{"id":460,"date":"2019-01-29T00:22:45","date_gmt":"2019-01-28T16:22:45","guid":{"rendered":"https:\/\/kaispace.cn\/?p=460"},"modified":"2019-01-29T00:22:45","modified_gmt":"2019-01-28T16:22:45","slug":"%e5%85%b3%e4%ba%8emysql%e9%9a%94%e7%a6%bb%e7%ba%a7%e5%88%ab","status":"publish","type":"post","link":"https:\/\/blog.kaispace.cn\/?p=460","title":{"rendered":"\u5173\u4e8eMysql\u9694\u79bb\u7ea7\u522b"},"content":{"rendered":"

\u8c08Mysql\u9694\u79bb\u7ea7\u522b<\/h1>\n

\u6700\u8fd1\u770b\u4e66\u548c\u770b\u5404\u79cd\u6587\u7ae0\u88ab\u5f04\u5f97\u7279\u522b\u6655\uff0c\u6240\u4ee5\u5199\u4e0b\u81ea\u5df1\u7efc\u5408\u4e66\u7c4d\u300a\u9ad8\u6027\u80fdMysql\u300b\u548c\u5b98\u65b9\u6587\u6863\u7684\u7406\u89e3\u3002<\/p>\n

\n

\u6570\u636e\u5e93\u7684\u9694\u79bb\u7ea7\u522b\u901a\u5e38\u5206\u4e3a\u56db\u7c7b<\/p>\n

    \n
  1. \u672a\u63d0\u4ea4\u8bfb<\/strong> (READ_UNCOMMITTED)<\/li>\n
  2. \u63d0\u4ea4\u8bfb<\/strong> (READ_COMMITTED)<\/li>\n
  3. \u53ef\u91cd\u590d\u8bfb<\/strong> (REPEATABLE_READ)<\/li>\n
  4. \u53ef\u4e32\u884c\u5316<\/strong> (SERIALIZABLE_READ)<\/li>\n<\/ol>\n

    \n \u5927\u591a\u6570\u6570\u636e\u5e93\u7684\u9ed8\u8ba4\u9694\u79bb\u7ea7\u522b\u90fd\u662fREAD CPMMITTED\u3002\u4f46\u662fMysql\u4e0d\u662f\uff0cMysql\u9ed8\u8ba4\u7684\u662fREPEATABLE_READ\u53ef\u91cd\u590d\u8bfb\u3002\n<\/p><\/blockquote>\n

    1.\u672a\u63d0\u4ea4\u8bfb<\/h3>\n

    \u9009\u7528\u672a\u63d0\u4ea4\u8bfb\uff0c\u4e8b\u52a1\u7684\u4fee\u6539\u5373\u4f7f\u6ca1\u6709\u63d0\u4ea4<\/strong>\u5bf9\u5176\u4ed6\u4e8b\u52a1\u4e5f\u662f\u53ef\u89c1\u7684\u3002\u5f53\u524d\u4e8b\u52a1\u5bf9\u6570\u636e\u7684CUD\u90fd\u5bf9\u5176\u4ed6\u4e8b\u52a1\u53ef\u89c1\u3002
    \n\u8fd9\u79cd\u9694\u79bb\u7ea7\u522b\u4e0b\u4f1a\u4ea7\u751f\u810f\u8bfb<\/strong>\u73b0\u8c61\u3002<\/p>\n

    \n \u810f\u8bfb<\/strong>\u6307\u7684\u662f\u5f53\u524d\u4e8b\u52a1\u67e5\u8be2\u7684\u6570\u636e\u662f\u4e0d\u53ef\u9760\u7684\uff0c \u53ef\u80fd\u662f\u88ab\u5176\u4ed6\u672a\u63d0\u4ea4\u4e8b\u52a1\u6240\u66f4\u6539\u7684\u3002\u662f\u4e0d\u6ee1\u8db3ACID\u4e2d\u7684I\u9694\u79bb\u6027\u7684\u3002\n<\/p><\/blockquote>\n

