{"id":201599,"date":"2025-05-10T08:48:04","date_gmt":"2025-05-10T00:48:04","guid":{"rendered":"https:\/\/server.hk\/cnblog\/201599\/"},"modified":"2025-05-10T08:48:04","modified_gmt":"2025-05-10T00:48:04","slug":"%e5%87%a0%e5%88%86%e9%92%9f%e6%95%99%e4%bd%a0%e6%8e%8c%e6%8f%a1redis%e7%ae%80%e5%8d%95%e5%8a%a8%e6%80%81%e5%ad%97%e7%ac%a6%e4%b8%b2sds","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/201599\/","title":{"rendered":"\u51e0\u5206\u949f\u6559\u4f60\u638c\u63e1Redis\u7b80\u5355\u52a8\u6001\u5b57\u7b26\u4e32SDS"},"content":{"rendered":"

<\/b> <\/p>\n

\u51e0\u5206\u949f\u6559\u4f60\u638c\u63e1Redis\u7b80\u5355\u52a8\u6001\u5b57\u7b26\u4e32SDS<\/h1>\n

<\/i>\u6536\u85cf<\/span> <\/p>\n

\u4ece\u73b0\u5728\u5f00\u59cb\uff0c\u6211\u4eec\u8981\u52aa\u529b\u5b66\u4e60\u5566\uff01\u4eca\u5929\u6211\u7ed9\u5927\u5bb6\u5e26\u6765\u300a\u51e0\u5206\u949f\u6559\u4f60\u638c\u63e1Redis\u7b80\u5355\u52a8\u6001\u5b57\u7b26\u4e32SDS\u300b<\/span>\uff0c\u611f\u5174\u8da3\u7684\u670b\u53cb\u8bf7\u7ee7\u7eed\u770b\u4e0b\u53bb\u5427\uff01\u4e0b\u6587\u4e2d\u7684\u5185\u5bb9\u6211\u4eec\u4e3b\u8981\u4f1a\u6d89\u53ca\u5230\u5b57\u7b26\u4e32\u3001sds\u3001Redis\u52a8\u6001<\/span>\u7b49\u7b49\u77e5\u8bc6\u70b9\uff0c\u5982\u679c\u5728\u9605\u8bfb\u672c\u6587\u8fc7\u7a0b\u4e2d\u6709\u9047\u5230\u4e0d\u6e05\u695a\u7684\u5730\u65b9\uff0c\u6b22\u8fce\u7559\u8a00\u5440\uff01\u6211\u4eec\u4e00\u8d77\u8ba8\u8bba\uff0c\u4e00\u8d77\u5b66\u4e60\uff01<\/p>\n

\u6b63\u6587<\/h2>\n

Redis \u6ca1\u6709\u76f4\u63a5\u4f7f\u7528 C \u8bed\u8a00\u4f20\u7edf\u7684\u5b57\u7b26\u4e32\u8868\u793a\uff08\u800c\u662f\u4ee5\u7a7a\u5b57\u7b26\u7ed3\u5c3e\u7684\u5b57\u7b26\u6570\u7ec4\uff0c\u4ee5\u4e0b\u7b80\u79f0 C \u5b57\u7b26\u4e32\uff09\uff0c\u81ea\u5df1\u6784\u5efa\u4e86\u4e00\u79cd\u540d\u4e3a\u7b80\u5355\u52a8\u6001\u5b57\u7b26\u4e32\uff08simple dynamic string\uff0cSDS\uff09 \u7684\u62bd\u8c61\u7c7b\u578b\uff0c\u5e76\u5c06 SDS \u7528\u4f5c Redis \u7684\u9ed8\u8ba4\u5b57\u7b26\u4e32\u8868\u793a\u3002<\/p>\n

