{"id":2083,"date":"2023-04-01T21:52:43","date_gmt":"2023-04-01T13:52:43","guid":{"rendered":"https:\/\/www.appblog.cn\/?p=2083"},"modified":"2023-04-06T15:48:50","modified_gmt":"2023-04-06T07:48:50","slug":"database-concurrency-processing-introduction-to-mysql-locks","status":"publish","type":"post","link":"https:\/\/www.appblog.cn\/index.php\/2023\/04\/01\/database-concurrency-processing-introduction-to-mysql-locks\/","title":{"rendered":"\u6570\u636e\u5e93\u5e76\u53d1\u5904\u7406 &#8211; MySQL\u9501\u7b80\u4ecb"},"content":{"rendered":"<h2>\u4e3a\u4ec0\u4e48\u8981\u6709\u9501\uff1f<\/h2>\n<p>\u6211\u4eec\u90fd\u662f\u77e5\u9053\uff0c\u6570\u636e\u5e93\u4e2d\u9501\u7684\u8bbe\u8ba1\u662f\u89e3\u51b3\u591a\u7528\u6237\u540c\u65f6\u8bbf\u95ee\u5171\u4eab\u8d44\u6e90\u65f6\u7684\u5e76\u53d1\u95ee\u9898\u3002\u5728\u8bbf\u95ee\u5171\u4eab\u8d44\u6e90\u65f6\uff0c\u9501\u5b9a\u4e49\u4e86\u7528\u6237\u8bbf\u95ee\u7684\u89c4\u5219\u3002\u6839\u636e\u52a0\u9501\u7684\u8303\u56f4\uff0cMySQL \u4e2d\u7684\u9501\u53ef\u5927\u81f4\u5206\u6210\u5168\u5c40\u9501\uff0c\u8868\u7ea7\u9501\u548c\u884c\u9501\u4e09\u7c7b\u3002\u5728\u672c\u7bc7\u6587\u7ae0\u4e2d\uff0c\u4f1a\u4f9d\u6b21\u4ecb\u7ecd\u4e09\u79cd\u7c7b\u578b\u7684\u9501\u3002\u5728\u9605\u8bfb\u672c\u7bc7\u6587\u7ae0\u540e\uff0c\u5e94\u8be5\u638c\u63e1\u5982\u4e0b\u7684\u5185\u5bb9\uff1a<\/p>\n<ol>\n<li>\u4e3a\u4ec0\u4e48\u8981\u5728\u5907\u4efd\u65f6\u4f7f\u7528\u5168\u5c40\u9501\uff1f<\/li>\n<li>\u4e3a\u4ec0\u4e48\u63a8\u8350\u4f7f\u7528 InnoDB \u4f5c\u4e3a\u5f15\u64ce\u8fdb\u884c\u5907\u4efd\uff1f<\/li>\n<li>\u8bbe\u7f6e\u5168\u5c40\u53ea\u8bfb\u7684\u65b9\u6cd5<\/li>\n<li>\u8868\u7ea7\u9501\u7684\u4e24\u79cd\u7c7b\u578b<\/li>\n<li>MDL \u5bfc\u81f4\u6570\u636e\u5e93\u6302\u6389\u7684\u95ee\u9898<\/li>\n<li>\u5982\u4f55\u5229\u7528\u4e24\u6bb5\u9501\u534f\u8bae\u51cf\u5c11\u9501\u51b2\u7a81<\/li>\n<li>\u5982\u4f55\u89e3\u51b3\u6b7b\u9501<\/li>\n<li>\u5bf9\u4e8e\u70ed\u70b9\u8868\uff0c\u5982\u4f55\u907f\u514d\u6b7b\u9501\u68c0\u6d4b\u7684\u635f\u8017\uff1f<\/li>\n<\/ol>\n<p><!-- more --><\/p>\n<h2>\u5168\u5c40\u9501<\/h2>\n<h3>\u4ec0\u4e48\u662f\u5168\u5c40\u9501\uff1f<\/h3>\n<p>\u5168\u5c40\u9501\u4f1a\u8ba9\u6574\u4e2a\u5e93\u5904\u4e8e\u53ea\u8bfb\u72b6\u6001\uff0c\u5176\u4ed6\u7ebf\u7a0b\u8bed\u53e5\uff08DML\uff0cDDL\uff0c\u66f4\u65b0\u4e8b\u52a1\u7c7b\uff09\u7684\u8bed\u53e5\u90fd\u88ab\u4f1a\u963b\u585e\u3002<\/p>\n<h3>\u4f7f\u7528\u5168\u5c40\u9501\u7684\u573a\u666f<\/h3>\n<p>\u5728\u505a\u5168\u5e93\u903b\u8f91\u5907\u4efd\u65f6\uff0c\u4f1a\u628a\u6574\u5e93\u8fdb\u884c select \u7136\u540e\u4fdd\u5b58\u6210\u6587\u672c\u3002<\/p>\n<h3>\u4e3a\u4ec0\u4e48\u8981\u4f7f\u7528\u5168\u5c40\u9501\uff1f<\/h3>\n<p>\u60f3\u8c61\u8fd9\u6837\u4e00\u4e2a\u573a\u666f\uff0c\u8981\u5907\u4efd\u4e00\u4e2a\u8d2d\u4e70\u7cfb\u7edf\uff0c\u5176\u4e2d\u8d2d\u4e70\u64cd\u4f5c\u6d89\u53ca\u5230\u66f4\u65b0\u8d26\u53f7\u4f59\u989d\u8868\u548c\u7528\u6237\u8bfe\u7a0b\u8868\u3002<\/p>\n<p>\u73b0\u5728\u8fdb\u884c\u903b\u8f91\u5907\u4efd\uff0c\u5728\u5907\u4efd\u8fc7\u7a0b\u4e2d\uff0c\u4e00\u4f4d\u7528\u6237\u8d2d\u4e70\u4e86\u4e00\u95e8\u8bfe\u7a0b\uff0c\u8fd9\u65f6\u9700\u8981\u5728\u4f59\u989d\u8868\u6263\u6389\u4f59\u989d\uff0c\u7136\u540e\u5728\u8d2d\u4e70\u7684\u8bfe\u7a0b\u4e2d\u52a0\u4e0a\u4e00\u95e8\u8bfe\u3002\u6b63\u786e\u7684\u987a\u5e8f\u80af\u5b9a\u662f\u5148\u8fdb\u884c\u8d2d\u4e70\u64cd\u4f5c\uff0c\u51cf\u5c11\u4f59\u989d\u548c\u589e\u52a0\u8bfe\u7a0b\u7136\u540e\u5728\u8fdb\u884c\u5907\u4efd\u3002\u4f46\u5374\u6709\u53ef\u80fd\u51fa\u73b0\u8fd9\u6837\u7684\u95ee\u9898\uff1a<\/p>\n<ol>\n<li>\u5982\u679c\u5728\u65f6\u95f4\u987a\u5e8f\u4e0a\u5148\u5907\u4efd\u4f59\u989d\u8868 (u_account)\uff0c\u7136\u540e\u7528\u6237\u8d2d\u4e70(\u64cd\u4f5c\u4e24\u5f20\u8868)\uff0c\u518d\u5907\u4efd\u7528\u6237\u8bfe\u7a0b\u8868(u_course)\uff1f<\/li>\n<\/ol>\n<p>\u8fd9\u65f6\u7528\u5907\u4efd\u7684\u6570\u636e\u505a\u6062\u590d\u65f6\uff0c\u4f1a\u53d1\u73b0\u7528\u6237\u6ca1\u82b1\u94b1\u5374\u4e70\u4e86\u4e00\u5802\u8bfe\u3002\u539f\u56e0\u5728\u4e8e\uff0c\u5148\u5907\u4efd\u4f59\u989d\u8868\uff0c\u8bf4\u660e\u7528\u6237\u4f59\u989d\u4e0d\u53d8\u3002\u4e4b\u540e\u624d\u8fdb\u884c\u8d2d\u4e70\u64cd\u4f5c\uff0c\u4f59\u989d\u8868\u51cf\u94b1\uff0c\u8bfe\u7a0b\u8868\u589e\u52a0\u4e00\u95e8\u8bfe\u7a0b\u3002\u63a5\u7740\u5907\u4efd\u8bfe\u7a0b\u8868\uff0c\u8bfe\u7a0b\u8868\u8bfe\u7a0b\u52a0\u4e00\u3002\u8d2d\u4e70\u64cd\u4f5c\u5728\u5df2\u7ecf\u5907\u4efd\u5b8c\u7684\u4f59\u989d\u8868\u540e\u8fdb\u884c\u3002<\/p>\n<ol