fill-rule='evenodd' fill-opacity='0'%3E%3Cg transform='translate(-249.000000, -126.000000)' fill='%23FFFFFF'%3E%3Crect x='249' y='126' width='1' height='1'%3E%3C\/rect%3E%3C\/g%3E%3C\/g%3E%3C\/svg%3E)<\/p>\n<p>master \u4e3b\u8282\u70b9\u7684 binlog \u4f20\u5230 slave \u4ece\u8282\u70b9\u540e\uff0c\u88ab\u5199\u5165 relay log \u91cc\uff0c\u4ece\u8282\u70b9\u7684 slave sql \u7ebf\u7a0b\u4ece relaylog \u91cc\u8bfb\u53d6\u65e5\u5fd7\u7136\u540e\u5e94\u7528\u5230 slave \u4ece\u8282\u70b9\u672c\u5730\u3002<\/p>\n<p>\u4ece\u670d\u52a1\u5668 I\/O \u7ebf\u7a0b\u5c06\u4e3b\u670d\u52a1\u5668\u7684\u4e8c\u8fdb\u5236\u65e5\u5fd7\u8bfb\u53d6\u8fc7\u6765\u8bb0\u5f55\u5230\u4ece\u670d\u52a1\u5668\u672c\u5730\u6587\u4ef6\uff0c\u7136\u540e SQL \u7ebf\u7a0b\u4f1a\u8bfb\u53d6 relay-log \u65e5\u5fd7\u7684\u5185\u5bb9\u5e76\u5e94\u7528\u5230\u4ece\u670d\u52a1\u5668\uff0c\u4ece\u800c<strong>\u4f7f\u4ece\u670d\u52a1\u5668\u548c\u4e3b\u670d\u52a1\u5668\u7684\u6570\u636e\u4fdd\u6301\u4e00\u81f4<\/strong>\u3002<\/p>\n<h3>19\u3001\u7d22\u5f15<\/h3>\n<p>\u7d22\u5f15\u5176\u5b9e\u662f\u4e00\u79cd\u6570\u636e\u7ed3\u6784\uff0c\u80fd\u591f\u5e2e\u52a9\u6211\u4eec\u5feb\u901f\u7684\u68c0\u7d22\u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e\u3002<\/p>\n<p>\u7d22\u5f15\u7684\u4f5c\u7528\u5c31\u76f8\u5f53\u4e8e\u4e66\u7684\u76ee\u5f55\u3002\u6253\u4e2a\u6bd4\u65b9: \u6211\u4eec\u5728\u67e5\u5b57\u5178\u7684\u65f6\u5019\uff0c\u5982\u679c\u6ca1\u6709\u76ee\u5f55\uff0c\u90a3\u6211\u4eec\u5c31\u53ea\u80fd\u4e00\u9875\u4e00\u9875\u7684\u53bb\u627e\u6211\u4eec\u9700\u8981\u67e5\u7684\u90a3\u4e2a\u5b57\uff0c\u901f\u5ea6\u5f88\u6162\u3002\u5982\u679c\u6709\u76ee\u5f55\u4e86\uff0c\u6211\u4eec\u53ea\u9700\u8981\u5148\u53bb\u76ee\u5f55\u91cc\u67e5\u627e\u5b57\u7684\u4f4d\u7f6e\uff0c\u7136\u540e\u76f4\u63a5\u7ffb\u5230\u90a3\u4e00\u9875\u5c31\u884c\u4e86\u3002<\/p>\n<h3>20\u3001Hash \u7d22\u5f15<\/h3>\n<p>\u54c8\u5e0c\u8868\u662f\u952e\u503c\u5bf9\u7684\u96c6\u5408\uff0c\u901a\u8fc7\u952e(key)\u5373\u53ef\u5feb\u901f\u53d6\u51fa\u5bf9\u5e94\u7684\u503c(value)\uff0c\u56e0\u6b64\u54c8\u5e0c\u8868\u53ef\u4ee5\u5feb\u901f\u68c0\u7d22\u6570\u636e\uff08\u63a5\u8fd1 O\uff081\uff09\uff09\u3002<\/p>\n<p>\u4f46\u662f\uff01\u54c8\u5e0c\u7b97\u6cd5\u6709\u4e2a Hash \u51b2\u7a81\u95ee\u9898\uff0c\u4e5f\u5c31\u662f\u8bf4\u591a\u4e2a\u4e0d\u540c\u7684 key \u6700\u540e\u5f97\u5230\u7684 index \u76f8\u540c\u3002\u901a\u5e38\u60c5\u51b5\u4e0b\uff0c\u6211\u4eec\u5e38\u7528\u7684\u89e3\u51b3\u529e\u6cd5\u662f <strong>\u94fe\u5730\u5740\u6cd5<\/strong>\u3002<\/p>\n<p>\u94fe\u5730\u5740\u6cd5\u5c31\u662f\u5c06\u54c8\u5e0c\u51b2\u7a81\u6570\u636e\u5b58\u653e\u5728\u94fe\u8868\u4e2d\u3002\u5c31\u6bd4\u5982 JDK1.8 \u4e4b\u524d HashMap \u5c31\u662f\u901a\u8fc7\u94fe\u5730\u5740\u6cd5\u6765\u89e3\u51b3\u54c8\u5e0c\u51b2\u7a81\u7684\u3002\u4e0d\u8fc7\uff0cJDK1.8 \u4ee5\u540e HashMap \u4e3a\u4e86\u51cf\u5c11\u94fe\u8868\u8fc7\u957f\u7684\u65f6\u5019\u641c\u7d22\u65f6\u95f4\u8fc7\u957f\u5f15\u5165\u4e86\u7ea2\u9ed1\u6811\u3002<\/p>\n<p>\u4e3a\u4e86\u51cf\u5c11 Hash \u51b2\u7a81\u7684\u53d1\u751f\uff0c\u4e00\u4e2a\u597d\u7684\u54c8\u5e0c\u51fd\u6570\u5e94\u8be5\u201c\u5747\u5300\u5730\u201d\u5c06\u6570\u636e\u5206\u5e03\u5728\u6574\u4e2a\u53ef\u80fd\u7684\u54c8\u5e0c\u503c\u96c6\u5408\u4e2d\u3002<\/p>\n<p><strong>\u65e2\u7136\u54c8\u5e0c\u8868\u8fd9\u4e48\u5feb\uff0c\u4e3a\u4ec0\u4e48 MySQL \u6ca1\u6709\u4f7f\u7528\u5176\u4f5c\u4e3a\u7d22\u5f15\u7684\u6570\u636e\u7ed3\u6784\u5462\uff1f<\/strong> \u4e3b\u8981\u662f\u56e0\u4e3a Hash \u7d22\u5f15<strong>\u4e0d\u652f\u6301\u987a\u5e8f\u548c\u8303\u56f4\u67e5\u8be2<\/strong>\u3002\u5047\u5982\u6211\u4eec\u8981\u5bf9\u8868\u4e2d\u7684\u6570\u636e\u8fdb\u884c\u6392\u5e8f\u6216\u8005\u8fdb\u884c\u8303\u56f4\u67e5\u8be2\uff0c\u90a3 Hash \u7d22\u5f15\u53ef\u5c31\u4e0d\u884c\u4e86\uff0c\u5e76\u4e14\u6bcf\u6b21 IO \u53ea\u80fd\u53d6\u4e00\u4e2a\u3002<\/p>\n<h3>21\u3001B\u6811\u548cB+ \u6811<\/h3>\n<ul>\n<li>B \u6811\u7684\u6240\u6709\u8282\u70b9\u65e2\u5b58\u653e\u952e(key) \u4e5f\u5b58\u653e\u6570\u636e(data)\uff0c\u800c B+\u6811\u53ea\u6709\u53f6\u5b50\u8282\u70b9\u5b58\u653e key \u548c data\uff0c\u5176\u4ed6\u5185\u8282\u70b9\u53ea\u5b58\u653e key\u3002<\/li>\n<li>B \u6811\u7684\u53f6\u5b50\u8282\u70b9\u90fd\u662f\u72ec\u7acb\u7684\uff1bB+\u6811\u7684\u53f6\u5b50\u8282\u70b9\u6709\u4e00\u6761\u5f15\u7528\u94fe\u6307\u5411\u4e0e\u5b83\u76f8\u90bb\u7684\u53f6\u5b50\u8282\u70b9\u3002<\/li>\n<li>B \u6811\u7684\u68c0\u7d22\u7684\u8fc7\u7a0b\u76f8\u5f53\u4e8e\u5bf9\u8303\u56f4\u5185\u7684\u6bcf\u4e2a\u8282\u70b9\u7684\u5173\u952e\u5b57\u505a\u4e8c\u5206\u67e5\u627e\uff0c\u53ef\u80fd\u8fd8\u6ca1\u6709\u5230\u8fbe\u53f6\u5b50\u8282\u70b9\uff0c\u68c0\u7d22\u5c31\u7ed3\u675f\u4e86\u3002\u800c B+\u6811\u7684\u68c0\u7d22\u6548\u7387\u5c31\u5f88\u7a33\u5b9a\u4e86\uff0c\u4efb\u4f55\u67e5\u627e\u90fd\u662f\u4ece\u6839\u8282\u70b9\u5230\u53f6\u5b50\u8282\u70b9\u7684\u8fc7\u7a0b\uff0c\u53f6\u5b50\u8282\u70b9\u7684\u987a\u5e8f\u68c0\u7d22\u5f88\u660e\u663e\u3002<\/li>\n<\/ul>\n<h3>22\u3001\u4e3b\u952e\u7d22\u5f15<\/h3>\n<p>\u6570\u636e\u8868\u7684\u4e3b\u952e\u5217\u4f7f\u7528\u7684\u5c31\u662f\u4e3b\u952e\u7d22\u5f15\uff0c\u4e00\u79cd\u7279\u6b8a\u7684\u552f\u4e00\u7d22\u5f15\u3002<\/p>\n<p>\u5728 MySQL \u7684 InnoDB \u7684\u8868\u4e2d\uff0c\u5f53\u6ca1\u6709\u663e\u793a\u7684\u6307\u5b9a\u8868\u7684\u4e3b\u952e\u65f6\uff0cInnoDB \u4f1a\u81ea\u52a8\u5148\u68c0\u67e5\u8868\u4e2d\u662f\u5426\u6709\u552f\u4e00\u7d22\u5f15\u4e14\u4e0d\u5141\u8bb8\u5b58\u5728 null \u503c\u7684\u5b57\u6bb5\uff0c\u5982\u679c\u6709\uff0c\u5219\u9009\u62e9\u8be5\u5b57\u6bb5\u4e3a\u9ed8\u8ba4\u7684\u4e3b\u952e\uff0c\u5426\u5219 InnoDB \u5c06\u4f1a\u81ea\u52a8\u521b\u5efa\u4e00\u4e2a 6Byte \u7684\u81ea\u589e\u4e3b\u952e\u3002<\/p>\n<h3>23\u3001\u4e8c\u7ea7\u7d22\u5f15<\/h3>\n<p>\u4e8c\u7ea7\u7d22\u5f15\u53c8\u79f0\u4e3a\u8f85\u52a9\u7d22\u5f15\uff0c\u662f\u56e0\u4e3a\u4e8c\u7ea7\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u7684\u6570\u636e\u662f\u4e3b\u952e\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u901a\u8fc7\u4e8c\u7ea7\u7d22\u5f15\uff0c\u53ef\u4ee5\u5b9a\u4f4d\u4e3b\u952e\u7684\u4f4d\u7f6e\u3002<\/p>\n<p>\u552f\u4e00\u7d22\u5f15\uff0c\u666e\u901a\u7d22\u5f15\uff0c\u524d\u7f00\u7d22\u5f15\u7b49\u7d22\u5f15\u5c5e\u4e8e\u4e8c\u7ea7\u7d22\u5f15\u3002<\/p>\n<ul>\n<li>\u552f\u4e00\u7d22\u5f15(Unique Key) \uff1a\u552f\u4e00\u7d22\u5f15\u4e5f\u662f\u4e00\u79cd\u7ea6\u675f\u3002\u7d22\u5f15\u5217\u7684\u503c\u5fc5\u987b\u552f\u4e00\uff0c\u4f46\u5141\u8bb8\u6709\u7a7a\u503c\uff1b\u5982\u679c\u662f<strong>\u7ec4\u5408\u7d22\u5f15<\/strong>\uff0c\u5219\u5217\u503c\u7684\u7ec4\u5408\u5fc5\u987b\u552f\u4e00\u3002\u4e00\u5f20\u8868\u5141\u8bb8\u521b\u5efa\u591a\u4e2a\u552f\u4e00\u7d22\u5f15\u3002\u5efa\u7acb\u552f\u4e00\u7d22\u5f15\u7684\u76ee\u7684\u5927\u90e8\u5206\u65f6\u5019\u90fd\u662f\u4e3a\u4e86\u8be5\u5c5e\u6027\u5217\u7684<strong>\u6570\u636e\u7684\u552f\u4e00\u6027\uff0c\u800c\u4e0d\u662f\u4e3a\u4e86\u67e5\u8be2\u6548\u7387<\/strong>\u3002<\/li>\n<li>\u666e\u901a\u7d22\u5f15(Index) \uff1a\u666e\u901a\u7d22\u5f15\u7684\u552f\u4e00\u4f5c\u7528\u5c31\u662f\u4e3a\u4e86\u5feb\u901f\u67e5\u8be2\u6570\u636e\uff0c\u4e00\u5f20\u8868\u5141\u8bb8\u521b\u5efa\u591a\u4e2a\u666e\u901a\u7d22\u5f15\uff0c\u5e76\u5141\u8bb8\u6570\u636e\u91cd\u590d\u548c NULL\u3002<\/li>\n<li>\u524d\u7f00\u7d22\u5f15(Prefix) \uff1a\u524d\u7f00\u7d22\u5f15\u53ea\u9002\u7528\u4e8e<strong>\u5b57\u7b26\u4e32<\/strong>\u7c7b\u578b\u7684\u6570\u636e\u3002\u524d\u7f00\u7d22\u5f15\u662f\u5bf9<strong>\u6587\u672c\u7684\u524d\u51e0\u4e2a\u5b57\u7b26\u521b\u5efa\u7d22\u5f15<\/strong>\uff0c\u76f8\u6bd4\u666e\u901a\u7d22\u5f15\u5efa\u7acb\u7684\u6570\u636e\u66f4\u5c0f\uff0c \u56e0\u4e3a\u53ea\u53d6\u524d\u51e0\u4e2a\u5b57\u7b26\u3002<\/li>\n<li>\u7ec4\u5408\u7d22\u5f15\uff1a\u6307\u591a\u4e2a\u5b57\u6bb5\u4e0a\u521b\u5efa\u7684\u7d22\u5f15\uff0c\u53ea\u6709\u5728\u67e5\u8be2\u6761\u4ef6\u4e2d\u4f7f\u7528\u4e86\u521b\u5efa\u7d22\u5f15\u65f6\u7684\u7b2c\u4e00\u4e2a\u5b57\u6bb5\uff0c\u7d22\u5f15\u624d\u4f1a\u88ab\u4f7f\u7528\u3002\u4f7f\u7528\u7ec4\u5408\u7d22\u5f15\u65f6\u9075\u5faa<strong>\u6700\u5de6\u524d\u7f00\u96c6\u5408<\/strong>\uff08\u540e\u6587\u4ecb\u7ecd\uff09\uff1b<\/li>\n<li>\u5168\u6587\u7d22\u5f15(Full Text) \uff1a\u5168\u6587\u7d22\u5f15\u4e3b\u8981\u662f\u4e3a\u4e86\u68c0\u7d22\u5927\u6587\u672c\u6570\u636e\u4e2d\u7684\u5173\u952e\u5b57\u7684\u4fe1\u606f\uff0c\u662f\u76ee\u524d\u641c\u7d22\u5f15\u64ce\u6570\u636e\u5e93\u4f7f\u7528\u7684\u4e00\u79cd\u6280\u672f\u3002Mysql5.6 \u4e4b\u524d\u53ea\u6709 MYISAM \u5f15\u64ce\u652f\u6301\u5168\u6587\u7d22\u5f15\uff0c5.6 \u4e4b\u540e InnoDB \u4e5f\u652f\u6301\u4e86\u5168\u6587\u7d22\u5f15\u3002<\/li>\n<\/ul>\n<blockquote>\n<p>MySQL \u4e2d\u7684\u5168\u6587\u7d22\u5f15\uff0c\u6709\u4e24\u4e2a\u53d8\u91cf\uff0c<strong>\u6700\u5c0f\u641c\u7d22\u957f\u5ea6\u548c\u6700\u5927\u641c\u7d22\u957f\u5ea6<\/strong>\uff0c\u5bf9\u4e8e\u957f\u5ea6\u5c0f\u4e8e\u6700\u5c0f\u641c\u7d22\u957f\u5ea6\u548c\u5927\u4e8e\u6700\u5927\u641c\u7d22\u957f\u5ea6\u7684\u8bcd\u8bed\uff0c\u90fd\u4e0d\u4f1a\u88ab\u7d22\u5f15\u3002<\/p>\n<\/blockquote>\n<h3>24\u3001\u805a\u7c07\u7d22\u5f15\u4e0e\u975e\u805a\u7c07\u7d22\u5f15<\/h3>\n<p>\u805a\u7c07\u7d22\u5f15\u5373\u7d22\u5f15\u7ed3\u6784\u548c\u6570\u636e\u4e00\u8d77\u5b58\u653e\u7684\u7d22\u5f15\uff0c\u5e76\u4e0d\u662f\u4e00\u79cd\u5355\u72ec\u7684\u7d22\u5f15\u7c7b\u578b\u3002InnoDB \u7684\u4e3b\u952e\u7d22\u5f15\u7684\u53f6\u5b50\u8282\u70b9\u4e2d\u5b58\u653e\u7684\u5c31\u662f\u6570\u636e\u884c\uff0c\u6240\u4ee5\u5b83\u5c5e\u4e8e\u805a\u7c07\u7d22\u5f15\u3002<\/p>\n<p>\u5728 MySQL \u4e2d\uff0cInnoDB \u5f15\u64ce\u7684\u8868\u7684 .ibd \u6587\u4ef6\u5c31\u5305\u542b\u4e86\u8be5\u8868\u7684\u7d22\u5f15\u548c\u6570\u636e\uff0c\u5bf9\u4e8e InnoDB \u5f15\u64ce\u8868\u6765\u8bf4\uff0c\u8be5\u8868\u7684\u7d22\u5f15(B+\u6811)\u7684\u6bcf\u4e2a\u975e\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u7d22\u5f15\uff0c\u53f6\u5b50\u8282\u70b9\u5b58\u50a8\u7d22\u5f15\u548c\u7d22\u5f15\u5bf9\u5e94\u7684\u6570\u636e\u3002<\/p>\n<p>\u975e\u805a\u7c07\u7d22\u5f15\u5373\u7d22\u5f15\u7ed3\u6784\u548c\u6570\u636e\u5206\u5f00\u5b58\u653e\u7684\u7d22\u5f15\uff0c\u5e76\u4e0d\u662f\u4e00\u79cd\u5355\u72ec\u7684\u7d22\u5f15\u7c7b\u578b\u3002\u4e8c\u7ea7\u7d22\u5f15(\u8f85\u52a9\u7d22\u5f15)\u5c31\u5c5e\u4e8e\u975e\u805a\u7c07\u7d22\u5f15\u3002MySQL \u7684 MyISAM \u5f15\u64ce\uff0c\u4e0d\u7ba1\u4e3b\u952e\u8fd8\u662f\u975e\u4e3b\u952e\uff0c\u4f7f\u7528\u7684\u90fd\u662f\u975e\u805a\u7c07\u7d22\u5f15\u3002<\/p>\n<p>\u8f85\u52a9\u7d22\u5f15\u662f\u6211\u4eec\u4eba\u4e3a\u521b\u5efa\u7684\u7d22\u5f15\uff0c\u5b83\u7684\u53f6\u5b50\u8282\u70b9\u4e2d\u5b58\u653e\u7684\u662f\u4e3b\u952e\uff0c\u5f53\u6211\u4eec\u901a\u8fc7\u8f85\u52a9\u7d22\u5f15\u67e5\u627e\u5230\u4e3b\u952e\u4e4b\u540e\uff0c\u518d\u901a\u8fc7\u67e5\u627e\u7684\u4e3b\u952e\u53bb<strong>\u56de\u8868<\/strong>\u67e5\u627e\u4e3b\u952e\u7d22\u5f15\u3002<\/p>\n<h3>25\u3001\u56de\u8868<\/h3>\n<p>\u56de\u8868\u5c31\u662f\u5148\u901a\u8fc7\u6570\u636e\u5e93\u7d22\u5f15\u626b\u63cf\u51fa\u8be5\u7d22\u5f15\u6811\u4e2d\u6570\u636e\u6240\u5728\u7684\u884c\uff0c\u53d6\u5230\u4e3b\u952e id\uff0c\u518d\u901a\u8fc7\u4e3b\u952e id \u53d6\u51fa\u4e3b\u952e\u7d22\u5f15\u6570\u4e2d\u7684\u6570\u636e\uff0c\u5373\u57fa\u4e8e\u975e\u4e3b\u952e\u7d22\u5f15\u7684\u67e5\u8be2\u9700\u8981\u591a\u626b\u63cf\u4e00\u68f5\u7d22\u5f15\u6811\u3002<\/p>\n<h3>26\u3001\u8986\u76d6\u7d22\u5f15\u548c\u8054\u5408\u7d22\u5f15<\/h3>\n<p>\u5982\u679c\u4e00\u4e2a\u7d22\u5f15\u5305\u542b\uff08\u6216\u8005\u8bf4\u8986\u76d6\uff09\u6240\u6709\u9700\u8981\u67e5\u8be2\u7684\u5b57\u6bb5\u7684\u503c\uff0c\u6211\u4eec\u5c31\u79f0\u4e4b\u4e3a\u201c\u8986\u76d6\u7d22\u5f15\u201d\u3002\u6307\u7684\u662f\u901a\u8fc7\u7d22\u5f15\u5c31\u80fd\u67e5\u8be2\u5230\u6211\u4eec\u6240\u9700\u8981\u7684\u6570\u636e\uff0c\u800c\u4e0d\u9700\u8981\u6839\u636e\u7d22\u5f15\u518d\u53bb\u67e5\u8be2\u6570\u636e\u8868\u4e2d\u7684\u6570\u636e\uff08 \u56de\u8868\uff09\uff0c\u8fd9\u6837\u5c31\u51cf\u5c11\u4e86\u6570\u636e\u5e93\u7684 io \u64cd\u4f5c\uff0c\u63d0\u9ad8\u67e5\u8be2\u6548\u7387\u3002<\/p>\n<p>\u4f7f\u7528\u8868\u4e2d\u7684\u591a\u4e2a\u5b57\u6bb5\u521b\u5efa\u7d22\u5f15\uff0c\u5c31\u662f\u8054\u5408\u7d22\u5f15\uff0c\u4e5f\u53eb\u7ec4\u5408\u7d22\u5f15\u6216\u590d\u5408\u7d22\u5f15\u3002<\/p>\n<h3>27\u3001\u6700\u5de6\u524d\u7f00\u5339\u914d\u539f\u5219<\/h3>\n<p>\u6700\u5de6\u524d\u7f00\u5339\u914d\u539f\u5219\u6307\u7684\u662f\u5728\u4f7f\u7528\u8054\u5408\u7d22\u5f15\u65f6\uff0cMySQL \u4f1a\u6839\u636e\u8054\u5408\u7d22\u5f15\u4e2d\u7684\u5b57\u6bb5\u987a\u5e8f\uff0c\u4ece\u5de6\u5230\u53f3\u4f9d\u6b21\u5230\u67e5\u8be2\u6761\u4ef6\u4e2d\u53bb\u5339\u914d\uff0c\u5982\u679c\u67e5\u8be2\u6761\u4ef6\u4e2d\u5b58\u5728\u4e0e\u8054\u5408\u7d22\u5f15\u4e2d\u6700\u5de6\u4fa7\u5b57\u6bb5\u76f8\u5339\u914d\u7684\u5b57\u6bb5\uff0c\u5219\u5c31\u4f1a\u4f7f\u7528\u8be5\u5b57\u6bb5\u8fc7\u6ee4\u4e00\u6279\u6570\u636e\uff0c\u76f4\u81f3\u8054\u5408\u7d22\u5f15\u4e2d\u5168\u90e8\u5b57\u6bb5\u5339\u914d\u5b8c\u6210\uff0c\u6216\u8005\u5728\u6267\u884c\u8fc7\u7a0b\u4e2d\u9047\u5230\u8303\u56f4\u67e5\u8be2\uff0c\u5982 &gt;\u3001&lt;\u3001between \u548c \u4ee5%\u5f00\u5934\u7684like\u67e5\u8be2 \u7b49\u6761\u4ef6\uff0c\u624d\u4f1a\u505c\u6b62\u5339\u914d\u3002<\/p>\n<p>\u6240\u4ee5\uff0c\u6211\u4eec\u5728\u4f7f\u7528\u8054\u5408\u7d22\u5f15\u65f6\uff0c\u53ef\u4ee5\u5c06\u533a\u5206\u5ea6\u9ad8\u7684\u5b57\u6bb5\u653e\u5728\u6700\u5de6\u8fb9\uff0c\u8fd9\u4e5f\u53ef\u4ee5\u8fc7\u6ee4\u66f4\u591a\u6570\u636e\u3002<\/p>\n<h3>28\u3001\u7d22\u5f15\u4e0b\u63a8<\/h3>\n<p>\u7d22\u5f15\u4e0b\u63a8\uff08Index Condition Pushdown\uff09 \u662f MySQL 5.6 \u7248\u672c\u4e2d\u63d0\u4f9b\u7684\u4e00\u9879\u7d22\u5f15\u4f18\u5316\u529f\u80fd\uff0c\u53ef\u4ee5\u5728\u975e\u805a\u7c07\u7d22\u5f15\u904d\u5386\u8fc7\u7a0b\u4e2d\uff0c\u5bf9\u7d22\u5f15\u4e2d\u5305\u542b\u7684\u5b57\u6bb5\u5148\u505a\u5224\u65ad\uff0c\u8fc7\u6ee4\u6389\u4e0d\u7b26\u5408\u6761\u4ef6\u7684\u8bb0\u5f55\uff0c\u51cf\u5c11\u56de\u8868\u6b21\u6570\u3002<\/p>\n<h3>29\u3001\u9690\u5f0f\u8f6c\u6362<\/h3>\n<p>\u5f53\u64cd\u4f5c\u7b26\u4e0e\u4e0d\u540c\u7c7b\u578b\u7684\u64cd\u4f5c\u6570\u4e00\u8d77\u4f7f\u7528\u65f6\uff0c\u4f1a\u53d1\u751f\u7c7b\u578b\u8f6c\u6362\u4ee5\u4f7f\u64cd\u4f5c\u6570\u517c\u5bb9\u3002\u67d0\u4e9b\u8f6c\u6362\u662f\u9690\u5f0f\u53d1\u751f\u7684\u3002\u4f8b\u5982\uff0cMySQL \u4f1a\u6839\u636e\u9700\u8981\u81ea\u52a8\u5c06\u5b57\u7b26\u4e32\u8f6c\u6362\u4e3a\u6570\u5b57\uff0c\u53cd\u4e4b\u4ea6\u7136\u3002\u4ee5\u4e0b\u89c4\u5219\u63cf\u8ff0\u4e86\u6bd4\u8f83\u64cd\u4f5c\u7684\u8f6c\u6362\u65b9\u5f0f\uff1a<\/p>\n<ol>\n<li>\u4e24\u4e2a\u53c2\u6570\u81f3\u5c11\u6709\u4e00\u4e2a\u662fNULL\u65f6\uff0c\u6bd4\u8f83\u7684\u7ed3\u679c\u4e5f\u662fNULL\uff0c\u7279\u6b8a\u7684\u60c5\u51b5\u662f\u4f7f\u7528&lt;=&gt;\u5bf9\u4e24\u4e2aNULL\u505a\u6bd4\u8f83\u65f6\u4f1a\u8fd4\u56de1\uff0c\u8fd9\u4e24\u79cd\u60c5\u51b5\u90fd\u4e0d\u9700\u8981\u505a\u7c7b\u578b\u8f6c\u6362\uff1b<\/li>\n<li>\u4e24\u4e2a\u53c2\u6570\u90fd\u662f\u5b57\u7b26\u4e32\uff0c\u4f1a\u6309\u7167\u5b57\u7b26\u4e32\u6765\u6bd4\u8f83\uff0c\u4e0d\u505a\u7c7b\u578b\u8f6c\u6362\uff1b<\/li>\n<li>\u4e24\u4e2a\u53c2\u6570\u90fd\u662f\u6574\u6570\uff0c\u6309\u7167\u6574\u6570\u6765\u6bd4\u8f83\uff0c\u4e0d\u505a\u7c7b\u578b\u8f6c\u6362\uff1b<\/li>\n<li>\u5341\u516d\u8fdb\u5236\u7684\u503c\u548c\u975e\u6570\u5b57\u505a\u6bd4\u8f83\u65f6\uff0c\u4f1a\u88ab\u5f53\u505a\u4e8c\u8fdb\u5236\u4e32\uff1b<\/li>\n<li>\u6709\u4e00\u4e2a\u53c2\u6570\u662fTIMESTAMP\u6216DATETIME\uff0c\u5e76\u4e14\u53e6\u5916\u4e00\u4e2a\u53c2\u6570\u662f\u5e38\u91cf\uff0c\u5e38\u91cf\u4f1a\u88ab\u8f6c\u6362\u4e3atimestamp\uff1b<\/li>\n<li>\u6709\u4e00\u4e2a\u53c2\u6570\u662fdecimal\u7c7b\u578b\uff0c\u5982\u679c\u53e6\u5916\u4e00\u4e2a\u53c2\u6570\u662fdecimal\u6216\u8005\u6574\u6570\uff0c\u4f1a\u5c06\u6574\u6570\u8f6c\u6362\u4e3adecimal\u540e\u8fdb\u884c\u6bd4\u8f83\uff0c\u5982\u679c\u53e6\u5916\u4e00\u4e2a\u53c2\u6570\u662f\u6d6e\u70b9\u6570\uff0c\u5219\u4f1a\u628adecimal\u8f6c\u6362\u4e3a\u6d6e\u70b9\u6570\u8fdb\u884c\u6bd4\u8f83\uff1b<\/li>\n<li>\u6240\u6709\u5176\u4ed6\u60c5\u51b5\u4e0b\uff0c\u4e24\u4e2a\u53c2\u6570\u90fd\u4f1a\u88ab\u8f6c\u6362\u4e3a\u6d6e\u70b9\u6570\u518d\u8fdb\u884c\u6bd4\u8f83\uff1b<\/li>\n<\/ol>\n<h3>30\u3001\u666e\u901a\u7d22\u5f15\u548c\u552f\u4e00\u7d22\u5f15\u8be5\u600e\u4e48\u9009\u62e9?