\u5728 Redis \u91cc\u9762\uff0cC \u5b57\u7b26\u4e32\u53ea\u4f1a\u4f5c\u4e3a\u5b57\u7b26\u4e32\u5b57\u9762\u91cf\uff08string literal\uff09\uff0c\u7528\u5728\u4e00\u4e9b\u65e0\u987b\u5bf9\u5b57\u7b26\u4e32\u503c\u8fdb\u884c\u4fee\u6539\u7684\u5730\u65b9\uff0c\u6bd4\u5982\u6253\u5370\u65e5\u5fd7\uff1a<\/p>\n

redisLog(REDIS_WARNING,”Redis is now ready to exit, bye bye…”);<\/h2>\n

\u5f53 Redis \u9700\u8981\u7684\u4e0d\u4ec5\u4ec5\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32\u5b57\u9762\u91cf\uff0c\u800c\u662f\u4e00\u4e2a\u53ef\u4ee5\u88ab\u4fee\u6539\u7684\u5b57\u7b26\u4e32\u503c\u65f6\uff0cRedis \u5c31\u4f1a\u4f7f\u7528 SDS \u6765\u8868\u793a\u5b57\u7b26\u4e32\u503c\uff1a\u6bd4\u5982\u5728 Redis \u7684\u6570\u636e\u5e93\u91cc\u9762\uff0c\u5305\u542b\u5b57\u7b26\u4e32\u7684\u952e\u503c\u5bf9\u5728\u5e95\u5c42\u90fd\u662f\u7531 SDS \u5b9e\u73b0\u7684\u3002<\/p>\n

\u4e3e\u4e2a\u4f8b\u5b50\uff0c\u5982\u679c\u5ba2\u6237\u7aef\u6267\u884c\u547d\u4ee4\uff1a<\/p>\n

