{"id":525,"date":"2021-07-28T20:38:55","date_gmt":"2021-07-28T12:38:55","guid":{"rendered":"https:\/\/egonlin.com\/?p=525"},"modified":"2025-06-12T16:49:35","modified_gmt":"2025-06-12T08:49:35","slug":"%e4%ba%8b%e5%8a%a1%e9%9a%94%e7%a6%bb%e6%9c%ba%e5%88%b6","status":"publish","type":"post","link":"https:\/\/egonlin.com\/?p=525","title":{"rendered":"\u4e8b\u52a1\u9694\u79bb\u673a\u5236"},"content":{"rendered":"<h1>\u4e00 \u4e8b\u52a1\u9694\u79bb\u673a\u5236\/\u7ea7\u522b\u4ecb\u7ecd<\/h1>\n<p>\u4e8b\u52a1\u5177\u6709\u539f\u5b50\u6027\u3001\u4e00\u81f4\u6027\u3001\u9694\u79bb\u6027\u3001\u6301\u4e45\u6027\u56db\u5927\u7279\u6027\uff0c\u800c\u9694\u79bb\u6027\u987e\u540d\u601d\u4e49\u6307\u7684\u5c31\u662f\u4e8b\u52a1\u5f7c\u6b64\u4e4b\u95f4\u9694\u79bb\u5f00\uff0c\u591a\u4e2a\u4e8b\u52a1\u5728\u540c\u65f6\u5904\u7406\u4e00\u4e2a\u6570\u636e\u65f6\u5f7c\u6b64\u4e4b\u95f4\u4e92\u76f8\u4e0d\u5f71\u54cd\uff0c\u5982\u5982\u679c\u9694\u79bb\u7684\u4e0d\u591f\u597d\u5c31\u6709\u53ef\u80fd\u4f1a\u4ea7\u751f\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u5ea6\u3001\u5e7b\u8bfb\u7b49\u8bfb\u73b0\u8c61\uff0c\u4e3a\u6b64\uff0c\u9694\u79bb\u6027\u603b\u5171\u5206\u4e3a\u56db\u79cd\u7ea7\u522b<\/p>\n<p>\u7531\u4f4e\u5230\u9ad8\u4f9d\u6b21\u4e3a<span class=\"importance\">Read uncommitted\u00a0\u3001Read committed\u00a0\u3001Repeatable read\u00a0\u3001Serializable\u00a0\uff0c\u8fd9\u56db\u4e2a\u7ea7\u522b\u53ef\u4ee5\u9010\u4e2a\u89e3\u51b3\u810f\u8bfb\u00a0\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\u00a0\u3001\u5e7b\u8bfb\u00a0\u8fd9\u51e0\u7c7b\u95ee\u9898\u3002<\/span><\/p>\n<p>\u221a: \u53ef\u80fd\u51fa\u73b0\u00a0\u00a0\u00a0\u00a0\u00d7: \u4e0d\u4f1a\u51fa\u73b0<\/p>\n<div class=\"table-wrapper\">\n<table border=\"1\" cellspacing=\"0\" cellpadding=\"4\">\n<tbody>\n<tr>\n<td><\/td>\n<td>\u7279\u70b9<\/td>\n<td>\u810f\u8bfb<\/td>\n<td>\u4e0d\u53ef\u91cd\u590d\u8bfb<\/td>\n<td>\u5e7b\u8bfb<\/td>\n<\/tr>\n<tr>\n<td>Read uncommitted\uff08\u8bfb\u672a\u63d0\u4ea4\uff09<\/td>\n<td>\u5141\u8bb8\u4e8b\u52a1\u8bfb\u53d6\u5230\u5176\u4ed6\u4e8b\u52a1\u6240\u6267\u884c\u5b8c\u7684\u3001\u4f46\u672a\u63d0\u4ea4\u66f4\u6539<\/p>\n<p>\u4f8b\uff1a<\/p>\n<p>\u4e8b\u52a1A\u4fee\u6539\u4e86\u6570\u636e\u540e\u8fd8\u6ca1\u6709\u8fdb\u884c\u63d0\u4ea4\uff0c\u6b64\u65f6\u4e8b\u52a1B\u53bb\u8bfb\u8fd9\u4e2a\u6570\u636e\uff0c\u5374\u5df2\u7ecf\u80fd\u8bfb\u51fa\u4e86\u4fee\u6539\u540e\u7684\u6570\u636e\u3002\u4e5f\u5c31\u662f\u4f1a\u4ea7\u751f\u201c\u810f\u8bfb\u201d\u73b0\u8c61\u3002<\/td>\n<td>\u221a<\/td>\n<td>\u221a<\/td>\n<td>\u221a<\/td>\n<\/tr>\n<tr>\n<td>Read committed\uff08\u8bfb\u5df2\u63d0\u4ea4\uff09<\/td>\n<td>\u5141\u8bb8\u5176\u4ed6\u4e8b\u52a1\u67e5\u770b\u5df2\u7ecf\u63d0\u4ea4\u7684\u4e8b\u52a1<\/p>\n<p>\u4f8b\uff1a<\/p>\n<p data-pid=\"6Z0uYge5\">\u4e8b\u52a1B\u53bb\u8bfb\u4e8b\u52a1A\u4e2d\u7684\u6570\u636eD\uff0c \u7136\u540e\u4e8b\u52a1A\u4fee\u6539\u4e86\u6570\u636eD\uff0c\u8bb0\u4f5cD&#8217;, \u5e76\u63d0\u4ea4\uff0c\u6b64\u65f6\u4e8b\u52a1B\u518d\u53bb\u8bfb\u4e8b\u52a1A\u4e2d\u7684\u6570\u636eD\uff0c\u5df2\u7ecf\u53d8\u6210\u4e86D&#8217;, \u8fd9\u89e3\u51b3\u4e86\u4e4b\u524d\u7684\u810f\u8bfb\u95ee\u9898\uff0c\u4f46\u5bf9\u4e8e\u4e8b\u52a1B\u6765\u8bf4\uff0c\u524d\u540e\u4e24\u6b21\u8bfb\u5230\u7684\u6570\u636e\u4e0d\u540c\uff0c\u4ece\u800c\u4ea7\u751f\u201d\u4e0d\u53ef\u91cd\u590d\u8bfb\u201c\u95ee\u9898\uff0cOracle\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\u5c31\u662f\u8fd9\u4e2a<\/p>\n<div><\/div>\n<\/td>\n<td>\u00d7<\/td>\n<td>\u221a<\/td>\n<td>\u221a<\/td>\n<\/tr>\n<tr>\n<td>Repeatable read\uff08\u53ef\u91cd\u590d\u8bfb\uff0cinnodb\u5f15\u64ce\u9ed8\u8ba4\uff09<\/td>\n<td>\u786e\u4fdd\u6bcf\u4e2a\u4e8b\u52a1\u7684 SELECT \u8f93\u51fa\u4e00\u81f4\u00a0 InnoDB \u7684\u9ed8\u8ba4\u7ea7\u522b\u00a0 #commit\u4e4b\u540e\uff0c\u5176\u4ed6\u7a97\u53e3\u770b\u4e0d\u5230\u6570\u636e\uff0c\u5fc5\u987b\u9000\u51fa\u91cd\u65b0\u767b\u5f55\u67e5\u770b<\/p>\n<p>\u4f8b\uff1a<\/p>\n<p>\u8fd8\u662f\u62ff\u4e0a\u9762\u90a3\u4e2a\u7c7b\u6bd4\uff0c \u4e8b\u52a1B\u53bb\u8bfb\u4e8b\u52a1A\u4e2d\u7684\u6570\u636eD\uff0c \u7136\u540e\u4e8b\u52a1A\u4fee\u6539\u4e86\u6570\u636eD\uff0c\u8bb0\u4f5cD&#8217;, \u5e76\u63d0\u4ea4\uff0c\u6b64\u65f6\u4e8b\u52a1B\u518d\u53bb\u8bfb\u4e8b\u52a1A\u4e2d\u7684\u6570\u636eD\uff0c\u5b83\u4ecd\u7136\u662fD\u3002\u4e5f\u5c31\u662f\u8bf4\uff0c\u5728\u540c\u4e00\u6b21\u4e8b\u52a1\u4e2d\uff0c\u5373\u4fbf\u6570\u636e\u88ab\u5176\u4ed6\u4e8b\u52a1\u6240\u4fee\u6539\u5e76\u63d0\u4ea4\u4e86\uff0c\u4f46\u524d\u540e\u4e24\u6b21\u8bfb\u5230\u7684\u6570\u636e\u76f8\u540c\uff0c\u4ece\u800c\u907f\u514d\u4e86\u201c\u4e0d\u53ef\u91cd\u590d\u8bfb\u201d\u95ee\u9898\u3002MySQL Innodb\u5f15\u64ce\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\u5c31\u662f\u8fd9\u4e2a\u3002<\/td>\n<td>\u00d7<\/td>\n<td>\u00d7<\/td>\n<td>\u221a<\/td>\n<\/tr>\n<tr>\n<td>Serializable\uff08\u5e8f\u5217\u5316\u3001\u4e32\u884c\u5316\uff09<\/td>\n<td>\u5c06\u4e00\u4e2a\u4e8b\u52a1\u4e8e\u5176\u4ed6\u4e8b\u52a1\u5b8c\u5168\u9694\u79bb\uff0c\u5373\u4e32\u884c\u5316\u00a0 \u00a0#\u5f53\u4e00\u4e2a\u4e8b\u52a1\u6ca1\u6709\u63d0\u4ea4\uff0c\u67e5\u8be2\u4e5f\u4e0d\u884c\u3002\u4f8b\u5982\uff1a\u6211\u6539\u5fae\u4fe1\u5934\u50cf\u7684\u65f6\u5019\u4f60\u4e0d\u80fd\u770b\u6211\u7684\u4fe1\u606f\uff0c\u6211\u770b\u4f60\u670b\u53cb\u5708\u7684\u65f6\u5019\u4f60\u4e0d\u80fd\u53d1\u670b\u53cb\u5708\u4e5f\u4e0d\u80fd\u770b\u670b\u53cb\u5708<\/p>\n<p>&nbsp;<\/p>\n<p>\u4f8b\uff1a<\/p>\n<p>\u5176\u5b9e\u4e4b\u524d\u7684\u4e09\u79cd\u9694\u79bb\u7ea7\u522b\u90fd\u6ca1\u6709\u89e3\u51b3\u4e00\u79cd\u95ee\u9898\uff0c\u4e5f\u5c31\u662f\u201c\u5e7b\u8bfb\u201d\u95ee\u9898\uff0c\u6240\u8c13\u5e7b\u8bfb\u95ee\u9898\u5c31\u662f\uff0c \u4e8b\u52a1A\u5148\u67e5\u6570\u636e\uff0c\u53d1\u73b0\u53ea\u670910\u6761\u6570\u636e\uff0c\u7136\u540e\u51c6\u5907\u63d2\u5165\u4e00\u4e2aID\u4e3a11\u7684\u6570\u636e\uff0c\u4e8b\u52a1B\u8fd9\u65f6\u5019\u63d2\u5165\u4e00\u4e2aID\u4e3a11\u7684\u6570\u636e\uff0c\u5e76\u4e14\u8fdb\u884c\u4e86\u63d0\u4ea4\uff0c\u8fd9\u65f6\u5019A\u7684\u8fd9\u6761\u8bb0\u5f55\u5c31\u63d2\u4e0d\u8fdb\u53bb\u4e86\uff0c\u5373\u4fbf\u4ed6\u67e5\u8868\u6ca1\u6709\u53d1\u73b0ID\u4e3a11\u7684\u6570\u636e\uff0c\u4eff\u4f5b\u51fa\u73b0\u4e86\u5e7b\u89c9\u4e00\u822c\u3002\u5e8f\u5217\u5316\u5c31\u662f\u89e3\u51b3\u8fd9\u79cd\u95ee\u9898\u7684\uff0c\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u201c\u8bfb-\u5199\u201d\uff0c \u201c\u5199-\u8bfb\u201d\u8fd9\u6837\u7684\u5e76\u53d1\u64cd\u4f5c\uff0c\u4ee5\u727a\u7272\u5e76\u53d1\u901f\u5ea6\uff0c\u89e3\u51b3\u4e86\u201c\u810f\u8bfb\u201d\u95ee\u9898<\/td>\n<td>\u00d7<\/td>\n<td>\u00d7<\/td>\n<td>\u00d7<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>&nbsp;<\/p>\n<p>\u9700\u8981\u5f3a\u8c03\u7684\u662f\uff1a\u6211\u4eec\u786e\u5b9e\u53ef\u4ee5\u91c7\u7528\u63d0\u9ad8\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b\u7684\u65b9\u5f0f\u6765\u89e3\u51b3\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\u3001\u5e7b\u8bfb\u7b49\u95ee\u9898\uff0c\u4f46\u4e0e\u6b64\u540c\u65f6\uff0c\u4e8b\u52a1\u7684\u9694\u79bb\u7ea7\u522b\u8d8a\u9ad8\uff0c\u5e76\u53d1\u80fd\u529b\u4e5f\u5c31\u8d8a\u4f4e\u3002\u6240\u4ee5\uff0c\u8fd8\u9700\u8981\u8bfb\u8005\u6839\u636e\u4e1a\u52a1\u9700\u8981\u8fdb\u884c\u6743\u8861\u3002<\/p>\n<h1>\u4e8c \u672a\u63d0\u4ea4\u8bfb(Read uncommitted)<\/h1>\n<p>\u672a\u63d0\u4ea4\u8bfb(READ UNCOMMITTED)\u662f\u6700\u4f4e\u7684\u9694\u79bb\u7ea7\u522b\u3002\u901a\u8fc7\u540d\u5b57\u6211\u4eec\u5c31\u53ef\u4ee5\u77e5\u9053\uff0c\u5728\u8fd9\u79cd\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u4e0b\uff0c\u4e00\u4e2a\u4e8b\u52a1\u53ef\u4ee5\u8bfb\u5230\u53e6\u5916\u4e00\u4e2a\u4e8b\u52a1\u672a\u63d0\u4ea4\u7684\u6570\u636e\u3002<\/p>\n<p><strong>\u672a\u63d0\u4ea4\u8bfb\u7684\u6570\u636e\u5e93\u9501\u60c5\u51b5\uff08\u5b9e\u73b0\u539f\u7406\uff09<\/strong><\/p>\n<blockquote><p>\u4e8b\u52a1\u5728\u8bfb\u6570\u636e\u7684\u65f6\u5019\u5e76\u672a\u5bf9\u6570\u636e\u52a0\u9501\u3002<\/p>\n<p>\u52a1\u5728\u4fee\u6539\u6570\u636e\u7684\u65f6\u5019\u53ea\u5bf9\u6570\u636e\u589e\u52a0\u884c\u7ea7\u5171\u4eab\u9501\u3002<\/p><\/blockquote>\n<p>\u73b0\u8c61\uff1a<\/p>\n<blockquote><p>\u4e8b\u52a11\u8bfb\u53d6\u67d0\u884c\u8bb0\u5f55\u65f6\uff0c\u4e8b\u52a12\u4e5f\u80fd\u5bf9\u8fd9\u884c\u8bb0\u5f55\u8fdb\u884c\u8bfb\u53d6\u3001\u66f4\u65b0\uff08\u56e0\u4e3a\u4e8b\u52a1\u4e00\u5e76\u672a\u5bf9\u6570\u636e\u589e\u52a0\u4efb\u4f55\u9501\uff09<\/p>\n<p>\u5f53\u4e8b\u52a12\u5bf9\u8be5\u8bb0\u5f55\u8fdb\u884c\u66f4\u65b0\u65f6\uff0c\u4e8b\u52a11\u518d\u6b21\u8bfb\u53d6\u8be5\u8bb0\u5f55\uff0c\u80fd\u8bfb\u5230\u4e8b\u52a12\u5bf9\u8be5\u8bb0\u5f55\u7684\u4fee\u6539\u7248\u672c\uff08\u56e0\u4e3a\u4e8b\u52a1\u4e8c\u53ea\u589e\u52a0\u4e86\u5171\u4eab\u8bfb\u9501\uff0c\u4e8b\u52a1\u4e00\u53ef\u4ee5\u518d\u589e\u52a0\u5171\u4eab\u8bfb\u9501\u8bfb\u53d6\u6570\u636e\uff09\uff0c\u5373\u4f7f\u8be5\u4fee\u6539\u5c1a\u672a\u88ab\u63d0\u4ea4\uff0c\u82e5\u6b64\u65f6\u4e8b\u52a12\u56de\u6eda\uff0c\u90a3\u4e8b\u52a11\u8bfb\u5230\u7684\u5c31\u810f\u6570\u636e\u4e86\uff0c\u8fd9\u5c31\u5f15\u53d1\u4e86\u810f\u8bfb\u73b0\u8c61<\/p>\n<p>\u4e8b\u52a11\u66f4\u65b0\u67d0\u884c\u8bb0\u5f55\u65f6\uff0c\u4e8b\u52a12\u4e0d\u80fd\u5bf9\u8fd9\u884c\u8bb0\u5f55\u505a\u66f4\u65b0\uff0c\u76f4\u5230\u4e8b\u52a11\u7ed3\u675f\u3002\uff08\u56e0\u4e3a\u4e8b\u52a1\u4e00\u5bf9\u6570\u636e\u589e\u52a0\u4e86\u5171\u4eab\u8bfb\u9501\uff0c\u4e8b\u52a1\u4e8c\u4e0d\u80fd\u589e\u52a0\u6392\u4ed6\u5199\u9501\u8fdb\u884c\u6570\u636e\u7684\u4fee\u6539\uff09<\/p><\/blockquote>\n<p><strong>\u4e3e\u4f8b<\/strong><\/p>\n<p>\u4e0b\u9762\u8fd8\u662f\u501f\u7528\u6211\u5728\u6570\u636e\u5e93\u7684\u8bfb\u73b0\u8c61\u6d45\u6790\u4e00\u6587\u4e2d\u4e3e\u7684\u4f8b\u5b50\u6765\u8bf4\u660e\u5728\u672a\u63d0\u4ea4\u8bfb\u7684\u9694\u79bb\u7ea7\u522b\u4e2d\u4e24\u4e2a\u4e8b\u52a1\u4e4b\u95f4\u7684\u9694\u79bb\u60c5\u51b5\u3002<\/p>\n<div class=\"table-wrapper\">\n<table border=\"1\">\n<tbody>\n<tr>\n<th>\u4e8b\u52a1\u4e00<\/th>\n<th>\u4e8b\u52a1\u4e8c<\/th>\n<\/tr>\n<tr>\n<td><code>\/* Query 1 *\/<\/code><br \/>\n<code><br \/>\nSELECT age FROM users WHERE id = 1;<br \/>\n<\/code><br \/>\n<code>\/* will read 20 *\/<\/code><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td><code><br \/>\n\/* Query 2 *\/<\/code><br \/>\n<code>UPDATE users SET age = 21 WHERE id = 1;<\/code><br \/>\n<code><br \/>\n\/* No commit here *\/<\/code><\/td>\n<\/tr>\n<tr>\n<td><code><br \/>\n\/* Query 1 *\/<\/code><br \/>\n<code>SELECT age FROM users WHERE id = 1;<\/code><br \/>\n<code>\/* will read 21 *\/<\/code><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td><code><br \/>\nROLLBACK;<\/code><br \/>\n<code>\/* lock-based DIRTY READ *\/<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>\u4e8b\u52a1\u4e00\u5171\u67e5\u8be2\u4e86\u4e24\u6b21\uff0c\u5728\u4e24\u6b21\u67e5\u8be2\u7684\u8fc7\u7a0b\u4e2d\uff0c\u4e8b\u52a1\u4e8c\u5bf9\u6570\u636e\u8fdb\u884c\u4e86\u4fee\u6539\uff0c\u5e76\u672a\u63d0\u4ea4\uff08commit\uff09\u3002\u4f46\u662f\u4e8b\u52a1\u4e00\u7684\u7b2c\u4e8c\u6b21\u67e5\u8be2\u67e5\u5230\u4e86\u4e8b\u52a1\u4e8c\u7684\u4fee\u6539\u7ed3\u679c\u3002\u5728\u6570\u636e\u5e93\u7684\u8bfb\u73b0\u8c61\u6d45\u6790\u4e2d\u6211\u4eec\u4ecb\u7ecd\u8fc7\uff0c\u8fd9\u79cd\u73b0\u8c61\u6211\u4eec\u79f0\u4e4b\u4e3a\u810f\u8bfb\u3002<\/p>\n<p>\u6240\u4ee5\uff0c\u672a\u63d0\u4ea4\u8bfb\u4f1a\u5bfc\u81f4\u810f\u8bfb<\/p>\n<h1>\u4e09 \u63d0\u4ea4\u8bfb(Read committed)<\/h1>\n<p>\u63d0\u4ea4\u8bfb(READ COMMITTED)\u4e5f\u53ef\u4ee5\u7ffb\u8bd1\u6210\u8bfb\u5df2\u63d0\u4ea4\uff0c\u901a\u8fc7\u540d\u5b57\u4e5f\u53ef\u4ee5\u5206\u6790\u51fa\uff0c\u5728\u4e00\u4e2a\u4e8b\u52a1\u4fee\u6539\u6570\u636e\u8fc7\u7a0b\u4e2d\uff0c\u5982\u679c\u4e8b\u52a1\u8fd8\u6ca1\u63d0\u4ea4\uff0c\u5176\u4ed6\u4e8b\u52a1\u4e0d\u80fd\u8bfb\u8be5\u6570\u636e\u3002<\/p>\n<p><strong>\u63d0\u4ea4\u8bfb\u7684\u6570\u636e\u5e93\u9501\u60c5\u51b5<\/strong><\/p>\n<blockquote><p>\u4e8b\u52a1\u5bf9\u5f53\u524d\u88ab\u8bfb\u53d6\u7684\u6570\u636e\u52a0 \u884c\u7ea7\u5171\u4eab\u9501\uff08\u5f53\u8bfb\u5230\u65f6\u624d\u52a0\u9501\uff09\uff0c\u4e00\u65e6\u8bfb\u5b8c\u8be5\u884c\uff0c\u7acb\u5373\u91ca\u653e\u8be5\u884c\u7ea7\u5171\u4eab\u9501\uff1b<\/p>\n<p>\u4e8b\u52a1\u5728\u66f4\u65b0\u67d0\u6570\u636e\u7684\u77ac\u95f4\uff08\u5c31\u662f\u53d1\u751f\u66f4\u65b0\u7684\u77ac\u95f4\uff09\uff0c\u5fc5\u987b\u5148\u5bf9\u5176\u52a0 \u884c\u7ea7\u6392\u4ed6\u9501\uff0c\u76f4\u5230\u4e8b\u52a1\u7ed3\u675f\u624d\u91ca\u653e\u3002<\/p><\/blockquote>\n<p>\u73b0\u8c61\uff1a<\/p>\n<blockquote><p>\u4e8b\u52a11\u5728\u8bfb\u53d6\u67d0\u884c\u8bb0\u5f55\u7684\u6574\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u4e8b\u52a12\u90fd\u53ef\u4ee5\u5bf9\u8be5\u884c\u8bb0\u5f55\u8fdb\u884c\u8bfb\u53d6\uff08\u56e0\u4e3a\u4e8b\u52a1\u4e00\u5bf9\u8be5\u884c\u8bb0\u5f55\u589e\u52a0\u884c\u7ea7\u5171\u4eab\u9501\u7684\u60c5\u51b5\u4e0b\uff0c\u4e8b\u52a1\u4e8c\u540c\u6837\u53ef\u4ee5\u5bf9\u8be5\u6570\u636e\u589e\u52a0\u5171\u4eab\u9501\u6765\u8bfb\u6570\u636e\u3002\uff09\u3002<\/p>\n<p>\u4e8b\u52a11\u8bfb\u53d6\u67d0\u884c\u7684\u4e00\u77ac\u95f4\uff0c\u4e8b\u52a12\u4e0d\u80fd\u4fee\u6539\u8be5\u884c\u6570\u636e\uff0c\u4f46\u662f\uff0c\u53ea\u8981\u4e8b\u52a11\u8bfb\u53d6\u5b8c\u6539\u884c\u6570\u636e\uff0c\u4e8b\u52a12\u5c31\u53ef\u4ee5\u5bf9\u8be5\u884c\u6570\u636e\u8fdb\u884c\u4fee\u6539\u3002\uff08\u4e8b\u52a1\u4e00\u5728\u8bfb\u53d6\u7684\u4e00\u77ac\u95f4\u4f1a\u5bf9\u6570\u636e\u589e\u52a0\u5171\u4eab\u9501\uff0c\u4efb\u4f55\u5176\u4ed6\u4e8b\u52a1\u90fd\u4e0d\u80fd\u5bf9\u8be5\u884c\u6570\u636e\u589e\u52a0\u6392\u4ed6\u9501\u3002\u4f46\u662f\u4e8b\u52a1\u4e00\u53ea\u8981\u8bfb\u5b8c\u8be5\u884c\u6570\u636e\uff0c\u5c31\u4f1a\u91ca\u653e\u884c\u7ea7\u5171\u4eab\u9501\uff0c\u4e00\u65e6\u9501\u91ca\u653e\uff0c\u4e8b\u52a1\u4e8c\u5c31\u53ef\u4ee5\u5bf9\u6570\u636e\u589e\u52a0\u6392\u4ed6\u9501\u5e76\u4fee\u6539\u6570\u636e\uff09<\/p>\n<p>\u4e8b\u52a11\u66f4\u65b0\u67d0\u884c\u8bb0\u5f55\u65f6\uff0c\u4e8b\u52a12\u4e0d\u80fd\u5bf9\u8fd9\u884c\u8bb0\u5f55\u505a\u66f4\u65b0\uff0c\u76f4\u5230\u4e8b\u52a11\u7ed3\u675f\u3002\uff08\u4e8b\u52a1\u4e00\u5728\u66f4\u65b0\u6570\u636e\u7684\u65f6\u5019\uff0c\u4f1a\u5bf9\u8be5\u884c\u6570\u636e\u589e\u52a0\u6392\u4ed6\u9501\uff0c\u77e5\u9053\u4e8b\u52a1\u7ed3\u675f\u624d\u4f1a\u91ca\u653e\u9501\uff0c\u6240\u4ee5\uff0c\u5728\u4e8b\u52a1\u4e8c\u6ca1\u6709\u63d0\u4ea4\u4e4b\u524d\uff0c\u4e8b\u52a1\u4e00\u90fd\u80fd\u4e0d\u5bf9\u6570\u636e\u589e\u52a0\u5171\u4eab\u9501\u8fdb\u884c\u6570\u636e\u7684\u8bfb\u53d6\u3002\u6240\u4ee5\uff0c\u63d0\u4ea4\u8bfb\u53ef\u4ee5\u89e3\u51b3<code>\u810f\u8bfb<\/code>\u7684\u73b0\u8c61\uff09<\/p><\/blockquote>\n<p><strong>\u4e3e\u4f8b<\/strong><\/p>\n<div class=\"table-wrapper\">\n<table border=\"1\">\n<tbody>\n<tr>\n<th>\u4e8b\u52a1\u4e00<\/th>\n<th>\u4e8b\u52a1\u4e8c<\/th>\n<\/tr>\n<tr>\n<td><code>\/* Query 1 *\/<\/code><br \/>\n<code><br \/>\nSELECT * FROM users WHERE id = 1;<br \/>\n<\/code><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td><code><br \/>\n\/* Query 2 *\/<\/code><br \/>\n<code>UPDATE users SET age = 21 WHERE id = 1;<\/code><br \/>\n<code><br \/>\nCOMMIT;<\/code><br \/>\n<code><br \/>\n\/* in multiversion concurrency<br \/>\ncontrol, or lock-based READ COMMITTED *\/<br \/>\n<\/code><\/td>\n<\/tr>\n<tr>\n<td><code><br \/>\n\/* Query 1 *\/<\/code><br \/>\n<code>SELECT * FROM users WHERE id = 1;<\/code><br \/>\n<code><br \/>\nCOMMIT;<\/code><br \/>\n<code>\/*lock-based REPEATABLE READ *\/<\/code><\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>\u5728\u63d0\u4ea4\u8bfb\u9694\u79bb\u7ea7\u522b\u4e2d\uff0c\u5728\u4e8b\u52a1\u4e8c\u63d0\u4ea4\u4e4b\u524d\uff0c\u4e8b\u52a1\u4e00\u4e0d\u80fd\u8bfb\u53d6\u6570\u636e\u3002\u53ea\u6709\u5728\u4e8b\u52a1\u4e8c\u63d0\u4ea4\u4e4b\u540e\uff0c\u4e8b\u52a1\u4e00\u624d\u80fd\u8bfb\u6570\u636e\u3002<\/p>\n<p>\u4f46\u662f\u4ece\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u6211\u4eec\u4e5f\u770b\u5230\uff0c\u4e8b\u52a1\u4e00\u4e24\u6b21\u8bfb\u53d6\u7684\u7ed3\u679c\u5e76\u4e0d\u4e00\u81f4\uff0c\u6240\u4ee5\u63d0\u4ea4\u8bfb\u4e0d\u80fd\u89e3\u51b3\u4e0d\u53ef\u91cd\u590d\u8bfb\u7684\u8bfb\u73b0\u8c61\u3002<\/p>\n<p>\u7b80\u800c\u8a00\u4e4b\uff0c\u63d0\u4ea4\u8bfb\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u4fdd\u8bc1\u4e86\u8bfb\u5230\u7684\u4efb\u4f55\u6570\u636e\u90fd\u662f\u63d0\u4ea4\u7684\u6570\u636e\uff0c\u907f\u514d\u4e86\u810f\u8bfb(dirty reads)\u3002\u4f46\u662f\u4e0d\u4fdd\u8bc1\u4e8b\u52a1\u91cd\u65b0\u8bfb\u7684\u65f6\u5019\u80fd\u8bfb\u5230\u76f8\u540c\u7684\u6570\u636e\uff0c\u56e0\u4e3a\u5728\u6bcf\u6b21\u6570\u636e\u8bfb\u5b8c\u4e4b\u540e\u5176\u4ed6\u4e8b\u52a1\u53ef\u4ee5\u4fee\u6539\u521a\u624d\u8bfb\u5230\u7684\u6570\u636e\u3002<\/p>\n<h1>\u56db \u53ef\u91cd\u590d\u8bfb(Repeatable reads)<\/h1>\n<p>\u53ef\u91cd\u590d\u8bfb(REPEATABLE READS),\u7531\u4e8e\u63d0\u4ea4\u8bfb\u9694\u79bb\u7ea7\u522b\u4f1a\u4ea7\u751f\u4e0d\u53ef\u91cd\u590d\u8bfb\u7684\u8bfb\u73b0\u8c61\u3002\u6240\u4ee5\uff0c\u6bd4\u63d0\u4ea4\u8bfb\u66f4\u9ad8\u4e00\u4e2a\u7ea7\u522b\u7684\u9694\u79bb\u7ea7\u522b\u5c31\u53ef\u4ee5\u89e3\u51b3\u4e0d\u53ef\u91cd\u590d\u8bfb\u7684\u95ee\u9898\u3002\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u5c31\u53eb\u53ef\u91cd\u590d\u8bfb\uff08\u8fd9\u540d\u5b57\u8d77\u7684\u662f\u4e0d\u662f\u5f88\u4efb\u6027\uff01\uff01\uff09<\/p>\n<p><strong>\u53ef\u91cd\u590d\u8bfb\u7684\u6570\u636e\u5e93\u9501\u60c5\u51b5<\/strong><\/p>\n<blockquote><p>\u4e8b\u52a1\u5728\u8bfb\u53d6\u67d0\u6570\u636e\u7684\u77ac\u95f4\uff08\u5c31\u662f\u5f00\u59cb\u8bfb\u53d6\u7684\u77ac\u95f4\uff09\uff0c\u5fc5\u987b\u5148\u5bf9\u5176\u52a0 \u884c\u7ea7\u5171\u4eab\u9501\uff0c\u76f4\u5230\u4e8b\u52a1\u7ed3\u675f\u624d\u91ca\u653e\uff1b<\/p>\n<p>\u4e8b\u52a1\u5728\u66f4\u65b0\u67d0\u6570\u636e\u7684\u77ac\u95f4\uff08\u5c31\u662f\u53d1\u751f\u66f4\u65b0\u7684\u77ac\u95f4\uff09\uff0c\u5fc5\u987b\u5148\u5bf9\u5176\u52a0 \u884c\u7ea7\u6392\u4ed6\u9501\uff0c\u76f4\u5230\u4e8b\u52a1\u7ed3\u675f\u624d\u91ca\u653e\u3002<\/p><\/blockquote>\n<p>\u73b0\u8c61<\/p>\n<blockquote><p>\u4e8b\u52a11\u5728\u8bfb\u53d6\u67d0\u884c\u8bb0\u5f55\u7684\u6574\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u4e8b\u52a12\u90fd\u53ef\u4ee5\u5bf9\u8be5\u884c\u8bb0\u5f55\u8fdb\u884c\u8bfb\u53d6\uff08\u56e0\u4e3a\u4e8b\u52a1\u4e00\u5bf9\u8be5\u884c\u8bb0\u5f55\u589e\u52a0\u884c\u7ea7\u5171\u4eab\u9501\u7684\u60c5\u51b5\u4e0b\uff0c\u4e8b\u52a1\u4e8c\u540c\u6837\u53ef\u4ee5\u5bf9\u8be5\u6570\u636e\u589e\u52a0\u5171\u4eab\u9501\u6765\u8bfb\u6570\u636e\u3002\uff09\u3002<\/p>\n<p>\u4e8b\u52a11\u5728\u8bfb\u53d6\u67d0\u884c\u8bb0\u5f55\u7684\u6574\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u4e8b\u52a12\u90fd\u4e0d\u80fd\u4fee\u6539\u8be5\u884c\u6570\u636e\uff08\u4e8b\u52a1\u4e00\u5728\u8bfb\u53d6\u7684\u6574\u4e2a\u8fc7\u7a0b\u4f1a\u5bf9\u6570\u636e\u589e\u52a0\u5171\u4eab\u9501\uff0c\u76f4\u5230\u4e8b\u52a1\u63d0\u4ea4\u624d\u4f1a\u91ca\u653e\u9501\uff0c\u6240\u4ee5\u6574\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u4efb\u4f55\u5176\u4ed6\u4e8b\u52a1\u90fd\u4e0d\u80fd\u5bf9\u8be5\u884c\u6570\u636e\u589e\u52a0\u6392\u4ed6\u9501\u3002\u6240\u4ee5\uff0c\u53ef\u91cd\u590d\u8bfb\u80fd\u591f\u89e3\u51b3<code>\u4e0d\u53ef\u91cd\u590d\u8bfb<\/code>\u7684\u8bfb\u73b0\u8c61\uff09<\/p>\n<p>\u4e8b\u52a11\u66f4\u65b0\u67d0\u884c\u8bb0\u5f55\u65f6\uff0c\u4e8b\u52a12\u4e0d\u80fd\u5bf9\u8fd9\u884c\u8bb0\u5f55\u505a\u66f4\u65b0\uff0c\u76f4\u5230\u4e8b\u52a11\u7ed3\u675f\u3002\uff08\u4e8b\u52a1\u4e00\u5728\u66f4\u65b0\u6570\u636e\u7684\u65f6\u5019\uff0c\u4f1a\u5bf9\u8be5\u884c\u6570\u636e\u589e\u52a0\u6392\u4ed6\u9501\uff0c\u77e5\u9053\u4e8b\u52a1\u7ed3\u675f\u624d\u4f1a\u91ca\u653e\u9501\uff0c\u6240\u4ee5\uff0c\u5728\u4e8b\u52a1\u4e8c\u6ca1\u6709\u63d0\u4ea4\u4e4b\u524d\uff0c\u4e8b\u52a1\u4e00\u90fd\u80fd\u4e0d\u5bf9\u6570\u636e\u589e\u52a0\u5171\u4eab\u9501\u8fdb\u884c\u6570\u636e\u7684\u8bfb\u53d6\u3002\u6240\u4ee5\uff0c\u63d0\u4ea4\u8bfb\u53ef\u4ee5\u89e3\u51b3<code>\u810f\u8bfb<\/code>\u7684\u73b0\u8c61\uff09<\/p><\/blockquote>\n<p><strong>\u4e3e\u4f8b<\/strong><\/p>\n<div class=\"table-wrapper\">\n<table border=\"1\">\n<tbody>\n<tr>\n<th>\u4e8b\u52a1\u4e00<\/th>\n<th>\u4e8b\u52a1\u4e8c<\/th>\n<\/tr>\n<tr>\n<td><code>\/* Query 1 *\/<\/code><br \/>\n<code><br \/>\nSELECT * FROM users WHERE id = 1;<br \/>\n<\/code><br \/>\n<code><br \/>\nCOMMIT;<br \/>\n<\/code><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td><code><br \/>\n\/* Query 2 *\/<\/code><br \/>\n<code>UPDATE users SET age = 21 WHERE id = 1;<\/code><br \/>\n<code><br \/>\nCOMMIT;<\/code><br \/>\n<code><br \/>\n\/* in multiversion concurrency<br \/>\ncontrol, or lock-based READ COMMITTED *\/<br \/>\n<\/code><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>\u5728\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\uff0c\u53ea\u6709\u5728\u4e8b\u52a1\u4e00\u63d0\u4ea4\u4e4b\u540e\uff0c\u4e8b\u52a1\u4e8c\u624d\u80fd\u66f4\u6539\u8be5\u884c\u6570\u636e\u3002\u6240\u4ee5\uff0c\u53ea\u8981\u5728\u4e8b\u52a1\u4e00\u4ece\u5f00\u59cb\u5230\u7ed3\u675f\u7684\u8fd9\u6bb5\u65f6\u95f4\u5185\uff0c\u65e0\u8bba\u4ed6\u8bfb\u53d6\u8be5\u884c\u6570\u636e\u591a\u5c11\u6b21\uff0c\u7ed3\u679c\u90fd\u662f\u4e00\u6837\u7684\u3002<\/p>\n<p>\u4ece\u4e0a\u9762\u7684\u4f8b\u5b50\u4e2d\u6211\u4eec\u53ef\u4ee5\u5f97\u5230\u7ed3\u8bba\uff1a\u53ef\u91cd\u590d\u8bfb\u9694\u79bb\u7ea7\u522b\u53ef\u4ee5\u89e3\u51b3\u4e0d\u53ef\u91cd\u590d\u8bfb\u7684\u8bfb\u73b0\u8c61\u3002\u4f46\u662f\u53ef\u91cd\u590d\u8bfb\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u4e2d\uff0c\u8fd8\u6709\u53e6\u5916\u4e00\u79cd\u8bfb\u73b0\u8c61\u4ed6\u89e3\u51b3\u4e0d\u4e86\uff0c\u90a3\u5c31\u662f\u5e7b\u8bfb\u3002\u770b\u4e0b\u9762\u7684\u4f8b\u5b50\uff1a<\/p>\n<div class=\"table-wrapper\">\n<table border=\"1\">\n<tbody>\n<tr>\n<th>\u4e8b\u52a1\u4e00<\/th>\n<th>\u4e8b\u52a1\u4e8c<\/th>\n<\/tr>\n<tr>\n<td><code>\/* Query 1 *\/<\/code><br \/>\n<code><br \/>\nSELECT * FROM users<br \/>\nWHERE age BETWEEN 10 AND 30;<br \/>\n<\/code><\/td>\n<td><\/td>\n<\/tr>\n<tr>\n<td><\/td>\n<td><code><br \/>\n\/* Query 2 *\/<\/code><br \/>\n<code>INSERT INTO users VALUES ( 3, 'Bob', 27 );<\/code><br \/>\n<code><br \/>\nCOMMIT;<\/code><\/td>\n<\/tr>\n<tr>\n<td><code><br \/>\n\/* Query 1 *\/<\/code><br \/>\n<code>SELECT * FROM users<br \/>\nWHERE age BETWEEN 10 AND 30;<\/code><\/td>\n<td><\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<p>\u4e0a\u9762\u7684\u4e24\u4e2a\u4e8b\u52a1\u6267\u884c\u60c5\u51b5\u53ca\u73b0\u8c61\u5982\u4e0b\uff1a<\/p>\n<p>1.\u4e8b\u52a1\u4e00\u7684\u7b2c\u4e00\u6b21\u67e5\u8be2\u6761\u4ef6\u662f<code>age BETWEEN 10 AND 30;<\/code>\u5982\u679c\u8fd9\u662f\u6709\u5341\u6761\u8bb0\u5f55\u7b26\u5408\u6761\u4ef6\u3002\u8fd9\u65f6\uff0c\u4ed6\u4f1a\u7ed9\u7b26\u5408\u6761\u4ef6\u7684\u8fd9\u5341\u6761\u8bb0\u5f55\u589e\u52a0\u884c\u7ea7\u5171\u4eab\u9501\u3002\u4efb\u4f55\u5176\u4ed6\u4e8b\u52a1\u65e0\u6cd5\u66f4\u6539\u8fd9\u5341\u6761\u8bb0\u5f55\u3002<\/p>\n<p>2.\u4e8b\u52a1\u4e8c\u6267\u884c\u4e00\u6761sql\u8bed\u53e5\uff0c\u8bed\u53e5\u7684\u5185\u5bb9\u662f\u5411\u8868\u4e2d\u63d2\u5165\u4e00\u6761\u6570\u636e\u3002\u56e0\u4e3a\u6b64\u65f6\u6ca1\u6709\u4efb\u4f55\u4e8b\u52a1\u5bf9\u8868\u589e\u52a0\u8868\u7ea7\u9501\uff0c\u6240\u4ee5\uff0c\u8be5\u64cd\u4f5c\u53ef\u4ee5\u987a\u5229\u6267\u884c\u3002<\/p>\n<p>3.\u4e8b\u52a1\u4e00\u518d\u6b21\u6267\u884c<code>SELECT * FROM users WHERE age BETWEEN 10 AND 30;<\/code>\u65f6\uff0c\u7ed3\u679c\u8fd4\u56de\u7684\u8bb0\u5f55\u53d8\u6210\u4e86\u5341\u4e00\u6761\uff0c\u6bd4\u521a\u521a\u589e\u52a0\u4e86\u4e00\u6761\uff0c\u589e\u52a0\u7684\u8fd9\u6761\u6b63\u662f\u4e8b\u52a1\u4e8c\u521a\u521a\u63d2\u5165\u7684\u90a3\u6761\u3002<\/p>\n<p>\u6240\u4ee5\uff0c\u4e8b\u52a1\u4e00\u7684\u4e24\u6b21\u8303\u56f4\u67e5\u8be2\u7ed3\u679c\u5e76\u4e0d\u76f8\u540c\u3002\u8fd9\u4e5f\u5c31\u662f\u6211\u4eec\u63d0\u5230\u7684\u5e7b\u8bfb<\/p>\n<h1>\u4e94 \u53ef\u5e8f\u5217\u5316(Serializable)<\/h1>\n<p>\u53ef\u5e8f\u5217\u5316(Serializable)\u662f\u6700\u9ad8\u7684\u9694\u79bb\u7ea7\u522b\uff0c\u524d\u9762\u63d0\u5230\u7684\u6240\u6709\u7684\u9694\u79bb\u7ea7\u522b\u90fd\u65e0\u6cd5\u89e3\u51b3\u7684\u5e7b\u8bfb\uff0c\u5728\u53ef\u5e8f\u5217\u5316\u7684\u9694\u79bb\u7ea7\u522b\u4e2d\u53ef\u4ee5\u89e3\u51b3\u3002<\/p>\n<p>\u6211\u4eec\u8bf4\u8fc7\uff0c\u4ea7\u751f\u5e7b\u8bfb\u7684\u539f\u56e0\u662f\u4e8b\u52a1\u4e00\u5728\u8fdb\u884c\u8303\u56f4\u67e5\u8be2\u7684\u65f6\u5019\u6ca1\u6709\u589e\u52a0\u8303\u56f4\u9501(range-locks\uff1a\u7ed9SELECT \u7684\u67e5\u8be2\u4e2d\u4f7f\u7528\u4e00\u4e2a\u201cWHERE\u201d\u5b50\u53e5\u63cf\u8ff0\u8303\u56f4\u52a0\u9501\uff09\uff0c\u6240\u4ee5\u5bfc\u81f4\u5e7b\u8bfb\u3002<\/p>\n<p><strong>\u53ef\u5e8f\u5217\u5316\u7684\u6570\u636e\u5e93\u9501\u60c5\u51b5<\/strong><\/p>\n<blockquote><p>\u4e8b\u52a1\u5728\u8bfb\u53d6\u6570\u636e\u65f6\uff0c\u5fc5\u987b\u5148\u5bf9\u5176\u52a0 \u8868\u7ea7\u5171\u4eab\u9501 \uff0c\u76f4\u5230\u4e8b\u52a1\u7ed3\u675f\u624d\u91ca\u653e\uff1b<\/p>\n<p>\u4e8b\u52a1\u5728\u66f4\u65b0\u6570\u636e\u65f6\uff0c\u5fc5\u987b\u5148\u5bf9\u5176\u52a0 \u8868\u7ea7\u6392\u4ed6\u9501 \uff0c\u76f4\u5230\u4e8b\u52a1\u7ed3\u675f\u624d\u91ca\u653e\u3002<\/p><\/blockquote>\n<p>\u73b0\u8c61<\/p>\n<blockquote><p>\u4e8b\u52a11\u6b63\u5728\u8bfb\u53d6A\u8868\u4e2d\u7684\u8bb0\u5f55\u65f6\uff0c\u5219\u4e8b\u52a12\u4e5f\u80fd\u8bfb\u53d6A\u8868\uff0c\u4f46\u4e0d\u80fd\u5bf9A\u8868\u505a\u66f4\u65b0\u3001\u65b0\u589e\u3001\u5220\u9664\uff0c\u76f4\u5230\u4e8b\u52a11\u7ed3\u675f\u3002(\u56e0\u4e3a\u4e8b\u52a1\u4e00\u5bf9\u8868\u589e\u52a0\u4e86\u8868\u7ea7\u5171\u4eab\u9501\uff0c\u5176\u4ed6\u4e8b\u52a1\u53ea\u80fd\u589e\u52a0\u5171\u4eab\u9501\u8bfb\u53d6\u6570\u636e\uff0c\u4e0d\u80fd\u8fdb\u884c\u5176\u4ed6\u4efb\u4f55\u64cd\u4f5c\uff09<\/p>\n<p>\u4e8b\u52a11\u6b63\u5728\u66f4\u65b0A\u8868\u4e2d\u7684\u8bb0\u5f55\u65f6\uff0c\u5219\u4e8b\u52a12\u4e0d\u80fd\u8bfb\u53d6A\u8868\u7684\u4efb\u610f\u8bb0\u5f55\uff0c\u66f4\u4e0d\u53ef\u80fd\u5bf9A\u8868\u505a\u66f4\u65b0\u3001\u65b0\u589e\u3001\u5220\u9664\uff0c\u76f4\u5230\u4e8b\u52a11\u7ed3\u675f\u3002\uff08\u4e8b\u52a1\u4e00\u5bf9\u8868\u589e\u52a0\u4e86\u8868\u7ea7\u6392\u4ed6\u9501\uff0c\u5176\u4ed6\u4e8b\u52a1\u4e0d\u80fd\u5bf9\u8868\u589e\u52a0\u5171\u4eab\u9501\u6216\u6392\u4ed6\u9501\uff0c\u4e5f\u5c31\u65e0\u6cd5\u8fdb\u884c\u4efb\u4f55\u64cd\u4f5c\uff09<\/p><\/blockquote>\n<p>\u867d\u7136\u53ef\u5e8f\u5217\u5316\u89e3\u51b3\u4e86\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\u3001\u5e7b\u8bfb\u7b49\u8bfb\u73b0\u8c61\u3002\u4f46\u662f\u5e8f\u5217\u5316\u4e8b\u52a1\u4f1a\u4ea7\u751f\u4ee5\u4e0b\u6548\u679c\uff1a<\/p>\n<p>1.\u65e0\u6cd5\u8bfb\u53d6\u5176\u5b83\u4e8b\u52a1\u5df2\u4fee\u6539\u4f46\u672a\u63d0\u4ea4\u7684\u8bb0\u5f55\u3002<\/p>\n<p>2.\u5728\u5f53\u524d\u4e8b\u52a1\u5b8c\u6210\u4e4b\u524d\uff0c\u5176\u5b83\u4e8b\u52a1\u4e0d\u80fd\u4fee\u6539\u76ee\u524d\u4e8b\u52a1\u5df2\u8bfb\u53d6\u7684\u8bb0\u5f55\u3002<\/p>\n<p>3.\u5728\u5f53\u524d\u4e8b\u52a1\u5b8c\u6210\u4e4b\u524d\uff0c\u5176\u5b83\u4e8b\u52a1\u6240\u63d2\u5165\u7684\u65b0\u8bb0\u5f55\uff0c\u5176\u7d22\u5f15\u952e\u503c\u4e0d\u80fd\u5728\u5f53\u524d\u4e8b\u52a1\u7684\u4efb\u4f55\u8bed\u53e5\u6240\u8bfb\u53d6\u7684\u7d22\u5f15\u952e\u8303\u56f4\u4e2d\u3002<\/p>\n<hr \/>\n<p>\u56db\u79cd\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u4ece\u9694\u79bb\u7a0b\u5ea6\u4e0a\u8d8a\u6765\u8d8a\u9ad8\uff0c\u4f46\u540c\u65f6\u5728\u5e76\u53d1\u6027\u4e0a\u4e5f\u5c31\u8d8a\u6765\u8d8a\u4f4e\u3002\u4e4b\u6240\u4ee5\u6709\u8fd9\u4e48\u51e0\u79cd\u9694\u79bb\u7ea7\u522b\uff0c\u5c31\u662f\u4e3a\u4e86\u65b9\u4fbf\u5f00\u53d1\u4eba\u5458\u5728\u5f00\u53d1\u8fc7\u7a0b\u4e2d\u6839\u636e\u4e1a\u52a1\u9700\u8981\u9009\u62e9\u6700\u5408\u9002\u7684\u9694\u79bb\u7ea7\u522b\u3002<\/p>\n<h1>\u516d InnoDB\u5b58\u50a8\u5f15\u64ce<\/h1>\n<p>\u524d\u6587\u6211\u4eec\u63d0\u5230\u8fc7InnoDB\u652f\u6301\u884c\u9501\uff08\u9501\u5b9a\u5b57\u6bb5\u542b\u6709\u7d22\u5f15\u7684\u60c5\u51b5\u4e0b\uff0c\u5426\u5219\u8d70\u8868\u9501\uff09\uff0c\u4f46\u9501\u5b9a\u65b9\u5f0f\u5e76\u975e\u7b80\u5355\u7684\u9501\u5b9a\u6307\u5b9a\u884c\u4e0a\u7684\u7d22\u5f15\uff0c\u800c\u662f\u5206\u4e3a3\u79cd\u9501\u5b9a\u7b97\u6cd5\uff1a<br \/>\n1\uff09\u8bb0\u5f55\u9501\uff08Record Locks\uff09\uff1a\u9501\u5b9a\u6307\u5b9a\u884c\u7684\u7d22\u5f15\u9879<br \/>\n2\uff09Gap Locks\uff1a\u9501\u5b9a\u67d0\u4e00\u4e2a\u8303\u56f4\u5185\u7684\u7d22\u5f15\uff0c\u4f46\u4e0d\u5305\u62ec\u8bb0\u5f55\u672c\u8eab<br \/>\n3\uff09\u95f4\u9699\u9501\u5b9a\uff08Next-Key Locks\uff09\uff1a\u9501\u5b9a\u4e00\u4e2a\u8303\u56f4\u5185\u7684\u7d22\u5f15\uff0c\u5e76\u4e14\u9501\u5b9a\u8bb0\u5f55\u672c\u8eab \u00a0 Next-Key Locks = Record Locks + Gap Locks<br \/>\nA next-key lock is a combination of a record lock on the index record and a gap lock on the gap before the index record<\/p>\n<p>&nbsp;<\/p>\n<p>\u800cInnoDB \u5b58\u50a8\u5f15\u64ce\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\u4e3a\u53ef\u91cd\u590d\u8bfb\uff08Repeatable Read\uff09\uff0c\u8be5\u9694\u79bb\u7ea7\u522b\u4e0b\uff0c\u5bf9\u4e8e\u7d22\u5f15\u7684\u67e5\u8be2\u91c7\u7528 next-key locks\u3002\u8fd9\u6837\u505a\u907f\u514d\u4e86\u5e7b\u8bfb\u73b0\u8c61\u7684\u4ea7\u751f\u3002<\/p>\n<p><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2021\/07\/20170629164324742.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" class=\"alignnone size-full wp-image-11542\" data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2021\/07\/20170629164324742.