{"id":313235,"date":"2024-01-17T17:51:18","date_gmt":"2024-01-17T09:51:18","guid":{"rendered":"https:\/\/www.idc.net\/help\/313235\/"},"modified":"2024-01-17T17:51:18","modified_gmt":"2024-01-17T09:51:18","slug":"%e6%b7%b1%e5%85%a5%e7%90%86%e8%a7%a3mysql-%e9%94%81%e3%80%81%e4%ba%8b%e5%8a%a1%e4%b8%8e%e5%b9%b6%e5%8f%91%e6%8e%a7%e5%88%b6","status":"publish","type":"post","link":"https:\/\/idc.net\/help\/313235\/","title":{"rendered":"\u6df1\u5165\u7406\u89e3MySQL\u2014\u2014\u9501\u3001\u4e8b\u52a1\u4e0e\u5e76\u53d1\u63a7\u5236"},"content":{"rendered":"

\u672c\u6587\u5bf9\u9501\u3001\u4e8b\u52a1\u3001\u5e76\u53d1\u63a7\u5236\u505a\u4e00\u4e2a\u603b\u7ed3\uff0c\u770b\u4e86\u7f51\u4e0a\u5f88\u591a\u6587\u7ae0\uff0c\u63cf\u8ff0\u975e\u5e38\u4e0d\u51c6\u786e\u3002\u5982\u6709\u4e0e\u60a8\u89c2\u70b9\u4e0d\u4e00\u81f4\uff0c\u6b22\u8fce\u6709\u7406\u6709\u636e\u7684\u62cd\u7816\uff01<\/span> <\/p>\n

mysql\u670d\u52a1\u5668\u903b\u8f91\u67b6\u6784<\/strong><\/span><\/h3>\n

\n

\u6bcf\u4e2a\u8fde\u63a5\u90fd\u4f1a\u5728mysql\u670d\u52a1\u7aef\u4ea7\u751f\u4e00\u4e2a\u7ebf\u7a0b\uff08\u5185\u90e8\u901a\u8fc7\u7ebf\u7a0b\u6c60\u7ba1\u7406\u7ebf\u7a0b\uff09\uff0c\u6bd4\u5982\u4e00\u4e2aselect\u8bed\u53e5\u8fdb\u5165\uff0cmysql\u9996\u5148\u4f1a\u5728\u67e5\u8be2\u7f13\u5b58\u4e2d\u67e5\u627e\u662f\u5426\u7f13\u5b58\u4e86\u8fd9\u4e2aselect\u7684\u7ed3\u679c\u96c6\uff0c\u5982\u679c\u6ca1\u6709\u5219\u7ee7\u7eed\u6267\u884c \u89e3\u6790\u3001\u4f18\u5316\u3001\u6267\u884c\u7684\u8fc7\u7a0b\uff1b\u5426\u5219\u4f1a\u4e4b\u95f4\u4ece\u7f13\u5b58\u4e2d\u83b7\u53d6\u7ed3\u679c\u96c6\u3002<\/p>\n

mysql\u5e76\u53d1\u63a7\u5236\u2014\u2014\u5171\u4eab\u9501\u3001\u6392\u4ed6\u9501<\/strong><\/span><\/h3>\n

\u5171\u4eab\u9501<\/strong><\/span><\/p>\n

\u5171\u4eab\u9501\u4e5f\u79f0\u4e3a\u8bfb\u9501\uff0c\u8bfb\u9501\u5141\u8bb8\u591a\u4e2a\u8fde\u63a5\u53ef\u4ee5\u540c\u4e00\u65f6\u523b\u5e76\u53d1\u7684\u8bfb\u53d6\u540c\u4e00\u8d44\u6e90,\u4e92\u4e0d\u5e72\u6270\uff1b<\/p>\n

\u6392\u4ed6\u9501<\/strong><\/span><\/p>\n

\u6392\u4ed6\u9501\u4e5f\u79f0\u4e3a\u5199\u9501\uff0c\u4e00\u4e2a\u5199\u9501\u4f1a\u963b\u585e\u5176\u4ed6\u7684\u5199\u9501\u6216\u8bfb\u9501\uff0c\u4fdd\u8bc1\u540c\u4e00\u65f6\u523b\u53ea\u6709\u4e00\u4e2a\u8fde\u63a5\u53ef\u4ee5\u5199\u5165\u6570\u636e\uff0c\u540c\u65f6\u9632\u6b62\u5176\u4ed6\u7528\u6237\u5bf9\u8fd9\u4e2a\u6570\u636e\u7684\u8bfb\u5199\u3002<\/p>\n

\u9501\u7b56\u7565<\/strong><\/span><\/p>\n

\u9501\u7684\u5f00\u9500\u662f\u8f83\u4e3a\u6602\u8d35\u7684\uff0c\u9501\u7b56\u7565\u5176\u5b9e\u5c31\u662f\u4fdd\u8bc1\u4e86\u7ebf\u7a0b\u5b89\u5168\u7684\u540c\u65f6\u83b7\u53d6\u6700\u5927\u7684\u6027\u80fd\u4e4b\u95f4\u7684\u5e73\u8861\u7b56\u7565\u3002<\/p>\n

    \n
  • \n

    mysql\u9501\u7b56\u7565\uff1atalbe lock(\u8868\u9501)<\/span><\/p>\n<\/li>\n<\/ul>\n

    \u8868\u9501\u662fmysql\u6700\u57fa\u672c\u7684\u9501\u7b56\u7565\uff0c\u4e5f\u662f\u5f00\u9500\u6700\u5c0f\u7684\u9501\uff0c\u5b83\u4f1a\u9501\u5b9a\u6574\u4e2a\u8868\uff1b<\/p>\n

    \u5177\u4f53\u60c5\u51b5\u662f\uff1a\u82e5\u4e00\u4e2a\u7528\u6237\u6b63\u5728\u6267\u884c\u5199\u64cd\u4f5c\uff0c\u4f1a\u83b7\u53d6\u6392\u4ed6\u7684\u201c\u5199\u9501\u201d\uff0c\u8fd9\u53ef\u80fd\u4f1a\u9501\u5b9a\u6574\u4e2a\u8868\uff0c\u963b\u585e\u5176\u4ed6\u7528\u6237\u7684\u8bfb\u3001\u5199\u64cd\u4f5c\uff1b<\/p>\n

    \u82e5\u4e00\u4e2a\u7528\u6237\u6b63\u5728\u6267\u884c\u8bfb\u64cd\u4f5c\uff0c\u4f1a\u5148\u83b7\u53d6\u5171\u4eab\u9501\u201c\u8bfb\u9501\u201d\uff0c\u8fd9\u4e2a\u9501\u8fd0\u884c\u5176\u4ed6\u8bfb\u9501\u5e76\u53d1\u7684\u5bf9\u8fd9\u4e2a\u8868\u8fdb\u884c\u8bfb\u53d6\uff0c\u4e92\u4e0d\u5e72\u6270\u3002\u53ea\u8981\u6ca1\u6709\u5199\u9501\u7684\u8fdb\u5165\uff0c\u8bfb\u9501\u53ef\u4ee5\u662f\u5e76\u53d1\u8bfb\u53d6\u7edf\u4e00\u8d44\u6e90\u7684\u3002<\/p>\n

    \u901a\u5e38\u53d1\u751f\u5728DDL\u8bed\u53e5\\DML\u4e0d\u8d70\u7d22\u5f15\u7684\u8bed\u53e5\u4e2d\uff0c\u6bd4\u5982\u8fd9\u4e2aDML update table set columnA=\u201dA\u201d where columnB=\u201cB\u201d. 
    \u5982\u679ccolumnB\u5b57\u6bb5\u4e0d\u5b58\u5728\u7d22\u5f15\uff08\u6216\u8005\u4e0d\u662f\u7ec4\u5408\u7d22\u5f15\u524d\u7f00\uff09\uff0c\u4f1a\u9501\u4f4f\u6240\u6709\u8bb0\u5f55\u4e5f\u5c31\u662f\u9501\u8868\u3002\u5982\u679c\u8bed\u53e5\u7684\u6267\u884c\u80fd\u591f\u6267\u884c\u4e00\u4e2acolumnB\u5b57\u6bb5\u7684\u7d22\u5f15\uff0c\u90a3\u4e48\u4f1a\u9501\u4f4f\u6ee1\u8db3where\u7684\u884c(\u884c\u9501)\u3002<\/p>\n

      \n
    • \n

      mysql\u9501\u7b56\u7565\uff1arow lock(\u884c\u9501)<\/span><\/p>\n<\/li>\n<\/ul>\n

      \u884c\u9501\u53ef\u4ee5\u6700\u5927\u9650\u5ea6\u7684\u652f\u6301\u5e76\u53d1\u5904\u7406\uff0c\u5f53\u7136\u4e5f\u5e26\u6765\u4e86\u6700\u5927\u5f00\u9500\uff0c\u987e\u540d\u601d\u4e49\uff0c\u884c\u9501\u7684\u7c92\u5ea6\u5b9e\u5728\u6bcf\u4e00\u6761\u884c\u6570\u636e\u3002<\/p>\n

