\u9664\u4e86redis\u8fd9\u7c7b\u5355\u7ebf\u7a0b\u7684\u6570\u636e\u5e93\uff0c\u4e00\u822c\u7684\u591a\u7ebf\u7a0b\u6570\u636e\u5e93\u5728\u8bfb\u5199\u6570\u636e\u7684\u65f6\u5019\u5fc5\u7136\u4f1a\u6d89\u53ca\u5230\u8d44\u6e90\u7684\u62a2\u5360\u6216\u540c\u65f6\u64cd\u4f5c\u4e00\u884c\u6570\u636e\u5e26\u6765\u7684\u7248\u672c\u63a7\u5236\u95ee\u9898\u3002\u8bf4\u767d\u4e86\u5c31\u662f\uff0c\u67d0\u6b21\u8bfb\u53ef\u4ee5\u8bfb\u5230\u54ea\u4e9b\u5199\u3001\u9700\u8981\u5c4f\u853d\u54ea\u4e9b\u5199\u3001\u9700\u8981\u6682\u65f6\u963b\u585e\u4f4f\u54ea\u4e9b\u8bf7\u6c42\u3002\u4e8e\u662f\u5c31\u9700\u8981\u5c06\u8bfb\u5199\u8bf7\u6c42\u7ef4\u62a4\u51fa\u4e00\u4e2a\u201c\u987a\u5e8f\u201d\u6765\u3002<\/p>\n
<\/p>\n
Cassandra\u4e0d\u9700\u8981\u592a\u591a\u7684\u4fdd\u8bc1\u8bfb\u5199\u987a\u5e8f\uff0c\u56e0\u4e3a\u6700\u540e\u90fd\u662f\u9760\u65f6\u95f4\u6233\u63a7\u5236\u7248\u672c\u3002\u9700\u8981\u8003\u8651\u987a\u5e8f\u7684\u4e3b\u8981\u662f\u6d89\u53ca\u5230MemTable\u9700\u8981switch\u6216\u8005flush\u7684\u65f6\u5019\u4fdd\u8bc1\u4e0d\u4f1a\u56e0\u4e3aMemTable\u88ab\u6e05\u7a7a\u800c\u5bfc\u81f4\u8bfb\u5199\u5931\u8d25\u3002\u57282.0\u548c\u4e4b\u524d\u7684\u7248\u672c\uff0c\u76f4\u63a5\u901a\u8fc7 ReentrantReadWriteLock\u6765\u52a0\u9501\u7ef4\u62a4\uff0c\u8bfb\u5199\u64cd\u4f5c\u90fd\u662f\u8bfb\u9501\uff0c\u5207\u6362MemTable\u662f\u5199\u9501\u3002\u57282.1\u5f00\u59cb\u7528\u4e86\u4e00\u4e2aOpOrder\u7684\u6982\u5ff5\u6765\u65e0\u9501\u5730\u63a7\u5236\u987a\u5e8f\uff0c\u53ea\u9700\u8981\u5728\u9700\u8981\u63a7\u5236\u987a\u5e8f\u7684\u5730\u65b9\u7528jdk7\u7684\u65b0\u8bed\u6cd5\u7cd6\u6765\u83b7\u53d6\u4e00\u4e2a\u5bf9\u8c61\u5e76\u81ea\u52a8close\uff1a<\/p>\n
try (OpOrder.Group op = writeOrdering.start()){\r\n \/\/do anything\r\n}\r\n<\/pre>\n\u82e5\u5e72\u4e2a\u901a\u8fc7\u8fd9\u79cd\u65b9\u5f0f\u7ef4\u62a4\u7684\u64cd\u4f5c\u88ab\u56ca\u62ec\u5728\u4e00\u4e2aGroup\u5185\uff0c\u6bcf\u4e2aGroup\u5185\u90e8\u901a\u8fc7cas\u7ef4\u62a4\u4e00\u4e2a\u539f\u5b50\u8ba1\u6570\u5668\uff0c\u53ef\u4ee5\u7406\u89e3\u4e3astart\u4e00\u6b21+1\uff0cclose\u4e00\u6b21-1\u3002\u9700\u8981\u5728\u82e5\u5e72\u6b21\u64cd\u4f5c\u7684\u5e8f\u5217\u4e2d\u5236\u9020\u4e00\u4e2a\u95f4\u9694\u70b9\u65f6\u2014\u2014\u6bd4\u5982\u5f53MemTable\u9700\u8981flush\u65f6\uff0c\u786e\u4fdd\u67d0\u6b21\u5199\u5165\u53ca\u4e4b\u524d\u7684\u8bfb\u53d6\u8fd8\u53ef\u4ee5\u5199\u5165\u8fd9\u4e2aMemTable\uff0c\u7b49\u90fd\u5199\u5b8c\u4e86\u624dflush\uff0c\u5e76\u786e\u4fdd\u4e0b\u4e00\u6b21\u5199\u5165\u5c31\u9700\u8981\u53bb\u5199\u5176\u4ed6\u7684MemTable \u2014\u2014\u4e5f\u5c31\u7c7b\u4f3c\u4e4b\u524d\u9700\u8981\u83b7\u53d6\u5199\u9501\u7684\u65f6\u5019\uff0c\u6267\u884c\u4e24\u4e2a\u64cd\u4f5c\u2014\u2014\u83b7\u53d6\u548c\u7b49\u5f85\uff1a<\/p>\n
