{"id":4376,"date":"2020-07-07T19:15:52","date_gmt":"2020-07-07T11:15:52","guid":{"rendered":"https:\/\/damogame.cn\/wordpress\/?p=4376"},"modified":"2020-07-07T19:15:52","modified_gmt":"2020-07-07T11:15:52","slug":"lsm-tree-%e5%9f%ba%e6%9c%ac%e5%8e%9f%e7%90%86%e5%8f%8a%e5%ba%94%e7%94%a8","status":"publish","type":"post","link":"https:\/\/i007.cc\/wordpress\/archives\/4376","title":{"rendered":"LSM-tree \u57fa\u672c\u539f\u7406\u53ca\u5e94\u7528"},"content":{"rendered":"
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\u539f\u6587\u5730\u5740<\/a><\/div>\n
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<\/i>1<\/span>
LSM-tree \u5728 NoSQL \u7cfb\u7edf\u91cc\u975e\u5e38\u5e38\u89c1\uff0c\u57fa\u672c\u5df2\u7ecf\u6210\u4e3a\u5fc5\u9009\u65b9\u6848\u4e86\u3002\u4eca\u5929\u4ecb\u7ecd\u4e00\u4e0b LSM-tree \u7684\u4e3b\u8981\u601d\u60f3\uff0c\u518d\u4e3e\u4e00\u4e2a LevelDB \u7684\u4f8b\u5b50\u3002<\/p>\n

\u8f6c\u8f7d\u81ea\uff1ahttps:\/\/kuaibao.qq.com\/s\/20181105G13VZ000?refer=cp_1026<\/a><\/p>\n

LSM-tree<\/h3>\n

LSM-tree\u8d77\u6e90\u4e8e 1996 \u5e74\u7684\u4e00\u7bc7\u8bba\u6587\u300aThe Log-Structured Merge-Tree (LSM-Tree)\u300b\uff0c\u4eca\u5929\u7684\u5185\u5bb9\u548c\u56fe\u7247\u4e3b\u8981\u6765\u6e90\u4e8e FAST’16 \u7684\u300aWiscKey: Separating Keys from Values in SSD-conscious Storage\u300b\u3002<\/p>\n

\u5148\u770b\u540d\u5b57\uff0clog-structured\uff0c\u65e5\u5fd7\u7ed3\u6784\u7684\uff0c\u65e5\u5fd7\u662f\u8f6f\u4ef6\u7cfb\u7edf\u6253\u51fa\u6765\u7684\uff0c\u5c31\u8ddf\u4eba\u5199\u65e5\u8bb0\u4e00\u6837\uff0c\u4e00\u9875\u4e00\u9875\u5f80\u4e0b\u5199\uff0c\u800c\u4e14\u7cfb\u7edf\u5199\u65e5\u5fd7\u4e0d\u4f1a\u5199\u9519\uff0c\u6240\u4ee5\u4e0d\u9700\u8981\u66f4\u6539\uff0c\u53ea\u9700\u8981\u5728\u540e\u8fb9\u8ffd\u52a0\u5c31\u597d\u4e86\u3002\u5404\u79cd\u6570\u636e\u5e93\u7684\u5199\u524d\u65e5\u5fd7\u4e5f\u662f\u8ffd\u52a0\u578b\u7684\uff0c\u56e0\u6b64\u65e5\u5fd7\u7ed3\u6784\u7684\u57fa\u672c\u5c31\u6307\u4ee3\u8ffd\u52a0\u3002\u6ce8\u610f\u4ed6\u8fd8\u662f\u4e2a \u201cMerge-tree\u201d\uff0c\u4e5f\u5c31\u662f\u201c\u5408\u5e76-\u6811\u201d\uff0c\u5408\u5e76\u5c31\u662f\u628a\u591a\u4e2a\u5408\u6210\u4e00\u4e2a\u3002<\/p>\n

