\u524d\u7f6e\u8bf4\u660e：MySQL \u4e2d\u53ea\u6709 InnoDB \u5b58\u50a8\u5f15\u64ce \u5b8c\u6574\u652f\u6301\u4e8b\u52a1，MyISAM \u4e0d\u652f\u6301\u4e8b\u52a1，\u4ec5\u64c5\u957f\u53ea\u8bfb\u67e5\u8be2\u573a\u666f\u3002\u56e0\u6b64\u4e0b\u6587\u6240\u6709\u8bb2\u89e3\u5747\u57fa\u4e8e InnoDB \u5f15\u64ce\u3002<\/p>\n
\n
\u524d\u7f6e：\u7edf\u4e00\u6d4b\u8bd5\u8868<\/h3>\n
\u4e0b\u6587\u6240\u6709\u6f14\u793a\u5747\u57fa\u4e8e\u8fd9\u5f20\u5b66\u751f\u8868：<\/p>\n
CREATE TABLE `student` (
\n `id` int NOT NULL AUTO_INCREMENT,
\n `ename` varchar(10) NOT NULL,
\n `age` int NOT NULL DEFAULT '18',
\n PRIMARY KEY (`id`)
\n) ENGINE=InnoDB DEFAULT CHARSET=utf8mb3;<\/p>\n
\n
\u4e00\u3001\u539f\u5b50\u6027（Atomicity）<\/h3>\n1.1 \u6838\u5fc3\u6982\u5ff5<\/h4>\n
\u539f\u5b50\u6027\u6307\u4e00\u4e2a\u4e8b\u52a1\u662f\u4e0d\u53ef\u5206\u5272\u7684\u6700\u5c0f\u6267\u884c\u5355\u5143，\u6700\u7ec8\u53ea\u4f1a\u5448\u73b0\u4e24\u79cd\u72b6\u6001：\u8981\u4e48\u5168\u90e8\u6267\u884c\u5b8c\u6210，\u8981\u4e48\u5b8c\u5168\u6ca1\u6709\u6267\u884c，\u4e0d\u4f1a\u5b58\u5728 \u201c\u6267\u884c\u4e86\u4e00\u534a\u201d \u7684\u4e2d\u95f4\u72b6\u6001\u3002<\/p>\n
1.2 \u81ea\u52a8\u63d0\u4ea4（autocommit）<\/h4>\n
\u81ea\u52a8\u63d0\u4ea4\u662f MySQL \u7684\u9ed8\u8ba4\u884c\u4e3a，\u4e5f\u662f\u7406\u89e3\u4e8b\u52a1\u7684\u524d\u63d0\u3002<\/p>\n
- \n
- \u67e5\u770b\u81ea\u52a8\u63d0\u4ea4\u72b6\u6001：\n
SHOW VARIABLES LIKE 'autocommit';<\/p>\n<\/li>\n
- \u8bbe\u7f6e\u81ea\u52a8\u63d0\u4ea4\u72b6\u6001：\n
SET autocommit = OFF; — \u5173\u95ed\u81ea\u52a8\u63d0\u4ea4，0 \u7b49\u4ef7\u4e8e OFF
\nSET autocommit = ON; — \u5f00\u542f\u81ea\u52a8\u63d0\u4ea4，1 \u7b49\u4ef7\u4e8e ON<\/p>\n<\/li>\n<\/ul>\n\u6838\u5fc3\u89c4\u5219<\/h5>\n
- \n
- autocommit = ON（\u9ed8\u8ba4）：\u6bcf\u4e00\u6761 SQL \u8bed\u53e5\u90fd\u4f1a\u88ab\u81ea\u52a8\u5305\u88f9\u6210\u4e00\u4e2a\u72ec\u7acb\u4e8b\u52a1，\u8bed\u53e5\u6267\u884c\u5b8c\u81ea\u52a8\u63d0\u4ea4\u3002\u5bf9\u7528\u6237\u6765\u8bf4，\u51e0\u4e4e\u611f\u77e5\u4e0d\u5230\u4e8b\u52a1\u7684\u5b58\u5728\u3002<\/li>\n
- autocommit = OFF：\u5f53\u524d\u4f1a\u8bdd\u4f1a\u9690\u5f0f\u5f00\u542f\u4e00\u4e2a\u4e8b\u52a1，\u6240\u6709 SQL \u8bed\u53e5\u90fd\u5728\u8fd9\u4e2a\u4e8b\u52a1\u5185，\u76f4\u5230\u7528\u6237\u624b\u52a8\u6267\u884c COMMIT \u63d0\u4ea4\u6216 ROLLBACK \u56de\u6eda\u3002<\/li>\n
- \u624b\u52a8\u5f00\u542f\u4e8b\u52a1（START TRANSACTION \/ BEGIN）：\u4e00\u65e6\u624b\u52a8\u6267\u884c BEGIN \u6216 START TRANSACTION，\u65e0\u8bba autocommit \u662f\u5f00\u662f\u5173，\u90fd\u4f1a\u5f00\u542f\u4e00\u4e2a\u65b0\u7684\u663e\u5f0f\u4e8b\u52a1，\u5fc5\u987b\u624b\u52a8\u63d0\u4ea4 \/ \u56de\u6eda，\u4e0d\u518d\u89e6\u53d1\u81ea\u52a8\u63d0\u4ea4\u3002<\/li>\n<\/ul>\n
1.3 \u4e8b\u52a1\u57fa\u7840\u64cd\u4f5c\u4e0e\u4fdd\u5b58\u70b9<\/h4>\n
— \u5f00\u542f\u4e00\u4e2a\u663e\u5f0f\u4e8b\u52a1
\nSTART TRANSACTION; — \u7b49\u4ef7\u4e8e BEGIN;<\/p>\n— \u6267\u884cDML\u64cd\u4f5c
\nINSERT INTO student (ename, age) VALUES ('\u5b59\u6743', 19), ('\u5415\u5e03', 20);<\/p>\n— \u8bbe\u7f6e\u4fdd\u5b58\u70b9 save1
\nSAVEPOINT save1;<\/p>\nINSERT INTO student (ename, age) VALUES ('\u5218\u5907', 19), ('\u5218\u7985', 20);<\/p>\n
SAVEPOINT save2;<\/p>\n
INSERT INTO student (ename, age) VALUES ('\u8d75\u4e91', 19), ('\u5f20\u98de', 20);<\/p>\n
SAVEPOINT save3;<\/p>\n
\u6b64\u65f6\u67e5\u8be2\u53ef\u4ee5\u770b\u5230 6 \u6761\u8bb0\u5f55\u3002<\/p>\n
\u90e8\u5206\u56de\u6eda（\u56de\u6eda\u5230\u4fdd\u5b58\u70b9）<\/h5>\n
ROLLBACK TO save2;<\/p>\n
\u6267\u884c\u540e，save2 \u4e4b\u540e\u7684\u64cd\u4f5c（\u8d75\u4e91\u3001\u5f20\u98de\u7684\u63d2\u5165）\u5168\u90e8\u64a4\u9500，\u8868\u4e2d\u53ea\u5269\u4e0b 4 \u6761\u8bb0\u5f55\u3002<\/p>\n
- \n
- \u4fdd\u5b58\u70b9\u662f\u4e8b\u52a1\u5185\u90e8\u7684 \u201c\u8fdb\u5ea6\u951a\u70b9\u201d，\u5141\u8bb8\u4e8b\u52a1\u5185\u7684\u90e8\u5206\u56de\u6eda，\u4e0d\u7834\u574f\u4e8b\u52a1\u7684\u539f\u5b50\u6027；<\/li>\n
- \u4fdd\u5b58\u70b9\u53ea\u80fd\u5728\u5f53\u524d\u4e8b\u52a1\u5185\u4f7f\u7528，\u4e8b\u52a1\u63d0\u4ea4\u6216\u56de\u6eda\u540e\u81ea\u52a8\u5931\u6548\u3002<\/li>\n<\/ul>\n