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" width=\"337\" height=\"140\" \/><\/div><\/p>\n<h1>\u4e03\u00a0\u4fee\u6539\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b<\/h1>\n<p>\u5728 MySQL \u4e2d\uff0c\u53ef\u4ee5\u901a\u8fc7show variables like &#8216;%tx_isolation%&#8217;\u6216select @@tx_isolation;\u8bed\u53e5\u6765\u67e5\u770b\u5f53\u524d\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u3002<\/p>\n<p>\u67e5\u770b\u5f53\u524d\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u7684 SQL \u8bed\u53e5\u548c\u8fd0\u884c\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n<div class=\"jb51code\">\n<div id=\"highlighter_205649\" class=\"syntaxhighlighter xml\">\n<div class=\"table-wrapper\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<div class=\"line number11 index10 alt2\">11<\/div>\n<div class=\"line number12 index11 alt1\">12<\/div>\n<div class=\"line number13 index12 alt2\">13<\/div>\n<div class=\"line number14 index13 alt1\">14<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"xml plain\">mysql&gt; show variables like '%tx_isolation%';<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"xml plain\">+---------------+-----------------+<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"xml plain\">| Variable_name | Value\u00a0\u00a0\u00a0\u00a0\u00a0 |<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"xml plain\">+---------------+-----------------+<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"xml plain\">| tx_isolation | REPEATABLE-READ |<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"xml plain\">+---------------+-----------------+<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"xml plain\">1 row in set, 1 warning (0.17 sec\uff09<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"xml plain\">mysql&gt; select @@tx_isolation;<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"xml plain\">+-----------------+<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"xml plain\">| @@tx_isolation |<\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"xml plain\">+-----------------+<\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"xml plain\">| REPEATABLE-READ |<\/code><\/div>\n<div class=\"line number13 index12 alt2\"><code class=\"xml plain\">+-----------------+<\/code><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"xml plain\">1 row in set, 1 warning (0.00 sec)<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u7ed3\u679c\u663e\u793a\uff0c\u76ee\u524d MySQL \u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u662f REPEATABLE-READ\u3002<\/p>\n<p>\u53e6\u5916\uff0c\u8fd8\u53ef\u4ee5\u4f7f\u7528\u4e0b\u5217\u8bed\u53e5\u5206\u522b\u67e5\u8be2\u5168\u5c40\u548c\u4f1a\u8bdd\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff1a<\/p>\n<div class=\"jb51code\">\n<div id=\"highlighter_432002\" class=\"syntaxhighlighter sql\">\n<div class=\"table-wrapper\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"sql keyword\">SELECT<\/code>\u00a0<code class=\"sql plain\">@@<\/code><code class=\"sql keyword\">global<\/code><code class=\"sql plain\">.tx_isolation;<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"sql keyword\">SELECT<\/code>\u00a0<code class=\"sql plain\">@@session.tx_isolation;<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u63d0\u793a\uff1a\u5728MySQL 8.0.3 \u4e2d\uff0ctx_isolation \u53d8\u91cf\u88ab transaction_isolation \u53d8\u91cf\u66ff\u6362\u4e86\u3002\u5728 MySQL 8.0.3 \u7248\u672c\u4e2d\u67e5\u8be2\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0c\u53ea\u8981\u628a\u4e0a\u8ff0\u67e5\u8be2\u8bed\u53e5\u4e2d\u7684 tx_isolation \u53d8\u91cf\u66ff\u6362\u6210 transaction_isolation \u53d8\u91cf\u5373\u53ef\u3002<\/p>\n<p><strong>\u4fee\u6539\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b<\/strong><\/p>\n<p>MySQL \u63d0\u4f9b\u4e86 SET TRANSACTION \u8bed\u53e5\uff0c\u8be5\u8bed\u53e5\u53ef\u4ee5\u6539\u53d8\u5355\u4e2a\u4f1a\u8bdd\u6216\u5168\u5c40\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u3002\u8bed\u6cd5\u683c\u5f0f\u5982\u4e0b\uff1a<\/p>\n<blockquote><p>SET [SESSION | GLOBAL] TRANSACTION ISOLATION LEVEL {READ UNCOMMITTED | READ COMMITTED | REPEATABLE READ | SERIALIZABLE}<\/p><\/blockquote>\n<p>\u5176\u4e2d\uff0cSESSION \u548c GLOBAL \u5173\u952e\u5b57\u7528\u6765\u6307\u5b9a\u4fee\u6539\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u7684\u8303\u56f4\uff1a<\/p>\n<ul>\n<li>SESSION\uff1a\u8868\u793a\u4fee\u6539\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u5c06\u5e94\u7528\u4e8e\u5f53\u524d session\uff08\u5f53\u524d cmd \u7a97\u53e3\uff09\u5185\u7684\u6240\u6709\u4e8b\u52a1\uff1b<\/li>\n<li>GLOBAL\uff1a\u8868\u793a\u4fee\u6539\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u5c06\u5e94\u7528\u4e8e\u6240\u6709 session\uff08\u5168\u5c40\uff09\u4e2d\u7684\u6240\u6709\u4e8b\u52a1\uff0c\u4e14\u5f53\u524d\u5df2\u7ecf\u5b58\u5728\u7684 session \u4e0d\u53d7\u5f71\u54cd\uff1b<\/li>\n<li>\u5982\u679c\u7701\u7565 SESSION \u548c GLOBAL\uff0c\u8868\u793a\u4fee\u6539\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u5c06\u5e94\u7528\u4e8e\u5f53\u524d session \u5185\u7684\u4e0b\u4e00\u4e2a\u8fd8\u672a\u5f00\u59cb\u7684\u4e8b\u52a1\u3002<\/li>\n<\/ul>\n<p>\u4efb\u4f55\u7528\u6237\u90fd\u80fd\u6539\u53d8\u4f1a\u8bdd\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0c\u4f46\u662f\u53ea\u6709\u62e5\u6709 SUPER \u6743\u9650\u7684\u7528\u6237\u624d\u80fd\u6539\u53d8\u5168\u5c40\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\u3002<\/p>\n<p>\u5982\u679c\u4f7f\u7528\u666e\u901a\u7528\u6237\u4fee\u6539\u5168\u5c40\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0c\u5c31\u4f1a\u63d0\u793a\u9700\u8981\u8d85\u7ea7\u6743\u9650\u624d\u80fd\u6267\u884c\u6b64\u64cd\u4f5c\u7684\u9519\u8bef\u4fe1\u606f\uff0cSQL \u8bed\u53e5\u548c\u8fd0\u884c\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n<div class=\"jb51code\">\n<div id=\"highlighter_193358\" class=\"syntaxhighlighter xml\">\n<div class=\"table-wrapper\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<div class=\"line number11 index10 alt2\">11<\/div>\n<div class=\"line number12 index11 alt1\">12<\/div>\n<div class=\"line number13 index12 alt2\">13<\/div>\n<div class=\"line number14 index13 alt1\">14<\/div>\n<div class=\"line number15 index14 alt2\">15<\/div>\n<div class=\"line number16 index15 alt1\">16<\/div>\n<div class=\"line number17 index16 alt2\">17<\/div>\n<div class=\"line number18 index17 alt1\">18<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"xml plain\">&gt;mysql -utestuser -p<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"xml plain\">Enter password: ******<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"xml plain\">Welcome to the MySQL monitor. Commands end with ; or \\g.