redis> SET msg \"hello world\"\nOK\n<\/pre>\n
\u90a3\u4e48 Redis \u5c06\u5728\u6570\u636e\u5e93\u4e2d\u521b\u5efa\u4e86\u4e00\u4e2a\u65b0\u7684\u952e\u503c\u5bf9\uff0c\u5176\u4e2d\uff1a<\/p>\n
    \n
  • \u952e\u503c\u5bf9\u7684\u952e\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61\uff0c\u5bf9\u8c61\u7684\u5e95\u5c42\u5b9e\u73b0\u662f\u4e00\u4e2a\u4fdd\u5b58\u7740\u5b57\u7b26\u4e32 \"msg\"<\/code> \u7684 SDS \u3002<\/li>\n
  • \u952e\u503c\u5bf9\u7684\u503c\u4e5f\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61\uff0c\u5bf9\u8c61\u7684\u5e95\u5c42\u5b9e\u73b0\u662f\u4e00\u4e2a\u4fdd\u5b58\u7740\u5b57\u7b26\u4e32 \"hello world\"<\/code> \u7684SDS\u3002<\/li>\n<\/ul>\n
    \u53c8\u6bd4\u5982\u8bf4\uff0c\u5982\u679c\u5ba2\u6237\u7aef\u6267\u884c\u547d\u4ee4\uff1a<\/p>\n
    redis> RPUSH fruits \"apple\" \"banana\" \"cherry\"\n(integer) 3\n<\/pre>\n
    \u90a3\u4e48 Redis \u5c06\u5728\u6570\u636e\u5e93\u4e2d\u521b\u5efa\u4e00\u4e2a\u65b0\u7684\u952e\u503c\u5bf9\uff0c\u5176\u4e2d\uff1a<\/p>\n
      \n
    • \u952e\u503c\u5bf9\u7684\u952e\u662f\u4e00\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61\uff0c\u5bf9\u8c61\u7684\u5e95\u5c42\u5b9e\u73b0\u662f\u4e00\u4e2a\u4fdd\u5b58\u4e86\u5b57\u7b26\u4e32 \"fruits\"<\/code> \u7684 SDS \u3002<\/li>\n
    • \u952e\u503c\u5bf9\u7684\u503c\u662f\u4e00\u4e2a\u5217\u8868\u5bf9\u8c61\uff0c\u5217\u8868\u5bf9\u8c61\u5305\u542b\u4e86\u4e09\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61\uff0c\u8fd9\u4e09\u4e2a\u5b57\u7b26\u4e32\u5bf9\u8c61\u5206\u522b\u7531\u4e09\u4e2a SDS \u5b9e\u73b0\uff1a\u7b2c\u4e00\u4e2a SDS \u4fdd\u5b58\u7740\u5b57\u7b26\u4e32 \"apple\"<\/code> \uff0c\u7b2c\u4e8c\u4e2a SDS \u4fdd\u5b58\u7740\u5b57\u7b26\u4e32 \"banana\"<\/code> \uff0c\u7b2c\u4e09\u4e2a SDS \u4fdd\u5b58\u7740\u5b57\u7b26\u4e32 \"cherry\"<\/code> \u3002<\/li>\n<\/ul>\n
      \u9664\u4e86\u7528\u6765\u4fdd\u5b58\u6570\u636e\u5e93\u4e2d\u7684\u5b57\u7b26\u4e32\u503c\u4e4b\u5916\uff0cSDS \u8fd8\u88ab\u7528\u4f5c\u7f13\u51b2\u533a\uff08buffer\uff09\uff1aAOF \u6a21\u5757\u4e2d\u7684 AOF \u7f13\u51b2\u533a\uff0c\u4ee5\u53ca\u5ba2\u6237\u7aef\u72b6\u6001\u4e2d\u7684\u8f93\u5165\u7f13\u51b2\u533a\uff0c\u90fd\u662f\u7531 SDS \u5b9e\u73b0\u7684\uff0c\u5728\u4e4b\u540e\u4ecb\u7ecd AOF \u6301\u4e45\u5316\u548c\u5ba2\u6237\u7aef\u72b6\u6001\u7684\u65f6\u5019\uff0c\u6211\u4eec\u4f1a\u770b\u5230 SDS \u5728\u8fd9\u4e24\u4e2a\u6a21\u5757\u4e2d\u7684\u5e94\u7528\u3002<\/p>\n
      AOF\u4e2d\u8bb0\u5f55\u7684\u662f\u6bcf\u4e00\u4e2a\u547d\u4ee4\u7684\u8be6\u7ec6\u4fe1\u606f\uff0c\u5305\u62ec\u5b8c\u6574\u7684\u547d\u4ee4\u7c7b\u578b\u3001\u53c2\u6570\u7b49\u3002\u53ea\u8981\u4ea7\u751f\u5199\u547d\u4ee4\uff0c\u5c31\u4f1a\u5b9e\u65f6\u5199\u5165\u5230AOF\u6587\u4ef6\u4e2d<\/p>\n