writeBarrier = writeOrder.newBarrier();\r\nwriteBarrier.issue();\r\n\r\nwriteBarrier.await();\r\n<\/pre>\n\u5728\u8fd9\u4e2aOpOrder\u5bf9\u8c61\u4e2d\u65b0\u5efa\u4e00\u4e2aBarrier\uff0c\u5e76\u5c06\u8fd9\u4e2aBarrier issue\uff08\u6ca1issue\u7684barrier\u4e0d\u5f71\u54cd\u8fd9\u4e2aOpOrder\uff09\u3002issue\u64cd\u4f5c\u4f1a\u5c06OpOrder\u5f53\u524d\u7684Group\u8fc7\u671f\uff0c\u4e4b\u540e\u518d\u6267\u884cstart\u8fd4\u56de\u7684\u4f1a\u662f\u4e0b\u4e00\u4e2a\u65b0\u7684Group\u3002\u8fc7\u671f\u7684Group\u7ee7\u7eed\u76d1\u63a7\u8ba1\u6570\u5668\uff0c\u4e00\u65e6\u5176\u5bf9\u5e94\u7684\u5404\u79cd\u64cd\u4f5c\u90fdclose\u6389\uff0c\u5219\u8fd9\u4e2aGroup\u7684\u6240\u6709\u64cd\u4f5c\u90fd\u6267\u884c\u5b8c\u6bd5\uff0c\u8fd9\u65f6\u4f1a\u5c06\u81ea\u5df1unlink\u3002Barrier\u88abissue\u540e\u53ef\u4ee5\u5728\u9700\u8981\u7684\u65f6\u5019\u6267\u884cawait\uff0c\u4e5f\u5c31\u662f\u963b\u585e\u7b49\u5f85\u4e4b\u524d\u7684Group unlink\u3002\u540c\u65f6\u6bcf\u4e2agroup\u5bf9\u8c61\u4e5f\u53ef\u4ee5\u8ddf\u67d0\u4e2abarrier\u6bd4\u5bf9\uff0c\u5982\u679cgroup\u00a0“after” barrier\uff0c\u5c31\u610f\u5473\u7740\u4e0d\u80fd\u8fdb\u884c\u5bf9\u5e94\u7684\u64cd\u4f5c\u3002\u6bd4\u5982\u67d0\u4e2aMemTable\u7684barrier “before” \u67d0\u4e2a\u5199\u5165\u64cd\u4f5c\u7684Group\uff0c\u90a3\u4e48\u8fd9\u4e2a\u5199\u5165\u64cd\u4f5c\u5c31\u4e0d\u80fd\u5f80\u8fd9\u4e2aMemTable\u5199\uff0c\u9700\u8981\u627e\u522b\u7684MemTable\u5185\u5b58\u6c60\u3002<\/p>\n
\u8bfb\u53d6\u7684\u65f6\u5019\u903b\u8f91\u66f4\u7b80\u5355\uff0c\u6bcf\u4e2aGroup\u4e0d\u9700\u8981\u5224\u65ad\u548cbarrier\u7684\u5173\u7cfb\uff0c\u800c\u662f\u4e0a\u5c42\u903b\u8f91\u786e\u4fdd\u6bcf\u4e2aMemTable\u5728flush\u540e\u3001\u5220\u9664\u524d\uff0c\u7b49\u5f85\u8fd9\u4e2a\u65f6\u95f4\u70b9\u4e4b\u524d\u5f00\u542f\u7684\u8bfb\u53d6\u64cd\u4f5c\u5b8c\u6210\uff08\u5373\u67d0\u4e2areadBarrier\u7b49\u5f85readOrder\u7684\u8fd9\u4e2agroup\u5168\u90e8close\uff09\u518d\u5220\u6389\u8fd9\u4e2aMemTable\u5373\u53ef\u3002\u6807\u8bb0\u4e3aflush\u7684MemTable\u76f8\u5f53\u4e8e\u53d8\u6210\u53ea\u8bfb\u3002<\/p>\n
