{"id":202310,"date":"2025-05-10T15:27:29","date_gmt":"2025-05-10T07:27:29","guid":{"rendered":"https:\/\/server.hk\/cnblog\/202310\/"},"modified":"2025-05-10T15:27:29","modified_gmt":"2025-05-10T07:27:29","slug":"redis%e4%b8%ba%e4%bb%80%e4%b9%88%e8%a6%81%e9%81%bf%e5%85%8dbig-key","status":"publish","type":"post","link":"https:\/\/server.hk\/cnblog\/202310\/","title":{"rendered":"Redis\u4e3a\u4ec0\u4e48\u8981\u907f\u514dbig key"},"content":{"rendered":"

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

Redis\u4e3a\u4ec0\u4e48\u8981\u907f\u514dbig key<\/h1>\n

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

\u600e\u4e48\u5165\u95e8\u6570\u636e\u5e93\u7f16\u7a0b\uff1f\u9700\u8981\u5b66\u4e60\u54ea\u4e9b\u77e5\u8bc6\u70b9\uff1f\u8fd9\u662f\u65b0\u624b\u4eec\u521a\u63a5\u89e6\u7f16\u7a0b\u65f6\u5e38\u89c1\u7684\u95ee\u9898\uff1b\u4e0b\u9762golang\u5b66\u4e60\u7f51\u5c31\u6765\u7ed9\u5927\u5bb6\u6574\u7406\u5206\u4eab\u4e00\u4e9b\u77e5\u8bc6\u70b9\uff0c\u5e0c\u671b\u80fd\u591f\u7ed9\u521d\u5b66\u8005\u4e00\u4e9b\u5e2e\u52a9\u3002\u672c\u7bc7\u6587\u7ae0\u5c31\u6765\u4ecb\u7ecd\u300aRedis\u4e3a\u4ec0\u4e48\u8981\u907f\u514dbig key\u300b\uff0c\u6d89\u53ca\u5230\uff0c\u6709\u9700\u8981\u7684\u53ef\u4ee5\u6536\u85cf\u4e00\u4e0b<\/p>\n

\u907f\u514d big key<\/h3>\n

Redis \u6267\u884c\u547d\u4ee4\u662f\u5355\u7ebf\u7a0b\u7684\uff0c\u8fd9\u610f\u5473\u7740 Redis \u64cd\u4f5c\u300cbig key\u300d\u6709\u963b\u585e\u7684\u98ce\u9669\u3002<\/p>\n

big key \u901a\u5e38\u6307\u7684\u662f Redis \u5b58\u50a8\u7684 value \u8fc7\u5927\u3002\u5305\u62ec\uff1a<\/p>\n

    \n
  • \n

    \u5355\u4e2a value \u8fc7\u5927\u3002\u5982 200M \u5927\u5c0f\u7684 String\u3002<\/p>\n<\/li>\n

  • \n

    \u96c6\u5408\u5143\u7d20\u8fc7\u591a\u3002\u5982 List\u3001Hash\u3001Set\u3001ZSet \u4e2d\u6709\u51e0\u767e\u3001\u4e0a\u5343\u4e07\u6570\u636e\u3002<\/p>\n<\/li>\n<\/ul>\n

    \u4e3e\u4e2a\u4f8b\u5b50\uff0c\u5047\u8bbe\u6211\u4eec\u6709\u4e00\u4e2a 200M \u5927\u5c0f\u7684 String key\uff0c\u540d\u79f0\u4e3a\u300cfoo\u300d\u3002<\/p>\n