\u5168\u90e8\u56de\u6eda<\/h5>\n
ROLLBACK;<\/p>\n
\u76f4\u63a5\u56de\u6eda\u6574\u4e2a\u4e8b\u52a1，\u4e8b\u52a1\u6240\u505a\u7684\u6240\u6709\u4fee\u6539\u5168\u90e8\u64a4\u9500，\u4e8b\u52a1\u7ed3\u675f，\u6570\u636e\u56de\u5230\u4e8b\u52a1\u5f00\u59cb\u524d\u7684\u72b6\u6001\u3002<\/p>\n
\u63d0\u4ea4\u4e8b\u52a1<\/h5>\n
COMMIT;<\/p>\n
\u63d0\u4ea4\u540e，\u4e8b\u52a1\u6240\u505a\u7684\u6240\u6709\u4fee\u6539\u6c38\u4e45\u751f\u6548，\u4e8b\u52a1\u7ed3\u675f\u3002<\/p>\n
1.4 \u539f\u5b50\u6027\u7684\u672c\u8d28<\/h4>\n
\u539f\u5b50\u6027\u7684\u6838\u5fc3\u4fdd\u969c\u662f：\u4e8b\u52a1\u6267\u884c\u8fc7\u7a0b\u4e2d\u53d1\u751f\u4efb\u4f55\u5f02\u5e38（MySQL \u5d29\u6e83\u3001\u64cd\u4f5c\u7cfb\u7edf\u5d29\u6e83\u3001\u65ad\u7535），\u672a\u63d0\u4ea4\u7684\u4e8b\u52a1\u90fd\u4f1a\u88ab\u5168\u90e8\u56de\u6eda，\u4e0d\u4f1a\u7559\u4e0b\u534a\u5b8c\u6210\u7684\u6570\u636e\u3002\u6700\u7ec8\u4e8b\u52a1\u53ea\u6709\u4e24\u79cd\u7ed3\u679c：\u63d0\u4ea4\u6210\u529f（\u5168\u90e8\u751f\u6548）\u3001\u56de\u6eda \/ \u5931\u8d25（\u5168\u90e8\u4e0d\u751f\u6548）\u3002<\/p>\n
\n\u4e8c\u3001\u6301\u4e45\u6027（Durability）<\/h3>\n
2.1 \u6838\u5fc3\u6982\u5ff5<\/h4>\n
\u6301\u4e45\u6027\u6307\u4e8b\u52a1\u4e00\u65e6\u63d0\u4ea4，\u5176\u5bf9\u6570\u636e\u5e93\u7684\u4fee\u6539\u5c31\u662f\u6c38\u4e45\u7684，\u540e\u7eed\u53d1\u751f\u4efb\u4f55\u6545\u969c（\u7cfb\u7edf\u5d29\u6e83\u3001\u65ad\u7535）\u90fd\u4e0d\u4f1a\u4e22\u5931\u5df2\u63d0\u4ea4\u7684\u6570\u636e\u3002<\/p>\n
2.2 \u5b9e\u73b0\u57fa\u7840：Redo Log（\u91cd\u505a\u65e5\u5fd7）<\/h4>\n
\u5f88\u591a\u521d\u5b66\u8005\u4f1a\u6df7\u6dc6 redo log \u548c undo log，\u8fd9\u91cc\u660e\u786e\u533a\u5206：<\/p>\n
- \n
- Undo Log（\u56de\u6eda\u65e5\u5fd7）：\u8bb0\u5f55\u6570\u636e\u4fee\u6539\u524d\u7684\u7248\u672c，\u7528\u4e8e\u4e8b\u52a1\u56de\u6eda\u548c MVCC \u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236；<\/li>\n
- Redo Log（\u91cd\u505a\u65e5\u5fd7）：\u8bb0\u5f55\u6570\u636e\u4fee\u6539\u540e\u7684\u64cd\u4f5c，\u7528\u4e8e\u5d29\u6e83\u6062\u590d，\u4fdd\u8bc1\u6301\u4e45\u6027\u3002<\/li>\n<\/ul>\n
\u4e8b\u52a1\u6267\u884c DML \u65f6，\u4e0d\u662f\u76f4\u63a5\u4fee\u6539\u78c1\u76d8\u4e0a\u7684\u6570\u636e\u6587\u4ef6，\u800c\u662f\u5148\u5199\u5165 Redo Log Buffer，\u518d\u6309\u7b56\u7565\u5237\u5230\u78c1\u76d8\u3002\u5f53\u6570\u636e\u5e93\u5d29\u6e83\u91cd\u542f\u65f6，\u901a\u8fc7 redo log \u628a\u5df2\u63d0\u4ea4\u4f46\u8fd8\u6ca1\u5237\u5230\u6570\u636e\u6587\u4ef6\u7684\u64cd\u4f5c\u91cd\u505a\u4e00\u904d，\u4fdd\u8bc1\u6570\u636e\u4e0d\u4e22\u3002<\/p>\n
2.3 \u5237\u76d8\u7b56\u7565：innodb_flush_log_at_trx_commit<\/h4>\n
\u8be5\u53c2\u6570\u63a7\u5236\u4e8b\u52a1\u63d0\u4ea4\u65f6 redo log \u7684\u5237\u76d8\u884c\u4e3a，\u76f4\u63a5\u51b3\u5b9a\u4e86\u6301\u4e45\u6027\u4e0e\u6027\u80fd\u7684\u6743\u8861：<\/p>\n
\n
\u53c2\u6570\u503c\u5237\u76d8\u65f6\u673a\u6570\u636e\u4e22\u5931\u98ce\u9669\u6027\u80fdACID \u7b26\u5408\u5ea6<\/tr>\n \n\n 1（\u9ed8\u8ba4）<\/td>\n \u6bcf\u6b21\u4e8b\u52a1\u63d0\u4ea4\u65f6，\u7acb\u5373\u5c06 redo log buffer \u5237\u5165\u78c1\u76d8，\u5e76\u6267\u884c fsync \u843d\u76d8<\/td>\n \u6781\u4f4e（\u4ec5\u78c1\u76d8\u786c\u4ef6\u6545\u969c\u53ef\u80fd\u4e22\u6570\u636e）<\/td>\n \u6700\u5dee<\/td>\n \u4e25\u683c\u6ee1\u8db3\u6301\u4e45\u6027<\/td>\n<\/tr>\n \n 0<\/td>\n \u6bcf\u79d2\u7531\u540e\u53f0\u7ebf\u7a0b\u7edf\u4e00\u5237\u76d8，\u4e8b\u52a1\u63d0\u4ea4\u4e0d\u89e6\u53d1\u5237\u76d8<\/td>\n MySQL \u8fdb\u7a0b\u5d29\u6e83\u65f6，\u4e22\u5931\u7ea6 1 \u79d2\u5185\u5df2\u63d0\u4ea4\u7684\u4e8b\u52a1<\/td>\n \u6700\u597d<\/td>\n \u4e0d\u6ee1\u8db3<\/td>\n<\/tr>\n \n 2<\/td>\n \u4e8b\u52a1\u63d0\u4ea4\u65f6\u5199\u5230\u64cd\u4f5c\u7cfb\u7edf Page Cache，\u6bcf\u79d2\u5237\u76d8<\/td>\n MySQL \u8fdb\u7a0b\u5d29\u6e83\u4e0d\u4e22；\u64cd\u4f5c\u7cfb\u7edf\u5d29\u6e83 \/ \u65ad\u7535\u65f6，\u4e22\u5931\u7ea6 1 \u79d2\u6570\u636e<\/td>\n \u4e2d\u7b49<\/td>\n \u4e0d\u4e25\u683c\u6ee1\u8db3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u751f\u4ea7\u73af\u5883\u5982\u679c\u8981\u6c42\u4e25\u683c\u7684 ACID \u6301\u4e45\u6027，\u5fc5\u987b\u4fdd\u6301\u9ed8\u8ba4\u503c 1；\u8ffd\u6c42\u6781\u81f4\u6027\u80fd\u53ef\u914c\u60c5\u8c03\u6574，\u4f46\u9700\u63a5\u53d7\u5bf9\u5e94\u7684\u6570\u636e\u4e22\u5931\u98ce\u9669\u3002<\/p>\n