start=\"2\">\n<li>\u5982\u679c\u5728\u65f6\u95f4\u987a\u5e8f\u4e0a\u5148\u5907\u4efd\u7528\u6237\u8bfe\u7a0b\u8868(u_course)\uff0c\u7136\u540e\u7528\u6237\u8d2d\u4e70(\u64cd\u4f5c\u4e24\u5f20\u8868)\uff0c\u518d\u5907\u4efd\u4f59\u989d\u8868 (u_account)\uff1f<\/li>\n<\/ol>\n<p>\u540c\u6837\u7684\uff0c\u5982\u679c\u5148\u5907\u4efd\u8bfe\u7a0b\u8868\uff0c\u8bfe\u7a0b\u6ca1\u6709\u589e\u52a0\uff0c\u56e0\u4e3a\u6ca1\u6709\u8fdb\u884c\u8d2d\u4e70\u64cd\u4f5c\u3002\u4e4b\u540e\u8fdb\u884c\u8d2d\u4e70\u64cd\u4f5c\u540e\uff0c\u4f59\u989d\u8868\u51cf\u94b1\uff0c\u7136\u540e\u88ab\u5907\u4efd\u3002\u5c31\u51fa\u73b0\u4e86\uff0c\u7528\u6237\u82b1\u94b1\u5374\u6ca1\u6709\u8d2d\u4e70\u6210\u529f\u7684\u60c5\u51b5\u3002<\/p>\n<p>\u4e5f\u5c31\u662f\u8bf4\uff0c\u4e0d\u52a0\u9501\u7684\u8bdd\uff0c\u5907\u4efd\u7cfb\u7edf\u7684\u5f97\u5230\u7684\u5e93\u4e0d\u662f\u4e00\u4e2a\u903b\u8f91\u65f6\u95f4\u70b9\uff0c\u8fd9\u4e2a\u89c6\u56fe\u662f\u903b\u8f91\u4e0d\u4e00\u81f4\u3002<\/p>\n<h3>\u5982\u4f55\u89e3\u51b3\u89c6\u56fe\u903b\u8f91\u4e0d\u4e00\u81f4\u7684\u95ee\u9898\uff1f<\/h3>\n<p>\u5bf9\u4e8e\u4e0d\u652f\u6301\u4e8b\u52a1\u7684\u5f15\u64ce\uff0c\u50cf MyISAM\uff0c\u901a\u8fc7\u4f7f\u7528<code>Flush tables with read lock (FTWRL)<\/code>\u547d\u4ee4\u6765\u5f00\u542f\u5168\u5c40\u9501\u3002<\/p>\n<p>\u4f46\u4f7f\u7528 FTWRL \u5b58\u5728\u7684\u95ee\u9898\u662f\uff1a<\/p>\n<ul>\n<li>\u5728\u4e3b\u5e93\u4e0a\u5907\u4efd\u65f6\uff0c\u5907\u4efd\u671f\u95f4\u4e0d\u80fd\u6267\u884c\u66f4\u65b0\uff0c\u4e1a\u52a1\u57fa\u672c\u6682\u505c<\/li>\n<li>\u5728\u4ece\u5e93\u4e0a\u5907\u4efd\u65f6\uff0c\u5907\u4efd\u671f\u95f4\u4ece\u5e93\u4e0d\u80fd\u6267\u884c\u4e3b\u5e93\u540c\u6b65\u8fc7\u6765\u7684 binlog\uff0c\u5bfc\u81f4\u4e3b\u4ece\u5ef6\u8fdf<\/li>\n<\/ul>\n<p>\u5bf9\u4e8e\u652f\u6301\u4e8b\u52a1\u5e76\u4e14\u5f00\u542f\u4e00\u81f4\u6027\u89c6\u56fe\uff08\u53ef\u91cd\u590d\u8bfb\u7ea7\u522b\uff09\u4e0b\u914d\u5408\u4e0a MVCC \u7684\u529f\u80fd\u7684\u5f15\u64ce\uff08InnoDB\uff09\uff0c\u5907\u4efd\u5c31\u5f88\u7b80\u5355\u4e86\u3002<\/p>\n<p>\u4f7f\u7528\u5b98\u65b9\u7684<code>mysqldump<\/code>\u5de5\u5177\u65f6\uff0c\u52a0\u4e0a<code>--single-transaction<\/code>\u9009\u9879\uff0c\u518d\u5bfc\u51fa\u6570\u636e\u524d\u5c31\u4f1a\u542f\u52a8\u4e00\u4e2a\u4e8b\u52a1\uff0c\u6765\u786e\u4fdd\u62ff\u5230\u4e00\u81f4\u6027\u89c6\u56fe\u3002\u5e76\u4e14\u7531\u4e8e MVCC \u7684\u652f\u6301\uff0c\u540c\u65f6\u53ef\u4ee5\u8fdb\u884c\u66f4\u65b0\u64cd\u4f5c\u3002<\/p>\n<h3>\u5168\u5e93\u53ea\u8bfb\u8bbe\u7f6e\u65b9\u6cd5\u7684\u6bd4\u8f83<\/h3>\n<p>\u4e3a\u4ec0\u4e48\u4e0d\u63a8\u8350\u4f7f\u7528<code>set global readonly=true<\/code>\uff0c\u8981\u4f7f\u7528<code>FTWRL<\/code>\uff1a<\/p>\n<ol>\n<li>\n<p>\u5728\u6709\u4e9b\u7cfb\u7edf\u4e2d\uff0c<code>readonly<\/code>\u7684\u503c\u4f1a\u88ab\u7528\u6765\u505a\u5176\u4ed6\u903b\u8f91\uff0c\u6bd4\u5982\u7528\u6765\u5224\u65ad\u4e00\u4e2a\u5e93\u662f\u4e3b\u5e93\u8fd8\u662f\u5907\u5e93\u3002\u56e0\u6b64\uff0c\u4fee\u6539 global \u53d8\u91cf\u7684\u65b9\u5f0f\u5f71\u54cd\u9762\u66f4\u5927\uff0c\u4e0d\u5efa\u8bae\u4f7f\u7528\u3002<\/p>\n<\/li>\n<li>\n<p>\u5728\u5f02\u5e38\u5904\u7406\u673a\u5236\u4e0a\u6709\u5dee\u5f02\u3002<\/p>\n<\/li>\n<\/ol>\n<p>\u6267\u884c<code>FTWRL<\/code>\u547d\u4ee4\u4e4b\u540e\u7531\u4e8e\u5ba2\u6237\u7aef\u53d1\u751f\u5f02\u5e38\u65ad\u5f00\uff0c\u90a3\u4e48 MySQL \u4f1a\u81ea\u52a8\u91ca\u653e\u8fd9\u4e2a\u5168\u5c40\u9501\uff0c\u6574\u4e2a\u5e93\u56de\u5230\u53ef\u4ee5\u6b63\u5e38\u66f4\u65b0\u7684\u72b6\u6001\u3002<\/p>\n<p>\u5c06\u6574\u4e2a\u5e93\u8bbe\u7f6e\u4e3a<code>readonly<\/code>\u4e4b\u540e\uff0c\u5982\u679c\u5ba2\u6237\u7aef\u53d1\u751f\u5f02\u5e38\uff0c\u5219\u6570\u636e\u5e93\u5c31\u4f1a\u4e00\u76f4\u4fdd\u6301<code>readonly<\/code>\u72b6\u6001\uff0c\u8fd9\u6837\u4f1a\u5bfc\u81f4\u6574\u4e2a\u5e93\u957f\u65f6\u95f4\u5904\u4e8e\u4e0d\u53ef\u5199\u72b6\u6001\uff0c\u98ce\u9669\u8f83\u9ad8\u3002<\/p>\n<h2>\u8868\u7ea7\u9501<\/h2>\n<h3>\u4ec0\u4e48\u662f\u8868\u7ea7\u9501\uff1f<\/h3>\n<p>\u8868\u7ea7\u9501\u7684\u4f5c\u7528\u57df\u662f\u5bf9\u67d0\u5f20\u8868\u8fdb\u884c\u52a0\u9501\uff0c\u5728 