    2.\u63d0\u4ea4\u8bfb(\u7528\u5230MVCC)<\/h3>\n

    \u9009\u7528\u63d0\u4ea4\u8bfb\uff0c\u867d\u7136\u89e3\u51b3\u4e86\u810f\u8bfb<\/strong>\u73b0\u8c61\uff0c\u4f46\u662f\u7531\u4e8e\u6bcf\u6b21\u8bfb\u53d6\u90fd\u662f\u8bfb\u53d6\u6570\u636e\u7684\u6700\u65b0\u5feb\u7167<\/strong>\uff0c\u56e0\u6b64\u4e0d\u53ef\u907f\u514d\u7684\u4f1a\u53d1\u751f\u4e0d\u53ef\u91cd\u590d\u8bfb<\/strong>\u73b0\u8c61\u3002<\/p>\n

    \n \u4e0d\u53ef\u91cd\u590d\u8bfb<\/strong>\u6307\u7684\u662f\u540c\u4e00\u4e8b\u52a1\u524d\u540e\u67e5\u8be2\u7684\u540c\u4e00\u884c\u6570\u636e\u53ef\u80fd\u7531\u4e8e\u53e6\u4e00\u4e8b\u52a1\u7684\u4fee\u6539UPDATE\u63d0\u4ea4\u5bfc\u81f4\u6570\u636e\u4e0d\u4e00\u81f4\u3002\u8fd9\u91cc\u7684\u4e0d\u540c\u6307\u7684\u662f\u540c\u4e00\u4e3b\u952e\u7d22\u5f15\u4e0b\u7684\u6570\u636e\u4e0d\u540c\u3002
    \n \u56e0\u6b64\u4e0e\u810f\u8bfb\u7684\u73b0\u8c61\u4e0d\u540c\u5728\u4e8e\u5bfc\u81f4\u4e24\u8005\u53d1\u751f\u7684\u5916\u90e8\u4e8b\u52a1<\/strong>\u662f\u5426\u5df2\u7ecf\u63d0\u4ea4<\/strong>\u3002\n<\/p><\/blockquote>\n

    \u53c8\u56e0\u4e3a\u5176\u4e0d\u542f\u7528\u95f4\u9699\u9501<\/strong>(GAP LOCK),\u56e0\u6b64\u65e0\u6cd5\u907f\u514d\u7684\u4e5f\u4f1a\u51fa\u73b0\u5e7b\u8bfb\u73b0\u8c61\u3002<\/p>\n

    \n \u5e7b\u8bfb<\/strong>\u6307\u7684\u662f\u540c\u4e00\u4e8b\u52a1\u524d\u540e\u4e24\u6b21\u67e5\u8be2\uff0c\u7b2c\u4e8c\u6b21\u67e5\u8be2\u6570\u636e\u96c6\u5408\u4e2d\u51fa\u73b0\u4e86\u7b2c\u4e00\u6b21\u67e5\u8be2\u672a\u51fa\u73b0\u7684\u884c(\u5176\u4ed6\u4e8b\u52a1Insert\u65b0\u884c\u6216Update\u67d0\u884c\u4f7f\u5176\u6ee1\u8db3WHERE\u6761\u4ef6)\u3002\n<\/p><\/blockquote>\n

    3.\u53ef\u91cd\u590d\u8bfb(\u7528\u5230MVCC)<\/h3>\n

    \u65e0\u8bba\u662f\u5426\u9501\u5b9aSELECT,\u53ef\u91cd\u590d\u8bfb\u90fd\u4f1a\u901a\u8fc7\u7b2c\u4e00\u6b21\u8bfb\u53d6\u65f6\u5b9a\u4e0b\u4e00\u4efd\u5feb\u7167<\/strong>\uff0c\u5728\u8fd9\u6b21\u4e8b\u52a1\u4e2d\u53ea\u5bf9\u8fd9\u4efd\u5feb\u7167\u8fdb\u884cCRUD,\u4ece\u800c\u5b9e\u73b0\u4e00\u81f4\u6027\u3002<\/p>\n