\n\u4e09\u3001\u9694\u79bb\u6027（Isolation）<\/h3>\n
\u9694\u79bb\u6027\u662f\u4e8b\u52a1\u6700\u590d\u6742\u3001\u4e5f\u662f\u8003\u70b9\u6700\u591a\u7684\u90e8\u5206，\u51b3\u5b9a\u4e86\u5e76\u53d1\u4e8b\u52a1\u4e4b\u95f4\u7684\u6570\u636e\u53ef\u89c1\u6027\u3002<\/p>\n
3.1 \u6838\u5fc3\u6982\u5ff5<\/h4>\n
\u9694\u79bb\u6027\u6307\u591a\u4e2a\u5e76\u53d1\u4e8b\u52a1\u540c\u65f6\u8bfb\u5199\u540c\u4e00\u6570\u636e\u65f6，\u4fdd\u8bc1\u6570\u636e\u4e0d\u88ab\u5e72\u6270\u7684\u7279\u6027\u3002<\/p>\n
\u5e76\u53d1\u64cd\u4f5c\u7684\u4e09\u79cd\u7c7b\u578b<\/h5>\n
- \n
- \u8bfb\u8bfb\u5e76\u53d1：\u4ec5\u8bfb\u53d6\u6570\u636e，\u4e0d\u505a\u4fee\u6539，\u4e0d\u5b58\u5728\u6570\u636e\u5b89\u5168\u95ee\u9898，\u53ef\u5b8c\u5168\u5e76\u884c\u3002<\/li>\n
- \u5199\u5199\u5e76\u53d1：\u4fee\u6539\u540c\u4e00\u884c\u6570\u636e\u65f6，\u901a\u8fc7\u884c\u9501\u4e32\u884c\u5316；\u4e0d\u540c\u884c\u7684\u5199\u64cd\u4f5c\u53ef\u4ee5\u5e76\u884c，\u5e76\u975e\u6240\u6709\u5199\u64cd\u4f5c\u90fd\u4e32\u884c\u3002<\/li>\n
- \u8bfb\u5199\u5e76\u53d1：\u8bfb\u548c\u5199\u540c\u65f6\u8fdb\u884c\u65f6\u7684\u53ef\u89c1\u6027\u95ee\u9898，\u662f\u9694\u79bb\u6027\u8ba8\u8bba\u7684\u6838\u5fc3\u3002<\/li>\n<\/ul>\n
3.2 \u56db\u4e2a\u9694\u79bb\u7ea7\u522b<\/h4>\n
SQL \u6807\u51c6\u5b9a\u4e49\u4e86\u56db\u4e2a\u9694\u79bb\u7ea7\u522b，\u4ece\u4f4e\u5230\u9ad8\u5206\u522b\u662f：\u8bfb\u672a\u63d0\u4ea4\u3001\u8bfb\u63d0\u4ea4\u3001\u53ef\u91cd\u590d\u8bfb\u3001\u4e32\u884c\u5316\u3002\u7ea7\u522b\u8d8a\u9ad8，\u9694\u79bb\u6027\u8d8a\u5f3a，\u5e76\u53d1\u6027\u80fd\u8d8a\u5dee\u3002<\/p>\n
\u67e5\u770b\u9694\u79bb\u7ea7\u522b<\/h5>\n
— \u67e5\u770b\u5168\u5c40\u9694\u79bb\u7ea7\u522b
\nSELECT @@global.transaction_isolation;<\/p>\n— \u67e5\u770b\u5f53\u524d\u4f1a\u8bdd\u9694\u79bb\u7ea7\u522b
\nSELECT @@session.transaction_isolation;<\/p>\n\u4fee\u6539\u9694\u79bb\u7ea7\u522b<\/h5>\n
— \u4fee\u6539\u5f53\u524d\u4f1a\u8bdd\u9694\u79bb\u7ea7\u522b（\u4ec5\u5bf9\u5f53\u524d\u4f1a\u8bdd\u751f\u6548）
\nSET SESSION TRANSACTION ISOLATION LEVEL \u7ea7\u522b\u540d\u79f0;<\/p>\n— \u4fee\u6539\u5168\u5c40\u9694\u79bb\u7ea7\u522b（\u5bf9\u540e\u7eed\u65b0\u4f1a\u8bdd\u751f\u6548，\u5f53\u524d\u4f1a\u8bdd\u4e0d\u751f\u6548）
\nSET GLOBAL TRANSACTION ISOLATION LEVEL \u7ea7\u522b\u540d\u79f0;<\/p>\n\u8865\u5145：MySQL \u670d\u52a1\u542f\u52a8\u65f6\u4f1a\u8bfb\u53d6\u914d\u7f6e\u6587\u4ef6\u4e2d\u7684\u5168\u5c40\u53c2\u6570；\u4fee\u6539\u5168\u5c40\u53c2\u6570\u540e，\u5df2\u6709\u4f1a\u8bdd\u4e0d\u4f1a\u66f4\u65b0，\u65b0\u4f1a\u8bdd\u624d\u4f1a\u7ee7\u627f；\u91cd\u542f\u670d\u52a1\u540e\u5168\u5c40\u53c2\u6570\u4f1a\u91cd\u7f6e\u4e3a\u914d\u7f6e\u6587\u4ef6\u4e2d\u7684\u503c\u3002<\/p>\n
\n\u7ea7\u522b\u4e00：\u8bfb\u672a\u63d0\u4ea4（READ UNCOMMITTED，RU）<\/h5>\n
\u7279\u6027<\/h6>\n
\u4e00\u4e2a\u4e8b\u52a1\u8fd8\u6ca1\u63d0\u4ea4，\u5b83\u505a\u7684\u4fee\u6539\u5c31\u80fd\u88ab\u5176\u4ed6\u4e8b\u52a1\u770b\u5230\u3002<\/p>\n
\u73b0\u8c61：\u810f\u8bfb<\/h6>\n
\u8bfb\u5230\u4e86\u5176\u4ed6\u4e8b\u52a1\u672a\u63d0\u4ea4\u7684 \u201c\u810f\u6570\u636e\u201d，\u79f0\u4e3a\u810f\u8bfb\u3002<\/p>\n
\u6f14\u793a<\/h6>\n
\u4e8b\u52a1 A：<\/p>\n
BEGIN;
\nINSERT INTO student (ename, age) VALUES ('\u8bf8\u845b\u4eae', 39), ('\u5178\u97e6', 50);
\n— \u4e0d\u63d0\u4ea4<\/p>\n\u4e8b\u52a1 B（RU \u7ea7\u522b）：<\/p>\n
SET SESSION TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;
\nBEGIN;
\nSELECT * FROM student WHERE ename IN ('\u8bf8\u845b\u4eae', '\u5178\u97e6');<\/p>\n\u7ed3\u679c：\u4e8b\u52a1 B \u53ef\u4ee5\u67e5\u5230\u8fd9\u4e24\u6761\u672a\u63d0\u4ea4\u7684\u6570\u636e\u3002<\/p>\n
\u8bc4\u4ef7<\/h6>\n
\u9694\u79bb\u7ea7\u522b\u6700\u4f4e，\u5e76\u53d1\u6700\u9ad8，\u4f46\u810f\u8bfb\u95ee\u9898\u4e25\u91cd，\u751f\u4ea7\u4e1a\u52a1\u4e2d\u51e0\u4e4e\u4e0d\u7528\u3002<\/p>\n
\n\u7ea7\u522b\u4e8c：\u8bfb\u63d0\u4ea4（READ COMMITTED，RC）<\/h5>\n