      \u4e8b\u52a1<\/span><\/h3>\n

      \u4e8b\u52a1\u5c31\u662f\u4e00\u7ec4\u539f\u5b50\u6027\u7684sql\uff0c\u6216\u8005\u8bf4\u4e00\u4e2a\u72ec\u7acb\u7684\u5de5\u4f5c\u5355\u5143\u3002<\/span> 
      \u4e8b\u52a1\u5c31\u662f\u8bf4\uff0c\u8981\u4e48mysql\u5f15\u64ce\u4f1a\u5168\u90e8\u6267\u884c\u8fd9\u4e00\u7ec4sql\u8bed\u53e5\uff0c\u8981\u4e48\u5168\u90e8\u90fd\u4e0d\u6267\u884c\uff08\u6bd4\u5982\u5176\u4e2d\u4e00\u6761\u8bed\u53e5\u5931\u8d25\u7684\u8bdd\uff09\u3002<\/span><\/p>\n

      \u6bd4\u5982\uff0ctim\u8981\u7ed9bill\u8f6c\u8d26100\u5757\u94b1\uff1a 
      1.\u68c0\u67e5tim\u7684\u8d26\u6237\u4f59\u989d\u662f\u5426\u5927\u4e8e100\u5757\uff1b 
      2.tim\u7684\u8d26\u6237\u51cf\u5c11100\u5757\uff1b 
      3.bill\u7684\u8d26\u6237\u589e\u52a0100\u5757\uff1b 
      \u8fd9\u4e09\u4e2a\u64cd\u4f5c\u5c31\u662f\u4e00\u4e2a\u4e8b\u52a1\uff0c\u5fc5\u987b\u6253\u5305\u6267\u884c\uff0c\u8981\u4e48\u5168\u90e8\u6210\u529f\uff0c\u8981\u4e48\u5168\u90e8\u4e0d\u6267\u884c\uff0c\u5176\u4e2d\u4efb\u4f55\u4e00\u4e2a\u64cd\u4f5c\u7684\u5931\u8d25\u90fd\u4f1a\u5bfc\u81f4\u6240\u6709\u4e09\u4e2a\u64cd\u4f5c\u201c\u4e0d\u6267\u884c\u201d\u2014\u2014\u56de\u6eda\u3002  <\/p>\n