    \u82e5\u9501\u5b9a\u4e86SELECT\uff0c\u53ef\u91cd\u590d\u8bfb\u8fd8\u4f1a\u901a\u8fc7\u67e5\u8be2\u6761\u4ef6(WHERE)\u53bb\u51b3\u5b9a\u8be5\u91c7\u7528\u4ec0\u4e48\u9501\uff0c\u5f53\u67e5\u8be2\u6761\u4ef6\u6307\u5411\u552f\u4e00\u7d22\u5f15\u65f6\uff0c\u53ea\u4f1a\u4f7f\u7528\u884c\u7ea7\u9501(S\u5171\u4eab\u9501 OR X\u6392\u4ed6\u9501),\u800c\u5f53\u67e5\u8be2\u6761\u4ef6\u53ea\u5411\u4e00\u4e2a\u8303\u56f4\u65f6\u5219\u4f1a\u518d\u989d\u5916\u4f7f\u7528\u4e0b\u952e\u9501next-key lock<\/a>(\u7531\u8bb0\u5f55\u9501FOR UPDATE<\/a>+\u95f4\u9699\u9501<\/a>\u7ec4\u5408)\uff0c\u9632\u6b62Insert\u548cDelete\u3002<\/p>\n

    4.\u53ef\u4e32\u884c\u5316<\/h3>\n

    \u5f00\u542fAuto-commit\u5219\u4f1a\u9ed8\u8ba4\u4e3aSELECT\u52a0\u4e0a\u5171\u4eab\u9501(LOCK IN SHARE MODE),\u5373\u4e00\u5b9a\u4f1a\u4e3aSELECT\u52a0\u9501\uff0c\u8fd9\u6837\u4f1a\u5bfc\u81f4\u5f88\u591a\u591a\u4f59\u7684\u4e0a\u9501\u91ca\u653e\u64cd\u4f5c\uff0c\u5f71\u54cd\u6027\u80fd\u3002<\/p>\n

    \u603b\u7ed3<\/h2>\n

    \u810f\u8bfb\u5305\u62ec\u4e86\u4e0d\u53ef\u91cd\u590d\u8bfb\u548c\u5e7b\u8bfb\uff0c\u4f46\u5e7b\u8bfb\u548c\u4e0d\u53ef\u91cd\u590d\u8bfb\u4e0d\u540c\uff0c\u4e0d\u53ef\u91cd\u590d\u8bfb\u9488\u5bf9\u540c\u4e00\u884c\u6570\u636e\u524d\u540e\u5f02\u53d8\uff0c\u800c\u5e7b\u8bfb\u5219\u9488\u5bf9\u603b\u4f53\u662f\u5426\u53d1\u751f\u5f02\u53d8(\u51fa\u73b0\u65b0\u884c,\u5e7b\u5f71\u884c)\u3002
    \n\u4e0d\u53ef\u91cd\u590d\u8bfb\u7528MVCC\u591a\u7248\u672c\u5e76\u53d1\u63a7\u5236\u56fa\u5b9a\u7248\u672c\u53f7\u89e3\u51b3\uff0c\u5e7b\u8bfb\u4f7f\u7528next-key lock\u89e3\u51b3\u3002<\/p>\n

    \u8865\u5145<\/h2>\n

    MVCC<\/h3>\n

    MVCC\u662f\u4e00\u4e2a\u6982\u5ff5\uff0c\u4e0d\u540c\u5b58\u50a8\u5f15\u64ce\u5b9e\u73b0\u65b9\u5f0f\u4e0d\u540c\uff0c\u5206\u6709\u60b2\u89c2\u7248\u672c\u63a7\u5236\u548c\u4e50\u89c2\u7248\u672c\u63a7\u5236\uff0c\u60b2\u89c2\u7248\u672c\u63a7\u5236\u4f1a\u4e0a\u9501\uff0c\u5bfc\u81f4\u5176\u4ed6\u8bbf\u95ee\u5bf9\u8c61\u9700\u8981\u7b49\u5f85\uff0c\u800c\u4e50\u89c2\u7248\u672c\u63a7\u5236\u5219\u662f\u68c0\u67e5
    \n\u6570\u636e\u662f\u5426\u7b26\u5408\u6761\u4ef6(\u5f53\u524d\u7248\u672c\u662f\u5426\u4e00\u81f4\uff0c\u7c7b\u4f3c\u4e0eCAS\u673a\u5236)\u3002<\/p>\n