<\/h3>\n<ul>\n<li>\n<p>\u67e5\u8be2<\/p>\n<\/li>\n<li>\n<\/li>\n<li>\n<ul>\n<li>\u5f53\u666e\u901a\u7d22\u5f15\u4e3a\u6761\u4ef6\u65f6\u67e5\u8be2\u5230\u6570\u636e\u4f1a\u4e00\u76f4\u626b\u63cf\uff0c\u76f4\u5230\u626b\u5b8c\u6574\u5f20\u8868\uff1b<\/li>\n<li>\u5f53\u552f\u4e00\u7d22\u5f15\u4e3a\u67e5\u8be2\u6761\u4ef6\u65f6\uff0c\u67e5\u5230\u8be5\u6570\u636e\u4f1a\u76f4\u63a5\u8fd4\u56de\uff0c\u4e0d\u4f1a\u7ee7\u7eed\u626b\u8868\uff1b<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u66f4\u65b0<\/p>\n<\/li>\n<li>\n<\/li>\n<li>\n<ul>\n<li>\u666e\u901a\u7d22\u5f15\u4f1a\u76f4\u63a5\u5c06\u64cd\u4f5c\u66f4\u65b0\u5230 change buffer \u4e2d\uff0c\u7136\u540e\u7ed3\u675f<\/li>\n<li>\u552f\u4e00\u7d22\u5f15\u9700\u8981\u5224\u65ad\u6570\u636e\u662f\u5426\u51b2\u7a81<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<p>\u6240\u4ee5<strong>\u552f\u4e00\u7d22\u5f15\u66f4\u52a0\u9002\u5408\u67e5\u8be2\u7684\u573a\u666f\uff0c\u666e\u901a\u7d22\u5f15\u66f4\u9002\u5408\u63d2\u5165\u7684\u573a\u666f\u3002<\/strong><\/p>\n<h3>31\u3001\u907f\u514d\u7d22\u5f15\u5931\u6548<\/h3>\n<p>\u7d22\u5f15\u5931\u6548\u4e5f\u662f\u6162\u67e5\u8be2\u7684\u4e3b\u8981\u539f\u56e0\u4e4b\u4e00\uff0c\u5e38\u89c1\u7684\u5bfc\u81f4\u7d22\u5f15\u5931\u6548\u7684\u60c5\u51b5\u6709\u4e0b\u9762\u8fd9\u4e9b\uff1a<\/p>\n<ul>\n<li>\u4f7f\u7528 SELECT * \u8fdb\u884c\u67e5\u8be2;<\/li>\n<li>\u521b\u5efa\u4e86\u7ec4\u5408\u7d22\u5f15\uff0c\u4f46\u67e5\u8be2\u6761\u4ef6\u672a\u51c6\u5b88\u6700\u5de6\u5339\u914d\u539f\u5219;<\/li>\n<li>\u5728\u7d22\u5f15\u5217\u4e0a\u8fdb\u884c\u8ba1\u7b97\u3001\u51fd\u6570\u3001\u7c7b\u578b\u8f6c\u6362\u7b49\u64cd\u4f5c;<\/li>\n<li>\u4ee5 % \u5f00\u5934\u7684 LIKE \u67e5\u8be2\u6bd4\u5982 like '%abc';<\/li>\n<li>\u67e5\u8be2\u6761\u4ef6\u4e2d\u4f7f\u7528 or\uff0c\u4e14 or \u7684\u524d\u540e\u6761\u4ef6\u4e2d\u6709\u4e00\u4e2a\u5217\u6ca1\u6709\u7d22\u5f15\uff0c\u6d89\u53ca\u7684\u7d22\u5f15\u90fd\u4e0d\u4f1a\u88ab\u4f7f\u7528\u5230<\/li>\n<li>match() \u51fd\u6570\u4e2d\u7684\u6307\u5b9a\u7684\u5217\u5fc5\u987b\u4e0e\u5168\u6587\u7d22\u5f15\u4e2d\u6307\u5b9a\u7684\u5217\u5b8c\u5168\u76f8\u540c\uff0c\u5426\u5219\u4f1a\u62a5\u9519\uff0c\u65e0\u6cd5\u4f7f\u7528\u5168\u6587\u7d22\u5f15\u3002<\/li>\n<li>\u5168\u6587\u7d22\u5f15\u65f6\u8981\u6ce8\u610f\u641c\u7d22\u957f\u5ea6\u4f1a\u5bfc\u81f4\u7d22\u5f15\u5931\u6548<\/li>\n<\/ul>\n<h3>32\u3001\u5efa\u7acb\u7d22\u5f15\u7684\u89c4\u5219<\/h3>\n<ul>\n<li>\u4e0d\u4e3a NULL \u7684\u5b57\u6bb5 \uff1a\u7d22\u5f15\u5b57\u6bb5\u7684\u6570\u636e\u5e94\u8be5\u5c3d\u91cf\u4e0d\u4e3a NULL\uff0c\u56e0\u4e3a\u5bf9\u4e8e\u6570\u636e\u4e3a NULL \u7684\u5b57\u6bb5\uff0c\u6570\u636e\u5e93\u8f83\u96be\u4f18\u5316\u3002\u5982\u679c\u5b57\u6bb5\u9891\u7e41\u88ab\u67e5\u8be2\uff0c\u4f46\u53c8\u907f\u514d\u4e0d\u4e86\u4e3a NULL\uff0c\u5efa\u8bae\u4f7f\u7528 0,1,true,false \u8fd9\u6837\u8bed\u4e49\u8f83\u4e3a\u6e05\u6670\u7684\u77ed\u503c\u6216\u77ed\u5b57\u7b26\u4f5c\u4e3a\u66ff\u4ee3\u3002<\/li>\n<li>\u88ab\u9891\u7e41\u67e5\u8be2\u7684\u5b57\u6bb5 \uff1a\u6211\u4eec\u521b\u5efa\u7d22\u5f15\u7684\u5b57\u6bb5\u5e94\u8be5\u662f\u67e5\u8be2\u64cd\u4f5c\u975e\u5e38\u9891\u7e41\u7684\u5b57\u6bb5\u3002<\/li>\n<li>\u88ab\u4f5c\u4e3a\u6761\u4ef6\u67e5\u8be2\u7684\u5b57\u6bb5 \uff1a\u88ab\u4f5c\u4e3a WHERE \u6761\u4ef6\u67e5\u8be2\u7684\u5b57\u6bb5\uff0c\u5e94\u8be5\u88ab\u8003\u8651\u5efa\u7acb\u7d22\u5f15\u3002<\/li>\n<li>\u9891\u7e41\u9700\u8981\u6392\u5e8f\u7684\u5b57\u6bb5 \uff1a\u7d22\u5f15\u5df2\u7ecf\u6392\u5e8f\uff0c\u8fd9\u6837\u67e5\u8be2\u53ef\u4ee5\u5229\u7528\u7d22\u5f15\u7684\u6392\u5e8f\uff0c\u52a0\u5feb\u6392\u5e8f\u67e5\u8be2\u65f6\u95f4\u3002<\/li>\n<li>\u88ab\u7ecf\u5e38\u9891\u7e41\u7528\u4e8e\u8fde\u63a5\u7684\u5b57\u6bb5 \uff1a\u7ecf\u5e38\u7528\u4e8e\u8fde\u63a5\u7684\u5b57\u6bb5\u53ef\u80fd\u662f\u4e00\u4e9b\u5916\u952e\u5217\uff0c\u5bf9\u4e8e\u5916\u952e\u5217\u5e76\u4e0d\u4e00\u5b9a\u8981\u5efa\u7acb\u5916\u952e\uff0c\u53ea\u662f\u8bf4\u8be5\u5217\u6d89\u53ca\u5230\u8868\u4e0e\u8868\u7684\u5173\u7cfb\u3002\u5bf9\u4e8e\u9891\u7e41\u88ab\u8fde\u63a5\u67e5\u8be2\u7684\u5b57\u6bb5\u53ef\u4ee5\u8003\u8651\u5efa\u7acb\u7d22\u5f15\uff0c\u63d0\u9ad8\u591a\u8868\u8fde\u63a5\u67e5\u8be2\u7684\u6548\u7387\u3002<\/li>\n<li>\u88ab\u9891\u7e41\u66f4\u65b0\u7684\u5b57\u6bb5\u5e94\u8be5\u614e\u91cd\u5efa\u7acb\u7d22\u5f15\uff1b<\/li>\n<li>\u5c3d\u53ef\u80fd\u7684\u8003\u8651\u5efa\u7acb\u8054\u5408\u7d22\u5f15\u800c\u4e0d\u662f\u5355\u5217\u7d22\u5f15\uff1b<\/li>\n<li>\u8003\u8651\u5728\u5b57\u7b26\u4e32\u7c7b\u578b\u7684\u5b57\u6bb5\u4e0a\u4f7f\u7528\u524d\u7f00\u7d22\u5f15\u4ee3\u66ff\u666e\u901a\u7d22\u5f15\uff1b<\/li>\n<li>\u5220