\u7279\u6027<\/h6>\n
\u4e00\u4e2a\u4e8b\u52a1\u53ea\u80fd\u770b\u5230\u5176\u4ed6\u4e8b\u52a1\u5df2\u7ecf\u63d0\u4ea4\u7684\u4fee\u6539；\u672a\u63d0\u4ea4\u7684\u4fee\u6539\u5bf9\u5176\u4ed6\u4e8b\u52a1\u4e0d\u53ef\u89c1\u3002<\/p>\n
\u89e3\u51b3\u7684\u95ee\u9898：\u810f\u8bfb<\/h6>\n
\u5b58\u5728\u7684\u95ee\u9898：\u4e0d\u53ef\u91cd\u590d\u8bfb<\/h6>\n
\u540c\u4e00\u4e2a\u4e8b\u52a1\u5185，\u4e24\u6b21\u8bfb\u53d6\u540c\u4e00\u884c\u6570\u636e，\u4e2d\u95f4\u6709\u5176\u4ed6\u4e8b\u52a1\u63d0\u4ea4\u4e86\u4fee\u6539，\u4e24\u6b21\u8bfb\u5230\u7684\u7ed3\u679c\u4e0d\u4e00\u6837\u3002<\/p>\n
\u6f14\u793a<\/h6>\n
\u4e8b\u52a1 A：<\/p>\n
BEGIN;
\nINSERT INTO student (ename, age) VALUES ('\u5b59\u7b56', 19), ('\u5b59\u8191', 20);
\n— \u4e0d\u63d0\u4ea4<\/p>\n\u4e8b\u52a1 B（RC \u7ea7\u522b）：<\/p>\n
SET SESSION TRANSACTION ISOLATION LEVEL READ COMMITTED;
\nBEGIN;
\nSELECT * FROM student WHERE ename IN ('\u5b59\u7b56', '\u5b59\u8191'); — \u67e5\u4e0d\u5230<\/p>\n\u6b64\u65f6\u4e8b\u52a1 A \u63d0\u4ea4：<\/p>\n
COMMIT;<\/p>\n
\u4e8b\u52a1 B \u518d\u6b21\u67e5\u8be2：<\/p>\n
SELECT * FROM student WHERE ename IN ('\u5b59\u7b56', '\u5b59\u8191'); — \u53ef\u4ee5\u67e5\u5230<\/p>\n
\u540c\u4e00\u4e2a\u4e8b\u52a1\u5185，\u4e24\u6b21\u540c\u6837\u7684\u67e5\u8be2\u7ed3\u679c\u4e0d\u4e00\u81f4，\u5c31\u662f \u201c\u4e0d\u53ef\u91cd\u590d\u8bfb\u201d\u3002<\/p>\n
\n\u7ea7\u522b\u4e09：\u53ef\u91cd\u590d\u8bfb（REPEATABLE READ，RR）<\/h5>\n
\u7279\u6027<\/h6>\n
MySQL InnoDB \u7684\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\u3002\u540c\u4e00\u4e2a\u4e8b\u52a1\u5185，\u591a\u6b21\u8bfb\u53d6\u540c\u4e00\u884c\u6570\u636e\u7684\u7ed3\u679c\u59cb\u7ec8\u4e00\u81f4，\u4e0d\u53d7\u5176\u4ed6\u4e8b\u52a1\u63d0\u4ea4\u7684\u5f71\u54cd\u3002<\/p>\n
\u89e3\u51b3\u7684\u95ee\u9898：\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb<\/h6>\n
\u5b58\u5728\u7684\u95ee\u9898：\u5e7b\u8bfb（InnoDB \u901a\u8fc7 Next-Key Lock \u5f88\u5927\u7a0b\u5ea6\u4e0a\u89e3\u51b3\u4e86\u5e7b\u8bfb）<\/h6>\n
\u5176\u4ed6\u4e8b\u52a1\u5728\u8be5\u8303\u56f4\u5185\u63d2\u5165\u4e86\u65b0\u884c，\u5f53\u524d\u4e8b\u52a1\u518d\u6b21\u67e5\u8be2\u65f6\u5c31\u4f1a\u770b\u5230\u8fd9\u4e9b\u65b0\u589e\u884c，\u4ece\u800c\u5bfc\u81f4\u67e5\u8be2\u7ed3\u679c\u884c\u6570\u53d1\u751f\u53d8\u5316，<\/p>\n
\u6f14\u793a<\/h6>\n
\u4e8b\u52a1 A：<\/p>\n
BEGIN;
\nINSERT INTO student (ename, age) VALUES ('\u5b59\u7b56', 19), ('\u5b59\u8191', 20);
\nCOMMIT;<\/p>\n\u4e8b\u52a1 B（RR \u7ea7\u522b）：<\/p>\n
SET SESSION TRANSACTION ISOLATION LEVEL REPEATABLE READ;
\nBEGIN;
\nSELECT * FROM student WHERE ename IN ('\u5b59\u7b56', '\u5b59\u8191'); — \u67e5\u4e0d\u5230<\/p>\n\u5373\u4f7f\u4e8b\u52a1 A \u5df2\u7ecf\u63d0\u4ea4，\u4e8b\u52a1 B \u518d\u6b21\u67e5\u8be2，\u4f9d\u7136\u67e5\u4e0d\u5230\u6570\u636e\u3002<\/p>\n
\n\u7ea7\u522b\u56db：\u4e32\u884c\u5316（SERIALIZABLE）<\/h5>\n
\u7279\u6027<\/h6>\n
\u6700\u9ad8\u9694\u79bb\u7ea7\u522b，\u6240\u6709\u4e8b\u52a1\u4e32\u884c\u6267\u884c，\u4e0d\u5141\u8bb8\u5e76\u53d1\u3002<\/p>\n
\u89e3\u51b3\u7684\u95ee\u9898：\u810f\u8bfb\u3001\u4e0d\u53ef\u91cd\u590d\u8bfb\u3001\u5e7b\u8bfb<\/h6>\n
\u6548\u679c<\/h6>\n
\u6240\u6709\u8bfb\u64cd\u4f5c\u90fd\u4f1a\u52a0\u5171\u4eab\u9501，\u5199\u64cd\u4f5c\u52a0\u6392\u4ed6\u9501，\u8bfb\u5199\u3001\u5199\u5199\u90fd\u4e92\u65a5，\u5b8c\u5168\u4e32\u884c\u3002\u5e76\u53d1\u6027\u80fd\u6781\u5dee，\u4ec5\u5728\u5bf9\u6570\u636e\u4e00\u81f4\u6027\u8981\u6c42\u6781\u9ad8\u7684\u573a\u666f\u4f7f\u7528\u3002<\/p>\n
3.3 \u9694\u79bb\u7ea7\u522b\u4e0e\u95ee\u9898\u5bf9\u5e94\u8868<\/h4>\n
\n
\u9694\u79bb\u7ea7\u522b\u810f\u8bfb\u4e0d\u53ef\u91cd\u590d\u8bfb\u5e7b\u8bfb\u5e76\u53d1\u6027\u80fd<\/tr>\n \n\n \u8bfb\u672a\u63d0\u4ea4 RU<\/td>\n \u2705 \u5b58\u5728<\/td>\n \u2705 \u5b58\u5728<\/td>\n \u2705 \u5b58\u5728<\/td>\n \u6700\u9ad8<\/td>\n<\/tr>\n \n \u8bfb\u63d0\u4ea4 RC<\/td>\n \u274c \u89e3\u51b3<\/td>\n \u2705 \u5b58\u5728<\/td>\n \u2705 \u5b58\u5728<\/td>\n \u9ad8<\/td>\n<\/tr>\n \n \u53ef\u91cd\u590d\u8bfb RR<\/td>\n \u274c \u89e3\u51b3<\/td>\n \u274c \u89e3\u51b3<\/td>\n \u90e8\u5206\u89e3\u51b3<\/td>\n \u4e2d\u7b49<\/td>\n<\/tr>\n \n \u4e32\u884c\u5316 Serializable<\/td>\n \u274c \u89e3\u51b3<\/td>\n \u274c \u89e3\u51b3<\/td>\n \u274c \u89e3\u51b3<\/td>\n \u6700\u4f4e<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n