\u597d\uff0c\u4e0d\u626f\u6de1\u4e86\uff0c\u8bf4\u6b63\u6587\u4e86\u3002<\/p>\n

LSM-tree \u662f\u4e13\u95e8\u4e3a key-value \u5b58\u50a8\u7cfb\u7edf\u8bbe\u8ba1\u7684\uff0ckey-value \u7c7b\u578b\u7684\u5b58\u50a8\u7cfb\u7edf\u6700\u4e3b\u8981\u7684\u5c31\u4e24\u4e2a\u4e2a\u529f\u80fd\uff0cput\uff08k\uff0cv\uff09\uff1a\u5199\u5165\u4e00\u4e2a\uff08k\uff0cv\uff09\uff0cget\uff08k\uff09\uff1a\u7ed9\u5b9a\u4e00\u4e2a k \u67e5\u627e v\u3002<\/p>\n

LSM-tree \u6700\u5927\u7684\u7279\u70b9\u5c31\u662f\u5199\u5165\u901f\u5ea6\u5feb\uff0c\u4e3b\u8981\u5229\u7528\u4e86\u78c1\u76d8\u7684\u987a\u5e8f\u5199\uff0cpk\u6389\u4e86\u9700\u8981\u968f\u673a\u5199\u5165\u7684 B-tree\u3002\u5173\u4e8e\u78c1\u76d8\u7684\u987a\u5e8f\u548c\u968f\u673a\u5199\u53ef\u4ee5\u53c2\u8003\uff1a\u300a\u786c\u76d8\u7684\u5404\u79cd\u6982\u5ff5\u300b<\/p>\n

\u4e0b\u56fe\u662f LSM-tree \u7684\u7ec4\u6210\u90e8\u5206\uff0c\u662f\u4e00\u4e2a\u591a\u5c42\u7ed3\u6784\uff0c\u5c31\u66f4\u4e00\u4e2a\u6811\u4e00\u6837\uff0c\u4e0a\u5c0f\u4e0b\u5927\u3002\u9996\u5148\u662f\u5185\u5b58\u7684 C0 \u5c42\uff0c\u4fdd\u5b58\u4e86\u6240\u6709\u6700\u8fd1\u5199\u5165\u7684 \uff08k\uff0cv\uff09\uff0c\u8fd9\u4e2a\u5185\u5b58\u7ed3\u6784\u662f\u6709\u5e8f\u7684\uff0c\u5e76\u4e14\u53ef\u4ee5\u968f\u65f6\u539f\u5730\u66f4\u65b0\uff0c\u540c\u65f6\u652f\u6301\u968f\u65f6\u67e5\u8be2\u3002\u5269\u4e0b\u7684 C1 \u5230 Ck \u5c42\u90fd\u5728\u78c1\u76d8\u4e0a\uff0c\u6bcf\u4e00\u5c42\u90fd\u662f\u4e00\u4e2a\u5728 key \u4e0a\u6709\u5e8f\u7684\u7ed3\u6784\u3002<\/p>\n

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LSM-tree<\/div>\n<\/div>\n

\u5199\u5165\u6d41\u7a0b\uff1a<\/strong>\u4e00\u4e2a put\uff08k\uff0cv\uff09 \u64cd\u4f5c\u6765\u4e86\uff0c\u9996\u5148\u8ffd\u52a0\u5230\u5199\u524d\u65e5\u5fd7\uff08Write Ahead Log\uff0c\u4e5f\u5c31\u662f\u771f\u6b63\u5199\u5165\u4e4b\u524d\u8bb0\u5f55\u7684\u65e5\u5fd7\uff09\u4e2d\uff0c\u63a5\u4e0b\u6765\u52a0\u5230 C0 \u5c42\u3002\u5f53 C0 \u5c42\u7684\u6570\u636e\u8fbe\u5230\u4e00\u5b9a\u5927\u5c0f\uff0c\u5c31\u628a C0 \u5c42 \u548c C1 \u5c42\u5408\u5e76\uff0c\u7c7b\u4f3c\u5f52\u5e76\u6392\u5e8f\uff0c\u8fd9\u4e2a\u8fc7\u7a0b\u5c31\u662fCompaction\uff08\u5408\u5e76\uff09\u3002\u5408\u5e76\u51fa\u6765\u7684\u65b0\u7684 new-C1 \u4f1a\u987a\u5e8f\u5199\u78c1\u76d8\uff0c\u66ff\u6362\u6389\u539f\u6765\u7684 old-C1\u3002\u5f53 C1 \u5c42\u8fbe\u5230\u4e00\u5b9a\u5927\u5c0f\uff0c\u4f1a\u7ee7\u7eed\u548c\u4e0b\u5c42\u5408\u5e76\u3002\u5408\u5e76\u4e4b\u540e\u6240\u6709\u65e7\u6587\u4ef6\u90fd\u53ef\u4ee5\u5220\u6389\uff0c\u7559\u4e0b\u65b0\u7684\u3002<\/p>\n