MySQL \u4e2d\u8868\u7ea7\u522b\u7684\u9501\u6709\u4e24\u79cd\uff0c\u4e00\u79cd\u662f\u8868\u9501\uff0c\u4e00\u79cd\u662f\u5143\u6570\u636e\u9501\uff08meta data lock\uff0cMDL\uff09\u3002<\/p>\n<h3>\u8868\u9501<\/h3>\n<p>\u4e0e<code>FTWRL<\/code>\u7c7b\u4f3c\uff0c\u53ef\u4ee5\u4f7f\u7528<code>lock tables \u2026 read\/write<\/code>\u6765\u9501\u5b9a\u67d0\u5f20\u8868\u3002\u5728\u91ca\u653e\u65f6\uff0c\u53ef\u4ee5\u4f7f\u7528<code>unlock tables<\/code>\u6765\u91ca\u653e\u9501\u6216\u8005\u65ad\u5f00\u8fde\u63a5\u65f6\uff0c\u4e3b\u52a8\u91ca\u653e\u3002<\/p>\n<p>\u9700\u8981\u6ce8\u610f\u7684\u662f\uff0c\u8fd9\u6837\u65b9\u5f0f\u7684\u9501\u8868\uff0c\u4e0d\u4f46\u4f1a\u9650\u5236\u5176\u4ed6\u7ebf\u7a0b\u7684\u8bfb\u5199\uff0c\u4e5f\u9650\u5b9a\u4e86\u81ea\u5df1\u7ebf\u7a0b\u7684\u64cd\u4f5c\u5bf9\u8c61\u3002<\/p>\n<p>\u5047\u5982\uff0c\u7ebf\u7a0b A \u6267\u884c<code>lock tables t1 read, t2 write;<\/code>\u64cd\u4f5c\u3002<\/p>\n<p>\u8fd9\u65f6\u5bf9\u4e8e\u8868 t1 \u6765\u8bf4\uff0c\u5176\u4ed6\u7ebf\u7a0b\u53ea\u80fd\u53ea\u8bfb\uff0c\u7ebf\u7a0b A \u4e5f\u53ea\u80fd\u53ea\u8bfb\uff0c\u4e0d\u80fd\u5199\u3002<\/p>\n<p>\u5bf9\u4e8e\u8868 t2 \u6765\u8bf4\uff0c\u53ea\u5141\u8bb8\u7ebf\u7a0b A \u8bfb\u5199\uff0c\u5176\u4ed6\u7ebf\u7a0b\u8bfb\u5199\u90fd\u4f1a\u88ab\u963b\u585e\u3002<\/p>\n<h3>\u5143\u6570\u636e\u9501<\/h3>\n<p>\u4e0e\u8868\u9501\u624b\u52a8\u52a0\u9501\u4e0d\u540c\uff0c\u5143\u6570\u636e\u9501\u4f1a\u81ea\u52a8\u52a0\u4e0a\u3002<\/p>\n<p><strong>\u4e3a\u4ec0\u4e48\u8981\u6709 MDL\uff1f<\/strong><\/p>\n<p>MDL \u4fdd\u8bc1\u7684\u5c31\u662f\u8bfb\u5199\u7684\u6b63\u786e\u6027\uff0c\u6bd4\u5982\u5728\u67e5\u8be2\u4e00\u4e2a\u8868\u4e2d\u7684\u6570\u636e\u65f6\uff0c\u540c\u65f6\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u6539\u53d8\u4e86\u8868\u7ed3\u6784\uff0c\u67e5\u8be2\u7684\u7ed3\u679c\u548c\u8868\u7ed3\u6784\u4e0d\u4e00\u81f4\u80af\u5b9a\u4e0d\u884c\u3002\u7b80\u5355\u6765\u8bf4\uff0c<strong>MDL \u5c31\u662f\u89e3\u51b3 DML \u548c DDL \u4e4b\u95f4\u540c\u65f6\u64cd\u4f5c\u7684\u95ee\u9898<\/strong>\u3002<\/p>\n<p>\u5728 MySQL 5.5 \u5f15\u5165\u4e86 MDL\uff0c<strong>\u5728\u5bf9\u4e00\u4e2a\u8fdb\u884c DML \u65f6\uff0c\u4f1a\u52a0 MDL \u8bfb\u9501\u3002\u8fdb\u884c DDL \u65f6\uff0c\u4f1a\u52a0 MDL \u5199\u9501<\/strong>\u3002<\/p>\n<p>\u8bfb\u9501\u95f4\u4e0d\u4e92\u65a5\uff0c\u5141\u8bb8\u591a\u4e2a\u7ebf\u7a0b\u540c\u65f6\u5bf9\u540c\u4e00\u5f20\u8868\u8fdb\u884c DML\u3002<\/p>\n<p>\u8bfb\u5199\u9501\u4e4b\u95f4\u3001\u5199\u9501\u4e4b\u95f4\u662f\u4e92\u65a5\u7684\uff0c\u7528\u6765\u4fdd\u8bc1\u53d8\u66f4\u8868\u7ed3\u6784\u64cd\u4f5c\u7684\u5b89\u5168\u6027\u3002<\/p>\n<ol>\n<li>\u5982\u679c\u6709\u4e24\u4e2a\u7ebf\u7a0b\u8981\u540c\u65f6\u7ed9\u4e00\u4e2a\u8868\u52a0\u5b57\u6bb5\uff0c\u5176\u4e2d\u4e00\u4e2a\u8981\u7b49\u53e6\u4e00\u4e2a\u6267\u884c\u5b8c\u624d\u80fd\u5f00\u59cb\u6267\u884c<\/li>\n<li>\u5982\u679c\u4e00\u4e2a\u7ebf\u7a0b\u8981\u8bfb\uff0c\u53e6\u4e00\u4e2a\u7ebf\u7a0b\u8981\u5199\u3002\u6839\u636e\u8bbf\u95ee\u8868\u7684\u65f6\u95f4\uff0c\u4e00\u4e2a\u64cd\u4f5c\u8fdb\u884c\u5b8c\u4e4b\u540e\uff0c\u53e6\u4e00\u4e2a\u624d\u53ef\u4ee5\u8fdb\u884c<\/li>\n<\/ol>\n<p><strong>MDL \u5f15\u53d1\u7684\u95ee\u9898\uff1f<\/strong><\/p>\n<p>\u7ed9\u8868\u52a0\u5b57\u6bb5\uff0c\u5374\u5bfc\u81f4\u5e93\u6302\u4e86\uff1f<\/p>\n<p>\u7531\u4e8e MDL \u662f\u81ea\u52a8\u52a0\u7684\uff0c\u5e76\u4e14\u5728\u7ed9\u8868\u52a0\u5b57\u6bb5\u6216\u8005\u4fee\u6539\u5b57\u6bb5\u6216\u8005\u52a0\u7d22\u5f15\u65f6\uff0c\u9700\u8981\u626b\u63cf\u5168\u8868\u7684\u6570\u636e\u3002\u6240\u4ee5\u5728\u5bf9\u5927\u8868\u64cd\u4f5c\u65f6\uff0c\u8981\u975e\u5e38\u5c0f\u5fc3\uff0c\u4ee5\u514d\u5bf9\u7ebf\u4e0a\u7684\u670d\u52a1\u9020\u6210\u5f71\u54cd\u3002\u4f46\u5b9e\u9645\u4e0a\uff0c\u64cd\u4f5c\u5c0f\u8868\u65f6\uff0c\u4e5f\u53ef\u80fd\u51fa\u95ee\u9898\u3002\u5047\u8bbe t \u662f\u5c0f\u8868\u3002\u6309\u7167\u4e0b\u56fe\u6240\u793a\uff0c\u6253\u5f00\u56db\u4e2a