\n\u56db\u3001\u4e00\u81f4\u6027（Consistency）<\/h3>\n
4.1 \u6838\u5fc3\u6982\u5ff5<\/h4>\n
\u4e00\u81f4\u6027\u6307\u4e8b\u52a1\u6267\u884c\u524d\u540e，\u6570\u636e\u5e93\u59cb\u7ec8\u4fdd\u6301\u6570\u636e\u7684\u6b63\u786e\u6027\u4e0e\u5b8c\u6574\u6027 \u2014\u2014 \u65e2\u7b26\u5408\u6570\u636e\u5e93\u5c42\u9762\u7684\u7ea6\u675f\u5b9a\u4e49（\u4e3b\u952e\u3001\u552f\u4e00\u952e\u3001\u5916\u952e\u3001\u6570\u636e\u7c7b\u578b），\u4e5f\u7b26\u5408\u4e1a\u52a1\u903b\u8f91\u7684\u9884\u671f\u3002<\/p>\n
4.2 \u4e00\u81f4\u6027\u4e0e\u5176\u4ed6\u4e09\u5927\u7279\u6027\u7684\u5173\u7cfb<\/h4>\n
ACID \u4e2d，\u4e00\u81f4\u6027\u662f\u6700\u7ec8\u76ee\u7684，\u539f\u5b50\u6027\u3001\u9694\u79bb\u6027\u3001\u6301\u4e45\u6027\u662f\u5b9e\u73b0\u4e00\u81f4\u6027\u7684\u624b\u6bb5\u3002<\/p>\n
- \n
- \u539f\u5b50\u6027\u4fdd\u8bc1\u4e8b\u52a1\u6ca1\u6709\u4e2d\u95f4\u72b6\u6001，\u4e0d\u4f1a\u7834\u574f\u6570\u636e\u5b8c\u6574\u6027；<\/li>\n
- \u9694\u79bb\u6027\u4fdd\u8bc1\u5e76\u53d1\u64cd\u4f5c\u4e0d\u4f1a\u4e92\u76f8\u5e72\u6270，\u4e0d\u4f1a\u4ea7\u751f\u6570\u636e\u5f02\u5e38；<\/li>\n
- \u6301\u4e45\u6027\u4fdd\u8bc1\u63d0\u4ea4\u540e\u7684\u6570\u636e\u4e0d\u4f1a\u4e22\u5931\u3002<\/li>\n<\/ul>\n
\u4e09\u8005\u5171\u540c\u4fdd\u969c\u4e86\u6570\u636e\u5e93\u59cb\u7ec8\u5904\u4e8e\u4e00\u81f4\u7684\u72b6\u6001\u3002\u4f46\u4e00\u81f4\u6027\u540c\u65f6\u4e5f\u4f9d\u8d56\u4e8e\u4e1a\u52a1\u903b\u8f91\u7684\u6b63\u786e\u6027 \u2014\u2014 \u5982\u679c\u4e8b\u52a1\u672c\u8eab\u7684\u4e1a\u52a1\u903b\u8f91\u9519\u8bef（\u6bd4\u5982\u7ed9\u5de5\u8d44\u6263\u6210\u8d1f\u6570），\u6570\u636e\u5e93\u5c42\u9762\u65e0\u6cd5\u4fdd\u8bc1\u4e1a\u52a1\u4e00\u81f4\u6027\u3002<\/p>\n
\n\u4e94\u3001\u6df1\u5165\u9694\u79bb\u6027：MVCC \u5e95\u5c42\u539f\u7406<\/h3>\n
\u9694\u79bb\u6027\u7684\u6838\u5fc3\u5b9e\u73b0\u673a\u5236\u662f MVCC（\u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236）\u3002InnoDB \u901a\u8fc7 undo log \u4fdd\u7559\u6570\u636e\u7684\u5386\u53f2\u7248\u672c，\u914d\u5408 ReadView \u5b9e\u73b0 \u201c\u5feb\u7167\u8bfb\u201d，\u8ba9\u8bfb\u5199\u64cd\u4f5c\u4e0d\u7528\u52a0\u9501\u4e5f\u80fd\u4fdd\u8bc1\u9694\u79bb，\u5927\u5e45\u63d0\u5347\u5e76\u53d1\u6027\u80fd\u3002<\/p>\n
5.1 Undo Log \u4e0e\u7248\u672c\u94fe<\/h4>\n
\u56de\u6eda\u7684\u4e24\u79cd\u5b9e\u73b0\u601d\u8def<\/h5>\n
- \n
- \u65b9\u6848\u4e00：\u8bb0\u5f55\u53cd\u5411\u64cd\u4f5c（\u6bd4\u5982 INSERT \u5bf9\u5e94 DELETE），\u56de\u6eda\u65f6\u6267\u884c\u53cd\u5411\u64cd\u4f5c\u3002\u7f3a\u70b9\u662f\u4fee\u6539\u590d\u6742\u65f6\u5f00\u9500\u5927\u3002<\/li>\n
- \u65b9\u6848\u4e8c：\u4fdd\u7559\u6570\u636e\u7684\u5386\u53f2\u7248\u672c（\u5feb\u7167），\u56de\u6eda\u65f6\u76f4\u63a5\u6062\u590d\u65e7\u7248\u672c\u3002InnoDB \u91c7\u7528\u7684\u5c31\u662f\u8fd9\u79cd\u65b9\u6848，\u901a\u8fc7 undo log \u5b58\u50a8\u5386\u53f2\u7248\u672c\u3002<\/li>\n<\/ul>\n
5.2 \u884c\u7684\u9690\u85cf\u5b57\u6bb5<\/h4>\n
InnoDB \u6bcf\u884c\u6570\u636e\u9664\u4e86\u7528\u6237\u5b9a\u4e49\u7684\u663e\u5f0f\u5b57\u6bb5，\u8fd8\u5305\u542b 3 \u4e2a\u9690\u5f0f\u5b57\u6bb5\u548c\u5220\u9664\u6807\u8bb0：<\/p>\n
\n
\u9690\u5f0f\u5b57\u6bb5\u5b57\u8282\u6570\u4f5c\u7528<\/tr>\n \n\n DB_TRX_ID<\/td>\n 6 \u5b57\u8282<\/td>\n \u6700\u540e\u4e00\u6b21\u4fee\u6539（\u63d2\u5165 \/ \u66f4\u65b0）\u8be5\u884c\u7684\u4e8b\u52a1 ID<\/td>\n<\/tr>\n \n DB_ROLL_PTR<\/td>\n 7 \u5b57\u8282<\/td>\n \u56de\u6eda\u6307\u9488，\u6307\u5411\u8be5\u884c\u4e0a\u4e00\u4e2a\u7248\u672c\u5728 undo log \u4e2d\u7684\u4f4d\u7f6e<\/td>\n<\/tr>\n \n DB_ROW_ID<\/td>\n 6 \u5b57\u8282<\/td>\n \u9690\u85cf\u4e3b\u952e\u3002\u5f53\u8868\u6ca1\u6709\u5b9a\u4e49\u4e3b\u952e\u65f6，InnoDB \u81ea\u52a8\u751f\u6210\u8be5\u5b57\u6bb5\u4f5c\u4e3a\u805a\u7c07\u7d22\u5f15；\u6709\u4e3b\u952e\u5219\u4e0d\u5b58\u5728\u6b64\u5b57\u6bb5<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u53e6\u5916\u8fd8\u6709\u5220\u9664\u6807\u8bb0\u4f4d：\u6807\u8bc6\u8be5\u884c\u662f\u5426\u88ab\u5220\u9664\u3002\u5220\u9664\u64cd\u4f5c\u672c\u8d28\u662f\u6253\u6807\u8bb0，\u4e0d\u662f\u7269\u7406\u5220\u9664，\u65e2\u9ad8\u6548\u53c8\u652f\u6301\u56de\u6eda，\u548c\u6587\u4ef6\u7cfb\u7edf\u7684\u6570\u636e\u5757\u5220\u9664\u903b\u8f91\u7c7b\u4f3c\u3002<\/p>\n