    InnoDB\u4e24\u79cd\u90fd\u6709\uff0c\u4e50\u89c2\u7248\u672c\u63a7\u5236\u662f\u901a\u8fc7\u4e3a\u6bcf\u884c\u8bb0\u5f55\u540e\u9762\u6dfb\u52a0\u4e24\u5217\uff0c\u4e00\u4e2a\u4fdd\u5b58\u884c\u521b\u5efa\u65f6\u95f4\uff0c\u4e00\u4e2a\u4fdd\u5b58\u884c\u5220\u9664\u65f6\u95f4\u3002(\u5b9e\u9645\u4fdd\u5b58\u7684\u662f\u7248\u672c\u53f7)<\/p>\n

    \u5728\u53ef\u91cd\u590d\u8bfb\u9694\u79bb\u7ea7\u522b\u4e0b\uff1a<\/p>\n

    SELECT<\/p>\n

      \n
    1. \u7248\u672c\u53f7\u5148\u4e8e\u5f53\u524d\u4e8b\u52a1\u7248\u672c\u7684\u884c(\u4e8b\u52a1\u524d\u5df2\u5b58\u5728\u6216\u5f53\u524d\u4e8b\u52a1\u63d2\u5165\u7684)<\/li>\n
    2. \u884c\u5220\u9664\u7248\u672c\u4e3a\u5b9a\u4e49\u6216\u5927\u4e8e\u5f53\u524d\u4e8b\u52a1\u7248\u672c(\u4fdd\u8bc1\u8fd9\u4e2a\u4e8b\u52a1\u7248\u672c\u4e0b\u672a\u88ab\u5220\u9664)<\/li>\n<\/ol>\n

      INSERT<\/p>\n

        \n
      1. \u4e3a\u65b0\u63d2\u5165\u884c\u4fdd\u5b58\u5f53\u524d\u4e8b\u52a1\u7248\u672c\u53f7\u4e3a\u884c\u7248\u672c\u53f7<\/li>\n<\/ol>\n

        DELETE<\/p>\n

          \n
        1. \u4e3a\u5220\u9664\u7684\u6bcf\u4e00\u884c\u7684\u5220\u9664\u7248\u672c\u53f7\u8bbe\u5b9a\u4e3a\u5f53\u524d\u7248\u672c\u53f7<\/li>\n<\/ol>\n

          UPDATE<\/p>\n

            \n
          1. \u63d2\u5165\u65b0\u884c\uff0c\u65b0\u884c\u7248\u672c\u53f7\u9501\u5b9a\u4e3a\u5f53\u524d\u7248\u672c\u53f7\uff0c\u5411\u65e7\u884c\u7684\u5220\u9664\u7248\u672c\u53f7\u63d2\u5165\u4e3a\u5f53\u524d\u7248\u672c\u53f7\u3002<\/li>\n<\/ol>\n

            MVCC\u53ea\u5728REPEATABLE_READ<\/strong>\u548cREAD_COMMITTED<\/strong>\u4e0b\u5de5\u4f5c\uff0c\u56e0\u4e3aREAD_UNCOMMITTED<\/strong>\u53ea\u8bfb\u6700\u65b0\u884c\uff0c
            \nSERIALIZABLE_READ<\/strong>\u4f1a\u9ed8\u8ba4\u52a0\u9501\uff0c\u91c7\u7528\u60b2\u89c2\u7248\u672c\u63a7\u5236\uff0c\u4f7f\u7528MVCC\u591a\u4f59\u3002<\/p>\n

            \u53c2\u8003\u6587\u6863 : Mysql\u5b98\u65b9\u6587\u6863\u4e4b\u9694\u79bb\u7ea7\u522b<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

            \u8c08Mysql\u9694\u79bb\u7ea7\u522b \u6700\u8fd1\u770b\u4e66\u548c\u770b\u5404\u79cd\u6587\u7ae0\u88ab\u5f04\u5f97\u7279\u522b\u6655\uff0c\u6240\u4ee5\u5199\u4e0b\u81ea\u5df1\u7efc\u5408\u4e66\u7c4d\u300a\u9ad8\u6027\u80fdMysql\u300b\u548c\u5b98\u65b9\u6587\u6863\u7684\u7406…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[5],"tags":[],"_links":{"self":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/posts\/460"}],"collection":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=460"}],"version-history":[{"count":0,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=\/wp\/v2\/posts\/460\/revisions"}],"wp:attachment":[{"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=460"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=460"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.kaispace.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=460"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}