\u6ce8\u610f\u6570\u636e\u7684\u5199\u5165\u53ef\u80fd\u91cd\u590d\uff0c\u65b0\u7248\u672c\u9700\u8981\u8986\u76d6\u8001\u7248\u672c\u3002\u4ec0\u4e48\u53eb\u65b0\u7248\u672c\uff0c\u6211\u5148\u5199\uff08a=1\uff09\uff0c\u518d\u5199\uff08a=233\uff09\uff0c233 \u5c31\u662f\u65b0\u7248\u672c\u4e86\u3002\u5047\u5982 a \u8001\u7248\u672c\u5df2\u7ecf\u5230 Ck \u5c42\u4e86\uff0c\u8fd9\u65f6\u5019 C0 \u5c42\u6765\u4e86\u4e2a\u65b0\u7248\u672c\uff0c\u8fd9\u4e2a\u65f6\u5019\u4e0d\u4f1a\u53bb\u7ba1\u5e95\u4e0b\u7684\u6587\u4ef6\u6709\u6ca1\u6709\u8001\u7248\u672c\uff0c\u8001\u7248\u672c\u7684\u6e05\u7406\u662f\u5728\u5408\u5e76\u7684\u65f6\u5019\u505a\u7684\u3002<\/p>\n

\u5199\u5165\u8fc7\u7a0b\u57fa\u672c\u53ea\u7528\u5230\u4e86\u5185\u5b58\u7ed3\u6784\uff0cCompaction \u53ef\u4ee5\u540e\u53f0\u5f02\u6b65\u5b8c\u6210\uff0c\u4e0d\u963b\u585e\u5199\u5165\u3002<\/p>\n

\u67e5\u8be2\u6d41\u7a0b\uff1a<\/strong>\u5728\u5199\u5165\u6d41\u7a0b\u4e2d\u53ef\u4ee5\u770b\u5230\uff0c\u6700\u65b0\u7684\u6570\u636e\u5728 C0 \u5c42\uff0c\u6700\u8001\u7684\u6570\u636e\u5728 Ck \u5c42\uff0c\u6240\u4ee5\u67e5\u8be2\u4e5f\u662f\u5148\u67e5 C0 \u5c42\uff0c\u5982\u679c\u6ca1\u6709\u8981\u67e5\u7684 k\uff0c\u518d\u67e5 C1\uff0c\u9010\u5c42\u67e5\u3002<\/p>\n

\u4e00\u6b21\u67e5\u8be2\u53ef\u80fd\u9700\u8981\u591a\u6b21\u5355\u70b9\u67e5\u8be2\uff0c\u7a0d\u5fae\u6162\u4e00\u4e9b\u3002\u6240\u4ee5 LSM-tree \u4e3b\u8981\u9488\u5bf9\u7684\u573a\u666f\u662f\u5199\u5bc6\u96c6\u3001\u5c11\u91cf\u67e5\u8be2\u7684\u573a\u666f\u3002<\/p>\n

LSM-tree \u88ab\u7528\u5728\u5404\u79cd\u952e\u503c\u6570\u636e\u5e93\u4e2d\uff0c\u5982 LevelDB\uff0cRocksDB\uff0c\u8fd8\u6709\u5206\u5e03\u5f0f\u884c\u5f0f\u5b58\u50a8\u6570\u636e\u5e93 Cassandra \u4e5f\u7528\u4e86 LSM-tree \u7684\u5b58\u50a8\u67b6\u6784\u3002<\/p>\n