\u8fd9\u4e5f\u89e3\u91ca\u4e86\u4e00\u4e2a\u5e38\u89c1\u95ee\u9898：\u4e3a\u4ec0\u4e48\u8868\u6ca1\u6709\u4e3b\u952e\u65f6，\u5168\u8868\u626b\u63cf\u4f1a\u5f88\u6162？\u56e0\u4e3a\u6ca1\u6709\u663e\u5f0f\u4e3b\u952e\u65f6，\u67e5\u8be2\u6761\u4ef6\u4e0d\u4f1a\u547d\u4e2d\u9690\u85cf\u7684\u805a\u7c07\u7d22\u5f15，\u53ea\u80fd\u5168\u8868\u626b\u63cf\u3002<\/p>\n
5.3 \u7248\u672c\u94fe\u7684\u5f62\u6210<\/h4>\n
\u6bcf\u5f53\u5bf9\u4e00\u884c\u6570\u636e\u505a\u4fee\u6539\u65f6，\u90fd\u4f1a\u628a\u65e7\u7248\u672c\u5199\u5165 undo log，\u7136\u540e\u901a\u8fc7 DB_ROLL_PTR \u5f62\u6210\u4e00\u6761\u4ece\u6700\u65b0\u7248\u672c\u6307\u5411\u5386\u53f2\u7248\u672c\u7684\u94fe\u5f0f\u7ed3\u6784，\u79f0\u4e3a\u7248\u672c\u94fe\u3002<\/p>\n
\u793a\u4f8b<\/h5>\n
\u521d\u59cb\u63d2\u5165\u4e00\u884c（\u4e8b\u52a1 ID=1）：<\/p>\n
\n
idenameageDB_TRX_IDDB_ROLL_PTR<\/tr>\n \n\n 19<\/td>\n \u5f20\u4e09<\/td>\n 20<\/td>\n 1<\/td>\n NULL<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u6267\u884c\u66f4\u65b0 UPDATE student SET age = 30 WHERE ename = '\u5f20\u4e09'（\u4e8b\u52a1 ID=1）：<\/p>\n
- \u539f\u6765\u7684\u884c\u4f5c\u4e3a\u65e7\u7248\u672c\u5199\u5165 undo log，\u5730\u5740\u4e3a 0xaa；<\/li>\n
- \u5f53\u524d\u884c\u4fee\u6539\u4e3a\u65b0\u503c，\u66f4\u65b0 DB_ROLL_PTR \u6307\u5411\u65e7\u7248\u672c\u5730\u5740\u3002<\/li>\n
\u65b0\u7248\u672c\u884c：<\/p>\n
\n
idenameageDB_TRX_IDDB_ROLL_PTR<\/tr>\n \n\n 19<\/td>\n \u5f20\u4e09<\/td>\n 30<\/td>\n 1<\/td>\n 0xaa<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n \u7248\u672c\u94fe\u7684\u6bcf\u4e2a\u8282\u70b9，\u90fd\u5bf9\u5e94\u4e00\u6b21\u4fee\u6539\u7684\u5386\u53f2\u5feb\u7167；\u4e8b\u52a1\u56de\u6eda\u65f6，\u6cbf\u7740\u6307\u9488\u627e\u56de\u65e7\u7248\u672c\u5373\u53ef\u3002<\/p>\n
![\"\"](\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/09\/20260918201959-6aad9cefd8f59.png\")
<\/h4>\n5.4 \u5feb\u7167\u8bfb\u4e0e ReadView<\/h4>\n
\u4ec0\u4e48\u662f\u5feb\u7167<\/h5>\n
\u5feb\u7167，\u5b57\u9762\u610f\u601d\u5c31\u662f "\u5feb\u901f\u62cd\u6444\u7684\u7167\u7247"\u3002<\/p>\n
\u60f3\u8c61\u4f60\u7528\u624b\u673a\u7ed9\u4e00\u4e2a\u6b63\u5728\u53d8\u5316\u7684\u573a\u666f\u62cd\u4e86\u4e00\u5f20\u7167\u7247 \u2014\u2014 \u6309\u4e0b\u5feb\u95e8\u7684\u90a3\u4e00\u523b，\u753b\u9762\u5c31\u88ab\u5b9a\u683c\u4e86\u3002\u4e4b\u540e\u573a\u666f\u518d\u600e\u4e48\u53d8\u5316，\u7167\u7247\u91cc\u7684\u5185\u5bb9\u90fd\u4e0d\u4f1a\u53d8\u3002<\/p>\n
\u6570\u636e\u5e93\u4e2d\u7684\u5feb\u7167\u4e5f\u662f\u540c\u4e00\u4e2a\u9053\u7406：\u5728\u67d0\u4e2a\u65f6\u95f4\u70b9，\u7ed9\u6570\u636e\u5e93\u4e2d\u7684\u6570\u636e "\u62cd\u4e00\u5f20\u7167\u7247"，\u628a\u90a3\u4e00\u523b\u7684\u6570\u636e\u72b6\u6001\u5b8c\u6574\u4fdd\u5b58\u4e0b\u6765\u3002\u4e4b\u540e\u4e0d\u7ba1\u6570\u636e\u600e\u4e48\u88ab\u4fee\u6539\u3001\u88ab\u5176\u4ed6\u4e8b\u52a1\u63d0\u4ea4，\u8fd9\u5f20 "\u7167\u7247" \u91cc\u7684\u5185\u5bb9\u59cb\u7ec8\u4e0d\u53d8\u3002<\/p>\n
\u4ec0\u4e48\u662f\u5feb\u7167\u8bfb？<\/h5>\n
\u6211\u4eec\u5e73\u65f6\u6267\u884c\u7684\u666e\u901a SELECT \u5c31\u662f\u5feb\u7167\u8bfb：\u4e0d\u52a0\u9501，\u76f4\u63a5\u8bfb\u53d6\u6570\u636e\u7684\u53ef\u89c1\u7248\u672c，\u57fa\u4e8e ReadView \u5224\u65ad\u54ea\u4e2a\u7248\u672c\u53ef\u89c1\u3002<\/p>\n
\u4e0e\u4e4b\u5bf9\u5e94\u7684\u662f\u5f53\u524d\u8bfb：SELECT … FOR UPDATE\u3001INSERT\u3001UPDATE\u3001DELETE，\u8bfb\u53d6\u6700\u65b0\u7248\u672c\u5e76\u52a0\u9501\u3002<\/p>\n
ReadView \u7ed3\u6784<\/h5>\n