\u9664\u957f\u671f\u672a\u4f7f\u7528\u7684\u7d22\u5f15\uff1b<\/li>\n<\/ul>\n<h3>33\u3001\u4e8b\u52a1\u6781\u5176\u7279\u6027<\/h3>\n<p>\u4e00\u4e2a\u4e8b\u60c5\u7531n\u4e2a\u5355\u5143\u7ec4\u6210\uff0c\u8fd9n\u4e2a\u5355\u5143\u5728\u6267\u884c\u8fc7\u7a0b\u4e2d\uff0c\u8981\u4e48\u540c\u65f6\u6210\u529f\uff0c\u8981\u4e48\u540c\u65f6\u5931\u8d25\uff0c\u8fd9\u5c31\u628an\u4e2a\u5355\u5143\u653e\u5728\u4e86\u4e00\u4e2a\u4e8b\u52a1\u4e4b\u4e2d\u3002\u4e3e\u4e2a\u7b80\u5355\u7684\u4f8b\u5b50\uff1a\u5728\u4e0d\u8003\u8651\u8bd5\u9898\u6b63\u786e\u4e0e\u5426\u7684\u524d\u63d0\u4e0b\uff0c\u4e00\u5f20\u8bd5\u5377\u7531\u591a\u4e2a\u9898\u76ee\u6784\u6210\uff0c\u5f53\u4f60\u7b54\u5b8c\u9898\u4ea4\u7ed9\u8001\u5e08\u7684\u65f6\u5019\u662f\u5c06\u4e00\u6574\u5f20\u8bd5\u5377\u4ea4\u7ed9\u8001\u5e08\uff0c\u800c\u4e0d\u662f\u5c06\u6bcf\u9053\u9898\u5355\u72ec\u4ea4\u7ed9\u8001\u5e08\uff0c\u5728\u8fd9\u91cc\u8bd5\u5377\u5c31\u53ef\u4ee5\u7406\u89e3\u6210\u4e00\u4e2a\u4e8b\u52a1\u3002<\/p>\n<p>\u4e8b\u52a1\u7684\u7279\u6027\uff1a<\/p>\n<ul>\n<li>A\uff1a\u539f\u5b50\u6027\uff08<code>Atomicity<\/code>\uff09\uff0c\u539f\u5b50\u6027\u662f\u6307\u4e8b\u52a1\u662f\u4e00\u4e2a\u4e0d\u53ef\u5206\u5272\u7684\u5de5\u4f5c\u5355\u4f4d\uff0c\u4e8b\u52a1\u4e2d\u7684\u64cd\u4f5c\uff0c\u8981\u4e48\u90fd\u53d1\u751f\uff0c\u8981\u4e48\u90fd\u4e0d\u53d1\u751f\u3002<\/li>\n<li>C\uff1a\u4e00\u81f4\u6027\uff08<code>Consistency<\/code>\uff09\uff0c\u5728\u4e00\u4e2a\u4e8b\u52a1\u4e2d\uff0c\u4e8b\u52a1\u524d\u540e\u6570\u636e\u7684\u5b8c\u6574\u6027\u5fc5\u987b\u4fdd\u6301\u4e00\u81f4\u3002<\/li>\n<li>I\uff1a\u9694\u79bb\u6027\uff08<code>Isolation<\/code>\uff09\uff0c\u5b58\u5728\u4e8e\u591a\u4e2a\u4e8b\u52a1\u4e2d\uff0c\u4e8b\u52a1\u7684\u9694\u79bb\u6027\u662f\u6307\u591a\u4e2a\u7528\u6237\u5e76\u53d1\u8bbf\u95ee\u6570\u636e\u5e93\u65f6\uff0c\u4e00\u4e2a\u7528\u6237\u7684\u4e8b\u52a1\u4e0d\u80fd\u88ab\u5176\u5b83\u7528\u6237\u7684\u4e8b\u52a1\u6240\u5e72\u6270\uff0c\u591a\u4e2a\u5e76\u53d1\u4e8b\u52a1\u4e4b\u95f4\u6570\u636e\u8981\u76f8\u4e92\u9694\u79bb\u3002<\/li>\n<li>D\uff1a\u6301\u4e45\u6027\uff08<code>Durability<\/code>\uff09\uff0c\u6301\u4e45\u6027\u662f\u6307\u4e00\u4e2a\u4e8b\u52a1\u4e00\u65e6\u88ab\u63d0\u4ea4\uff0c\u5b83\u5bf9\u6570\u636e\u5e93\u4e2d\u6570\u636e\u7684\u6539\u53d8\u5c31\u662f\u6c38\u4e45\u6027\u7684\uff0c\u63a5\u4e0b\u6765\u5373\u4f7f\u6570\u636e\u5e93\u53d1\u751f\u6545\u969c\u4e5f\u4e0d\u5e94\u8be5\u5bf9\u5176\u6709\u4efb\u4f55\u5f71\u54cd\u3002<\/li>\n<\/ul>\n<h3>34\u3001\u5e76\u53d1\u4e8b\u52a1\u5e26\u6765\u7684\u95ee\u9898<\/h3>\n<ul>\n<li>\u810f\u8bfb\uff08Dirty read\uff09\uff1aB\u4e8b\u52a1\u8bfb\u53d6\u5230\u4e86A\u4e8b\u52a1\u5c1a\u672a\u63d0\u4ea4\u7684\u6570\u636e\uff1b<\/li>\n<li>\u4e22\u5931\u4fee\u6539\uff08Lost to modify\uff09\uff1a\u5728\u4e00\u4e2a\u4e8b\u52a1\u8bfb\u53d6\u4e00\u4e2a\u6570\u636e\u65f6\uff0c\u53e6\u5916\u4e00\u4e2a\u4e8b\u52a1\u4e5f\u8bbf\u95ee\u4e86\u8be5\u6570\u636e\uff0c\u90a3\u4e48\u5728\u7b2c\u4e00\u4e2a\u4e8b\u52a1\u4e2d\u4fee\u6539\u4e86\u8fd9\u4e2a\u6570\u636e\u540e\uff0c\u7b2c\u4e8c\u4e2a\u4e8b\u52a1\u4e5f\u4fee\u6539\u4e86\u8fd9\u4e2a\u6570\u636e\u3002\u8fd9\u6837\u7b2c\u4e00\u4e2a\u4e8b\u52a1\u5185\u7684\u4fee\u6539\u7ed3\u679c\u5c31\u88ab\u4e22\u5931\uff0c\u56e0\u6b64\u79f0\u4e3a\u4e22\u5931\u4fee\u6539\u3002<\/li>\n<li>\u4e0d\u53ef\u91cd\u590d\u8bfb\uff08Unrepeatable read\uff09\uff1aB\u4e8b\u52a1\u8bfb\u5230\u4e86A\u4e8b\u52a1\u5df2\u7ecf\u63d0\u4ea4\u7684\u6570\u636e\uff0c\u5373B\u4e8b\u52a1\u5728A\u4e8b\u52a1\u63d0\u4ea4\u4e4b\u524d\u548c\u63d0\u4ea4\u4e4b\u540e\u8bfb\u53d6\u5230\u7684\u6570\u636e<code>\u5185\u5bb9<\/code>\u4e0d\u4e00\u81f4\uff08AB\u4e8b\u52a1\u64cd\u4f5c\u7684\u662f\u540c\u4e00\u6761\u6570\u636e\uff09\uff1b<\/li>\n<li>\u5e7b\u8bfb\/\u865a\u8bfb\uff1aB\u4e8b\u52a1\u8bfb\u5230\u4e86A\u4e8b\u52a1\u5df2\u7ecf\u63d0\u4ea4\u7684\u6570\u636e\uff0c\u5373A\u4e8b\u52a1\u6267\u884c\u63d2\u5165\u64cd\u4f5c\uff0cB\u4e8b\u52a1\u5728A\u4e8b\u52a1\u524d\u540e\u8bfb\u5230\u7684\u6570\u636e<code>\u6570\u91cf<\/code>\u4e0d\u4e00\u81f4\u3002<\/li>\n<\/ul>\n<h3>35\u3001\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b<\/h3>\n<p>\u4e3a\u4e86\u89e3\u51b3\u4ee5\u4e0a\u9694\u79bb\u6027\u5f15\u53d1\u7684\u5e76\u53d1\u95ee\u9898\uff0c\u6570\u636e\u5e93\u63d0\u4f9b\u4e86\u4e8b\u52a1\u7684\u9694\u79bb\u673a\u5236\u3002<\/p>\n<ul>\n<li>read uncommitted\uff08\u8bfb\u672a\u63d0\u4ea4\uff09: \u4e00\u4e2a\u4e8b\u52a1\u8fd8\u6ca1\u63d0\u4ea4\u65f6\uff0c\u5b83\u505a\u7684\u53d8\u66f4\u5c31\u80fd\u88ab\u522b\u7684\u4e8b\u52a1\u770b\u5230\uff0c\u8bfb\u53d6\u5c1a\u672a\u63d0\u4ea4\u7684\u6570\u636e\uff0c\u54ea\u4e2a\u95ee\u9898\u90fd\u4e0d\u80fd\u89e3\u51b3\uff1b<\/li>\n<li>read committed\uff08\u8bfb\u5df2\u63d0\u4ea4\uff09\uff1a\u4e00\u4e2a\u4e8b\u52a1\u63d0\u4ea4\u4e4b\u540e\uff0c\u5b83\u505a\u7684\u53d8\u66f4\u624d\u4f1a\u88ab\u5176\u4ed6\u4e8b\u52a1\u770b\u5230\uff0c\u8bfb\u53d6\u5df2\u7ecf\u63d0\u4ea4\u7684\u6570\u636e\uff0c\u53ef\u4ee5\u89e3\u51b3\u810f\u8bfb ---- oracle\u9ed8\u8ba4\u7684\uff1b<\/li>\n<li>repeatable read\uff08\u53ef\u91cd\u590d\u8bfb\uff09\uff1a\u4e00\u4e2a\u4e8b\u52a1\u6267\u884c\u8fc7\u7a0b\u4e2d\u770b\u5230\u7684\u6570\u636e\uff0c\u603b\u662f\u8ddf\u8fd9\u4e2a\u4e8b\u52a1\u5728\u542f\u52a8\u65f6\u770b\u5230\u7684\u6570\u636e\u662f\u4e00\u81f4\u7684\uff0c\u53ef\u4ee5\u89e3\u51b3\u810f\u8bfb\u548c\u4e0d\u53ef\u91cd\u590d\u8bfb ---mysql\u9ed8\u8ba4\u7684\uff1b<\/li>\n<li>serializable\uff08\u4e32\u884c\u5316\uff09\uff1a\u987e\u540d\u601d\u4e49\u662f\u5bf9\u4e8e\u540c\u4e00\u884c\u8bb0\u5f55\uff0c\u201c\u5199\u201d\u4f1a\u52a0\u201c\u5199\u9501\u201d\uff0c\u201c\u8bfb\u201d\u4f1a\u52a0\u201c\u8bfb\u9501\u201d\u3002\u5f53\u51fa\u73b0\u8bfb\u5199\u9501\u51b2\u7a81\u7684\u65f6\u5019\uff0c\u540e\u8bbf\u95ee\u7684\u4e8b\u52a1\u5fc5\u987b\u7b49\u524d\u4e00\u4e2a\u4e8b\u52a1\u6267\u884c\u5b8c\u6210\uff0c\u624d\u80fd\u7ee7\u7eed\u6267\u884c\u3002\u53ef\u4ee5\u89e3\u51b3\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\u548c\u865a\u8bfb---\u76f8\u5f53\u4e8e\u9501\u8868\u3002<\/li>\n<\/ul>\n<p>\u867d\u7136 serializable \u7ea7\u522b\u53ef\u4ee5\u89e3\u51b3\u6240\u6709\u7684\u6570\u636e\u5e93\u5e76\u53d1\u95ee\u9898\uff0c\u4f46\u662f\u5b83\u4f1a\u5728\u8bfb\u53d6\u7684\u6bcf\u4e00\u884c\u6570\u636e\u4e0a\u90fd\u52a0\u9501\uff0c\u8fd9\u5c31\u53ef\u80fd\u5bfc\u81f4\u5927\u91cf\u7684\u8d85\u65f6\u548c\u9501\u7ade\u4e89\u95ee\u9898\uff0c\u4ece\u800c\u5bfc\u81f4\u6548\u7387\u4e0b\u964d\u3002\u6240\u4ee5\u6211\u4eec\u5728\u5b9e\u9645\u5e94\u7528\u4e2d\u4e5f\u5f88\u5c11\u4f7f\u7528 serializable\uff0c\u53ea\u6709\u5728\u975e\u5e38\u9700\u8981\u786e\u4fdd\u6570\u636e\u7684\u4e00\u81f4\u6027\u800c\u4e14\u53ef\u4ee5\u63a5\u53d7\u6ca1\u6709\u5e76\u53d1\u7684\u60c5\u51b5\u4e0b\uff0c\u624d\u8003\u8651\u91c7\u7528\u8be5\u7ea7\u522b\u3002<\/p>\n<h3>36\u3001MVCC<\/h3>\n<p>\u9501\u7684\u7c92\u5ea6\u8fc7\u5927\u4f1a\u5bfc\u81f4\u6027\u80fd\u7684\u4e0b\u964d\uff0c MySQL \u7684 InnoDB \u5f15\u64ce\u4e0b\u5b58\u5728\u4e00\u79cd\u6027\u80fd\u66f4\u4f18\u8d8a\u7684 MVCC \u65b9\u6cd5\u3002<\/p>\n<p>MVCC \u662f <code>Multi-Version Concurremt Control<\/code> \u7684\u7b80\u79f0\uff0c<strong>\u610f\u601d\u662f\u57fa\u4e8e\u591a\u7248\u672c\u7684\u5e76\u53d1\u63a7\u5236\u534f\u8bae\uff0c\u901a\u8fc7\u7248\u672c\u53f7\u907f\u514d\u540c\u4e00\u6570\u636e\u5728\u4e0d\u540c\u4e8b\u52a1\u95f4\u7684\u7ade\u4e89<\/strong>\u3002\u5b83\u4e3b\u8981\u662f\u4e3a\u4e86\u63d0\u9ad8\u6570\u636e\u5e93\u7684\u5e76\u53d1\u8bfb\u5199\u6027\u80fd\uff0c\u4e0d\u7528\u52a0\u9501\u5c31\u80fd\u8ba9\u591a\u4e2a\u4e8b\u52a1\u5e76\u53d1\u8bfb\u5199\u3002<\/p>\n<p>MVCC \u7684\u5b9e\u73b0\u4f9d\u8d56\u4e8e<strong>\u9690\u85cf\u5217\u3001Undo log\u3001 Read View<\/strong> \u3002<\/p>\n<p>\u4ece\u4e0a\u9762\u5bf9 SQL \u6807\u51c6\u5b9a\u4e49\u4e86\u56db\u4e2a\u9694\u79bb\u7ea7\u522b\u7684\u4ecb\u7ecd\u53ef\u4ee5\u770b\u51fa\uff0c<strong>\u6807\u51c6\u7684 SQL \u9694\u79bb\u7ea7\u522b\u5b9a\u4e49\u91cc\uff0cREPEATABLE-READ(\u53ef\u91cd\u590d\u8bfb)\u662f\u4e0d\u53ef\u4ee5\u9632\u6b62\u5e7b\u8bfb\u7684<\/strong>\u3002<\/p>\n<p>\u4f46\u662f InnoDB \u5b9e\u73b0\u7684 REPEATABLE-READ \u9694\u79bb\u7ea7\u522b\u5176\u5b9e\u662f\u53ef\u4ee5\u89e3\u51b3\u5e7b\u8bfb\u95ee\u9898\u53d1\u751f\u7684\uff0c\u4e3b\u8981\u6709\u4e0b\u9762\u4e24\u79cd\u60c5\u51b5\uff1a<\/p>\n<ul>\n<li>\u5feb\u7167\u8bfb \uff1a\u7531 MVCC \u673a\u5236\u6765\u4fdd\u8bc1\u4e0d\u51fa\u73b0\u5e7b\u8bfb\u3002<\/li>\n<li>\u5f53\u524d\u8bfb \uff1a\u4f7f\u7528 Next-Key Lock\uff08\u4e34\u952e\u9501\uff09 \u8fdb\u884c\u52a0\u9501\u6765\u4fdd\u8bc1\u4e0d\u51fa\u73b0\u5e7b\u8bfb\uff0cNext-Key Lock \u662f\u884c\u9501\uff08Record Lock\uff09\u548c\u95f4\u9699\u9501\uff08Gap Lock\uff09\u7684\u7ed3\u5408\uff0c\u884c\u9501\u53ea\u80fd\u9501\u4f4f\u5df2\u7ecf\u5b58\u5728\u7684\u884c\uff0c\u4e3a\u4e86\u907f\u514d\u63d2\u5165\u65b0\u884c\uff0c\u9700\u8981\u4f9d\u8d56\u95f4\u9699\u9501\u3002<\/li>\n<\/ul>\n<blockquote>\n<p>InnoDB \u5b58\u50a8\u5f15\u64ce\u5728\u5206\u5e03\u5f0f\u4e8b\u52a1\u7684\u60c5\u51b5\u4e0b\u4e00\u822c\u4f1a\u7528\u5230 SERIALIZABLE \u9694\u79bb\u7ea7\u522b\u3002<\/p>\n<\/blockquote>\n<p>\u5173\u4e8e MySQL \u4e8b\u52a1\u4ee5\u53ca\u89e3\u51b3\u5e7b\u8bfb\u7684\u8be6\u7ec6\u4ecb\u7ecd\uff0c\u53ef\u4ee5\u770b\u770b\u963fQ\u5199\u7684\u8fd9\u7bc7\u6587\u7ae0\uff1a<a href=\"https:\/\/mp.weixin.qq.com\/s?__biz=MzI5MDg2NjEzNA==&amp;mid=2247484182&amp;idx=1&amp;sn=09489278900940ff1ef90cd7c0c14f98&amp;scene=21#wechat_redirect\">InnoDB \u89e3\u51b3\u5e7b\u8bfb\u7684\u65b9\u6848--LBCC&amp;MVCC<\/a><\/p>\n<h3>37\u3001Mysql \u4e2d\u7684\u9501<\/h3>\n<p>\u5177\u4f53\u7684\u9501\u8be6\u60c5\u8bf7\u53c2\u8003\u963fQ\u7684\u6b64\u7bc7\u6587\u7ae0\uff1a<a href=\"https:\/\/mp.weixin.qq.com\/s?__biz=MzI5MDg2NjEzNA==&amp;mid=2247484201&amp;idx=1&amp;sn=57f339e7126a815fbbbfc7398090f6be&amp;scene=21#wechat_redirect\">\u9762\u8bd5\u5fc5\u5907\u5e38\u89c1\u5b58\u50a8\u5f15\u64ce\u4e0e\u9501\u7684\u5206\u7c7b\uff0c\u8bf7\u67e5\u6536<\/a><\/p>\n<h3>38\u3001\u67e5\u8be2\u8bed\u53e5\u6267\u884c\u8fc7\u7a0b<\/h3>\n<pre><code>select * from tb_student  s where s.age=&#039;18&#039; and s.name=&#039; \u5f20\u4e09 &#039;;<\/code><\/pre>\n<ul>\n<li>\n<p>\u5148\u68c0\u67e5\u8be5\u8bed\u53e5\u662f\u5426\u6709\u6743\u9650\uff0c\u5982\u679c\u6ca1\u6709\u6743\u9650\uff0c\u76f4\u63a5\u8fd4\u56de\u9519\u8bef\u4fe1\u606f\uff0c\u5982\u679c\u6709\u6743\u9650\uff0c\u5728 MySQL8.0 \u7248\u672c\u4ee5\u524d\uff0c\u4f1a\u5148\u67e5\u8be2\u7f13\u5b58\uff0c\u4ee5\u8fd9\u6761 SQL \u8bed\u53e5\u4e3a key \u5728\u5185\u5b58\u4e2d\u67e5\u8be2\u662f\u5426\u6709\u7ed3\u679c\uff0c\u5982\u679c\u6709\u76f4\u63a5\u7f13\u5b58\uff0c\u5982\u679c\u6ca1\u6709\uff0c\u6267\u884c\u4e0b\u4e00\u6b65\u3002<\/p>\n<\/li>\n<li>\n<p>\u901a\u8fc7\u5206\u6790\u5668\u8fdb\u884c\u8bcd\u6cd5\u5206\u6790\uff0c\u63d0\u53d6 SQL \u8bed\u53e5\u7684\u5173\u952e\u5143\u7d20\uff0c\u6bd4\u5982\u63d0\u53d6\u4e0a\u9762\u8fd9\u4e2a\u8bed\u53e5\u662f\u67e5\u8be2 select\uff0c\u63d0\u53d6\u9700\u8981\u67e5\u8be2\u7684\u8868\u540d\u4e3a tb_student\uff0c\u9700\u8981\u67e5\u8be2\u6240\u6709\u7684\u5217\uff0c\u67e5\u8be2\u6761\u4ef6\u662f\u8fd9\u4e2a\u8868\u7684 id='1'\u3002\u7136\u540e\u5224\u65ad\u8fd9\u4e2a SQL \u8bed\u53e5\u662f\u5426\u6709\u8bed\u6cd5\u9519\u8bef\uff0c\u6bd4\u5982\u5173\u952e\u8bcd\u662f\u5426\u6b63\u786e\u7b49\u7b49\uff0c\u5982\u679c\u68c0\u67e5\u6ca1\u95ee\u9898\u5c31\u6267\u884c\u4e0b\u4e00\u6b65\u3002<\/p>\n<\/li>\n<li>\n<p>\u63a5\u4e0b\u6765\u5c31\u662f\u4f18\u5316\u5668\u8fdb\u884c\u786e\u5b9a\u6267\u884c\u65b9\u6848\uff0c\u4e0a\u9762\u7684 SQL \u8bed\u53e5\uff0c\u53ef\u4ee5\u6709\u4e24\u79cd\u6267\u884c\u65b9\u6848\uff1a<\/p>\n<\/li>\n<li>\n<ul>\n<li>a.\u5148\u67e5\u8be2\u5b66\u751f\u8868\u4e2d\u59d3\u540d\u4e3a\u201c\u5f20\u4e09\u201d\u7684\u5b66\u751f\uff0c\u7136\u540e\u5224\u65ad\u662f\u5426\u5e74\u9f84\u662f 18\u3002<\/li>\n<li>b.\u5148\u627e\u51fa\u5b66\u751f\u4e2d\u5e74\u9f84 18 \u5c81\u7684\u5b66\u751f\uff0c\u7136\u540e\u518d\u67e5\u8be2\u59d3\u540d\u4e3a\u201c\u5f20\u4e09\u201d\u7684\u5b66\u751f\u3002\u90a3\u4e48\u4f18\u5316\u5668\u6839\u636e\u81ea\u5df1\u7684\u4f18\u5316\u7b97\u6cd5\u8fdb\u884c\u9009\u62e9\u6267\u884c\u6548\u7387\u6700\u597d\u7684\u4e00\u4e2a\u65b9\u6848\uff08\u4f18\u5316\u5668\u8ba4\u4e3a\uff0c\u6709\u65f6\u5019\u4e0d\u4e00\u5b9a\u6700\u597d\uff09\u3002\u90a3\u4e48\u786e\u8ba4\u4e86\u6267\u884c\u8ba1\u5212\u540e\u5c31\u51c6\u5907\u5f00\u59cb\u6267\u884c\u4e86\u3002<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u8fdb\u884c\u6743\u9650\u6821\u9a8c\uff0c\u5982\u679c\u6ca1\u6709\u6743\u9650\u5c31\u4f1a\u8fd4\u56de\u9519\u8bef\u4fe1\u606f\uff0c\u5982\u679c\u6709\u6743\u9650\u5c31\u4f1a\u8c03\u7528\u6570\u636e\u5e93\u5f15\u64ce\u63a5\u53e3\uff0c\u8fd4\u56de\u5f15\u64ce\u7684\u6267\u884c\u7ed3\u679c\u3002<\/p>\n<\/li>\n<\/ul>\n<p>\u67e5\u8be2\u8bed\u53e5\u7684\u6267\u884c\u6d41\u7a0b\u5982\u4e0b\uff1a\u6743\u9650\u6821\u9a8c\uff08\u5982\u679c\u547d\u4e2d\u7f13\u5b58\uff09---&gt;\u67e5\u8be2\u7f13\u5b58---&gt;\u5206\u6790\u5668---&gt;\u4f18\u5316\u5668---&gt;\u6743\u9650\u6821\u9a8c---&gt;\u6267\u884c\u5668---&gt;\u5f15\u64ce<\/p>\n<h3>39\u3001\u66f4\u65b0\u8bed\u53e5\u6267\u884c\u8fc7\u7a0b<\/h3>\n<pre><code>update tb_student A set A.age=&#039;19&#039; where A.name=&#039; \u5f20\u4e09 &#039;;<\/code><\/pre>\n<p>\u8fd9\u6761\u8bed\u53e5\u57fa\u672c\u4e0a\u4e5f\u4f1a\u6cbf\u7740\u4e0a\u4e00\u4e2a\u67e5\u8be2\u7684\u6d41\u7a0b\u8d70\uff0c\u53ea\u4e0d\u8fc7\u6267\u884c\u66f4\u65b0\u7684\u65f6\u5019\u8981\u8bb0\u5f55\u65e5\u5fd7\uff0c\u8fd9\u5c31\u4f1a\u5f15\u5165\u65e5\u5fd7\u6a21\u5757\u4e86\uff0cMySQL \u81ea\u5e26\u7684\u65e5\u5fd7\u6a21\u5757\u662f binlog\uff08\u5f52\u6863\u65e5\u5fd7\uff09 \uff0c\u6240\u6709\u7684\u5b58\u50a8\u5f15\u64ce\u90fd\u53ef\u4ee5\u4f7f\u7528\uff0c\u6211\u4eec\u5e38\u7528\u7684 InnoDB \u5f15\u64ce\u8fd8\u81ea\u5e26\u4e86\u4e00\u4e2a\u65e5\u5fd7\u6a21\u5757 redo log\uff08\u91cd\u505a\u65e5\u5fd7\uff09\uff0c\u6211\u4eec\u5c31\u4ee5 InnoDB \u6a21\u5f0f\u4e0b\u6765\u63a2\u8ba8\u8fd9\u4e2a\u8bed\u53e5\u7684\u6267\u884c\u6d41\u7a0b\u3002<\/p>\n<ul>\n<li>\u5148\u67e5\u8be2\u5230\u5f20\u4e09\u8fd9\u4e00\u6761\u6570\u636e\uff0c\u5982\u679c\u6709\u7f13\u5b58\uff0c\u4e5f\u662f\u4f1a\u7528\u5230\u7f13\u5b58\u3002<\/li>\n<li>\u7136\u540e\u62ff\u5230\u67e5\u8be2\u7684\u8bed\u53e5\u628a age \u6539\u4e3a 19\uff0c\u7136\u540e\u8c03\u7528\u5f15\u64ce API \u63a5\u53e3\u5199\u5165\u8fd9\u4e00\u884c\u6570\u636e\uff0cInnoDB \u5f15\u64ce\u628a\u6570\u636e\u4fdd\u5b58\u5728\u5185\u5b58\u4e2d\u540c\u65f6\u8bb0\u5f55 redo log\uff0c\u6b64\u65f6 redo log \u8fdb\u5165 prepare \u72b6\u6001\uff0c\u7136\u540e\u544a\u8bc9\u6267\u884c\u5668\u6267\u884c\u5b8c\u6210\u4e86\u968f\u65f6\u53ef\u4ee5\u63d0\u4ea4\u3002<\/li>\n<li>\u6267\u884c\u5668\u6536\u5230\u901a\u77e5\u540e\u8bb0\u5f55 binlog\uff0c\u7136\u540e\u8c03\u7528\u5f15\u64ce\u63a5\u53e3\uff0c\u63d0\u4ea4 redo log \u4e3a\u63d0\u4ea4\u72b6\u6001\u3002<\/li>\n<li>\u66f4\u65b0\u5b8c\u6210\u3002<\/li>\n<\/ul>\n<p>\u66f4\u65b0\u8bed\u53e5\u6267\u884c\u6d41\u7a0b\u5982\u4e0b\uff1a\u5206\u6790\u5668----&gt;\u6743\u9650\u6821\u9a8c----&gt;\u6267\u884c\u5668---&gt;\u5f15\u64ce---redo log(prepare \u72b6\u6001)---&gt; binlog ---&gt;redo log(commit\u72b6\u6001)<\/p>\n<h3>40\u3001sql \u4f18\u5316<\/h3>\n<ol>\n<li>\n<p>\u5e94\u5c3d\u91cf\u907f\u514d\u5168\u8868\u626b\u63cf\uff0c\u9996\u5148\u5e94\u8003\u8651\u5728 where \u53ca order by \u6d89\u53ca\u7684\u5217\u4e0a\u5efa\u7acb\u7d22\u5f15\uff1b<\/p>\n<\/li>\n<li>\n<p>\u5e94\u5c3d\u91cf\u907f\u514d\u5728 where \u5b50\u53e5\u4e2d\u4f7f\u7528\u4ee5\u4e0b\u8bed\u53e5\uff0c\u5426\u5219\u5c06\u5bfc\u81f4\u5f15\u64ce\u653e\u5f03\u4f7f\u7528\u7d22\u5f15\u800c\u8fdb\u884c\u5168\u8868\u626b\u63cf\uff1b<\/p>\n<\/li>\n<li>\n<ul>\n<li>\u5bf9\u5b57\u6bb5\u8fdb\u884c null \u503c\u5224\u65ad\uff0c<\/li>\n<li>\u4f7f\u7528!