<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"xml plain\">Your MySQL connection id is 41<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"xml plain\">Server version: 5.7.29-log MySQL Community Server (GPL)<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"xml spaces\">\u00a0<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"xml plain\">Copyright (c) 2000, 2020, Oracle and\/or its affiliates. All rights reserved.<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"xml spaces\">\u00a0<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"xml plain\">Oracle is a registered trademark of Oracle Corporation and\/or its<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"xml plain\">affiliates. Other names may be trademarks of their respective<\/code><\/div>\n<div class=\"line number11 index10 alt2\"><code class=\"xml plain\">owners.<\/code><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"xml spaces\">\u00a0<\/code><\/div>\n<div class=\"line number13 index12 alt2\"><code class=\"xml plain\">Type 'help;' or '\\h' for help. Type '\\c' to clear the current input statement.<\/code><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"xml spaces\">\u00a0<\/code><\/div>\n<div class=\"line number15 index14 alt2\"><code class=\"xml plain\">mysql&gt; SET GLOBAL TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;<\/code><\/div>\n<div class=\"line number16 index15 alt1\"><code class=\"xml plain\">ERROR 1227 (42000): Access denied; you need (at least one of) the SUPER privilege(s) for this operation<\/code><\/div>\n<div class=\"line number17 index16 alt2\"><code class=\"xml plain\">mysql&gt; SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;<\/code><\/div>\n<div class=\"line number18 index17 alt1\"><code class=\"xml plain\">Query OK, 0 rows affected (0.00 sec)<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u793a\u4f8b 1<\/p>\n<p>\u4f7f\u7528 SET TRANSACTION \u8bed\u53e5\u5206\u522b\u4fee\u6539 session \u548c\u5168\u5c40\u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522bSQL \u8bed\u53e5\u548c\u8fd0\u884c\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n<div class=\"jb51code\">\n<div id=\"highlighter_495317\" class=\"syntaxhighlighter xml\">\n<div class=\"table-wrapper\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<div class=\"line number11 index10 alt2\">11<\/div>\n<div class=\"line number12 index11 alt1\">12<\/div>\n<div class=\"line number13 index12 alt2\">13<\/div>\n<div class=\"line number14 index13 alt1\">14<\/div>\n<div class=\"line number15 index14 alt2\">15<\/div>\n<div class=\"line number16 index15 alt1\">16<\/div>\n<div class=\"line number17 index16 alt2\">17<\/div>\n<div class=\"line number18 index17 alt1\">18<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"xml plain\">mysql&gt; select @@session.tx_isolation;<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"xml plain\">+------------------------+<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><code class=\"xml plain\">| @@session.tx_isolation |<\/code><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"xml plain\">+------------------------+<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"xml plain\">| SERIALIZABLE\u00a0\u00a0\u00a0\u00a0\u00a0 |<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"xml plain\">+------------------------+<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"xml plain\">1 row in set, 1 warning (0.00 sec)<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"xml plain\">mysql&gt; SET GLOBAL TRANSACTION ISOLATION LEVEL REPEATABLE READ;<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"xml plain\">Query OK, 0 rows affected (0.00 sec)<\/code><\/div>\n<div class=\"line number11 index10 alt2\"><\/div>\n<div class=\"line number12 index11 alt1\"><code class=\"xml plain\">mysql&gt; select @@global.tx_isolation;<\/code><\/div>\n<div class=\"line number13 index12 alt2\"><code class=\"xml plain\">+-----------------------+<\/code><\/div>\n<div class=\"line number14 index13 alt1\"><code class=\"xml plain\">| @@global.tx_isolation |<\/code><\/div>\n<div class=\"line number15 index14 alt2\"><code class=\"xml plain\">+-----------------------+<\/code><\/div>\n<div class=\"line number16 index15 alt1\"><code class=\"xml plain\">| REPEATABLE-READ\u00a0\u00a0\u00a0 |<\/code><\/div>\n<div class=\"line number17 index16 alt2\"><code class=\"xml plain\">+-----------------------+<\/code><\/div>\n<div class=\"line number18 index17 alt1\"><code class=\"xml plain\">1 row in set, 1 warning (0.00 sec)<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u8fd8\u53ef\u4ee5\u4f7f\u7528 set tx_isolation \u547d\u4ee4\u76f4\u63a5\u4fee\u6539\u5f53\u524d session \u7684\u4e8b\u52a1\u9694\u79bb\u7ea7\u522b\uff0cSQL \u8bed\u53e5\u548c\u8fd0\u884c\u7ed3\u679c\u5982\u4e0b\uff1a<\/p>\n<div class=\"jb51code\">\n<div id=\"highlighter_134340\" class=\"syntaxhighlighter xml\">\n<div class=\"table-wrapper\">\n<table border=\"0\" cellspacing=\"0\" cellpadding=\"0\">\n<tbody>\n<tr>\n<td class=\"gutter\">\n<div class=\"line number1 index0 alt2\">1<\/div>\n<div class=\"line number2 index1 alt1\">2<\/div>\n<div class=\"line number3 index2 alt2\">3<\/div>\n<div class=\"line number4 index3 alt1\">4<\/div>\n<div class=\"line number5 index4 alt2\">5<\/div>\n<div class=\"line number6 index5 alt1\">6<\/div>\n<div class=\"line number7 index6 alt2\">7<\/div>\n<div class=\"line number8 index7 alt1\">8<\/div>\n<div class=\"line number9 index8 alt2\">9<\/div>\n<div class=\"line number10 index9 alt1\">10<\/div>\n<\/td>\n<td class=\"code\">\n<div class=\"container\">\n<div class=\"line number1 index0 alt2\"><code class=\"xml plain\">mysql&gt; set tx_isolation='READ-COMMITTED';<\/code><\/div>\n<div class=\"line number2 index1 alt1\"><code class=\"xml plain\">Query OK, 0 rows affected, 1 warning (0.00 sec)<\/code><\/div>\n<div class=\"line number3 index2 alt2\"><\/div>\n<div class=\"line number4 index3 alt1\"><code class=\"xml plain\">mysql&gt; select @@session.tx_isolation;<\/code><\/div>\n<div class=\"line number5 index4 alt2\"><code class=\"xml plain\">+------------------------+<\/code><\/div>\n<div class=\"line number6 index5 alt1\"><code class=\"xml plain\">| @@session.tx_isolation |<\/code><\/div>\n<div class=\"line