session<\/p>\n<p>\u5047\u8bbe\u6709\u4e00\u5f20\u53eb sync_test \u7684\u8868\uff1a<\/p>\n<pre><code class=\"language-sql\">mysql&gt; desc sync_test;\n+-------+--------------+------+-----+---------+----------------+\n| Field | Type         | Null | Key | Default | Extra          |\n+-------+--------------+------+-----+---------+----------------+\n| id    | int(11)      | NO   | PRI | NULL    | auto_increment |\n| name  | varchar(255) | NO   |     | NULL    |                |\n+-------+--------------+------+-----+---------+----------------+\n2 rows in set (0.00 sec)<\/code><\/pre>\n<p>\u5f00\u542f\u4e8b\u52a11\uff0c\u63d2\u5165\u6570\u636e\u3002\u5bf9\u4e8e\u4e8b\u52a1 1 \u6765\u8bf4\uff0c\u81ea\u52a8\u7533\u8bf7\u4e86\u8868 sync_test \u7684 MDL \u8bfb\u9501\uff1a<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nQuery OK, 0 rows affected (0.00 sec)\n\nmysql&gt; insert into sync_test value (NULL, &#039;yuwei-c1&#039;, 1);\nQuery OK, 1 row affected (0.00 sec)\n\nmysql&gt;<\/code><\/pre>\n<p>\u5f00\u542f\u4e8b\u52a12\uff0c\u63d2\u5165\u6570\u636e\u3002\u5bf9\u4e8e\u4e8b\u52a1 2 \u6765\u8bf4\uff0c\u81ea\u52a8\u7533\u8bf7\u4e86\u8868 sync_test \u7684 MDL \u8bfb\u9501\uff1a<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nQuery OK, 0 rows affected (0.00 sec)\n\nmysql&gt; insert into sync_test value (NULL, &#039;yuwei-c1&#039;, 1);\nQuery OK, 1 row affected (0.00 sec)\n\nmysql&gt;<\/code><\/pre>\n<p>\u5f00\u542f\u4e8b\u52a13\uff0c\u6539\u53d8\u8868\u7ed3\u6784\u3002\u5bf9\u4e8e\u4e8b\u52a1 3 \u6765\u8bf4\uff0c\u4f1a\u7533\u8bf7\u8868 sync_test \u7684 MDL \u5199\u9501\uff0c\u8fd9\u65f6\u7531\u4e8e\u8bfb\u5199\u9501\u4e92\u65a5\uff0c\u88ab\u963b\u585e\uff1a<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nQuery OK, 0 rows affected (0.00 sec)\n\nmysql&gt; alter table sync_test add z int;\n(block)<\/code><\/pre>\n<p>\u5f00\u542f\u4e8b\u52a1 4\uff0c\u63d2\u5165\u6570\u636e\u3002\u5bf9\u4e8e\u4e8b\u52a1 4 \u6765\u8bf4\uff0c\u4f1a\u7533\u8bf7 sync_test \u7684 MDL \u8bfb\u9501\uff0c\u7531\u4e8e\u4e4b\u524d\u4e8b\u52a1 3 \u63d0\u524d\u7533\u8bf7\u4e86\u5199\u9501\uff0c\u4e92\u65a5\u6240\u4ee5\u88ab\u963b\u585e\uff1a<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nQuery OK, 0 rows affected (0.00 sec)\n\nmysql&gt; insert into sync_test value (NULL, &#039;yuwei-dl&#039;, 1);\n(block)<\/code><\/pre>\n<p>\u8fd9\u65f6\u5982\u679c\u5728\u8fd9\u5f20\u8868\u4e0a\u7684\u67e5\u8be2\u8bed\u53e5\u5f88\u9891\u7e41\uff0c\u800c\u4e14\u5ba2\u6237\u7aef\u6709\u91cd\u8fde\u673a\u5236\uff0c\u5728\u8d85\u65f6\u540e\u4f1a\u518d\u8d77\u4e00\u4e2a\u65b0 session \u8bf7\u6c42\uff0c\u8fd9\u4e2a\u5e93\u7684\u7ebf\u7a0b\u5c31\u5f88\u5feb\u4f1a\u7206\u6ee1\u4e86\u3002<\/p>\n<blockquote>\n<p>\u6709\u4e00\u70b9\u9700\u8981\u6ce8\u610f\uff0c\u4e0d\u8981\u5c06 DDL \u5199\u5728\u4e8b\u52a1\u4e2d\uff0c\u56e0\u4e3a\u5bf9\u4e8e DDL \u64cd\u4f5c\u662f\u4e0d\u652f\u6301 rollback \u64cd\u4f5c\uff0c\u6240\u4ee5\u5728\u56de\u6eda\u65f6\u4f1a\u51fa\u73b0\u4e0d\u4e00\u81f4\u7684\u60c5\u51b5\u3002\u539f\u56e0\u4e5f\u53ef\u4ee5\u7406\u89e3\uff0cMVCC \u6240\u652f\u6301\u7684\u884c\u7ea7\u522b\u7684\u6570\u636e\uff0c\u5e76\u4e0d\u652f\u6301\u8868\u7ea7\u522b\u7684\u591a\u7248\u672c\u63a7\u5236\u3002<\/p>\n<\/blockquote>\n<h3>\u5982\u4f55\u5b89\u5168\u7684\u7ed9\u8868\u52a0\u8d44\u6e90\uff1f<\/h3>\n<p>\u901a\u8fc7\u4e0a\u9762\u7684\u4f8b\u5b50\u4e5f\u53ef\u4ee5\u770b\u5230\uff0cMDL \u4f1a\u76f4\u5230\u4e8b\u52a1\u63d0\u4ea4\u624d\u91ca\u653e\uff0c\u5728\u505a\u8868\u7ed3\u6784\u53d8\u66f4\u7684\u65f6\u5019\uff0c\u4e00\u5b9a\u8981\u5c0f\u5fc3\u4e0d\u8981\u5bfc\u81f4\u9501\u4f4f\u7ebf\u4e0a\u67e5\u8be2\u548c\u66f4\u65b0\u3002\u5728\u5f00\u542f\u4e8b\u52a1\u540e\uff0c\u5e76\u6ca1\u6709\u5728\u77ed\u65f6\u95f4\u5185\u7ed3\u675f\uff0c\u4e5f\u5c31\u662f\u7531\u4e8e\u6240\u8c13\u7684\u957f\u4e8b\u52a1\u9020\u6210\u7684\u3002\u5982\u679c\u60f3\u5bf9\u67d0\u4e2a\u8868\u8fdb\u884c DDL \u7684\u64cd\u4f5c\u65f6\uff0c\u53ef\u4ee5\u5148\u67e5\u8be2\u4e0b\u662f\u5426\u6709\u957f\u4e8b\u52a1\u7684\u8fd0\u884c\uff08<code>information_schema<\/code>\u4e0b\u7684<code>innodb_trx<\/code>\u8868\uff09\uff0c\u53ef\u4ee5\u5148 kill \u8fd9\u4e2a\u4e8b\u52a1\uff0c\u7136\u540e\u505a