      \n \n \n 
        \n  \n  \n  
      1. CREATE<\/span> <\/span>DATABASE<\/span> IF <\/span>NOT<\/span> EXISTS employees; <\/span><\/span><\/li>\n  \n  \n  
      2. USE employees; <\/span><\/li>\n  \n  \n  
      3.  <\/span><\/li>\n  \n  \n  
      4. CREATE<\/span> <\/span>TABLE<\/span> `employees`.`account` ( <\/span><\/span><\/li>\n  \n  \n  
      5.  `id` BIGINT<\/span> (11) <\/span>NOT<\/span> <\/span>NULL<\/span> AUTO_INCREMENT, <\/span><\/span><\/li>\n  \n  \n  
      6.  `p_name` VARCHAR<\/span> (4), <\/span><\/span><\/li>\n  \n  \n  
      7.  `p_money` DECIMAL<\/span> (10, 2) <\/span>NOT<\/span> <\/span>NULL<\/span> <\/span>DEFAULT<\/span> 0, <\/span><\/span><\/li>\n  \n  \n  
      8.  PRIMARY<\/span> <\/span>KEY<\/span> (`id`) <\/span><\/span><\/li>\n  \n  \n  
      9. ) ; <\/span><\/li>\n  \n  \n  
      10. INSERT<\/span> <\/span>INTO<\/span> `employees`.`account` (`id`, `p_name`, `p_money`) <\/span>VALUES<\/span> (<\/span>'1'<\/span>, <\/span>'tim'<\/span>, <\/span>'200'<\/span>);  <\/span><\/span><\/li>\n  \n  \n  
      11. INSERT<\/span> <\/span>INTO<\/span> `employees`.`account` (`id`, `p_name`, `p_money`) <\/span>VALUES<\/span> (<\/span>'2'<\/span>, <\/span>'bill'<\/span>, <\/span>'200'<\/span>);  <\/span><\/span><\/li>\n  \n  \n  
      12.  <\/span><\/li>\n  \n  \n  
      13. START TRANSACTION<\/span>; <\/span><\/span><\/li>\n  \n  \n  
      14. SELECT<\/span> p_money <\/span>FROM<\/span> account <\/span>WHERE<\/span> p_name=<\/span>\"tim\"<\/span>;<\/span>-- step1<\/span> <\/span><\/span><\/li>\n  \n  \n  
      15. UPDATE<\/span> account <\/span>SET<\/span> p_money=p_money-100 <\/span>WHERE<\/span> p_name=<\/span>\"tim\"<\/span>;<\/span>-- step2<\/span> <\/span><\/span><\/li>\n  \n  \n  
      16. UPDATE<\/span> account <\/span>SET<\/span> p_money=p_money+100 <\/span>WHERE<\/span> p_name=<\/span>\"bill\"<\/span>;<\/span>-- step3<\/span> <\/span><\/span><\/li>\n  \n  \n  
      17. COMMIT<\/span>; <\/span><\/span> <\/li>\n \n \n <\/ol><\/pre>\n
        \u4e00\u4e2a\u826f\u597d\u7684\u4e8b\u52a1\u7cfb\u7edf\uff0c\u5fc5\u987b\u6ee1\u8db3ACID\u7279\u70b9\uff1a<\/p>\n
        \u4e8b\u52a1\u7684ACID<\/span><\/h3>\n
          \n
        • \n
          A:atomiciy\u539f\u5b50\u6027<\/span> 
           \u4e00\u4e2a\u4e8b\u52a1\u5fc5\u987b\u4fdd\u8bc1\u5176\u4e2d\u7684\u64cd\u4f5c\u8981\u4e48\u5168\u90e8\u6267\u884c\uff0c\u8981\u4e48\u5168\u90e8\u56de\u6eda\uff0c\u4e0d\u53ef\u80fd\u5b58\u5728\u53ea\u6267\u884c\u4e86\u4e00\u90e8\u5206\u8fd9\u79cd\u60c5\u51b5\u51fa\u73b0\u3002<\/span><\/p>\n<\/li>\n
        • \n
          C:consistency\u4e00\u81f4\u6027<\/span> 
           \u6570\u636e\u5fc5\u987b\u4fdd\u8bc1\u4ece\u4e00\u79cd\u4e00\u81f4\u6027\u7684\u72b6\u6001\u8f6c\u6362\u4e3a\u53e6\u4e00\u79cd\u4e00\u81f4\u6027\u72b6\u6001<\/span>\u3002 
           \u6bd4\u5982\u4e0a\u4e00\u4e2a\u4e8b\u52a1\u4e2d\u6267\u884c\u4e86\u7b2c\u4e8c\u6b65\u65f6\u7cfb\u7edf\u5d29\u6e83\u4e86\uff0c\u6570\u636e\u4e5f\u4e0d\u4f1a\u51fa\u73b0bill\u7684\u8d26\u6237\u5c11\u4e86100\u5757\uff0c\u4f46\u662ftim\u7684\u8d26\u6237\u6ca1\u53d8\u7684\u60c5\u51b5\u3002\u8981\u4e48\u7ef4\u6301\u539f\u88c5\uff08\u5168\u90e8\u56de\u6eda\uff09\uff0c\u8981\u4e48bill\u5c11\u4e86100\u5757\u540c\u65f6tim\u591a\u4e86100\u5757\uff0c\u53ea\u6709\u8fd9\u4e24\u79cd\u4e00\u81f4\u6027\u72b6\u6001\u7684<\/p>\n<\/li>\n
        • \n
          I\uff1aisolation\u9694\u79bb\u6027<\/span> 
           \u5728\u4e00\u4e2a\u4e8b\u52a1\u672a\u6267\u884c\u5b8c\u6bd5\u65f6\uff0c\u901a\u5e38\u4f1a\u4fdd\u8bc1\u5176\u4ed6Session \u65e0\u6cd5\u770b\u5230\u8fd9\u4e2a\u4e8b\u52a1\u7684\u6267\u884c\u7ed3\u679c<\/span><\/p>\n<\/li>\n
        • \n
          D:durability\u6301\u4e45\u6027<\/span> 
           \u4e8b\u52a1\u4e00\u65e6commit\uff0c\u5219\u6570\u636e\u5c31\u4f1a\u4fdd\u5b58\u4e0b\u6765\uff0c\u5373\u4f7f\u63d0\u4ea4\u5b8c\u4e4b\u540e\u7cfb\u7edf\u5d29\u6e83\uff0c\u6570\u636e\u4e5f\u4e0d\u4f1a\u4e22\u5931\u3002<\/span><\/p>\n<\/li>\n<\/ul>\n
          \u9694\u79bb\u7ea7\u522b<\/span><\/h3>\n
           <\/h3>\n
          \r\n\r\n \u67e5\u770b\u7cfb\u7edf\u9694\u79bb\u7ea7\u522b\uff1a\r\n select @@global.tx_isolation;\r\n \u67e5\u770b\u5f53\u524d\u4f1a\u8bdd\u9694\u79bb\u7ea7\u522b\r\n select @@tx_isolation;\r\n \u8bbe\u7f6e\u5f53\u524d\u4f1a\u8bdd\u9694\u79bb\u7ea7\u522b\r\n SET session TRANSACTION ISOLATION LEVEL serializable;\r\n \u8bbe\u7f6e\u5168\u5c40\u7cfb\u7edf\u9694\u79bb\u7ea7\u522b\r\n SET GLOBAL TRANSACTION ISOLATION LEVEL READ UNCOMMITTED; \r\n <\/pre>\n
          \n
          READ UNCOMMITTED(\u672a\u63d0\u4ea4\u8bfb,\u53ef\u810f\u8bfb)<\/span><\/h3>\n
          \u4e8b\u52a1\u4e2d\u7684\u4fee\u6539\uff0c\u5373\u4f7f\u6ca1\u6709\u63d0\u4ea4\uff0c\u5bf9\u5176\u4ed6\u4f1a\u8bdd\u4e5f\u662f\u53ef\u89c1\u7684\u3002<\/span> 
           \u53ef\u4ee5\u8bfb\u53d6\u672a\u63d0\u4ea4\u7684\u6570\u636e<\/span>\u2014\u2014\u810f\u8bfb<\/span>\u3002\u810f\u8bfb\u4f1a\u5bfc\u81f4\u5f88\u591a\u95ee\u9898\uff0c\u4e00\u822c\u4e0d\u9002\u7528\u8fd9\u4e2a\u9694\u79bb\u7ea7\u522b\u3002 
           \u5b9e\u4f8b\uff1a  <\/p>\n
          \n \n \n 
            \n  \n  \n  
          1. -- ------------------------- read-uncommitted\u5b9e\u4f8b ------------------------------<\/span> <\/span><\/span><\/li>\n  \n  \n  
          2. -- \u8bbe\u7f6e\u5168\u5c40\u7cfb\u7edf\u9694\u79bb\u7ea7\u522b<\/span> <\/span><\/span><\/li>\n  \n  \n  
          3. SET<\/span> <\/span>GLOBAL<\/span> <\/span>TRANSACTION<\/span> <\/span>ISOLATION<\/span> <\/span>LEVEL<\/span> <\/span>READ<\/span> <\/span>UNCOMMITTED<\/span>; <\/span><\/span><\/li>\n  \n  \n  
          4. -- Session A<\/span> <\/span><\/span><\/li>\n  \n  \n  
          5. START TRANSACTION<\/span>; <\/span><\/span><\/li>\n  \n  \n  
          6. SELECT<\/span> * <\/span>FROM<\/span> <\/span>USER<\/span>; <\/span><\/span><\/li>\n  \n  \n  
          7. UPDATE<\/span> <\/span>USER<\/span> <\/span>SET<\/span> <\/span>NAME<\/span>=<\/span>\"READ UNCOMMITTED\"<\/span>; <\/span><\/span><\/li>\n  \n  \n  
          8. -- commit;<\/span> <\/span><\/span><\/li>\n  \n  \n  
          9.  <\/span><\/li>\n  \n  \n  
          10. -- Session B<\/span> <\/span><\/span><\/li>\n  \n  \n  
          11. SELECT<\/span> * <\/span>FROM<\/span> <\/span>USER<\/span>; <\/span><\/span><\/li>\n  \n  \n  
          12.  <\/span><\/li>\n  \n  \n  
          13. \/\/SessionB Console \u53ef\u4ee5\u770b\u5230Session A\u672a\u63d0\u4ea4\u7684\u4e8b\u7269\u5904\u7406\uff0c\u5728\u53e6\u4e00\u4e2aSession \u4e2d\u4e5f\u770b\u5230\u4e86\uff0c\u8fd9\u5c31\u662f\u6240\u8c13\u7684\u810f\u8bfb <\/span><\/li>\n  \n  \n  
          14. id  name<\/span> <\/span><\/span><\/li>\n  \n  \n  
          15. 2   READ<\/span> <\/span>UNCOMMITTED<\/span> <\/span><\/span><\/li>\n  \n  \n  