=\u6216&lt;&gt;<\/li>\n<li>or \u6765\u8fde\u63a5\u6761\u4ef6\uff08\u4f7f\u7528union all\u4ee3\u66ff\uff09<\/li>\n<li>in \u548c not in \u4e5f\u8981\u614e\u7528<\/li>\n<li>\u4e0d\u8981\u4f7f\u7528\u6a21\u7cca\u67e5\u8be2\uff08\u53ef\u7528\u5168\u6587\u7d22\u5f15\uff09<\/li>\n<li>\u51cf\u5c11\u8868\u8fbe\u5f0f\u64cd\u4f5c<\/li>\n<li>\u51fd\u6570\u64cd\u4f5c<\/li>\n<\/ul>\n<\/li>\n<li>\n<p>\u4efb\u4f55\u5730\u65b9\u90fd\u4e0d\u8981\u4f7f\u7528 select <em> from t \uff0c\u7528\u5177\u4f53\u7684\u5b57\u6bb5\u5217\u8868\u4ee3\u66ff\u201c<\/em> \u201d\uff0c\u4e0d\u8981\u8fd4\u56de\u7528\u4e0d\u5230\u7684\u4efb\u4f55\u5b57\u6bb5\uff1b<\/p>\n<\/li>\n<li>\n<p>\u4e00\u4e2a\u8868\u7684\u7d22\u5f15\u6570\u6700\u597d\u4e0d\u8981\u8d85\u8fc76\u4e2a\uff0c\u82e5\u592a\u591a\u5219\u5e94\u8003\u8651\u4e00\u4e9b\u4e0d\u5e38\u4f7f\u7528\u5230\u7684\u5217\u4e0a\u5efa\u7684\u7d22\u5f15\u662f\u5426\u6709\u5fc5\u8981\uff1b<\/p>\n<\/li>\n<li>\n<p>\u5f88\u591a\u65f6\u5019\u7528 exists \u4ee3\u66ff in \u662f\u4e00\u4e2a\u597d\u7684\u9009\u62e9\uff1b<\/p>\n<\/li>\n<li>\n<p>\u5c3d\u91cf\u51cf\u5c11\u591a\u8868\u8054\u5408\u67e5\u8be2\uff1b<\/p>\n<\/li>\n<li>\n<p>\u5206\u9875\u4f18\u5316\uff1b<\/p>\n<\/li>\n<li>\n<p>\u6b63\u786e\u4f7f\u7528\u7d22\u5f15\uff1b<\/p>\n<\/li>\n<\/ol>\n<h3>41\u3001\u4e3b\u4ece\u540c\u6b65\u6570\u636e<\/h3>\n<p><img src=\"https:\/\/lemon-guess.oss-cn-hangzhou.aliyuncs.com\/img\/640-1686215019036-5.png\" alt=\"\u56fe\u7247\" \/><\/p>\n<ul>\n<li>master \u4e3b\u5e93\u5c06\u6b64\u6b21\u66f4\u65b0\u7684\u4e8b\u4ef6\u7c7b\u578b<strong>\u5199\u5165\u5230\u4e3b\u5e93\u7684 binlog \u6587\u4ef6<\/strong>\u4e2d<\/li>\n<li>master <strong>\u521b\u5efa log dump \u7ebf\u7a0b\u901a\u77e5 slave<\/strong> \u9700\u8981\u66f4\u65b0\u6570\u636e<\/li>\n<li><strong>slave<\/strong> \u5411 master \u8282\u70b9\u53d1\u9001\u8bf7\u6c42\uff0c<strong>\u5c06\u8be5 binlog \u6587\u4ef6\u5185\u5bb9\u5b58\u5230\u672c\u5730\u7684 relaylog \u4e2d<\/strong><\/li>\n<li><strong>slave \u5f00\u542f sql \u7ebf\u7a0b<\/strong>\u8bfb\u53d6 relaylog \u4e2d\u7684\u5185\u5bb9\uff0c<strong>\u5c06\u5176\u4e2d\u7684\u5185\u5bb9\u5728\u672c\u5730\u91cd\u65b0\u6267\u884c\u4e00\u904d<\/strong>\uff0c\u5b8c\u6210\u4e3b\u4ece\u6570\u636e\u540c\u6b65<\/li>\n<\/ul>\n<p><strong>\u540c\u6b65\u7b56\u7565<\/strong>\uff1a<\/p>\n<ul>\n<li><strong>\u5168\u540c\u6b65\u590d\u5236<\/strong>\uff1a\u4e3b\u5e93\u5f3a\u5236\u540c\u6b65\u65e5\u5fd7\u5230\u4ece\u5e93\uff0c\u7b49\u5168\u90e8\u4ece\u5e93\u6267\u884c\u5b8c\u624d\u8fd4\u56de\u5ba2\u6237\u7aef\uff0c\u6027\u80fd\u5dee\uff1b<\/li>\n<li><strong>\u534a\u540c\u6b65\u590d\u5236<\/strong>\uff1a\u4e3b\u5e93\u6536\u5230\u81f3\u5c11\u4e00\u4e2a\u4ece\u5e93\u786e\u8ba4\u5c31\u8ba4\u4e3a\u64cd\u4f5c\u6210\u529f\uff0c\u4ece\u5e93\u5199\u5165\u65e5\u5fd7\u6210\u529f\u8fd4\u56de ack \u786e\u8ba4\uff1b<\/li>\n<\/ul>\n<h3>42\u3001\u4e3b\u4ece\u5ef6\u8fdf\u8981\u600e\u4e48\u89e3\u51b3<\/h3>\n<ul>\n<li>MySQL 5.6 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\u7ebf\u7a0b\u6765\u8fdb\u884c\u91cd\u653e<\/li>\n<li><strong>\u63d0\u9ad8\u673a\u5668\u914d\u7f6e<\/strong>(\u738b\u9053)<\/li>\n<li>\u5728\u4e1a\u52a1\u521d\u671f\u5c31\u9009\u62e9\u5408\u9002\u7684\u5206\u5e93\u3001\u5206\u8868\u7b56\u7565\uff0c<strong>\u907f\u514d\u5355\u8868\u5355\u5e93\u8fc7\u5927<\/strong>\u5e26\u6765\u989d\u5916\u7684\u590d\u5236\u538b\u529b<\/li>\n<li><strong>\u907f\u514d\u957f\u4e8b\u52a1<\/strong><\/li>\n<li><strong>\u907f\u514d\u8ba9\u6570\u636e\u5e93\u8fdb\u884c\u5404\u79cd\u5927\u91cf\u8fd0\u7b97<\/strong><\/li>\n<li>\u5bf9\u4e8e\u4e00\u4e9b\u5bf9\u5ef6\u8fdf\u5f88\u654f\u611f\u7684\u4e1a\u52a1<strong>\u76f4\u63a5\u4f7f\u7528\u4e3b\u5e93\u8bfb<\/strong><\/li>\n<\/ul>\n<h3>43\u3001\u4e3a\u4ec0\u4e48\u4e0d\u8981\u4f7f\u7528\u957f\u4e8b\u52a1<\/h3>\n<ul>\n<li>\u5e76\u53d1\u60c5\u51b5\u4e0b\uff0c\u6570\u636e\u5e93<strong>\u8fde\u63a5\u6c60\u5bb9\u6613\u88ab\u6491\u7206<\/strong><\/li>\n<li><strong>\u5bb9\u6613\u9020\u6210\u5927\u91cf\u7684\u963b\u585e\u548c\u9501\u8d85\u65f6<\/strong>\uff0c\u957f\u4e8b\u52a1\u8fd8\u5360\u7528\u9501\u8d44\u6e90\uff0c\u4e5f\u53ef\u80fd\u62d6\u57ae\u6574\u4e2a\u5e93<\/li>\n<li>\u6267\u884c\u65f6\u95f4\u957f\uff0c\u5bb9\u6613\u9020\u6210<strong>\u4e3b\u4ece\u5ef6\u8fdf<\/strong><\/li>\n<li><strong>\u56de\u6eda\u6240\u9700\u8981\u7684\u65f6\u95f4\u6bd4\u8f83\u957f<\/strong>\uff0c\u4e8b\u52a1\u8d8a\u957f\u6574\u4e2a\u65f6\u95f4\u6bb5\u5185\u7684\u4e8b\u52a1\u4e5f\u5c31\u8d8a\u591a<\/li>\n<li><strong>undolog 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&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"ngg_post_thumbnail":0},"categories":[23],"tags":[24,172],"_links":{"self":[{"href":"\/index.php?rest_route=\/wp\/v2\/posts\/8794"}],"collection":[{"href":"\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8794"}],"version-history":[{"count":1,"href":"\/index.php?rest_route=\/wp\/v2\/posts\/8794\/revisions"}],"predecessor-version":[{"id":8795,"href":"\/index.php?rest_route=\/wp\/v2\/posts\/8794\/revisions\/8795"}],"wp:attachment":[{"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8794"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8794"},{"taxonomy":"post_tag","embeddable":true,"href":"\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8794"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}