number7 index6 alt2\"><code class=\"xml plain\">+------------------------+<\/code><\/div>\n<div class=\"line number8 index7 alt1\"><code class=\"xml plain\">| READ-COMMITTED\u00a0\u00a0\u00a0\u00a0 |<\/code><\/div>\n<div class=\"line number9 index8 alt2\"><code class=\"xml plain\">+------------------------+<\/code><\/div>\n<div class=\"line number10 index9 alt1\"><code class=\"xml plain\">1 row in set, 1 warning (0.00 sec)<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>\u6c38\u4e45\u4fee\u6539\u5982\u4e0b<\/p>\n<div class=\"cnblogs_code\">\n<pre>[root@db01 ~]# vim \/etc\/my.cnf\r\n[mysqld]\r\ntransaction_isolation=read-uncommit<\/pre>\n<\/div>\n<h1>\u516b \u4e8b\u52a1\u9694\u79bb\u662f\u5982\u4f55\u5b9e\u73b0\u7684<\/h1>\n<p>\u4e8b\u52a1\u9694\u79bb\u662f\u57fa\u4e8emvcc\u5b9e\u73b0\u7684\uff0c<a href=\"https:\/\/egonlin.com\/?cat=88\" target=\"_blank\" rel=\"noopener\">\u70b9\u51fb\u67e5\u770bmvcc<\/a><\/p>\n<p data-pid=\"iIk2fPnz\">\u6240\u8c13\u7684MVCC \u5c31\u662fMultipleVersion Concurrency Control, \u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236\uff0c\u4ece\u540d\u5b57\u4e0a\u4e5f\u53ef\u4ee5\u770b\u51fa\u6765\uff0c\u5b83\u662f\u4f7f\u7528\u7248\u672c\u53f7\u6765\u5bf9\u6570\u636e\u8fdb\u884c\u5e76\u53d1\u63a7\u5236\u7684\u3002\u5b9e\u9645\u4e0a\uff0c\u5728\u6570\u636e\u8868\u7684\u6bcf\u4e00\u5217\uff0c\u90fd\u5b58\u50a8\u4e24\u4e2a\u9690\u85cf\u5217\uff0c\u4e00\u4e2a\u662ftrx_id,\u4ee3\u8868\u4e8b\u52a1\u7684ID\uff0c\u53e6\u4e00\u4e2a\u662froll_pointer,\u6307\u5411\u5176\u4e0a\u4e00\u4e2a\u7248\u672c\u7684\u8bb0\u5f55\uff0c\u5982\u6b64\u7ec4\u6210\u4e00\u4e2a\u8bb0\u5f55\u7684\u7248\u672c\u94fe\uff0c\u5982\u4e0b\u56fe\uff1a<\/p>\n<p data-pid=\"iIk2fPnz\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2021\/07\/1036857-20231228163628751-2135971828.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" class=\"alignnone size-full wp-image-11543\" data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2021\/07\/1036857-20231228163628751-2135971828.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" width=\"2350\" height=\"538\"  sizes=\"(max-width: 2350px) 100vw, 2350px\" \/><\/div><\/p>\n<p data-pid=\"FIUZ9ucF\">\u63a5\u4e0b\u6765\u5c31\u53ef\u4ee5\u8bb2ReadView\u4e86\uff0c\u5b83\u5b58\u50a8\u7740\u4e00\u79cd\u7528\u6765\u8bb0\u5f55\u5f53\u524d\u6d3b\u8dc3\u72b6\u6001\u7684\u8bfb\u5199\u4e8b\u52a1\uff0c\u7528\u4e8e\u5224\u5b9a\u8be5transaction\u53ef\u89c1\u5230\u7684\u6570\u636e\u7248\u672c\u3002<\/p>\n<p data-pid=\"XT4pAEEi\"><code>up_limit_id<\/code>\u4e3a\u5f53\u524d\u5df2\u7ecf\u63d0\u4ea4\u7684\u4e8b\u52a1\u53f7+1,\u5728\u8fd9\u4e4b\u524d\u7684\u4e8b\u52a1\u53f7\u90fd\u662f\u53ef\u89c1\u7684\u3002<code>low_limit_id<\/code>\u5f53\u524d\u6700\u5927\u7684\u4e8b\u52a1\u53f7+1,\u4e5f\u5c31\u662f\u5728ReadView\u89c6\u56fe\u521b\u5efa\u540e\u6240\u6267\u884c\u7684\u4e8b\u52a1\uff0c\u8fd9\u4e9b\u90fd\u662f\u4e0d\u53ef\u89c1\u7684\uff0c<code>trx_ids<\/code>\u5c31\u662f\u5728ReadView\u751f\u6210\u524d\uff0c\u672a\u63d0\u4ea4\u7684\u4e8b\u52a1\u5217\u8868\uff0c\u7531\u4e8e\u672a\u63d0\u4ea4\u6240\u4ee5\u8fd9\u90e8\u5206\u4e5f\u662f\u4e0d\u53ef\u89c1\u7684\uff0c\u5982\u4e0b\u56fe\u6240\u793a\uff1a<\/p>\n<p data-pid=\"XT4pAEEi\"><div class='fancybox-wrapper lazyload-container-unload' data-fancybox='post-images' href='https:\/\/egonlin.com\/wp-content\/uploads\/2021\/07\/1036857-20231228163628751-2135971828-1.png'><img class=\"lazyload lazyload-style-2\" src=\"data:image\/svg+xml;base64,PCEtLUFyZ29uTG9hZGluZy0tPgo8c3ZnIHdpZHRoPSIxIiBoZWlnaHQ9IjEiIHhtbG5zPSJodHRwOi8vd3d3LnczLm9yZy8yMDAwL3N2ZyIgc3Ryb2tlPSIjZmZmZmZmMDAiPjxnPjwvZz4KPC9zdmc+\"  loading=\"lazy\" class=\"alignnone size-full wp-image-11544\" data-original=\"https:\/\/egonlin.com\/wp-content\/uploads\/2021\/07\/1036857-20231228163628751-2135971828-1.png\" src=\"data:image\/png;base64,iVBORw0KGgoAAAANSUhEUgAAAAEAAAABCAYAAAAfFcSJAAAAAXNSR0IArs4c6QAAAARnQU1BAACxjwv8YQUAAAAJcEhZcwAADsQAAA7EAZUrDhsAAAANSURBVBhXYzh8+PB\/AAffA0nNPuCLAAAAAElFTkSuQmCC\" alt=\"\" width=\"2350\" height=\"538\"  sizes=\"(max-width: 2350px) 100vw, 2350px\" \/><\/div><\/p>\n<p data-pid=\"hga14OoJ\">Read Committed \u548cReaptable Read\u7684\u5dee\u522b\u5c31\u5728\u4e8e\u4f60\u6bcf\u6b21\u8fdb\u884c\u8bfb\u64cd\u4f5c\u65f6\uff0c\u662f\u5426\u91cd\u65b0\u751f\u6210\u4e00\u4e2aReadView, \u5982\u679c\u91cd\u65b0\u751f\u6210\uff0c<code>up_limit_id<\/code>\u4e5f\u5c31\u4f1a\u66f4\u65b0\u4e3a\u6700\u65b0\u7684<code>trx_id<\/code>, \u4f7f\u5176\u53ef\u4ee5\u770b\u89c1\u5176\u4ed6\u4e8b\u52a1\u66f4\u6539\u7684\u6570\u636e\u7ed3\u679c\uff0c\u4e5f\u5c31\u662fRead Commited\uff1b\u4e0d\u91cd\u65b0\u751f\u6210\u7684\u8bdd\uff0c<code>up_limit_id<\/code>\u4ecd\u7136\u4fdd\u6301\u4e8b\u52a1\u5f00\u542f\u65f6\u7684<code>up_limit_id<\/code>, \u4e5f\u5c31\u770b\u4e0d\u89c1\u5176\u540e\u4e8b\u52a1\u66f4\u6539\u7684\u6570\u636e\u7ed3\u679c,\u4ece\u800c\u5b9e\u73b0\u53ef\u91cd\u590d\u8bfb\u3002<\/p>\n","protected":false},"excerpt":{"rendered":"<p>\u4e00 \u4e8b\u52a1\u9694\u79bb\u673a\u5236\/\u7ea7\u522b\u4ecb\u7ecd \u4e8b\u52a1\u5177\u6709\u539f\u5b50\u6027\u3001\u4e00\u81f4\u6027\u3001\u9694\u79bb\u6027\u3001\u6301\u4e45\u6027\u56db\u5927\u7279\u6027\uff0c\u800c\u9694\u79bb\u6027\u987e\u540d\u601d\u4e49\u6307\u7684\u5c31\u662f\u4e8b\u52a1\u5f7c\u6b64\u4e4b [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[89],"tags":[21,19,99,22,100,20],"_links":{"self":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/525"}],"collection":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=525"}],"version-history":[{"count":3,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/525\/revisions"}],"predecessor-version":[{"id":11546,"href":"https:\/\/egonlin.com\/index.php?rest_route=\/wp\/v2\/posts\/525\/revisions\/11546"}],"wp:attachment":[{"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=525"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=525"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/egonlin.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=525"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}