          16. 34  READ<\/span> <\/span>UNCOMMITTED<\/span> <\/span><\/span> <\/li>\n \n \n <\/ol><\/pre>\n
            \n
            READ COMMITTED(\u63d0\u4ea4\u8bfb\u6216\u4e0d\u53ef\u91cd\u590d\u8bfb\uff0c\u5e7b\u8bfb)<\/span><\/h3>\n
            \u4e00\u822c\u6570\u636e\u5e93\u90fd\u9ed8\u8ba4\u4f7f\u7528\u8fd9\u4e2a\u9694\u79bb\u7ea7\u522b\uff08mysql\u4e0d\u662f\uff09\uff0c\u8fd9\u4e2a\u9694\u79bb\u7ea7\u522b\u4fdd\u8bc1\u4e86\u4e00\u4e2a\u4e8b\u52a1\u5982\u679c\u6ca1\u6709\u5b8c\u5168\u6210\u529f\uff08commit\u6267\u884c\u5b8c\uff09\uff0c\u4e8b\u52a1\u4e2d\u7684\u64cd\u4f5c\u5bf9\u5176\u4ed6\u4f1a\u8bdd\u662f\u4e0d\u53ef\u89c1\u7684<\/span>\u3002  <\/p>\n
            \n \n \n 
              \n  \n  \n  
            1. -- ------------------------- read-cmmitted\u5b9e\u4f8b ------------------------------<\/span> <\/span><\/span><\/li>\n  \n  \n  
            2. -- \u8bbe\u7f6e\u5168\u5c40\u7cfb\u7edf\u9694\u79bb\u7ea7\u522b<\/span> <\/span><\/span><\/li>\n  \n  \n  
            3. SET<\/span> <\/span>GLOBAL<\/span> <\/span>TRANSACTION<\/span> <\/span>ISOLATION<\/span> <\/span>LEVEL<\/span> <\/span>READ<\/span>  <\/span>COMMITTED<\/span>; <\/span><\/span><\/li>\n  \n  \n  
            4. -- Session A<\/span> <\/span><\/span><\/li>\n  \n  \n  
            5. START TRANSACTION<\/span>; <\/span><\/span><\/li>\n  \n  \n  
            6. SELECT<\/span> * <\/span>FROM<\/span> <\/span>USER<\/span>; <\/span><\/span><\/li>\n  \n  \n  
            7. UPDATE<\/span> <\/span>USER<\/span> <\/span>SET<\/span> <\/span>NAME<\/span>=<\/span>\"READ COMMITTED\"<\/span>; <\/span><\/span><\/li>\n  \n  \n  
            8. -- COMMIT;<\/span> <\/span><\/span><\/li>\n  \n  \n  
            9.  <\/span><\/li>\n  \n  \n  
            10. -- Session B<\/span> <\/span><\/span><\/li>\n  \n  \n  
            11. SELECT<\/span> * <\/span>FROM<\/span> <\/span>USER<\/span>; <\/span><\/span><\/li>\n  \n  \n  
            12.  <\/span><\/li>\n  \n  \n  
            13. \/\/Console OUTPUT<\/span>: <\/span><\/span><\/li>\n  \n  \n  
            14. id  name<\/span> <\/span><\/span><\/li>\n  \n  \n  
            15. 2   READ<\/span> <\/span>UNCOMMITTED<\/span> <\/span><\/span><\/li>\n  \n  \n  
            16. 34  READ<\/span> <\/span>UNCOMMITTED<\/span> <\/span><\/span><\/li>\n  \n  \n  
            17.  <\/span><\/li>\n  \n  \n  
            18.  <\/span><\/li>\n  \n  \n  
            19. ---------------------------------------------------<\/span> <\/span><\/span><\/li>\n  \n  \n  
            20. -- \u5f53 Session  A\u6267\u884c\u4e86commit\uff0cSession B\u5f97\u5230\u5982\u4e0b\u7ed3\u679c\uff1a<\/span> <\/span><\/span><\/li>\n  \n  \n  
            21. id  name<\/span> <\/span><\/span><\/li>\n  \n  \n  
            22. 2   READ<\/span> <\/span>COMMITTED<\/span> <\/span><\/span><\/li>\n  \n  \n  
            23. 34  READ<\/span> <\/span>COMMITTED<\/span> <\/span><\/span> <\/li>\n \n \n <\/ol><\/pre>\n
              \u4e5f\u5c31\u9a8c\u8bc1\u4e86read committed<\/span>\u7ea7\u522b\u5728\u4e8b\u7269\u672a\u5b8c\u6210commit\u64cd\u4f5c\u4e4b\u524d\u4fee\u6539\u7684\u6570\u636e\u5bf9\u5176\u4ed6Session \u4e0d\u53ef\u89c1\uff0c\u6267\u884c\u4e86commit\u4e4b\u540e\u624d\u4f1a\u5bf9\u5176\u4ed6Session \u53ef\u89c1\u3002 
               \u6211\u4eec\u53ef\u4ee5\u770b\u5230Session B\u4e24\u6b21\u67e5\u8be2\u5f97\u5230\u4e86\u4e0d\u540c\u7684\u6570\u636e\u3002<\/p>\n
              read committed\u9694\u79bb\u7ea7\u522b\u89e3\u51b3\u4e86\u810f\u8bfb\u7684\u95ee\u9898\uff0c\u4f46\u662f\u4f1a\u5bf9\u5176\u4ed6Session \u4ea7\u751f\u4e24\u6b21\u4e0d\u4e00\u81f4\u7684\u8bfb\u53d6\u7ed3\u679c\uff08\u56e0\u4e3a\u53e6\u4e00\u4e2aSession \u6267\u884c\u4e86\u4e8b\u52a1\uff0c\u4e00\u81f4\u6027\u53d8\u5316\uff09\u3002<\/span><\/p>\n
              \n
              REPEATABLE READ(\u53ef\u91cd\u590d\u8bfb)<\/span><\/h3>\n
              \u4e00\u4e2a\u4e8b\u52a1\u4e2d\u591a\u6b21\u6267\u884c\u7edf\u4e00\u8bfbSQL,\u8fd4\u56de\u7ed3\u679c\u4e00\u6837\u3002 
               \u8fd9\u4e2a\u9694\u79bb\u7ea7\u522b\u89e3\u51b3\u4e86\u810f\u8bfb\u7684\u95ee\u9898\uff0c\u5e7b\u8bfb\u95ee\u9898\u3002\u8fd9\u91cc\u6307\u7684\u662finnodb\u7684rr\u7ea7\u522b\uff0cinnodb\u4e2d\u4f7f\u7528next-key\u9501\u5bf9\u201d\u5f53\u524d\u8bfb\u201d\u8fdb\u884c\u52a0\u9501\uff0c\u9501\u4f4f\u884c\u4ee5\u53ca\u53ef\u80fd\u4ea7\u751f\u5e7b\u8bfb\u7684\u63d2\u5165\u4f4d\u7f6e\uff0c\u963b\u6b62\u65b0\u7684\u6570\u636e\u63d2\u5165\u4ea7\u751f\u5e7b\u884c\u3002 
               \u4e0b\u6587\u4e2d\u8be6\u7ec6\u5206\u6790\u3002<\/p>\n
              \u5177\u4f53\u8bf7\u53c2\u8003mysql\u624b\u518c<\/p>\n
              https:\/\/dev.mysql.com\/doc\/refman\/5.7\/en\/innodb-storage-engine.html<\/p>\n
               <\/p>\n
              SERIALIZABLE(\u53ef\u4e32\u884c\u5316)<\/span><\/h3>\n
              \u6700\u5f3a\u7684\u9694\u79bb\u7ea7\u522b\uff0c\u901a\u8fc7\u7ed9\u4e8b\u52a1\u4e2d\u6bcf\u6b21\u8bfb\u53d6\u7684\u884c\u52a0\u9501\uff0c\u5199\u52a0\u5199\u9501\uff0c\u4fdd\u8bc1\u4e0d\u4ea7\u751f\u5e7b\u8bfb\u95ee\u9898\uff0c\u4f46\u662f\u4f1a\u5bfc\u81f4\u5927\u91cf\u8d85\u65f6\u4ee5\u53ca\u9501\u4e89\u7528\u95ee\u9898\u3002<\/p>\n
              \u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236-MVCC<\/span><\/h3>\n
              MVCC(multiple-version-concurrency-control\uff09\u662f\u4e2a\u884c\u7ea7\u9501<\/span>\u7684\u53d8\u79cd\uff0c\u5b83\u5728\u666e\u901a\u8bfb\u60c5\u51b5\u4e0b\u907f\u514d\u4e86\u52a0\u9501\u64cd\u4f5c\uff0c\u56e0\u6b64\u5f00\u9500\u66f4\u4f4e<\/span>\u3002 
               \u867d\u7136\u5b9e\u73b0\u4e0d\u540c\uff0c\u4f46\u901a\u5e38\u90fd\u662f\u5b9e\u73b0\u975e\u963b\u585e\u8bfb<\/span>\uff0c\u5bf9\u4e8e\u5199\u64cd\u4f5c\u53ea\u9501\u5b9a\u5fc5\u8981\u7684\u884c<\/span>\u3002<\/p>\n
                \n
              • \n
                \u4e00\u81f4\u6027\u8bfb \uff08\u5c31\u662f\u8bfb\u53d6\u5feb\u7167\uff09<\/span> 
                 select * from table \u2026.;<\/p>\n<\/li>\n
              • \n
                \u5f53\u524d\u8bfb(\u5c31\u662f\u8bfb\u53d6\u5b9e\u9645\u7684\u6301\u4e45\u5316\u7684\u6570\u636e)<\/span> 
                 \u7279\u6b8a\u7684\u8bfb\u64cd\u4f5c\uff0c\u63d2\u5165\/\u66f4\u65b0\/\u5220\u9664\u64cd\u4f5c\uff0c\u5c5e\u4e8e\u5f53\u524d\u8bfb\uff0c\u5904\u7406\u7684\u90fd\u662f\u5f53\u524d\u7684\u6570\u636e\uff0c\u9700\u8981\u52a0\u9501\u3002 
                 select * from table where ? lock in share mode; 
                 select * from table where ? for update; 
                 insert; 
                 update ; 
                 delete;<\/p>\n<\/li>\n<\/ul>\n