LevelDB<\/h3>\n

\u5176\u5b9e\u5149\u770b\u4e0a\u8fb9\u8fd9\u4e2a\u6a21\u578b\u8fd8\u6709\u70b9\u95ee\u9898\uff0c\u6bd4\u5982\u5c06 C0 \u8ddf C1 \u5408\u5e76\u4e4b\u540e\uff0c\u65b0\u7684\u5199\u5165\u600e\u4e48\u529e\uff1f\u53e6\u5916\uff0c\u6bcf\u6b21\u90fd\u8981\u5c06 C0 \u8ddf C1 \u5408\u5e76\uff0c\u8fd9\u4e2a\u540e\u53f0\u6574\u7406\u4e5f\u5f88\u9ebb\u70e6\u554a\u3002\u8fd9\u91cc\u4ee5 LevelDB \u4e3a\u4f8b\uff0c\u770b\u4e00\u4e0b\u5b9e\u9645\u7cfb\u7edf\u662f\u600e\u4e48\u5229\u7528 LSM-tree \u7684\u601d\u60f3\u7684\u3002<\/p>\n

\u4e0b\u8fb9\u8fd9\u4e2a\u56fe\u662f LevelDB \u7684\u67b6\u6784\uff0c\u9996\u5148\uff0cLSM-tree \u88ab\u5206\u6210\u4e09\u79cd\u6587\u4ef6\uff0c\u7b2c\u4e00\u79cd\u662f\u5185\u5b58\u4e2d\u7684\u4e24\u4e2a memtable\uff0c\u4e00\u4e2a\u662f\u6b63\u5e38\u7684\u63a5\u6536\u5199\u5165\u8bf7\u6c42\u7684 memtable\uff0c\u4e00\u4e2a\u662f\u4e0d\u53ef\u4fee\u6539\u7684immutable memtable\u3002<\/p>\n

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LevelDB<\/div>\n<\/div>\n

\u53e6\u5916\u4e00\u90e8\u5206\u662f\u78c1\u76d8\u4e0a\u7684 SStable \uff08Sorted String Table\uff09\uff0c\u6709\u5e8f\u5b57\u7b26\u4e32\u8868\uff0c\u8fd9\u4e2a\u6709\u5e8f\u7684\u5b57\u7b26\u4e32\u5c31\u662f\u6570\u636e\u7684 key\u3002SStable \u4e00\u5171\u6709\u4e03\u5c42\uff08L0 \u5230 L6\uff09\u3002\u4e0b\u4e00\u5c42\u7684\u603b\u5927\u5c0f\u9650\u5236\u662f\u4e0a\u4e00\u5c42\u7684 10 \u500d\u3002<\/p>\n

\u5199\u5165\u6d41\u7a0b\uff1a<\/strong>\u9996\u5148\u5c06\u5199\u5165\u64cd\u4f5c\u52a0\u5230\u5199\u524d\u65e5\u5fd7\u4e2d\uff0c\u63a5\u4e0b\u6765\u628a\u6570\u636e\u5199\u5230 memtable\u4e2d\uff0c\u5f53 memtable \u6ee1\u4e86\uff0c\u5c31\u5c06\u8fd9\u4e2a memtable \u5207\u6362\u4e3a\u4e0d\u53ef\u66f4\u6539\u7684 immutable memtable\uff0c\u5e76\u65b0\u5f00\u4e00\u4e2a memtable \u63a5\u6536\u65b0\u7684\u5199\u5165\u8bf7\u6c42\u3002\u800c\u8fd9\u4e2a immutable memtable \u5c31\u53ef\u4ee5\u5237\u78c1\u76d8\u4e86\u3002\u8fd9\u91cc\u5237\u78c1\u76d8\u662f\u76f4\u63a5\u5237\u6210 L0 \u5c42\u7684 SSTable \u6587\u4ef6\uff0c\u5e76\u4e0d\u76f4\u63a5\u8ddf L0 \u5c42\u7684\u6587\u4ef6\u5408\u5e76\u3002<\/p>\n