\u6b64\u5916\u5728Commitlog\u5c42\u9762\uff0c\u7ef4\u62a4\u4e86\u4e00\u4e2a\u987a\u5e8f\u53ebReplayPosition\u3002\u5185\u90e8\u5206segment\u548cposition\u3002\u540e\u8005\u662f\u4e2a\u539f\u5b50int\u6765\u4fdd\u8bc1\u6bcf\u6761commit log\u6709\u9012\u589e\u7684id\u3002\u540c\u65f6\u6bcf\u4e2aSSTable\u4f1a\u4fdd\u5b58\u81ea\u5df1\u6570\u636e\u6240\u5bf9\u5e94\u7684\u6700\u5927\u7684ReplayPosition\u3002\u8fd9\u6837\u5f53\u91cd\u542f\u8bfblog\u6062\u590d\u65f6\u76f4\u63a5\u4ece\u5bf9\u5e94segment\u7684\u6700\u5927\u7684position+1\u5f00\u59cb\u8bfb\u5373\u53ef\u3002<\/p>\n
<\/p>\n
\u7136\u540e\u662fHBase\u3002<\/p>\n
HBase\u6709region\u7684\u6982\u5ff5\uff0c\u5728HRegion\u5c42\u9762\u9996\u5148\u8981\u4fdd\u8bc1\u5404\u79cd\u589e\u5220\u6539\u67e5\u548cregion\u7684split\u4e0d\u51b2\u7a81\u3002\u4e8e\u662f\u7528\u4e86\u4e00\u4e2a\u8bfb\u5199\u9501\u6765\u4fdd\u8bc1\u3002\u5199\u9501\u53ea\u88absplit\u4e4b\u7c7b\u7684\u9501\u4f4f\uff0c\u5176\u4ed6\u7684\u666e\u901a\u64cd\u4f5c\u5305\u62eccompaction\u90fd\u662f\u9501\u4f4f\u8bfb\u9501\u3002\u611f\u89c9\u4e0a\u4f3c\u4e4e\u53ef\u4ee5\u4e5f\u6539\u6210OpOrder\u8fd9\u79cd\u65e0\u9501\u7684\u5f62\u5f0f\uff1f\u4e0d\u77e5\u9053\u4e24\u8005\u7684\u6027\u80fd\u5dee\u591a\u5c11\u3002<\/p>\n
\u5728\u5199\u64cd\u4f5c\u7684\u65f6\u5019\uff0cregion\u4f1a\u4ee5\u884c\u548c\u7ebf\u7a0b\u4e3a\u5355\u4f4d\u7ef4\u62a4\u9501\uff0c\u4e00\u4e2aConcurrentHashMap<Row,RowLock>\u6765\u5b58\u3002\u53d6\u7684\u65f6\u5019\u8981\u4fdd\u8bc1\u62ff\u51fa\u6765\u7684\u9501\u662f\u672c\u7ebf\u7a0b\u653e\u7684\uff0c\u5982\u679c\u4e0d\u662f\u9700\u8981\u7b49\u5bf9\u5e94\u7ebf\u7a0b\u91ca\u653e\u3002\u4e0d\u8fc7\u6ca1\u592a\u4ed4\u7ec6\u770b\u6ca1\u660e\u767d\u5565\u65f6\u5019\u4f1a\u5bfc\u81f4\u4e00\u4e2a\u7ebf\u7a0b\u53cd\u590d\u62ff\u9501\u3002\u62ff\u5230\u9501\u4e4b\u540e\u83b7\u53d6\u5f53\u524d\u7cfb\u7edf\u65f6\u95f4\u6233\uff08\u8c8c\u4f3c\u76f4\u63a5\u62ffSystem\u7684\uff0c\u4e0d\u77e5\u9053\u9047\u5230\u95f0\u79d2\u6216\u8005\u65f6\u95f4\u88ab\u4fee\u6539\u4e4b\u7c7b\u60c5\u51b5\u5982\u4f55\u5904\u7406\uff09\u4f5c\u4e3aCell\u5185\u90e8\u7684\u5404\u79cd\u65f6\u95f4\u6233\u3002\u7136\u540e\u62ff\u4e00\u4e2a”updateLock”\u8bfb\u5199\u9501\u7684\u8bfb\u9501\uff0c\u8fd9\u4e2a\u9501\u548cCassandra2.0\u7684\u8bfb\u5199\u9501\u7528\u5904\u5dee\u4e0d\u591a\uff0c\u8d1f\u8d23\u4fdd\u8bc1MemTable\u7684flush\u4e0d\u4f1a\u5f71\u54cd\u5199\u64cd\u4f5c\uff0c\u5e94\u8be5\u4e5f\u662f\u53ef\u4ee5\u6539\u6210\u7c7b\u4f3cOpOrder\u7684\u65e0\u9501\u7248\u672c\u7684\u3002<\/p>\n
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