                \u6ce8\u610f\uff1aselect \u2026\u2026 from where\u2026\u2026 \uff08\u6ca1\u6709\u989d\u5916\u52a0\u9501\u540e\u7f00\uff09\u4f7f\u7528MVCC\uff0c\u4fdd\u8bc1\u4e86\u8bfb\u5feb\u7167(mysql\u79f0\u4e3aconsistent read)\uff0c\u6240\u8c13\u4e00\u81f4\u6027\u8bfb\u6216\u8005\u8bfb\u5feb\u7167\u5c31\u662f\u8bfb\u53d6\u5f53\u524d\u4e8b\u52a1\u5f00\u59cb\u4e4b\u524d\u7684\u6570\u636e\u5feb\u7167\uff0c\u5728\u8fd9\u4e2a\u4e8b\u52a1\u5f00\u59cb\u4e4b\u540e\u7684\u66f4\u65b0\u4e0d\u4f1a\u88ab\u8bfb\u5230\u3002\u8be6\u7ec6\u60c5\u51b5\u4e0b\u6587select\u7684\u8be6\u8ff0\u3002<\/span><\/p>\n
                \u5bf9\u4e8e\u52a0\u9501\u8bfbSELECT with FOR UPDATE(\u6392\u4ed6\u9501) or LOCK IN SHARE MODE(\u5171\u4eab\u9501)\u3001update\u3001delete\u8bed\u53e5\uff0c\u8981\u8003\u8651\u662f\u5426\u662f\u552f\u4e00\u7d22\u5f15\u7684\u7b49\u503c\u67e5\u8be2\u3002<\/span><\/p>\n
                \u5199\u9501-recordLock,gapLock,next key lock<\/span><\/h3>\n
                \u5bf9\u4e8e\u4f7f\u7528\u5230\u552f\u4e00\u7d22\u5f15 \u7b49\u503c\u67e5\u8be2\uff1a\u6bd4\u5982\uff0cwhere columnA=\u201d\u2026\u201d \uff0c\u5982\u679ccolumnA\u4e0a\u7684\u7d22\u5f15\u88ab\u4f7f\u7528\u5230\uff0c<\/span> 
                 \u90a3\u4e48\u4f1a\u5728\u6ee1\u8db3where\u7684\u8bb0\u5f55\u4e0a\u52a0\u884c\u9501(for update\u662f\u6392\u4ed6\u9501,lock in shared \u662f\u5171\u4eab\u9501\uff0c\u5176\u4ed6\u5199\u64cd\u4f5c\u52a0\u6392\u4ed6\u9501)\u3002\u8fd9\u91cc\u662f\u884c\u7ea7\u9501\uff0crecord lock\u3002<\/span><\/p>\n
                \u5bf9\u4e8e\u8303\u56f4\u67e5\u8be2\uff08\u4f7f\u7528\u975e\u552f\u4e00\u7684\u7d22\u5f15\uff09\uff1a<\/span> 
                 \u6bd4\u5982(\u505a\u8303\u56f4\u67e5\u8be2)\uff1awhere columnA between 10 and 30 ,\u4f1a\u5bfc\u81f4\u5176\u4ed6\u4f1a\u8bdd\u4e2d10\u4ee5\u540e\u7684\u6570\u636e\u90fd\u65e0\u6cd5\u63d2\u5165(next key lock),\u4ece\u800c\u89e3\u51b3\u4e86\u5e7b\u8bfb\u95ee\u9898\u3002<\/span><\/p>\n
                \u8fd9\u91cc\u662fnext key lock \u4f1a\u5305\u62ec\u6d89\u53ca\u5230\u7684\u6240\u6709\u884c\u3002<\/span> 
                 next key lock=recordLock+gapLock\uff0c\u4e0d\u4ec5\u9501\u4f4f\u76f8\u5173\u6570\u636e\uff0c\u800c\u4e14\u9501\u4f4f\u8fb9\u754c\uff0c\u4ece\u800c\u5f7b\u5e95\u907f\u514d\u5e7b\u8bfb<\/span>\u3002<\/p>\n
                \u5bf9\u4e8e\u6ca1\u6709\u7d22\u5f15<\/span> 
                 \u9501\u8868<\/span> 
                 \u901a\u5e38\u53d1\u751f\u5728DDL\u8bed\u53e5\\DML\u4e0d\u8d70\u7d22\u5f15\u7684\u8bed\u53e5\u4e2d\uff0c\u6bd4\u5982\u8fd9\u4e2aDML update table set columnA=\u201dA\u201d where columnB=\u201cB\u201d. 
                 \u5982\u679ccolumnB\u5b57\u6bb5\u4e0d\u5b58\u5728\u7d22\u5f15\uff08\u6216\u8005\u4e0d\u662f\u7ec4\u5408\u7d22\u5f15\u524d\u7f00\uff09\uff0c\u4f1a\u9501\u4f4f\u6240\u6709\u8bb0\u5f55\u4e5f\u5c31\u662f\u9501\u8868\u3002\u5982\u679c\u8bed\u53e5\u7684\u6267\u884c\u80fd\u591f\u6267\u884c\u4e00\u4e2acolumnB\u5b57\u6bb5\u7684\u7d22\u5f15\uff0c\u90a3\u4e48\u4f1a\u9501\u4f4f\u6ee1\u8db3where\u7684\u884c(\u884c\u9501)\u3002<\/p>\n
                INNODB\u7684MVCC\u901a\u5e38\u662f\u901a\u8fc7\u5728\u6bcf\u884c\u6570\u636e\u540e\u8fb9\u4fdd\u5b58\u4e24\u4e2a\u9690\u85cf\u7684\u5217\u6765\u5b9e\u73b0(\u5176\u5b9e\u662f\u4e09\u5217\uff0c\u7b2c\u4e09\u5217\u662f\u7528\u4e8e\u4e8b\u52a1\u56de\u6eda\uff0c\u6b64\u5904\u7565\u53bb)\uff0c<\/span> 
                 \u4e00\u4e2a\u4fdd\u5b58\u4e86\u884c\u7684\u521b\u5efa\u7248\u672c\u53f7\uff0c\u53e6\u4e00\u4e2a\u4fdd\u5b58\u4e86\u884c\u7684\u66f4\u65b0\u7248\u672c\u53f7\uff08\u4e0a\u4e00\u6b21\u88ab\u66f4\u65b0\u6570\u636e\u7684\u7248\u672c\u53f7\uff09<\/span> 
                 \u8fd9\u4e2a\u7248\u672c\u53f7\u662f\u6bcf\u4e2a\u4e8b\u52a1\u7684\u7248\u672c\u53f7\uff0c\u9012\u589e\u7684\u3002<\/p>\n
                \u8fd9\u6837\u4fdd\u8bc1\u4e86innodb\u5bf9\u8bfb\u64cd\u4f5c\u4e0d\u9700\u8981\u52a0\u9501\u4e5f\u80fd\u4fdd\u8bc1\u6b63\u786e\u8bfb\u53d6\u6570\u636e\u3002<\/p>\n
                MVCC select\u65e0\u9501\u64cd\u4f5c \u4e0e \u7ef4\u62a4\u7248\u672c\u53f7<\/span><\/h3>\n
                \u4e0b\u8fb9\u5728mysql\u9ed8\u8ba4\u7684Repeatable Read\u9694\u79bb\u7ea7\u522b\u4e0b\uff0c\u5177\u4f53\u770b\u770bMVCC\u64cd\u4f5c\uff1a<\/p>\n
                  \n
                • \n
                  Select\uff08\u5feb\u7167\u8bfb\uff0c\u6240\u8c13\u8bfb\u5feb\u7167\u5c31\u662f\u8bfb\u53d6\u5f53\u524d\u4e8b\u52a1\u4e4b\u524d\u7684\u6570\u636e\u3002\uff09\uff1a<\/span> 
                   a.InnoDB\u53easelect\u67e5\u627e\u7248\u672c\u53f7\u65e9\u4e8e\u5f53\u524d\u7248\u672c\u53f7\u7684\u6570\u636e\u884c<\/span>\uff0c\u8fd9\u6837\u4fdd\u8bc1\u4e86\u8bfb\u53d6\u7684\u6570\u636e\u8981\u4e48\u662f\u5728\u8fd9\u4e2a\u4e8b\u52a1\u5f00\u59cb\u4e4b\u524d\u5c31\u5df2\u7ecfcommit\u4e86\u7684\uff08\u65e9\u4e8e\u5f53\u524d\u7248\u672c\u53f7\uff09\uff0c\u8981\u4e48\u662f\u5728\u8fd9\u4e2a\u4e8b\u52a1\u81ea\u8eab\u4e2d\u6267\u884c\u521b\u5efa\u64cd\u4f5c\u7684\u6570\u636e\uff08\u7b49\u4e8e\u5f53\u524d\u7248\u672c\u53f7\uff09\u3002<\/p>\n
                  b.\u67e5\u627e\u884c\u7684\u66f4\u65b0\u7248\u672c\u53f7\u8981\u4e48\u672a\u5b9a\u4e49\uff0c\u8981\u4e48\u5927\u4e8e\u5f53\u524d\u7684\u7248\u672c\u53f7(\u4e3a\u4e86\u4fdd\u8bc1\u4e8b\u52a1\u53ef\u4ee5\u8bfb\u5230\u8001\u6570\u636e)\uff0c\u8fd9\u6837\u4fdd\u8bc1\u4e86\u4e8b\u52a1\u8bfb\u53d6\u5230\u5728\u5f53\u524d\u4e8b\u52a1\u5f00\u59cb\u4e4b\u540e\u672a\u88ab\u66f4\u65b0\u7684\u6570\u636e\u3002 
                   \u6ce8\u610f\uff1a \u8fd9\u91cc\u7684select\u4e0d\u80fd\u6709for update\u3001lock in share \u8bed\u53e5\u3002 
                   \u603b\u4e4b\u8981\u53ea\u8fd4\u56de\u6ee1\u8db3\u4ee5\u4e0b\u6761\u4ef6\u7684\u884c\u6570\u636e\uff0c\u8fbe\u5230\u4e86\u5feb\u7167\u8bfb\u7684\u6548\u679c\uff1a  <\/p>\n<\/li>\n<\/ul>\n
                  \r\n(\u884c\u521b\u5efa\u7248\u672c\u53f7< =\u5f53\u524d\u7248\u672c\u53f7 && (\u884c\u66f4\u65b0\u7248\u672c\u53f7==null or \u884c\u66f4\u65b0\u7248\u672c\u53f7>\u5f53\u524d\u7248\u672c\u53f7 ) ) <\/pre>\n
                    \n
                  • \n
                    Insert<\/span><\/p>\n
                    InnoDB\u4e3a\u8fd9\u4e2a\u4e8b\u52a1\u4e2d\u65b0\u63d2\u5165\u7684\u884c\uff0c\u4fdd\u5b58\u5f53\u524d\u4e8b\u52a1\u7248\u672c\u53f7\u7684\u884c\u4f5c\u4e3a\u884c\u7684\u884c\u521b\u5efa\u7248\u672c\u53f7\u3002<\/p>\n<\/li>\n
                  • \n
                    Delete<\/span> 
                     InnoDB\u4e3a\u6bcf\u4e00\u4e2a\u5220\u9664\u7684\u884c\u4fdd\u5b58\u5f53\u524d\u4e8b\u52a1\u7248\u672c\u53f7\uff0c\u4f5c\u4e3a\u884c\u7684\u5220\u9664\u6807\u8bb0\u3002<\/p>\n<\/li>\n
                  • \n
                    Update<\/span><\/p>\n
                    \u5c06\u5b58\u5728\u4e24\u6761\u6570\u636e\uff0c\u4fdd\u6301\u5f53\u524d\u7248\u672c\u53f7\u4f5c\u4e3a\u66f4\u65b0\u540e\u7684\u6570\u636e\u7684\u65b0\u589e\u7248\u672c\u53f7\uff0c\u540c\u65f6\u4fdd\u5b58\u5f53\u524d\u7248\u672c\u53f7\u4f5c\u4e3a\u8001\u6570\u636e\u884c\u7684\u66f4\u65b0\u7248\u672c\u53f7\u3002<\/p>\n<\/li>\n<\/ul>\n