\u6bcf\u4e00\u5c42\u7684\u6240\u6709\u6587\u4ef6\u603b\u5927\u5c0f\u662f\u6709\u9650\u5236\u7684\uff0c\u6bcf\u4e0b\u4e00\u5c42\u5927\u5341\u500d\u3002\u4e00\u65e6\u67d0\u4e00\u5c42\u7684\u603b\u5927\u5c0f\u8d85\u8fc7\u9608\u503c\u4e86\uff0c\u5c31\u9009\u62e9\u4e00\u4e2a\u6587\u4ef6\u548c\u4e0b\u4e00\u5c42\u7684\u6587\u4ef6\u5408\u5e76\u3002\u5c31\u50cf\u73a9 2048 \u4e00\u6837\uff0c\u6bcf\u6b21\u80fd\u89e6\u53d1\u5408\u5e76\u90fd\u4f1a\u89e6\u53d1\uff0c\u8fd9\u5728 2048 \u91cc\u662f\u6700\u723d\u7684\uff0c\u4f46\u662f\u5728\u7cfb\u7edf\u91cc\u662f\u633a\u9ebb\u70e6\u7684\u4e8b\uff0c\u56e0\u4e3a\u9700\u8981\u5012\u817e\u7684\u6570\u636e\u591a\uff0c\u4f46\u662f\u4e5f\u4e0d\u662f\u574f\u4e8b\uff0c\u56e0\u4e3a\u8fd9\u6837\u53ef\u4ee5\u52a0\u901f\u67e5\u8be2\u3002<\/p>\n

\u8fd9\u91cc\u6ce8\u610f\uff0c\u6240\u6709\u4e0b\u4e00\u5c42\u88ab\u5f71\u54cd\u5230\u7684\u6587\u4ef6\u90fd\u4f1a\u53c2\u4e0e Compaction\u3002\u5408\u5e76\u4e4b\u540e\uff0c\u4fdd\u8bc1 L1 \u5230 L6 \u5c42\u7684\u6bcf\u4e00\u5c42\u7684\u6570\u636e\u90fd\u662f\u5728 key \u4e0a\u5168\u5c40\u6709\u5e8f\u7684\u3002\u800c L0 \u5c42\u662f\u53ef\u4ee5\u6709\u91cd\u53e0\u7684\u3002<\/p>\n

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Compaction<\/div>\n<\/div>\n

\u4e0a\u56fe\u662f\u4e2a\u4f8b\u5b50\uff0c\u4e00\u4e2a immutable memtable \u5237\u5230 L0 \u5c42\u540e\uff0c\u89e6\u53d1 L0 \u548c L1 \u7684\u5408\u5e76\uff0c\u5047\u5982\u9ec4\u8272\u7684\u6587\u4ef6\u662f\u6d89\u53ca\u672c\u6b21\u5408\u5e76\u7684\uff0c\u5408\u5e76\u540e\uff0cL0 \u5c42\u7684\u5c31\u88ab\u5220\u6389\u4e86\uff0cL1 \u5c42\u7684\u5c31\u66f4\u65b0\u4e86\uff0cL1 \u5c42\u8fd8\u662f\u5168\u5c40\u6709\u5e8f\u7684\uff0c\u4e09\u4e2a\u6587\u4ef6\u7684\u6570\u636e\u987a\u5e8f\u662f abcdef\u3002<\/p>\n

\u867d\u7136 L0 \u5c42\u7684\u591a\u4e2a\u6587\u4ef6\u5728\u540c\u4e00\u5c42\uff0c\u4f46\u4e5f\u662f\u6709\u5148\u540e\u5173\u7cfb\u7684\uff0c\u540e\u9762\u7684\u540c\u4e2a key \u7684\u6570\u636e\u4e5f\u4f1a\u8986\u76d6\u524d\u9762\u7684\u3002\u8fd9\u91cc\u600e\u4e48\u533a\u5206\u5462\uff1f\u4e3a\u6bcf\u4e2akey-value\u52a0\u4e2a\u7248\u672c\u53f7\u3002\u6240\u4ee5\u5728 Compaction \u65f6\u5019\u5e94\u8be5\u53ea\u4f1a\u7559\u4e0b\u6700\u65b0\u7684\u7248\u672c\u3002<\/p>\n