DDL \u64cd\u4f5c\u3002<\/p>\n<p>\u4f46\u6709\u65f6 kill \u4e5f\u672a\u5fc5\u53ef\u4ee5\uff0c\u5728\u8868\u88ab\u9891\u7e41\u4f7f\u7528\u65f6\uff0c\u65b0\u7684\u4e8b\u52a1\u53ef\u80fd\u9a6c\u4e0a\u5c31\u6765\u4e86\u3002\u6bd4\u8f83\u7406\u60f3\u7684\u60c5\u51b5\uff0c\u5728<code>alter table<\/code>\u4e2d\u8bbe\u5b9a\u7b49\u5f85\u65f6\u95f4\uff0c\u5982\u679c\u5728\u65f6\u95f4\u5185\u62ff\u5230\u6700\u597d\uff0c\u5426\u5219\u5c31\u653e\u5f03\uff0c\u4e0d\u8981\u963b\u585e\u8bed\u53e5\u3002\u4e4b\u540e\u518d\u91cd\u590d\u8fd9\u4e2a\u64cd\u4f5c\u3002<\/p>\n<p>MariaDB \u5df2\u7ecf\u5408\u5e76\u4e86 AliSQL \u7684\u8fd9\u4e2a\u529f\u80fd\uff0c\u6240\u4ee5\u8fd9\u4e24\u4e2a\u5f00\u6e90\u5206\u652f\u76ee\u524d\u90fd\u652f\u6301<code>DDL NOWAIT\/WAIT n<\/code>\u8fd9\u4e2a\u8bed\u6cd5\u3002<\/p>\n<pre><code class=\"language-sql\">ALTER TABLE tbl_name NOWAIT add column ...\nALTER TABLE tbl_name WAIT N add column ...<\/code><\/pre>\n<h2>\u884c\u7ea7\u9501<\/h2>\n<h3>\u4ec0\u4e48\u662f\u884c\u7ea7\u9501\uff1f<\/h3>\n<p>MySQL \u7684\u884c\u9501\u662f\u7531\u5f15\u64ce\u5c42\u81ea\u5df1\u5b9e\u73b0\u7684\uff0c\u4e0d\u662f\u6240\u6709\u7684\u5f15\u64ce\u90fd\u6267\u884c\u884c\u9501\uff0c\u6bd4\u5982\u5728 MyISAM \u5f15\u64ce\u5c31\u4e0d\u652f\u6301\u884c\u9501\u3002\u4e0d\u652f\u6301\u884c\u9501\u610f\u5473\u7740\u5e76\u53d1\u63a7\u5236\u53ea\u80fd\u7528\u8868\u9501\uff0c\u8fd9\u5c31\u9020\u6210\u4e86\u5728\u540c\u4e00\u65f6\u523b\u53ea\u6709\u4e00\u4e2a\u66f4\u65b0\u5728\u6267\u884c\uff0c\u5c31\u5f71\u54cd\u5230\u4e86\u4e1a\u52a1\u7684\u5e76\u53d1\u5ea6\u3002InnoDB \u652f\u6301\u884c\u9501\u662f\u8ba9 MyISAM \u88ab\u53d6\u4ee3\u7684\u91cd\u8981\u539f\u56e0\u3002<\/p>\n<p>\u884c\u9501\u5c31\u662f\u5bf9\u6570\u636e\u5e93\u8868\u4e2d\u884c\u8bb0\u5f55\u7684\u9501\u3002\u6bd4\u5982\u4e8b\u52a1 A\uff0cB \u540c\u65f6\u60f3\u8981\u66f4\u65b0\u4e00\u884c\u6570\u636e\uff0c\u5728\u66f4\u65b0\u65f6\u4e00\u5b9a\u4f1a\u6309\u7167\u4e00\u5b9a\u7684\u987a\u5e8f\u8fdb\u884c\uff0c\u800c\u4e0d\u80fd\u540c\u65f6\u66f4\u65b0\u3002<\/p>\n<p>\u884c\u9501\u7684\u76ee\u7684\u5c31\u662f\u51cf\u5c11\u50cf\u8868\u7ea7\u522b\u7684\u9501\u51b2\u7a81\uff0c\u6765\u63d0\u5347\u4e1a\u52a1\u7684\u5e76\u53d1\u5ea6\u3002<\/p>\n<h3>\u4e24\u9636\u6bb5\u9501\u534f\u8bae<\/h3>\n<p>\u5728 InnoDB \u7684\u4e8b\u52a1\u4e2d\uff0c\u884c\u9501\u662f\u5728\u9700\u8981\u7684\u65f6\u5019\u5728\u52a0\u4e0a\uff0c\u4f46\u5e76\u4e0d\u662f\u4f7f\u7528\u5b8c\u5c31\u91ca\u653e\uff0c\u800c\u662f\u5728\u4e8b\u52a1\u7ed3\u675f\u540e\u624d\u91ca\u653e\uff0c\u8fd9\u5c31\u662f\u4e24\u9636\u6bb5\u9501\u534f\u8bae\u3002<\/p>\n<p>\u5047\u8bbe\u6709\u4e00\u4e2a\u8868 t\uff0c\u4e8b\u52a1 A, B \u64cd\u4f5c\u8868 t \u7684\u8fc7\u7a0b\u5982\u4e0b\uff1a<\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">\u4e8b\u52a1 A<\/th>\n<th style=\"text-align: left;\">\u4e8b\u52a1 B<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\">begin;<\/td>\n<td style=\"text-align: left;\"><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">UPDATE t SET k=k+1 where id=1;<\/td>\n<td style=\"text-align: left;\"><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">UPDATE t SET k=k+1 where id=2;<\/td>\n<td style=\"text-align: left;\">begin;<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><\/td>\n<td style=\"text-align: left;\">UPDATE t SET k=k+2 where id=1;<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">commit;<\/td>\n<td style=\"text-align: left;\"><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u5728\u4e8b\u52a1 A \u7684\u4e24\u6761\u8bed\u53e5\u66f4\u65b0\u540e\uff0c\u4e8b\u52a1 B \u66f4\u65b0\u64cd\u4f5c\u4f1a\u88ab\u963b\u585e\u3002\u76f4\u5230\u4e8b\u52a1 A \u4e2d\u6267\u884c commit \u64cd\u4f5c\u540e\u624d\u80fd\u6267\u884c\u3002<\/p>\n<h3>\u4e24\u9636\u6bb5\u9501\u5728\u4e8b\u52a1\u4e0a\u7684\u5e2e\u52a9<\/h3>\n<p>\u7531\u4e8e\u4e24\u9636\u6bb5\u9501\u7684\u7279\u70b9\uff0c\u5728\u4e8b\u52a1\u7ed3\u675f\u65f6\u624d\u4f1a\u91ca\u653e\u9501\uff0c\u6240\u4ee5\u9700\u8981\u9075\u5faa\u7684\u4e00\u4e2a\u539f\u5219\u662f<strong>\u4e8b\u52a1\u4e2d\u9700\u8981\u9501\u591a\u4e2a\u884c\u65f6\uff0c\u628a\u6709\u53ef\u80fd\u9020\u6210\u9501\u51b2\u7a81\uff0c\u6700\u53ef\u80fd\u5f71\u54cd\u5e76\u53d1\u5ea6\u7684\u9501\u5c3d\u91cf\u5411\u540e\u653e<\/strong>\u3002<\/p>\n<p>\u6bd4\u5982\u8d2d\u4e70\u8bfe\u7a0b\u7684\u4f8b\u5b50\uff0c\u987e\u5ba2 