                     <\/p>\n
                    \r\n\u5f53\u524d\u7248\u672c\u53f7\u2014\u5199\u2014>\u65b0\u6570\u636e\u884c\u521b\u5efa\u7248\u672c\u53f7 && \u5f53\u524d\u7248\u672c\u53f7\u2014\u5199\u2014>\u8001\u6570\u636e\u66f4\u65b0\u7248\u672c\u53f7(); <\/pre>\n
                    \u810f\u8bfb vs \u5e7b\u8bfb vs \u4e0d\u53ef\u91cd\u590d\u8bfb<\/span><\/h3>\n
                    \u810f\u8bfb<\/span>\uff1a\u4e00\u4e8b\u52a1\u672a\u63d0\u4ea4\u7684\u4e2d\u95f4\u72b6\u6001\u7684\u66f4\u65b0\u6570\u636e \u88ab\u5176\u4ed6\u4f1a\u8bdd\u8bfb\u53d6\u5230\u3002<\/span> \u5f53\u4e00\u4e2a\u4e8b\u52a1\u6b63\u5728\u8bbf\u95ee\u6570\u636e\uff0c\u5e76\u4e14\u5bf9\u6570\u636e\u8fdb\u884c\u4e86\u4fee\u6539\uff0c\u800c\u8fd9\u79cd\u4fee\u6539\u8fd8\u6ca1\u6709 \u63d0\u4ea4\u5230\u6570\u636e\u5e93\u4e2d(commit\u672a\u6267\u884c)\uff0c\u8fd9\u65f6\uff0c\u53e6\u5916\u4f1a\u8bdd\u4e5f\u8bbf\u95ee\u8fd9\u4e2a\u6570\u636e\uff0c\u56e0\u4e3a\u8fd9\u4e2a\u6570\u636e\u662f\u8fd8\u6ca1\u6709\u63d0\u4ea4\uff0c \u90a3\u4e48\u53e6\u5916\u4e00\u4e2a\u4f1a\u8bdd\u8bfb\u5230\u7684\u8fd9\u4e2a\u6570\u636e\u662f\u810f\u6570\u636e\uff0c\u4f9d\u636e\u810f\u6570\u636e\u6240\u505a\u7684\u64cd\u4f5c\u4e5f\u53ef\u80fd\u662f\u4e0d\u6b63\u786e\u7684\u3002<\/p>\n
                    \u4e0d\u53ef\u91cd\u590d\u8bfb<\/span>\uff1a\u7b80\u5355\u6765\u8bf4\u5c31\u662f\u5728\u4e00\u4e2a\u4e8b\u52a1\u4e2d\u8bfb\u53d6\u7684\u6570\u636e\u53ef\u80fd\u4ea7\u751f\u53d8\u5316\uff0cReadCommitted\u4e5f\u79f0\u4e3a\u4e0d\u53ef\u91cd\u590d\u8bfb<\/span>\u3002<\/p>\n
                    \u5728\u540c\u4e00\u4e8b\u52a1\u4e2d\uff0c\u591a\u6b21\u8bfb\u53d6\u540c\u4e00\u6570\u636e\u8fd4\u56de\u7684\u7ed3\u679c\u6709\u6240\u4e0d\u540c\u3002\u6362\u53e5\u8bdd\u8bf4\u5c31\u662f\uff0c\u540e\u7eed\u8bfb\u53d6\u53ef\u4ee5\u8bfb\u5230\u53e6\u4e00\u4f1a\u8bdd\u4e8b\u52a1\u5df2\u63d0\u4ea4\u7684\u66f4\u65b0\u6570\u636e\u3002 \u76f8\u53cd\uff0c\u201c\u53ef\u91cd\u590d\u8bfb\u201d\u5728\u540c\u4e00\u4e8b\u52a1\u4e2d\u591a\u6b21\u8bfb\u53d6\u6570\u636e\u65f6\uff0c\u80fd\u591f\u4fdd\u8bc1\u6240\u8bfb\u6570\u636e\u4e00\u6837\uff0c\u4e5f\u5c31\u662f\uff0c\u540e\u7eed\u8bfb\u53d6\u4e0d\u80fd\u8bfb\u5230\u53e6\u4e00\u4f1a\u8bdd\u4e8b\u52a1\u5df2\u63d0\u4ea4\u7684\u66f4\u65b0\u6570\u636e\u3002<\/p>\n
                    \u5e7b\u8bfb<\/span>\uff1a\u4f1a\u8bddT1\u4e8b\u52a1\u4e2d\u6267\u884c\u4e00\u6b21\u67e5\u8be2\uff0c\u7136\u540e\u4f1a\u8bddT2\u65b0\u63d2\u5165\u4e00\u884c\u8bb0\u5f55\uff0c\u8fd9\u884c\u8bb0\u5f55\u6070\u597d\u53ef\u4ee5\u6ee1\u8db3T1\u6240\u4f7f\u7528\u7684\u67e5\u8be2\u7684\u6761\u4ef6<\/span>\u3002\u7136\u540eT1\u53c8\u4f7f\u7528\u76f8\u540c \u7684\u67e5\u8be2\u518d\u6b21\u5bf9\u8868\u8fdb\u884c\u68c0\u7d22\uff0c\u4f46\u662f\u6b64\u65f6\u5374\u770b\u5230\u4e86\u4e8b\u52a1T2\u521a\u624d\u63d2\u5165\u7684\u65b0\u884c\u3002\u8fd9\u4e2a\u65b0\u884c\u5c31\u79f0\u4e3a\u201c\u5e7b\u50cf\u201d\uff0c\u56e0\u4e3a\u5bf9T1\u6765\u8bf4\u8fd9\u4e00\u884c\u5c31\u50cf\u7a81\u7136 \u51fa\u73b0\u7684\u4e00\u6837\u3002 
                     innoDB\u7684RR\u7ea7\u522b\u65e0\u6cd5\u505a\u5230\u5b8c\u5168\u907f\u514d\u5e7b\u8bfb\uff0c\u4e0b\u6587\u8be6\u7ec6\u5206\u6790\u3002  <\/p>\n
                    \n \n \n 
                      \n  \n  \n  
                    1. ----------------------------------\u524d\u7f6e\u51c6\u5907----------------------------------------<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    2. prerequisite\uff1a <\/span><\/li>\n  \n  \n  
                    3. -- \u521b\u5efa\u8868<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    4. mysql> <\/span><\/li>\n  \n  \n  
                    5. CREATE<\/span> <\/span>TABLE<\/span> `t_bitfly` ( <\/span><\/span><\/li>\n  \n  \n  
                    6.   `id` bigint<\/span>(20) <\/span>NOT<\/span> <\/span>NULL<\/span> <\/span>DEFAULT<\/span> <\/span>'0'<\/span>, <\/span><\/span><\/li>\n  \n  \n  
                    7.   `value` varchar<\/span>(32) <\/span>DEFAULT<\/span> <\/span>NULL<\/span>, <\/span><\/span><\/li>\n  \n  \n  
                    8.   PRIMARY<\/span> <\/span>KEY<\/span> (`id`) <\/span><\/span><\/li>\n  \n  \n  
                    9. ) <\/span><\/li>\n  \n  \n  
                    10.  <\/span><\/li>\n  \n  \n  
                    11. -- \u786e\u4fdd\u5f53\u524d\u9694\u79bb\u7ea7\u522b\u4e3a\u9ed8\u8ba4\u7684RR\u7ea7\u522b<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    12.  <\/span><\/li>\n  \n  \n  
                    13. mysql> select<\/span> @@<\/span>global<\/span>.tx_isolation, @@tx_isolation; <\/span><\/span><\/li>\n  \n  \n  
                    14. +-----------------------+-----------------+<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    15. | @@global<\/span>.tx_isolation | @@tx_isolation  | <\/span><\/span><\/li>\n  \n  \n  
                    16. +-----------------------+-----------------+<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    17. | REPEATABLE<\/span>-<\/span>READ<\/span>       | <\/span>REPEATABLE<\/span>-<\/span>READ<\/span> | <\/span><\/span><\/li>\n  \n  \n  
                    18. +-----------------------+-----------------+<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    19. 1 row in<\/span> <\/span>set<\/span> (0.00 sec) <\/span><\/span><\/li>\n  \n  \n  
                    20. ---------------------------------------\u5f00\u59cb--------------------------------------------- <\/span> <\/span><\/span><\/li>\n  \n  \n  
                    21.  <\/span><\/li>\n  \n  \n  
                    22.  <\/span><\/li>\n  \n  \n  
                    23. session A                                           |   session B <\/span><\/li>\n  \n  \n  
                    24.                                                    | <\/span><\/li>\n  \n  \n  
                    25.                                                    | <\/span><\/li>\n  \n  \n  
                    26. mysql> START TRANSACTION<\/span>;                           |   mysql> START <\/span>TRANSACTION<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                    27. Query OK, 0 rows<\/span> affected (0.00 sec)                |   Query OK, 0 <\/span>rows<\/span> affected (0.00 sec)                                         <\/span><\/span><\/li>\n  \n  \n  
                    28.                                                     |    <\/span><\/li>\n  \n  \n  
                    29.                                                    | <\/span><\/li>\n  \n  \n  
                    30. mysql> SELECT<\/span> * <\/span>FROM<\/span> test.t_bitfly;                 |   mysql> <\/span>SELECT<\/span> * <\/span>FROM<\/span> test.t_bitfly;  <\/span><\/span><\/li>\n  \n  \n  