\u67e5\u8be2\u6d41\u7a0b\uff1a<\/strong>\u5148\u67e5memtable\uff0c\u518d\u67e5 immutable memtable\uff0c\u7136\u540e\u67e5 L0 \u5c42\u7684\u6240\u6709\u6587\u4ef6\uff0c\u6700\u540e\u4e00\u5c42\u4e00\u5c42\u5f80\u4e0b\u67e5\u3002<\/p>\n

LSM-tree\u8bfb\u5199\u653e\u5927<\/h3>\n

\u8bfb\u5199\u653e\u5927\uff08read and write amplification\uff09\u662f LSM-tree \u7684\u4e3b\u8981\u95ee\u9898\uff0c\u8fd9\u4e48\u5b9a\u4e49\u7684\uff1a\u8bfb\u5199\u653e\u5927 = \u78c1\u76d8\u4e0a\u5b9e\u9645\u8bfb\u5199\u7684\u6570\u636e\u91cf \/ \u7528\u6237\u9700\u8981\u7684\u6570\u636e\u91cf\u3002\u6ce8\u610f\u662f\u548c\u78c1\u76d8\u4ea4\u4e92\u7684\u6570\u636e\u91cf\u624d\u7b97\uff0c\u8fd9\u4efd\u6570\u636e\u5728\u5185\u5b58\u91cc\u8ba1\u7b97\u4e86\u591a\u5c11\u6b21\u662f\u4e0d\u5173\u5fc3\u7684\u3002\u6bd4\u5982\u7528\u6237\u672c\u6765\u8981\u5199 1KB \u6570\u636e\uff0c\u7ed3\u679c\u4f60\u5728\u5185\u5b58\u91cc\u8ba1\u7b97\u4e861\u4e2a\u5c0f\u65f6\uff0c\u6700\u540e\u5f80\u78c1\u76d8\u5199\u4e86 10KB \u7684\u6570\u636e\uff0c\u5199\u653e\u5927\u5c31\u662f 10\uff0c\u8bfb\u4e5f\u7c7b\u4f3c\u3002<\/p>\n

\u5199\u653e\u5927\uff1a\u6211\u4eec\u4ee5 RocksDB \u7684 Level Style Compaction \u673a\u5236\u4e3a\u4f8b\uff0c\u8fd9\u79cd\u5408\u5e76\u673a\u5236\u6bcf\u6b21\u62ff\u4e0a\u4e00\u5c42\u7684\u6240\u6709\u6587\u4ef6\u548c\u4e0b\u4e00\u5c42\u5408\u5e76\uff0c\u4e0b\u4e00\u5c42\u5927\u5c0f\u662f\u4e0a\u4e00\u5c42\u7684 r \u500d\u3002\u8fd9\u6837\u5355\u6b21\u5408\u5e76\u7684\u5199\u653e\u5927\u5c31\u662f r \u500d\uff0c\u8fd9\u91cc\u662f r \u500d\u8fd8\u662f r+1 \u500d\u8ddf\u5177\u4f53\u5b9e\u73b0\u6709\u5173\uff0c\u6211\u4eec\u4e3e\u4e2a\u4f8b\u5b50\u3002<\/p>\n