      SDS\u7684\u5b9a\u4e49<\/p>\n
      struct sdshdr {\n    \/\/ \u8bb0\u5f55 buf \u6570\u7ec4\u4e2d\u5df2\u4f7f\u7528\u5b57\u8282\u7684\u6570\u91cf\n    int len;\n    \/\/ \u8bb0\u5f55 buf \u6570\u7ec4\u4e2d\u672a\u4f7f\u7528\u5b57\u8282\u7684\u6570\u91cf\n    int free;\n    \/\/ \u5b57\u8282\u6570\u7ec4\uff0c\u7528\u4e8e\u4fdd\u5b58\u5b57\u7b26\u4e32\n    char buf[];\n};\n<\/pre>\n
      \u4e0eC\u5b57\u7b26\u4e32\u7684\u533a\u522b<\/h2>\n
      C\u8bed\u8a00\u4f7f\u7528\u957f\u5ea6\u4e3a N+1<\/code> \u7684\u5b57\u7b26\u6570\u7ec4\u6765\u8868\u793a\u957f\u5ea6\u4e3a N<\/code> \u7684\u5b57\u7b26\u4e32\uff0c\u5e76\u4e14\u5b57\u7b26\u6570\u7ec4\u7684\u6700\u540e\u4e00\u4e2a\u5143\u7d20\u603b\u662f\u7a7a\u5b57\u7b26 '\\0'<\/code>\u3002<\/p>\n
      <\/p>\n
      \u83b7\u53d6\u5b57\u7b26\u4e32\u957f\u5ea6<\/h3>\n
      \u56e0\u4e3a C \u5b57\u7b26\u4e32\u5e76\u4e0d\u8bb0\u5f55\u81ea\u8eab\u7684\u957f\u5ea6\u4fe1\u606f\uff0c\u6240\u4ee5\u4e3a\u4e86\u83b7\u53d6\u4e00\u4e2a C \u5b57\u7b26\u4e32\u7684\u957f\u5ea6\uff0c\u7a0b\u5e8f\u5fc5\u987b\u904d\u5386\u6574\u4e2a\u5b57\u7b26\u4e32O(N)O(N)O(N) \u3002<\/p>\n
      \u548c C \u5b57\u7b26\u4e32\u4e0d\u540c\uff0c\u56e0\u4e3a SDS \u5728 len<\/code> \u5c5e\u6027\u4e2d\u8bb0\u5f55\u4e86 SDS \u672c\u8eab\u7684\u957f\u5ea6\uff0c\u6240\u4ee5\u83b7\u53d6\u4e00\u4e2a SDS \u957f\u5ea6\u7684\u590d\u6742\u5ea6\u4ec5\u4e3a O(1)O(1)O(1) \u3002<\/p>\n
      \u675c\u7edd\u7f13\u51b2\u533a\u6ea2\u51fa<\/h3>\n
      C \u5b57\u7b26\u4e32\u4e0d\u8bb0\u5f55\u81ea\u8eab\u957f\u5ea6\u5e26\u6765\u7684\u53e6\u4e00\u4e2a\u95ee\u9898\u662f\u5bb9\u6613\u9020\u6210\u7f13\u51b2\u533a\u6ea2\u51fa\uff08buffer overflow\uff09\u3002<\/p>\n
      \u5047\u8bbe\u7a0b\u5e8f\u91cc\u6709\u4e24\u4e2a\u5728\u5185\u5b58\u4e2d\u7d27\u90bb\u7740\u7684 C \u5b57\u7b26\u4e32 s1 \u548c s2 \uff0c\u5176\u4e2d s1 \u4fdd\u5b58\u4e86\u5b57\u7b26\u4e32 “Redis” \uff0c\u800c s2 \u5219\u4fdd\u5b58\u4e86\u5b57\u7b26\u4e32 “MongoDB” .<\/p>\n
      <\/p>\n
      \u5982\u679c\u4e00\u4e2a\u7a0b\u5e8f\u5458\u51b3\u5b9a\u901a\u8fc7\u6267\u884c\uff1astrcat(s1, \"Cluster\")<\/code>\u5c06 s1 \u7684\u5185\u5bb9\u4fee\u6539\u4e3a “Redis Cluster” \uff0c\u4f46\u7c97\u5fc3\u7684\u4ed6\u5374\u5fd8\u4e86\u5728\u6267\u884c strcat<\/code> \u4e4b\u524d\u4e3a s1 \u5206\u914d\u8db3\u591f\u7684\u7a7a\u95f4\uff0c\u90a3\u4e48\u5728 strcat \u51fd\u6570\u6267\u884c\u4e4b\u540e\uff0cs1 \u7684\u6570\u636e\u5c06\u6ea2\u51fa\u5230 s2 \u6240\u5728\u7684\u7a7a\u95f4\u4e2d\uff0c\u5bfc\u81f4 s2 \u4fdd\u5b58\u7684\u5185\u5bb9\u88ab\u610f\u5916\u5730\u4fee\u6539\u3002<\/p>\n
      <\/p>\n