                    31. Empty set<\/span> (0.00 sec)                                |   Empty <\/span>set<\/span> (0.00 sec) <\/span><\/span><\/li>\n  \n  \n  
                    32.                                                    | <\/span><\/li>\n  \n  \n  
                    33.                                                    |   mysql> INSERT<\/span> <\/span>INTO<\/span> t_bitfly <\/span>VALUES<\/span> (1, <\/span>'test'<\/span>); <\/span><\/span><\/li>\n  \n  \n  
                    34.                                                     |   Query OK, 1 row affected (0.00 sec) <\/span><\/li>\n  \n  \n  
                    35.                                                    | <\/span><\/li>\n  \n  \n  
                    36.                                                    | <\/span><\/li>\n  \n  \n  
                    37. mysql> SELECT<\/span> * <\/span>FROM<\/span> test.t_bitfly;                 | <\/span><\/span><\/li>\n  \n  \n  
                    38. Empty set<\/span> (0.00 sec)                                | <\/span><\/span><\/li>\n  \n  \n  
                    39.                                                    | <\/span><\/li>\n  \n  \n  
                    40.                                                    |   mysql> commit<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                    41.                                                    |   Query OK, 0 rows<\/span> affected (0.01 sec)                                                 <\/span><\/span><\/li>\n  \n  \n  
                    42. mysql> SELECT<\/span> * <\/span>FROM<\/span> test.t_bitfly;                 | <\/span><\/span><\/li>\n  \n  \n  
                    43. Empty set<\/span> (0.00 sec)                                | <\/span><\/span><\/li>\n  \n  \n  
                    44. -- \u53ef\u4ee5\u770b\u5230\u867d\u7136\u4e24\u6b21\u6267\u884c\u7ed3\u679c\u8fd4\u56de\u7684\u6570\u636e\u4e00\u81f4\uff0c         |<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    45. -- \u4f46\u662f\u4e0d\u80fd\u8bf4\u660e\u6ca1\u6709\u5e7b\u8bfb\u3002\u63a5\u7740\u770b\uff1a                   |<\/span> <\/span><\/span><\/li>\n  \n  \n  
                    46.                                                    | <\/span><\/li>\n  \n  \n  
                    47. mysql> INSERT<\/span> <\/span>INTO<\/span> t_bitfly <\/span>VALUES<\/span> (1, <\/span>'test'<\/span>);     | <\/span><\/span><\/li>\n  \n  \n  
                    48. ERROR 1062 (23000):                                 | <\/span><\/li>\n  \n  \n  
                    49. Duplicate entry '1'<\/span> <\/span>for<\/span> <\/span>key<\/span> <\/span>'PRIMARY'<\/span>               | <\/span><\/span><\/li>\n  \n  \n  
                    50.                                                    | <\/span><\/li>\n  \n  \n  
                    51. -- \u660e\u660e\u4e3a\u7a7a\u7684\u8868\uff0c\u4e3a\u4ec0\u4e48\u8bf4\u4e3b\u952e\u91cd\u590d\uff1f\u2014\u2014\u5e7b\u8bfb\u51fa\u73b0 \uff01\uff01\uff01       |<\/span> <\/span><\/span> <\/li>\n \n \n <\/ol><\/pre>\n
                      \u5982\u4f55\u4fdd\u8bc1rr\u7ea7\u522b\u7edd\u5bf9\u4e0d\u4ea7\u751f\u5e7b\u8bfb\uff1f<\/span><\/h3>\n
                      \u5728\u4f7f\u7528\u7684select \u2026where\u8bed\u53e5\u4e2d\u52a0\u5165 for update(\u6392\u4ed6\u9501) \u6216\u8005 lock in share mode(\u5171\u4eab\u9501)\u8bed\u53e5\u6765\u5b9e\u73b0\u3002\u5176\u5b9e\u5c31\u662f\u9501\u4f4f\u4e86\u53ef\u80fd\u9020\u6210\u5e7b\u8bfb\u7684\u6570\u636e\uff0c\u963b\u6b62\u6570\u636e\u7684\u5199\u5165\u64cd\u4f5c\u3002<\/span><\/p>\n
                      \u5176\u5b9e\u662f\u56e0\u4e3a\u6570\u636e\u7684\u5199\u5165\u64cd\u4f5c(insert \u3001update)\u9700\u8981\u5148\u83b7\u53d6\u5199\u9501\uff0c\u7531\u4e8e\u53ef\u80fd\u4ea7\u751f\u5e7b\u8bfb\u7684\u90e8\u5206\uff0c\u5df2\u7ecf\u83b7\u53d6\u5230\u4e86\u67d0\u79cd\u9501\uff0c\u6240\u4ee5\u8981\u5728\u53e6\u5916\u4e00\u4e2a\u4f1a\u8bdd\u4e2d\u83b7\u53d6\u5199\u9501\u7684\u524d\u63d0\u662f\u5f53\u524d\u4f1a\u8bdd\u4e2d\u91ca\u653e\u6240\u6709\u56e0\u52a0\u9501\u8bed\u53e5\u4ea7\u751f\u7684\u9501\u3002<\/p>\n
                      mysql\u6b7b\u9501\u95ee\u9898<\/span><\/h3>\n
                      \u6b7b\u9501\uff0c\u5c31\u662f\u4ea7\u751f\u4e86\u5faa\u73af\u7b49\u5f85\u94fe\u6761\uff0c\u6211\u7b49\u5f85\u4f60\u7684\u8d44\u6e90\uff0c\u4f60\u5374\u7b49\u5f85\u6211\u7684\u8d44\u6e90\uff0c\u6211\u4eec\u90fd\u76f8\u4e92\u7b49\u5f85\uff0c\u8c01\u4e5f\u4e0d\u91ca\u653e\u81ea\u5df1\u5360\u6709\u7684\u8d44\u6e90\uff0c\u5bfc\u81f4\u65e0\u7ebf\u7b49\u5f85\u4e0b\u53bb\u3002 
                       \u6bd4\u5982\uff1a  <\/p>\n
                      \n \n \n 
                        \n  \n  \n  
                      1. \/\/Session A <\/span><\/span><\/li>\n  \n  \n  
                      2. START TRANSACTION<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                      3. UPDATE<\/span> account <\/span>SET<\/span> p_money=p_money-100 <\/span>WHERE<\/span> p_name=<\/span>\"tim\"<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                      4. UPDATE<\/span> account <\/span>SET<\/span> p_money=p_money+100 <\/span>WHERE<\/span> p_name=<\/span>\"bill\"<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                      5. COMMIT<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                      6. \/\/Thread B <\/span><\/li>\n  \n  \n  
                      7. START TRANSACTION<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                      8. UPDATE<\/span> account <\/span>SET<\/span> p_money=p_money+100 <\/span>WHERE<\/span> p_name=<\/span>\"bill\"<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                      9. UPDATE<\/span> account <\/span>SET<\/span> p_money=p_money-100 <\/span>WHERE<\/span> p_name=<\/span>\"tim\"<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                      10. COMMIT<\/span>; <\/span><\/span> <\/li>\n \n \n <\/ol><\/pre>\n
                        \u5f53\u7ebf\u7a0bA\u6267\u884c\u5230\u7b2c\u4e00\u6761\u8bed\u53e5UPDATE account SET p_money=p_money-100 WHERE p_name=\u201dtim\u201d;\u9501\u5b9a\u4e86p_name=\u201dtim\u201d\u7684\u884c\u6570\u636e\uff1b\u5e76\u4e14\u8bd5\u56fe\u83b7\u53d6p_name=\u201dbill\u201d\u7684\u6570\u636e\uff1b<\/p>\n
                        \uff0c\u6b64\u65f6\uff0c\u6070\u597d\uff0c\u7ebf\u7a0bB\u4e5f\u6267\u884c\u5230\u7b2c\u4e00\u6761\u8bed\u53e5\uff1aUPDATE account SET p_money=p_money+100 WHERE p_name=\u201dbill\u201d;<\/p>\n
                        \u9501\u5b9a\u4e86 p_name=\u201dbill\u201d\u7684\u6570\u636e\uff0c\u540c\u65f6\u8bd5\u56fe\u83b7\u53d6p_name=\u201dtim\u201d\u7684\u6570\u636e\uff1b 