    \u6267\u884c\u5982\u4e0b\u547d\u4ee4<\/p>\n

    127.0.0.1:6379> GET foo<\/pre>\n
    \u5f53\u8fd4\u56de\u7ed3\u679c\u65f6\uff0cRedis \u4f1a\u5206\u914d 200m \u7684\u5185\u5b58\uff0c\u5e76\u6267\u884c memcpy \u62f7\u8d1d\u3002<\/p>\n
    void _addReplyProtoToList(client *c, const char *s, size_t len) {\n    ...\n    if (len) {\n        \/* Create a new node, make sure it is allocated to at\n         * least PROTO_REPLY_CHUNK_BYTES *\/\n        size_t size = len < PROTO_REPLY_CHUNK_BYTES? PROTO_REPLY_CHUNK_BYTES: len;\n        \/\/ \u5206\u914d\u5185\u5b58\uff08\u4f8b\u5b50\u4e2d\u4e3a 200m\uff09\n        tail = zmalloc(size + sizeof(clientReplyBlock));\n        \/* take over the allocation's internal fragmentation *\/\n        tail->size = zmalloc_usable_size(tail) - sizeof(clientReplyBlock);\n        tail->used = len;\n        \/\/ \u5185\u5b58\u62f7\u8d1d\n        memcpy(tail->buf, s, len);\n        listAddNodeTail(c->reply, tail);\n        c->reply_bytes += tail->size;\n\n        closeClientOnOutputBufferLimitReached(c, 1);\n    }}<\/pre>\n
    \u800c Redis \u8f93\u51fa buf \u4e3a 16k<\/p>\n
    \/\/ server.h#define PROTO_REPLY_CHUNK_BYTES (16*1024) \/* 16k output buffer *\/typedef struct client {\n    ...\n    char buf[PROTO_REPLY_CHUNK_BYTES];} client;<\/pre>\n
    \u8fd9\u610f\u5473\u7740 Redis \u65e0\u6cd5\u5355\u6b21\u8fd4\u56de\u54cd\u5e94\u6570\u636e\uff0c\u9700\u8981\u6ce8\u518c\u300c\u53ef\u5199\u4e8b\u4ef6\u300d\uff0c\u4ece\u800c\u89e6\u53d1\u591a\u6b21 write \u7cfb\u7edf\u8c03\u7528\u3002<\/p>\n
    \u8fd9\u91cc\u6709\u4e24\u4e2a\u8017\u65f6\u70b9\uff1a<\/p>\n
      \n
    • \n
      \u5206\u914d\u5927\u5185\u5b58\uff08\u4e5f\u53ef\u80fd\u91ca\u653e\u5185\u5b58\uff0c\u5982 DEL \u547d\u4ee4\uff09<\/p>\n<\/li>\n
    • \n
      \u89e6\u53d1\u591a\u6b21\u53ef\u5199\u4e8b\u4ef6\uff08\u9891\u7e41\u6267\u884c\u7cfb\u7edf\u8c03\u7528\uff0c\u5982 write\u3001epoll_wait\uff09<\/p>\n<\/li>\n<\/ul>\n
      \u90a3\u4e48\uff0c\u5982\u4f55\u627e\u51fa big key \u5462\uff1f<\/p>\n
      \u5982\u679c slow log \u51fa\u73b0\u4e86\u7b80\u5355\u547d\u4ee4\uff0c\u5982 GET\u3001SET\u3001DEL\uff0c\u5927\u6982\u7387\u662f\u51fa\u73b0\u4e86 big key\u3002<\/p>\n
      127.0.0.1:6379> SLOWLOG GET\n    3) (integer) 201323  \/\/ \u5355\u4f4d\u5fae\u5999\n    4) 1) \"GET\"\n       2) \"foo\"<\/pre>\n
      \u5176\u6b21\uff0c\u53ef\u4ee5\u901a\u8fc7 Redis \u5206\u6790\u5de5\u5177\u6765\u67e5\u627e big key\u3002<\/p>\n
      $ redis-cli --bigkeys -i 0.1\n...\n[00.00%] Biggest string found so far '\"foo\"' with 209715200 bytes\n\n-------- summary -------\n\nSampled 1 keys in the keyspace!\nTotal key length in bytes is 3 (avg len 3.00)\n\nBiggest string found '\"foo\"' has 209715200 bytes\n\n1 strings with 209715200 bytes (100.00% of keys, avg size 209715200.00)\n0 lists with 0 items (00.00% of keys, avg size 0.00)\n0 hashs with 0 fields (00.00% of keys, avg size 0.00)\n0 streams with 0 entries (00.00% of keys, avg size 0.00)\n0 sets with 0 members (00.00% of keys, avg size 0.00)\n0 zsets with 0 members (00.00% of keys, avg size 0.00)<\/pre>\n
      \u5bf9\u4e8e big key\uff0c\u6709\u4ee5\u4e0b\u51e0\u70b9\u5efa\u8bae\uff1a<\/p>\n
      1.\u4e1a\u52a1\u4e2d\u5c3d\u91cf\u907f\u514d big key \u51fa\u73b0\u3002\u5f53\u51fa\u73b0 big key \u65f6\uff0c\u4f60\u8981\u5224\u65ad\u8fd9\u6837\u8bbe\u8ba1\u662f\u5426\u5408\u7406\uff0c\u53c8\u6216\u8005\u662f\u51fa\u73b0\u4e86 bug\u3002<\/p>\n
      2.\u5c06 big key \u62c6\u5206\u4e3a\u591a\u4e2a\u5c0f key\u3002<\/p>\n
      3.\u4f7f\u7528\u66ff\u4ee3\u547d\u4ee4\u3002<\/p>\n
        \n
      • \n
        \u5982\u679c Redis \u7248\u672c\u5927\u4e8e 4.0\uff0c\u53ef\u4f7f\u7528 UNLINK \u547d\u4ee4\u66ff\u4ee3 DEL\u3002Redis \u7248\u672c\u5927\u4e8e 6.0\uff0c\u53ef\u5f00\u542f lazy-free \u673a\u5236\u3002\u5c06\u91ca\u653e\u5185\u5b58\u64cd\u4f5c\uff0c\u653e\u5230\u540e\u53f0\u7ebf\u7a0b\u6267\u884c\u3002<\/p>\n<\/li>\n
      • \n
        LRANGE\u3001HGETALL \u7b49\u66ff\u6362\u4e3a LSCAN\u3001HSCAN \u5206\u6b21\u83b7\u53d6\u3002<\/p>\n<\/li>\n<\/ul>\n
        \u4f46\u6211\u8fd8\u662f\u5efa\u8bae\u5728\u4e1a\u52a1\u4e2d\u907f\u514d big key\u3002<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"
        Redis\u4e3a\u4ec0\u4e48\u8981\u907f\u514dbig k...<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-202310","post","type-post","status-publish","format-standard","hentry","category-database"],"_links":{"self":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202310","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/comments?post=202310"}],"version-history":[{"count":0,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/posts\/202310\/revisions"}],"wp:attachment":[{"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/media?parent=202310"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/categories?post=202310"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/server.hk\/cnblog\/wp-json\/wp\/v2\/tags?post=202310"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}