ReadView \u662f\u4e8b\u52a1\u6267\u884c\u5feb\u7167\u8bfb\u65f6\u751f\u6210\u7684 \u201c\u8bfb\u89c6\u56fe\u201d，\u8bb0\u5f55\u4e86\u751f\u6210\u89c6\u56fe\u90a3\u4e00\u523b\u7cfb\u7edf\u4e2d\u6d3b\u8dc3\u4e8b\u52a1\u7684\u72b6\u6001，\u7528\u6765\u5224\u65ad\u7248\u672c\u94fe\u4e0a\u7684\u54ea\u4e2a\u7248\u672c\u5bf9\u5f53\u524d\u4e8b\u52a1\u53ef\u89c1\u3002<\/p>\n
\u6838\u5fc3\u7ed3\u6784：<\/p>\n
class ReadView {
\nprivate:
\n trx_id_t m_up_limit_id; \/\/ \u4f4e\u6c34\u4f4d：\u6d3b\u8dc3\u4e8b\u52a1\u4e2d\u6700\u5c0f\u7684\u4e8b\u52a1ID
\n trx_id_t m_low_limit_id; \/\/ \u9ad8\u6c34\u4f4d：\u7cfb\u7edf\u4e0b\u4e00\u4e2a\u5f85\u5206\u914d\u7684\u4e8b\u52a1ID（\u5f53\u524d\u6700\u5927\u4e8b\u52a1ID+1）
\n trx_id_t m_creator_trx_id; \/\/ \u521b\u5efa\u8be5ReadView\u7684\u4e8b\u52a1ID
\n ids_t m_ids; \/\/ \u751f\u6210ReadView\u65f6，\u6240\u6709\u6d3b\u8dc3（\u672a\u63d0\u4ea4）\u4e8b\u52a1\u7684ID\u5217\u8868
\n \/\/ …
\n};<\/p>\n\u5404\u5b57\u6bb5\u542b\u4e49：<\/p>\n
- m_ids：\u751f\u6210 ReadView \u7684\u77ac\u95f4，\u7cfb\u7edf\u4e2d\u6240\u6709\u6b63\u5728\u6d3b\u8dc3\u3001\u672a\u63d0\u4ea4\u7684\u4e8b\u52a1 ID \u5217\u8868（\u4e0d\u5305\u542b\u5f53\u524d\u4e8b\u52a1\u81ea\u5df1）\u3002<\/li>\n
- m_up_limit_id（\u4f4e\u6c34\u4f4d）：m_ids \u5217\u8868\u4e2d\u6700\u5c0f\u7684\u4e8b\u52a1 ID\u3002<\/li>\n
- m_low_limit_id（\u9ad8\u6c34\u4f4d）：\u751f\u6210 ReadView \u65f6，\u7cfb\u7edf\u5c1a\u672a\u5206\u914d\u7684\u4e0b\u4e00\u4e2a\u4e8b\u52a1 ID，\u4e5f\u5c31\u662f\u5f53\u524d\u5df2\u51fa\u73b0\u8fc7\u7684\u6700\u5927\u4e8b\u52a1 ID + 1\u3002<\/li>\n
- m_creator_trx_id：\u521b\u5efa\u5f53\u524d ReadView \u7684\u4e8b\u52a1\u81ea\u8eab\u7684 ID\u3002<\/li>\n
5.5 \u53ef\u89c1\u6027\u5224\u65ad\u89c4\u5219<\/h4>\n
\u5bf9\u4e8e\u7248\u672c\u94fe\u4e0a\u7684\u67d0\u4e00\u4e2a\u7248\u672c（DB_TRX_ID \u4e3a\u4fee\u6539\u8be5\u7248\u672c\u7684\u4e8b\u52a1 ID），\u6309\u4ee5\u4e0b\u89c4\u5219\u5224\u65ad\u662f\u5426\u53ef\u89c1：<\/p>\n
- \u82e5 DB_TRX_ID < m_up_limit_id \u8be5\u7248\u672c\u7684\u4fee\u6539\u4e8b\u52a1，\u5728 ReadView \u751f\u6210\u524d\u5c31\u5df2\u7ecf\u63d0\u4ea4\u4e86，\u53ef\u89c1\u3002<\/li>\n
- \u82e5 DB_TRX_ID >= m_low_limit_id \u8be5\u7248\u672c\u7684\u4fee\u6539\u4e8b\u52a1，\u662f\u5728 ReadView \u751f\u6210\u4e4b\u540e\u624d\u5f00\u542f\u7684，\u4e0d\u53ef\u89c1\u3002<\/li>\n
- \u82e5 DB_TRX_ID \u5728\u4e24\u8005\u4e4b\u95f4\n
- \n
- \u5982\u679c DB_TRX_ID \u5728 m_ids \u5217\u8868\u4e2d：\u8bf4\u660e\u8be5\u4e8b\u52a1\u5728 ReadView \u751f\u6210\u65f6\u8fd8\u6d3b\u8dc3\u672a\u63d0\u4ea4，\u4e0d\u53ef\u89c1；<\/li>\n
- \u5982\u679c DB_TRX_ID \u4e0d\u5728 m_ids \u5217\u8868\u4e2d：\u8bf4\u660e\u8be5\u4e8b\u52a1\u5728 ReadView \u751f\u6210\u65f6\u5df2\u7ecf\u63d0\u4ea4，\u53ef\u89c1\u3002<\/li>\n<\/ul>\n<\/li>\n
\u5982\u679c\u5f53\u524d\u7248\u672c\u4e0d\u53ef\u89c1，\u5c31\u6cbf\u7740 DB_ROLL_PTR \u627e\u4e0a\u4e00\u4e2a\u7248\u672c，\u91cd\u590d\u5224\u65ad，\u76f4\u5230\u627e\u5230\u53ef\u89c1\u7684\u7248\u672c\u3002<\/p>\n
5.6 RC \u4e0e RR \u7684\u672c\u8d28\u533a\u522b<\/h4>\n
RC \u548c RR \u9694\u79bb\u7ea7\u522b\u6700\u6838\u5fc3\u7684\u533a\u522b，\u5c31\u662f ReadView \u7684\u751f\u6210\u65f6\u673a\u4e0d\u540c：<\/p>\n
1. \u8bfb\u63d0\u4ea4（RC）<\/h5>\n
\u6bcf\u6b21\u6267\u884c\u5feb\u7167\u8bfb（SELECT），\u90fd\u4f1a\u91cd\u65b0\u751f\u6210\u4e00\u4e2a\u65b0\u7684 ReadView\u3002 \u6240\u4ee5\u6bcf\u6b21\u67e5\u8be2\u90fd\u80fd\u770b\u5230\u6700\u65b0\u63d0\u4ea4\u7684\u4e8b\u52a1\u4fee\u6539，\u56e0\u6b64\u4f1a\u51fa\u73b0\u4e0d\u53ef\u91cd\u590d\u8bfb\u3002<\/p>\n
2. \u53ef\u91cd\u590d\u8bfb（RR）<\/h5>\n
\u53ea\u5728\u4e8b\u52a1\u4e2d\u7b2c\u4e00\u6b21\u6267\u884c\u5feb\u7167\u8bfb\u65f6，\u751f\u6210\u4e00\u4e2a ReadView，\u540e\u7eed\u6240\u6709\u5feb\u7167\u8bfb\u90fd\u590d\u7528\u8fd9\u4e2a ReadView\u3002 \u6240\u4ee5\u6574\u4e2a\u4e8b\u52a1\u5185\u770b\u5230\u7684\u6570\u636e\u7248\u672c\u90fd\u662f\u4e00\u81f4\u7684，\u4e0d\u53d7\u5176\u4ed6\u4e8b\u52a1\u63d0\u4ea4\u7684\u5f71\u54cd，\u5b9e\u73b0\u4e86\u53ef\u91cd\u590d\u8bfb\u3002<\/p>\n
\u4e3e\u4f8b\u7406\u89e3<\/h5>\n
\u5047\u8bbe\u7cfb\u7edf\u4e2d\u6709\u4e8b\u52a1 2\u30013\u30014\u30015 \u540c\u65f6\u6d3b\u8dc3：<\/p>\n
- \n
- \u4e8b\u52a1 3 \u5148\u63d0\u4ea4；<\/li>\n
- \u4e8b\u52a1 4 \u6267\u884c SELECT\u3002<\/li>\n