\u5047\u5982\u73b0\u5728\u6709\u4e09\u5c42\uff0c\u6587\u4ef6\u5927\u5c0f\u5206\u522b\u662f\uff1a9\uff0c90\uff0c900\uff0cr=10\u3002\u53c8\u5199\u4e86\u4e2a 1\uff0c\u8fd9\u65f6\u5019\u5c31\u4f1a\u4e0d\u65ad\u5408\u5e76\uff0c1+9=10\uff0c10+90=100\uff0c100+900=1000\u3002\u603b\u5171\u5199\u4e86 10+100+1000\u3002\u6309\u7406\u6765\u8bf4\u5199\u653e\u5927\u5e94\u8be5\u4e3a 1110\/1\uff0c\u4f46\u662f\u5404\u79cd\u8bba\u6587\u91cc\u4e0d\u662f\u8fd9\u4e48\u8bf4\u7684\uff0c\u8bba\u6587\u91cc\u8bf4\u7684\u662f\u7b49\u53f7\u53f3\u8fb9\u7684\u6bd4\u4e0a\u52a0\u53f7\u5de6\u8fb9\u7684\u548c\uff0c\u4e5f\u5c31\u662f10\/1 + 100\/10 + 1000\/100 = 30 = r * level\u3002\u4e2a\u4eba\u611f\u89c9\u5199\u653e\u5927\u662f\u4e00\u4e2a\u8fc7\u7a0b\uff0c\u7528\u4e00\u4e2a\u6570\u5b57\u8861\u91cf\u4e0d\u592a\u51c6\u786e\uff0c\u800c\u4e14\u8fd9\u4e5f\u53ea\u662f\u6700\u574f\u60c5\u51b5\u3002<\/p>\n

\u8bfb\u653e\u5927\uff1a\u4e3a\u4e86\u67e5\u8be2\u4e00\u4e2a 1KB \u7684\u6570\u636e\u3002\u6700\u574f\u9700\u8981\u8bfb L0 \u5c42\u7684 8 \u4e2a\u6587\u4ef6\uff0c\u518d\u8bfb L1 \u5230 L6 \u7684\u6bcf\u4e00\u4e2a\u6587\u4ef6\uff0c\u4e00\u5171 14 \u4e2a\u6587\u4ef6\u3002\u800c\u6bcf\u4e00\u4e2a\u6587\u4ef6\u5185\u90e8\u9700\u8981\u8bfb 16KB \u7684\u7d22\u5f15\uff0c4KB\u7684\u5e03\u9686\u8fc7\u6ee4\u5668\uff0c4KB\u7684\u6570\u636e\u5757\uff08\u770b\u4e0d\u61c2\u4e0d\u91cd\u8981\uff0c\u53ea\u8981\u77e5\u9053\u4ece\u4e00\u4e2aSSTable\u91cc\u67e5\u4e00\u4e2akey\uff0c\u9700\u8981\u8bfb\u8fd9\u4e48\u591a\u4e1c\u897f\u5c31\u53ef\u4ee5\u4e86\uff09\u3002\u4e00\u5171 24*14\/1=336\u500d\u3002key-value \u8d8a\u5c0f\u8bfb\u653e\u5927\u8d8a\u5927\u3002<\/p>\n

\u603b\u7ed3<\/h3>\n

\u5173\u4e8e LSM-tree \u7684\u5185\u5bb9\u548c LevelDB \u7684\u8bbe\u8ba1\u601d\u60f3\u5c31\u4ecb\u7ecd\u5b8c\u4e86\uff0c\u4e3b\u8981\u5305\u62ec\u5199\u524d\u65e5\u5fd7 WAL\uff0cmemtable\uff0cSStable \u4e09\u4e2a\u90e8\u5206\u3002\u9010\u5c42\u5408\u5e76\uff0c\u9010\u5c42\u67e5\u627e\u3002LSM-tree \u7684\u4e3b\u8981\u52a3\u52bf\u662f\u8bfb\u5199\u653e\u5927\uff0c\u5173\u4e8e\u8bfb\u5199\u653e\u5927\u53ef\u4ee5\u901a\u8fc7\u4e00\u4e9b\u5176\u4ed6\u7b56\u7565\u53bb\u964d\u4f4e\u3002<\/p>\n<\/article>\n","protected":false},"excerpt":{"rendered":"

\u539f\u6587\u5730\u5740 12019.05.18 10:<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"colormag_page_container_layout":"default_layout","colormag_page_sidebar_layout":"default_layout","footnotes":""},"categories":[],"tags":[119],"class_list":["post-4376","post","type-post","status-publish","format-standard","hentry","tag-03-"],"_links":{"self":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/4376","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/comments?post=4376"}],"version-history":[{"count":0,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/posts\/4376\/revisions"}],"wp:attachment":[{"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/media?parent=4376"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/categories?post=4376"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/i007.cc\/wordpress\/wp-json\/wp\/v2\/tags?post=4376"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}