                         \u6b64\u65f6\uff0c\u4e24\u4e2a\u7ebf\u7a0b\u5c31\u8fdb\u5165\u4e86\u6b7b\u9501\uff0c\u8c01\u4e5f\u65e0\u6cd5\u83b7\u53d6\u81ea\u5df1\u60f3\u8981\u83b7\u53d6\u7684\u8d44\u6e90\uff0c\u8fdb\u5165\u65e0\u7ebf\u7b49\u5f85\u4e2d\uff0c\u76f4\u5230\u8d85\u65f6\uff01<\/p>\n
                        innodb_lock_wait_timeout \u7b49\u5f85\u9501\u8d85\u65f6\u56de\u6eda\u4e8b\u52a1\uff1a<\/span> 
                         \u76f4\u89c2\u65b9\u6cd5\u662f\u5728\u4e24\u4e2a\u4e8b\u52a1\u76f8\u4e92\u7b49\u5f85\u65f6\uff0c\u5f53\u4e00\u4e2a\u7b49\u5f85\u65f6\u95f4\u8d85\u8fc7\u8bbe\u7f6e\u7684\u67d0\u4e00\u9600\u503c\u65f6\uff0c\u5bf9\u5176\u4e2d\u4e00\u4e2a\u4e8b\u52a1\u8fdb\u884c\u56de\u6eda\uff0c\u53e6\u4e00\u4e2a\u4e8b\u52a1\u5c31\u80fd\u7ee7\u7eed\u6267\u884c\u3002\u8fd9\u79cd\u65b9\u6cd5\u7b80\u5355\u6709\u6548\uff0c\u5728innodb\u4e2d\uff0c\u53c2\u6570innodb_lock_wait_timeout\u7528\u6765\u8bbe\u7f6e\u8d85\u65f6\u65f6\u95f4\u3002<\/p>\n
                        wait-for graph\u7b97\u6cd5\u6765\u4e3b\u52a8\u8fdb\u884c\u6b7b\u9501\u68c0\u6d4b\uff1a<\/span> 
                         innodb\u8fd8\u63d0\u4f9b\u4e86wait-for graph\u7b97\u6cd5\u6765\u4e3b\u52a8\u8fdb\u884c\u6b7b\u9501\u68c0\u6d4b\uff0c\u6bcf\u5f53\u52a0\u9501\u8bf7\u6c42\u65e0\u6cd5\u7acb\u5373\u6ee1\u8db3\u9700\u8981\u5e76\u8fdb\u5165\u7b49\u5f85\u65f6\uff0cwait-for graph\u7b97\u6cd5\u90fd\u4f1a\u88ab\u89e6\u53d1\u3002<\/p>\n
                        \u5982\u4f55\u5c3d\u53ef\u80fd\u907f\u514d\u6b7b\u9501<\/span><\/p>\n
                        1\uff09\u4ee5\u56fa\u5b9a\u7684\u987a\u5e8f\u8bbf\u95ee\u8868\u548c\u884c\u3002\u6bd4\u5982\u4e24\u4e2a\u66f4\u65b0\u6570\u636e\u7684\u4e8b\u52a1\uff0c\u4e8b\u52a1A \u66f4\u65b0\u6570\u636e\u7684\u987a\u5e8f \u4e3a1\uff0c2\uff1b\u4e8b\u52a1B\u66f4\u65b0\u6570\u636e\u7684\u987a\u5e8f\u4e3a2\uff0c1\u3002\u8fd9\u6837\u66f4\u53ef\u80fd\u4f1a\u9020\u6210\u6b7b\u9501\u3002<\/p>\n
                        2\uff09\u5927\u4e8b\u52a1\u62c6\u5c0f\u3002\u5927\u4e8b\u52a1\u66f4\u503e\u5411\u4e8e\u6b7b\u9501\uff0c\u5982\u679c\u4e1a\u52a1\u5141\u8bb8\uff0c\u5c06\u5927\u4e8b\u52a1\u62c6\u5c0f\u3002<\/p>\n
                        3\uff09\u5728\u540c\u4e00\u4e2a\u4e8b\u52a1\u4e2d\uff0c\u5c3d\u53ef\u80fd\u505a\u5230\u4e00\u6b21\u9501\u5b9a\u6240\u9700\u8981\u7684\u6240\u6709\u8d44\u6e90\uff0c\u51cf\u5c11\u6b7b\u9501\u6982\u7387\u3002<\/p>\n
                        4\uff09\u964d\u4f4e\u9694\u79bb\u7ea7\u522b\u3002\u5982\u679c\u4e1a\u52a1\u5141\u8bb8\uff0c\u5c06\u9694\u79bb\u7ea7\u522b\u8c03\u4f4e\u4e5f\u662f\u8f83\u597d\u7684\u9009\u62e9\uff0c\u6bd4\u5982\u5c06\u9694\u79bb\u7ea7\u522b\u4eceRR\u8c03\u6574\u4e3aRC\uff0c\u53ef\u4ee5\u907f\u514d\u6389\u5f88\u591a\u56e0\u4e3agap\u9501\u9020\u6210\u7684\u6b7b\u9501\u3002<\/p>\n
                        5\uff09\u4e3a\u8868\u6dfb\u52a0\u5408\u7406\u7684\u7d22\u5f15\u3002\u53ef\u4ee5\u770b\u5230\u5982\u679c\u4e0d\u8d70\u7d22\u5f15\u5c06\u4f1a\u4e3a\u8868\u7684\u6bcf\u4e00\u884c\u8bb0\u5f55\u6dfb\u52a0\u4e0a\u9501\uff0c\u6b7b\u9501\u7684\u6982\u7387\u5927\u5927\u589e\u5927\u3002<\/p>\n
                        \u663e\u5f0f\u9501 \u4e0e \u9690\u5f0f\u9501<\/span> 
                         \u9690\u5f0f\u9501<\/span>:\u6211\u4eec\u4e0a\u6587\u8bf4\u7684\u9501\u90fd\u5c5e\u4e8e\u4e0d\u9700\u8981\u989d\u5916\u8bed\u53e5\u52a0\u9501\u7684\u9690\u5f0f\u9501\u3002 
                         \u663e\u793a\u9501<\/span>\uff1a <\/p>\n
                        \r\nSELECT ... LOCK IN SHARE MODE(\u52a0\u5171\u4eab\u9501);\r\nSELECT ... FOR UPDATE(\u52a0\u6392\u4ed6\u9501); <\/pre>\n
                        \u8be6\u60c5\u4e0a\u6587\u5df2\u7ecf\u8bf4\u8fc7\u3002<\/p>\n
                        \u901a\u8fc7\u5982\u4e0bsql\u53ef\u4ee5\u67e5\u770b\u7b49\u5f85\u9501\u7684\u60c5\u51b5  <\/p>\n
                        \n \n \n 
                          \n  \n  \n  
                        1. select<\/span> * <\/span>from<\/span> information_schema.innodb_trx <\/span>where<\/span> trx_state=<\/span>\"lock wait\"<\/span>; 
                          <\/span><\/span><\/li>\n \n \n <\/ol><\/pre>\n
                           \u6216<\/p>\n
                          \n \n \n 
                            \n  \n  \n  
                          1. show engine innodb status; <\/span><\/span><\/li>\n \n \n <\/ol><\/pre>\n
                            mysql\u4e2d\u7684\u4e8b\u52a1<\/span>  <\/h3>\n
                            \n \n \n 
                              \n  \n  \n  
                            1. show variables <\/span>like<\/span> <\/span>\"autocommit\"<\/span>; <\/span><\/span><\/li>\n  \n  \n  
                            2.  <\/span><\/li>\n  \n  \n  
                            3. set<\/span> autocommit=0; \/\/0\u8868\u793aAutoCommit\u5173\u95ed <\/span><\/span><\/li>\n  \n  \n  
                            4. set<\/span> autocommit=1; \/\/1\u8868\u793aAutoCommit\u5f00\u542f <\/span><\/span> <\/li>\n \n \n <\/ol><\/pre>\n
                                \n
                              • \n
                                \u81ea\u52a8\u63d0\u4ea4\uff08AutoCommit\uff0cmysql\u9ed8\u8ba4\uff09<\/span><\/p>\n<\/li>\n<\/ul>\n
                                mysql\u9ed8\u8ba4\u91c7\u7528AutoCommit\u6a21\u5f0f\uff0c\u4e5f\u5c31\u662f\u6bcf\u4e2asql\u90fd\u662f\u4e00\u4e2a\u4e8b\u52a1\uff0c\u5e76\u4e0d\u9700\u8981\u663e\u793a\u7684\u6267\u884c\u4e8b\u52a1\u3002 <\/p>\n
                                \u5982\u679cautoCommit\u5173\u95ed\uff0c\u90a3\u4e48\u6bcf\u4e2asql\u90fd\u9ed8\u8ba4\u5f00\u542f\u4e00\u4e2a\u4e8b\u52a1\uff0c\u53ea\u6709\u663e\u5f0f\u7684\u6267\u884c\u201ccommit\u201d\u540e\u8fd9\u4e2a\u4e8b\u52a1\u624d\u4f1a\u88ab\u63d0\u4ea4\u3002<\/span> <\/p>\n","protected":false},"excerpt":{"rendered":"
                                \u672c\u6587\u5bf9\u9501\u3001\u4e8b\u52a1\u3001\u5e76\u53d1\u63a7\u5236\u505a\u4e00\u4e2a\u603b\u7ed3\uff0c\u770b\u4e86\u7f51\u4e0a\u5f88\u591a\u6587\u7ae0\uff0c\u63cf\u8ff0\u975e\u5e38\u4e0d\u51c6\u786e\u3002\u5982\u6709\u4e0e\u60a8\u89c2\u70b9\u4e0d\u4e00\u81f4\uff0c\u6b22\u8fce\u6709\u7406\u6709\u636e\u7684\u62cd\u7816\uff01 […]<\/p>\n","protected":false},"author":1,"featured_media":313236,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7038],"tags":[],"class_list":["post-313235","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts\/313235","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/comments?post=313235"}],"version-history":[{"count":0,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/posts\/313235\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/media\/313236"}],"wp:attachment":[{"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/media?parent=313235"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/categories?post=313235"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/idc.net\/help\/wp-json\/wp\/v2\/tags?post=313235"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}