- RC \u7ea7\u522b：\u4e8b\u52a1 4 \u6bcf\u6b21 SELECT \u90fd\u751f\u6210\u65b0\u7684 ReadView\u3002\u4e8b\u52a1 3 \u63d0\u4ea4\u540e，\u65b0\u7684 ReadView \u7684 m_ids \u91cc\u5c31\u6ca1\u6709 3 \u4e86，\u6240\u4ee5\u80fd\u770b\u5230\u4e8b\u52a1 3 \u7684\u4fee\u6539\u3002<\/li>\n
- RR \u7ea7\u522b：\u4e8b\u52a1 4 \u7b2c\u4e00\u6b21 SELECT \u751f\u6210 ReadView \u540e\u5c31\u4e0d\u518d\u53d8\u5316\u3002\u5373\u4f7f\u4e8b\u52a1 3 \u63d0\u4ea4\u4e86，m_ids \u5217\u8868\u4e5f\u4e0d\u53d8，\u6240\u4ee5\u8fd8\u662f\u770b\u4e0d\u5230\u4e8b\u52a1 3 \u7684\u4fee\u6539\u3002<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"
\u6211\u4eec\u5e38\u8bf4\u78c1\u76d8 \/ \u5185\u5b58\u7684\u7ba1\u7406\u9897\u7c92\u662f \u201c\u5757 \/ \u9875\u201d，\u90a3 MySQL \u6570\u636e\u5e93\u7684\u6267\u884c\u4e0e\u7ba1\u7406\u9897\u7c92\u662f\u4ec0\u4e48？\u7b54\u6848\u662f：\u4e8b\u52a1（Transaction）\u3002\u5728\u6ca1\u6709\u5b66\u4e60\u4e8b\u52a1\u4e4b\u524d，\u4f60\u53ef\u4ee5\u8ba4\u4e3a\u4e4b\u524d\u7684\u6bcf\u4e00\u6761\u5355\u53e5 SQL \u90fd\u81ea\u6210\u4e00\u4e2a\u4e8b\u52a1\u3002\u800c\u4e8b\u52a1\u7684\u672c\u8d28，\u662f\u4e00\u7ec4\u903b\u8f91\u4e0a\u4e0d\u53ef\u5206\u5272\u7684 SQL \u8bed\u53e5\u96c6\u5408 \u2014\u2014 \u8981\u4e48\u5168\u90e8\u6267\u884c\u6210\u529f，\u8981\u4e48\u5168\u90e8\u5931\u8d25\u56de\u6eda，\u662f\u6570\u636e\u5e93\u4fdd\u8bc1\u6570\u636e\u53ef\u9760\u6027\u3001\u5e76\u53d1\u6b63\u786e\u6027\u7684\u6838\u5fc3\u673a\u5236\u3002<\/p>\n","protected":false},"author":2,"featured_media":107147,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[58,114,768,100],"topic":[],"class_list":["post-107148","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-server","tag-linux","tag-mysql","tag-sql","tag-100"],"yoast_head":"\n
MySQL\u57fa\u7840\u7bc7\u4e4b\u4e8b\u52a1 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.wsisp.com\/helps\/107148.html\" \/>\n<meta property=\"og:locale\" content=\"zh_CN\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"MySQL\u57fa\u7840\u7bc7\u4e4b\u4e8b\u52a1 - \u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"og:description\" content=\"\u6211\u4eec\u5e38\u8bf4\u78c1\u76d8 \/ \u5185\u5b58\u7684\u7ba1\u7406\u9897\u7c92\u662f \u201c\u5757 \/ \u9875\u201d，\u90a3 MySQL \u6570\u636e\u5e93\u7684\u6267\u884c\u4e0e\u7ba1\u7406\u9897\u7c92\u662f\u4ec0\u4e48？\u7b54\u6848\u662f：\u4e8b\u52a1（Transaction）\u3002\u5728\u6ca1\u6709\u5b66\u4e60\u4e8b\u52a1\u4e4b\u524d，\u4f60\u53ef\u4ee5\u8ba4\u4e3a\u4e4b\u524d\u7684\u6bcf\u4e00\u6761\u5355\u53e5 SQL \u90fd\u81ea\u6210\u4e00\u4e2a\u4e8b\u52a1\u3002\u800c\u4e8b\u52a1\u7684\u672c\u8d28，\u662f\u4e00\u7ec4\u903b\u8f91\u4e0a\u4e0d\u53ef\u5206\u5272\u7684 SQL \u8bed\u53e5\u96c6\u5408 \u2014\u2014 \u8981\u4e48\u5168\u90e8\u6267\u884c\u6210\u529f，\u8981\u4e48\u5168\u90e8\u5931\u8d25\u56de\u6eda，\u662f\u6570\u636e\u5e93\u4fdd\u8bc1\u6570\u636e\u53ef\u9760\u6027\u3001\u5e76\u53d1\u6b63\u786e\u6027\u7684\u6838\u5fc3\u673a\u5236\u3002\" \/>\n<meta property=\"og:url\" content=\"https:\/\/www.wsisp.com\/helps\/107148.html\" \/>\n<meta property=\"og:site_name\" content=\"\u7f51\u7855\u4e92\u8054\u5e2e\u52a9\u4e2d\u5fc3\" \/>\n<meta property=\"article:published_time\" content=\"2026-09-18T20:20:01+00:00\" \/>\n<meta property=\"og:image\" content=\"https:\/\/www.wsisp.com\/helps\/wp-content\/uploads\/2026\/09\/20260918201959-6aad9cefd8f59.png\" \/>\n<meta name=\"author\" content=\"admin\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:label1\" content=\"\u4f5c\u8005\" \/>\n\t<meta name=\"twitter:data1\" content=\"admin\" \/>\n\t<meta name=\"twitter:label2\" content=\"\u9884\u8ba1\u9605\u8bfb\u65f6\u95f4\" \/>\n\t<meta name=\"twitter:data2\" content=\"5 \u5206\" \/>\n<script type=\"application\/ld+json\" class=\"yoast-schema-graph\">{\"@context\":\"https:\/\/schema.org\",\"@graph\":[{\"@type\":\"WebPage\",\"@id\":\"https:\/\/www.wsisp.com\/helps\/107148.html\",\"url\":\"https:\/\/www.wsisp.com\/helps\/107148.html\",\"name\":\"MySQL\u57fa\u7840\u7bc7\u4e4b\u4e8b\u52a1 - 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