A \u8d2d\u4e70\u57f9\u8bad\u673a\u6784 B \u4e00\u95e8\u8bfe\u7a0b\u3002\u6d89\u53ca\u5230\u64cd\u4f5c\uff1a<\/p>\n<ol>\n<li>\u987e\u5ba2 A \u7684\u4f59\u989d\u51cf\u5c11<\/li>\n<li>\u57f9\u8bad\u673a\u6784 B \u6240\u5728\u7684\u4f59\u989d\u589e\u52a0\u3002<\/li>\n<li>\u63d2\u5165\u4e00\u6761\u4ea4\u6613\u4fe1\u606f\u7684\u64cd\u4f5c\u3002<\/li>\n<\/ol>\n<p>\u5bf9\u4e8e\u7b2c\u4e8c\u4e2a\u64cd\u4f5c\uff0c\u5f53\u6709\u8bb8\u591a\u4eba\u540c\u65f6\u8d2d\u4e70\u65f6\u5e76\u53d1\u5ea6\u5c31\u8f83\u9ad8\uff0c\u51fa\u73b0\u9501\u51b2\u7a81\u7684\u60c5\u51b5\u4e5f\u8f83\u9ad8\u3002\u6240\u4ee5\u5c06\u64cd\u4f5c 2 \u653e\u7f6e\u4e00\u4e2a\u4e8b\u52a1\u7684\u6700\u540e\u5c31\u66f4\u597d\u3002<\/p>\n<p>\u5f53\u6709\u65f6\u5e76\u53d1\u5ea6\u8fc7\u5927\u65f6\uff0c\u6211\u4eec\u4f1a\u53d1\u73b0\u4e00\u79cd\u73b0\u8c61 CPU \u7684\u4f7f\u7528\u7387\u63a5\u8fd1 100%\uff0c\u4f46\u4e8b\u52a1\u6267\u884c\u6570\u91cf\u5374\u5f88\u5c11\u3002\u8fd9\u5c31\u53ef\u80fd\u51fa\u73b0\u4e86\u6b7b\u9501\u3002<\/p>\n<h3>\u6b7b\u9501\u7684\u68c0\u67e5<\/h3>\n<p>\u5f53\u5e76\u53d1\u7cfb\u7edf\u4e2d\u4e0d\u540c\u7684\u7ebf\u7a0b\u51fa\u73b0\u5faa\u73af\u7684\u8d44\u6e90\u4f9d\u8d56\uff0c\u7b49\u5f85\u522b\u7684\u7ebf\u7a0b\u91ca\u653e\u8d44\u6e90\u65f6\uff0c\u5c31\u4f1a\u8ba9\u6d89\u53ca\u7684\u7ebf\u7a0b\u5904\u4e8e\u4e00\u76f4\u7b49\u5f85\u7684\u60c5\u51b5\u3002\u8fd9\u5c31\u79f0\u4e3a\u6b7b\u9501\u3002<\/p>\n<table>\n<thead>\n<tr>\n<th style=\"text-align: left;\">\u4e8b\u52a1 A<\/th>\n<th style=\"text-align: left;\">\u4e8b\u52a1 B<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td style=\"text-align: left;\">begin;<\/td>\n<td style=\"text-align: left;\"><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">UPDATE t SET k=k+1 where id=1;<\/td>\n<td style=\"text-align: left;\"><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><\/td>\n<td style=\"text-align: left;\">begin;<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><\/td>\n<td style=\"text-align: left;\">UPDATE t SET k=k+1 where id=2;<\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\">UPDATE t SET k=k+1 where id=2;<\/td>\n<td style=\"text-align: left;\"><\/td>\n<\/tr>\n<tr>\n<td style=\"text-align: left;\"><\/td>\n<td style=\"text-align: left;\">UPDATE t SET k=k+1 where id=1;<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>\u5982\u4e0a\u56fe\u4e2d\uff0c\u4e8b\u52a1 A \u5bf9id =1 \u7684\u6240\u5728\u884c\uff0c\u52a0\u5165\u4e86\u884c\u9501\u3002\u7b49\u5f85 id=2 \u7684\u884c\u9501\u3002\u4e8b\u52a1 B \u5bf9 id = 2 \u7684\u884c\uff0c\u52a0\u5165\u4e86\u884c\u9501\u3002\u7b49\u5f85 id=1 \u7684\u884c\u9501\u3002\u4e8b\u52a1 A\uff0cB \u7b49\u5f85\u5bf9\u65b9\u8d44\u6e90\u7684\u91ca\u653e\u3002<\/p>\n<h3>\u5982\u4f55\u89e3\u51b3\u6b7b\u9501<\/h3>\n<p><strong>\u65b9\u5f0f\u4e00\uff1a\u8bbe\u7f6e\u6b7b\u9501\u7684\u7b49\u5f85\u65f6\u95f4<code>innodb_lock_wait_timeout<\/code><\/strong><\/p>\n<p>\u8fd8\u662f sync_test \u8fd9\u5f20\u8868\uff0c\u6a21\u62df\u7b80\u5355\u7684\u9501\u7b49\u5f85\u60c5\u51b5\uff0c\u6ce8\u610f\u8fd9\u91cc\u5e76\u4e0d\u662f\u6b7b\u9501\u3002\u5f00\u542f\u4e24\u4e2a\u4e8b\u52a1 A\uff0cB\u3002\u540c\u65f6\u5bf9 id=1 \u8fd9\u884c\u8fdb\u884c\u66f4\u65b0\u3002<\/p>\n<p>\u4e8b\u52a1 A \u66f4\u65b0\u64cd\u4f5c\uff1a<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nQuery OK, 0 rows affected (0.00 sec)\n\nmysql&gt; update sync_test set name=&quot;dead_lock_test&quot; where id = 1;\nQuery OK, 1 row affected (0.00 sec)\nRows matched: 1  Changed: 1  Warnings: 0<\/code><\/pre>\n<p>\u4e8b\u52a1 B \u66f4\u65b0\u64cd\u4f5c\uff1a<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nQuery OK, 0 rows affected (0.00 sec)\n\nmysql&gt; update sync_test set name=&quot;dead_lock_test2&quot; where id = 1;\nERROR 1205 (HY000): Lock wait timeout exceeded; try restarting transaction<\/code><\/pre>\n<p>\u53ef\u4ee5\u770b\u5230\u4e8b\u52a1 B \u629b\u51fa\u4e86\u6b7b\u9501\u7b49\u5f85\u7684\u9519\u8bef\u3002<\/p>\n<p>\u8bbe\u7f6e\u7b49\u5f85\u65f6\u95f4\u7684\u95ee\u9898\uff1a\u5728 InnoDB \u4e2d\uff0cMySQL \u9ed8\u8ba4\u7684\u6b7b\u9501\u7b49\u5f85\u65f6\u95f4\u662f 50s\u3002\u610f\u5473\u7740\u5728\u51fa\u73b0\u6b7b\u9501\u540e\uff0c\u88ab\u9501\u4f4f\u7684\u7ebf\u7a0b\u8981\u8fc7 50s \u88ab\u80fd\u9000\u51fa\uff0c\u8fd9\u5bf9\u4e8e\u5728\u7ebf\u670d\u52a1\u8bf4\uff0c\u7b49\u5f85\u65f6\u95f4\u8fc7\u957f\u3002\u4f46\u5982\u679c\u628a\u503c\u8bbe\u7f6e\u7684\u8fc7\u5c0f\uff0c\u5982\u679c\u662f\u50cf\u4e0a\u8ff0\u4f8b\u5b50\u8fd9\u6837\u662f\u7b80\u5355\u7684\u9501\u7b49\u5f85\u5462\uff0c\u5e76\u4e0d\u662f\u6b7b\u9501\u600e\u4e48\u529e\uff0c\u5c31\u4f1a\u51fa\u73b0\u8bef\u4f24\u7684\u60c5\u51b5\u3002<\/p>\n<p><strong>\u65b9\u5f0f\u4e8c\uff1a\u53d1\u8d77\u6b7b\u9501\u68c0\u6d4b\uff0c\u53d1\u73b0\u6b7b\u9501\u540e\uff0c\u4e3b\u52a8\u56de\u6eda\u67d0\u4e2a\u4e8b\u52a1\uff0c\u8ba9\u5176\u4ed6\u4e8b\u52a1\u7ee7\u7eed\u6267\u884c<\/strong><\/p>\n<p>MySQL \u4e2d\u9ed8\u8ba4\u5c31\u662f\u6253\u5f00\u72b6\u6001\uff0c\u80fd\u591f\u5feb\u901f\u53d1\u73b0\u6b7b\u9501\u7684\u60c5\u51b5\u3002<\/p>\n<pre><code class=\"language-sql\">set innodb_deadlock_detect=on<\/code><\/pre>\n<p>\u4e8b\u52a1 A\uff0cB \u4e92\u76f8\u4f9d\u8d56\uff0c\u9020\u6210\u6b7b\u9501\u7684\u4f8b\u5b50\uff1a<\/p>\n<p>\u5f00\u542f\u4e8b\u52a1 A:<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nmysql&gt; update sync_test set name=&quot;dead_lock_test1&quot; where id = 1;<\/code><\/pre>\n<p>\u5f00\u542f\u4e8b\u52a1 B:<\/p>\n<pre><code class=\"language-sql\">mysql&gt; begin;\nmysql&gt; update sync_test set name=&quot;dead_lock_test3&quot; where id = 3;<\/code><\/pre>\n<p>\u7ee7\u7eed\u64cd\u4f5c\u4e8b\u52a1 A:<\/p>\n<pre><code class=\"language-sql\">mysql&gt; update sync_test set name=&quot;dead_lock_test3_1&quot; where id = 3;\n\n# \u4f1a\u51fa\u73b0\u963b\u585e\u7684\u60c5\u51b5<\/code><\/pre>\n<p>\u7ee7\u7eed\u64cd\u4f5c\u4e8b\u52a1 B:<\/p>\n<pre><code class=\"language-sql\">mysql&gt; update sync_test set name=&quot;dead_lock_test1_2&quot; where id = 1;\nERROR 1213 (40001): Deadlock found when trying to get lock; try restarting transaction<\/code><\/pre>\n<p>\u6b64\u65f6\u4e8b\u52a1 A \u963b\u585e\u53d6\u6d88\uff0c\u6267\u884c\u6210\u529f\u3002<\/p>\n<p>\u4e0d\u8fc7\u68c0\u6d4b\u6b7b\u9501\u4e5f\u662f\u6709\u989d\u5916\u8d1f\u62c5\u7684\uff0c\u6bcf\u5f53\u4e00\u4e2a\u4e8b\u52a1\u88ab\u9501\u7684\u65f6\u5019\uff0c\u5c31\u8981\u770b\u770b\u5b83\u6240\u4f9d\u8d56\u7684\u7ebf\u7a0b\u6709\u6ca1\u6709\u88ab\u522b\u4eba\u9501\u4f4f\uff0c\u5982\u6b64\u5faa\u73af\uff0c\u6700\u540e\u5224\u65ad\u662f\u5426\u51fa\u73b0\u4e86\u5faa\u73af\u7b49\u5f85\uff0c\u4e5f\u5c31\u662f\u6b7b\u9501\u3002\u5982\u679c\u662f\u6240\u6709\u4e8b\u52a1\u90fd\u8981\u66f4\u65b0\u540c\u4e00\u884c\u7684\u573a\u666f\u5462\uff1f\u6bcf\u4e2a\u65b0\u6765\u7684\u88ab\u5835\u4f4f\u7684\u7ebf\u7a0b\uff0c\u90fd\u8981\u5224\u65ad\u4f1a\u4e0d\u4f1a\u7531\u4e8e\u81ea\u5df1\u7684\u52a0\u5165\u5bfc\u81f4\u4e86\u6b7b\u9501\uff0c\u8fd9\u662f\u4e00\u4e2a\u65f6\u95f4\u590d\u6742\u5ea6\u662f O(n) \u7684\u64cd\u4f5c\u3002\u5047\u8bbe\u6709 1000 \u4e2a\u5e76\u53d1\u7ebf\u7a0b\u8981\u540c\u65f6\u66f4\u65b0\u540c\u4e00\u884c\uff0c\u90a3\u4e48\u6b7b\u9501\u68c0\u6d4b\u64cd\u4f5c\u5c31\u662f 1000*1000=100 \u4e07\u8fd9\u4e2a\u91cf\u7ea7\u7684\u3002<\/p>\n<p>\u6240\u4ee5\uff0c<strong>\u5bf9\u4e8e\u66f4\u65b0\u9891\u7e41\u5e76\u53d1\u91cf\u5927\u7684\u8868\uff0c\u6b7b\u9501\u68c0\u6d4b\u4f1a\u5bfc\u81f4\u6d88\u8017\u5927\u91cf\u7684 CPU<\/strong><\/p>\n<h3>\u5982\u4f55\u907f\u514d\u6b7b\u9501\u68c0\u6d4b\u7684\u635f\u8017<\/h3>\n<p>\u65b9\u6cd5\u4e00\uff1a\u5982\u679c\u4fdd\u8bc1\u4e1a\u52a1\u4e00\u5b9a\u4e0d\u4f1a\u51fa\u73b0\u6b7b\u9501\uff0c\u53ef\u4ee5\u4e34\u65f6\u628a\u6b7b\u9501\u68c0\u67e5\u5173\u6389\u3002<\/p>\n<p>\u4f46\u8fd9\u6837\u5b58\u5728\u4e00\u5b9a\u7684\u98ce\u9669\uff0c\u56e0\u4e3a\u4e1a\u52a1\u8bbe\u8ba1\u65f6\u4e0d\u4f1a\u628a\u6b7b\u9501\u5f53\u505a\u4e25\u91cd\u7684\u95ee\u9898\uff0c\u51fa\u73b0\u6b7b\u9501\u540e\u56de\u6eda\u540e\uff0c\u518d\u91cd\u8bd5\u5c31\u6ca1\u6709\u95ee\u9898\u4e86\u3002\u4f46\u5173\u6389\u6b7b\u9501\u68c0\u6d4b\u540e\uff0c\u53ef\u80fd\u51fa\u73b0\u5927\u91cf\u8d85\u65f6\u7684\u60c5\u51b5\u3002<\/p>\n<p>\u65b9\u6cd5\u4e8c\uff1a\u63a7\u5236\u5e76\u53d1\u5ea6\u3002<\/p>\n<p>\u5982\u679c\u5bf9\u4e8e\u5e76\u53d1\u91cf\u80fd\u63a7\u5236\uff0c\u6bd4\u5982\u540c\u4e00\u884c\u540c\u65f6\u6700\u591a\u53ea\u6709 