      SDS \u7684\u7a7a\u95f4\u5206\u914d\u7b56\u7565\u5b8c\u5168\u675c\u7edd\u4e86\u53d1\u751f\u7f13\u51b2\u533a\u6ea2\u51fa\u7684\u53ef\u80fd\u6027\uff1a\u5f53 SDS API \u9700\u8981\u5bf9 SDS \u8fdb\u884c\u4fee\u6539\u65f6\uff0cAPI \u4f1a\u5148\u68c0\u67e5 SDS \u7684\u7a7a\u95f4\u662f\u5426\u6ee1\u8db3\u4fee\u6539\u6240\u9700\u7684\u8981\u6c42\uff0c\u5982\u679c\u4e0d\u6ee1\u8db3\u7684\u8bdd\uff0cAPI \u4f1a\u81ea\u52a8\u5c06 SDS \u7684\u7a7a\u95f4\u6269\u5c55\u81f3\u6267\u884c\u4fee\u6539\u6240\u9700\u7684\u5927\u5c0f\uff0c\u7136\u540e\u624d\u6267\u884c\u5b9e\u9645\u7684\u4fee\u6539\u64cd\u4f5c\uff0c\u6240\u4ee5\u4f7f\u7528 SDS \u65e2\u4e0d\u9700\u8981\u624b\u52a8\u4fee\u6539 SDS \u7684\u7a7a\u95f4\u5927\u5c0f\uff0c\u4e5f\u4e0d\u4f1a\u51fa\u73b0\u524d\u9762\u6240\u8bf4\u7684\u7f13\u51b2\u533a\u6ea2\u51fa\u95ee\u9898\u3002<\/p>\n
      \u51cf\u5c11\u5185\u5b58\u5206\u914d\u6b21\u6570<\/h3>\n
      \u56e0\u4e3a C \u5b57\u7b26\u4e32\u7684\u957f\u5ea6\u548c\u5e95\u5c42\u6570\u7ec4\u7684\u957f\u5ea6\u4e4b\u95f4\u5b58\u5728\u7740\u8fd9\u79cd\u5173\u8054\u6027\uff0c\u6240\u4ee5\u6bcf\u6b21\u589e\u957f\u6216\u8005\u7f29\u77ed\u4e00\u4e2a C \u5b57\u7b26\u4e32\uff0c\u7a0b\u5e8f\u90fd\u603b\u8981\u5bf9\u4fdd\u5b58\u8fd9\u4e2a C \u5b57\u7b26\u4e32\u7684\u6570\u7ec4\u8fdb\u884c\u4e00\u6b21\u5185\u5b58\u91cd\u5206\u914d\u64cd\u4f5c\uff0c\u5728 SDS \u4e2d\uff0c\u6570\u7ec4\u91cc\u9762\u53ef\u4ee5\u5305\u542b\u672a\u4f7f\u7528\u7684\u5b57\u8282\uff0c\u800c\u8fd9\u4e9b\u5b57\u8282\u7684\u6570\u91cf\u5c31\u7531 SDS \u7684 free<\/code> \u5c5e\u6027\u8bb0\u5f55\u3002\u5e76\u5b9e\u73b0\u4e86\u4e24\u79cd\u4f18\u5316\u7b56\u7565\uff1a<\/p>\n
      \u7a7a\u95f4\u9884\u5206\u914d\uff0c\u5f53\u8fdb\u884c\u5b57\u7b26\u4e32\u589e\u957f\u64cd\u4f5c\u65f6\uff0c\u7a0b\u5e8f\u4f1a\u989d\u5916\u5206\u914d\u7a7a\u95f4\uff0c\u5e76\u8bb0\u5f55\u7684free<\/code>\u5b57\u6bb5<\/p>\n
      \u6bd4\u5982\u539f\u957f\u5ea6\u4e3a8\u7684\u5b57\u7b26\u4e32,\u65b0\u589e5\u4e2a\u957f\u5ea6\u540e,\u603b\u5171\u4e3a13\u957f\u5ea6,\u5219\u9884\u5206\u914d13+13+1=27\u5b57\u8282(\u989d\u5916\u4e00\u5b57\u8282\u7528\u4e8e\u4fdd\u5b58\u7a7a\u5b57\u7b26\u4e32)<\/p>\n
      \u5bf9\u4e8e\u5927\u4e8e1M\u6765\u8bf4,\u5206\u914d\u7a7a\u95f4\u4e3a\u539f\u6709\u603b\u957f\u5ea6+1MB+1byte<\/p>\n
      \u6bd4\u5982\u589e\u52a0\u5b8c\u5b57\u7b26\u4e32\u540e\u957f\u5ea6\u4e3a15MB,\u5219\u4e3a15MB+1MB+1byte<\/p>\n
      \u60f0\u6027\u7a7a\u95f4\u91ca\u653e\uff0c\u5f53\u8fdb\u884c\u5b57\u7b26\u4e32\u7f29\u77ed\u64cd\u4f5c\u65f6\uff0c\u7a0b\u5e8f\u4e0d\u7acb\u5373\u91cd\u65b0\u5206\u914d\u5185\u5b58\uff0c\u800c\u662f\u7528free<\/code>\u5c5e\u6027\u5c06\u8fd9\u4e9b\u5b57\u8282\u7684\u6570\u91cf\u8bb0\u5f55\u8d77\u6765\u3002<\/p>\n
      \u4e8c\u8fdb\u5236\u5b89\u5168<\/h3>\n
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