10 \u4e2a\u7ebf\u7a0b\u5728\u66f4\u65b0\uff0c\u90a3\u4e48\u6b7b\u9501\u68c0\u6d4b\u7684\u6210\u672c\u5f88\u4f4e\uff0c\u5c31\u4e0d\u4f1a\u51fa\u73b0\u8fd9\u4e2a\u95ee\u9898\u3002\u5177\u4f53\u6765\u8bf4\u5728\u5ba2\u6237\u7aef\u505a\u5e76\u53d1\u63a7\u5236\uff0c\u4f46\u5bf9\u4e8e\u5ba2\u6237\u7aef\u8f83\u591a\u7684\u5e94\u7528\uff0c\u4e5f\u65e0\u6cd5\u63a7\u5236\u3002\u6240\u4ee5\u5e76\u53d1\u63a7\u5236\u5728\u6570\u636e\u5e93\u670d\u52a1\u7aef\uff0c\u5982\u679c\u6709\u4e2d\u95f4\u4ef6\uff0c\u4e5f\u53ef\u4ee5\u8003\u8651\u5728\u4e2d\u95f4\u4ef6\u4e2d\u5b9e\u73b0\u3002<\/p>\n<p>\u65b9\u6cd5\u4e09\uff1a\u964d\u4f4e\u6b7b\u9501\u7684\u6982\u7387<\/p>\n<p>\u5c06\u4e00\u884c\u7edf\u8ba1\u7684\u7ed3\u6784\uff0c\u62c6\u6210\u591a\u884c\u7d2f\u8ba1\u7684\u7ed3\u6784\u3002\u6bd4\u5982\u5c06\u4e4b\u524d\u67d0\u4e2a\u6559\u5b66\u673a\u6784\u7684\u91d1\u989d\u7531\u4e00\u884c\u62c6\u6210 10 \u884c\uff0c\u603b\u6536\u5165\u5c31\u7b49\u4e8e\u8fd9 10 \u884c\u6570\u636e\u7684\u7d2f\u8ba1\u3002\u8fd9\u6837\u539f\u6765\u9501\u51b2\u7a81\u7684\u6982\u7387\u53d8\u4e3a\u539f\u6765\u7684 1\/10\uff0c\u4e5f\u5c31\u51cf\u5c11\u4e86\u6b7b\u9501\u68c0\u6d4b\u7684 CPU \u6d88\u8017\u3002\u4f46\u5728\u4e00\u90e8\u5206\u884c\u8bb0\u5f55\u53d8\u62100\u65f6\uff0c\u4ee3\u7801\u9700\u8981\u7279\u6b8a\u5904\u7406\u3002<\/p>\n<h2>\u603b\u7ed3<\/h2>\n<p>\u672c\u7bc7\u6587\u7ae0\u4e2d\uff0c\u4f9d\u6b21\u4ecb\u7ecd\u4e86\u5168\u5c40\u9501\u3001\u8868\u7ea7\u9501\u548c\u884c\u9501\u7684\u6982\u5ff5\u3002<\/p>\n<p>\u5bf9\u4e8e\u5168\u5c40\u9501\u6765\u8bf4\uff0c\u4f7f\u7528 InnoDB \u5f15\u64ce \u5728 RR \u7ea7\u522b\u548c MVCC \u7684\u5e2e\u52a9\u4e0b\uff0c\u53ef\u4ee5\u8ba9\u5176\u5728\u5907\u4efd\u7684\u540c\u65f6\u66f4\u65b0\u6570\u636e\u3002<\/p>\n<p>\u5bf9\u4e8e\u8868\u7ea7\u9501\u6765\u8bf4\uff0c\u5bf9\u4e8e\u66f4\u65b0\u70ed\u70b9\u8868\u7684\u8868\u7ed3\u6784\u65f6\uff0c\u8981\u6ce8\u610f MDL \u8bfb\u5199\u9501\u4e92\u65a5\uff0c\u9020\u6210\u6570\u636e\u5e93\u6302\u6389\u7684\u60c5\u51b5\u3002<\/p>\n<p>\u5bf9\u4e8e\u884c\u7ea7\u9501\u6765\u8bf4\uff0c\u5408\u7406\u7684\u5229\u7528\u4e24\u6bb5\u9501\u534f\u8bae\uff0c\u964d\u4f4e\u9501\u7684\u51b2\u7a81\u3002\u5e76\u8981\u6ce8\u610f\u6b7b\u9501\u53d1\u751f\u7684\u60c5\u51b5\uff0c\u91c7\u53d6\u5408\u9002\u7684\u6b7b\u9501\u68c0\u6d4b\u624b\u6bb5\u3002<\/p>\n<p>\u53c2\u8003\uff1a<\/p>\n<ul>\n<li><a target=\"_blank\" rel=\"noopener\" href=\"https:\/\/dev.mysql.com\/doc\/refman\/5.7\/en\/innodb-deadlock-example.html\" title=\"\u6b7b\u9501\u4f8b\u5b50\">\u6b7b\u9501\u4f8b\u5b50<\/a><\/li>\n<li><a target=\"_blank\" rel=\"noopener\" href=\"https:\/\/dev.mysql.com\/doc\/refman\/5.7\/en\/cannot-roll-back.html\" title=\"DDL-ROLLBACK-FAILED\">DDL-ROLLBACK-FAILED<\/a><\/li>\n<\/ul>\n<blockquote>\n<p>\u8f6c\u8f7d\u81f3\uff1a<a target=\"_blank\" rel=\"noopener\" href=\"https:\/\/www.cnblogs.com\/michael9\/p\/12167434.html\">https:\/\/www.cnblogs.com\/michael9\/p\/12167434.html<\/a><\/p>\n<\/blockquote>\n","protected":false},"excerpt":{"rendered":"<p>\u4e3a\u4ec0\u4e48\u8981\u6709\u9501\uff1f \u6211\u4eec\u90fd\u662f\u77e5\u9053\uff0c\u6570\u636e\u5e93\u4e2d\u9501\u7684\u8bbe\u8ba1\u662f\u89e3\u51b3\u591a\u7528\u6237\u540c\u65f6\u8bbf\u95ee\u5171\u4eab\u8d44\u6e90\u65f6\u7684\u5e76\u53d1\u95ee\u9898\u3002\u5728\u8bbf\u95ee\u5171\u4eab\u8d44\u6e90\u65f6\uff0c\u9501\u5b9a [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[13],"tags":[52],"class_list":["post-2083","post","type-post","status-publish","format-standard","hentry","category-mysql","tag-lock"],"_links":{"self":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/2083","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/comments?post=2083"}],"version-history":[{"count":0,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/posts\/2083\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/media?parent=2083"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/categories?post=2083"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.appblog.cn\/index.php\/wp-json\/wp\/v2\/tags?post=2083"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}