{"id":224784,"date":"2014-08-15T22:19:42","date_gmt":"2014-08-15T14:19:42","guid":{"rendered":"http:\/\/yangzhe1991.org\/blog\/?p=224784"},"modified":"2014-08-15T22:19:42","modified_gmt":"2014-08-15T14:19:42","slug":"cassandra%e5%88%a0%e9%99%a4%e6%95%b0%e6%8d%ae%e7%9a%84%e5%9d%91","status":"publish","type":"post","link":"https:\/\/yangzhe1991.org\/blog\/2014\/08\/cassandra%e5%88%a0%e9%99%a4%e6%95%b0%e6%8d%ae%e7%9a%84%e5%9d%91\/","title":{"rendered":"Cassandra\u5220\u9664\u6570\u636e\u7684\u5751"},"content":{"rendered":"<p>\u6700\u8fd1\u88ab\u67d0\u670d\u52a1\u6298\u817e\uff0c\u4ea4\u4e86\u70b9\u5b66\u8d39\u4f46\u81f3\u5c11\u5bf9Cassandra\u5220\u9664\u6570\u636e\u8fd9\u5757\u7684\u7406\u89e3\u66f4\u6df1\u4e86\u4e00\u4e9b\u3002\u603b\u7ed3\u7684\u7ecf\u9a8c\u5982\u4e0b\u3002<\/p>\n<p><!--more--><\/p>\n<p>Cassandra\u901a\u8fc7\u5199\u4e00\u6761\u201ctombstone\u201d\u6765\u6807\u8bb0\u4e00\u4e2a\u6570\u636e\u88ab\u5220\u9664\u4e86\u3002\u88ab\u6807\u8bb0\u7684\u6570\u636e\u9ed8\u8ba4\u898110\u5929(\u914d\u7f6e\u6587\u4ef6\u4e2d\u7684gc_grace_seconds)\u540e\u4e14\u88abcompaction\u6216cleanup\u6267\u884c\u5230\u5bf9\u5e94\u7684SSTable\u65f6\u624d\u4f1a\u88ab\u771f\u6b63\u4ece\u78c1\u76d8\u5220\u9664\uff0c\u56e0\u4e3a\u5982\u679c\u5f53\u65f6\u8fd9\u4e2adelete\u64cd\u4f5c\u53ea\u57283\u4e2a\u8282\u70b9\u4e2d\u76842\u4e2a\u6267\u884c\u6210\u529f\uff0c\u90a3\u4e48\u4e00\u65e62\u4e2a\u6709tombstone\u7684\u8282\u70b9\u628a\u6570\u636e\u5220\u4e86\uff0c\u96c6\u7fa4\u4e0a\u53ea\u5269\u4e0b\u6ca1tombstone\u7684\u90a3\u4e2a\u8282\u70b9\uff0c\u4e0b\u6b21\u8bfb\u8fd9\u4e2akey\u7684\u65f6\u5019\u5c31\u53c8\u8fd4\u56de\u5bf9\u5e94\u7684\u6570\u636e\uff0c\u4ece\u800c\u5bfc\u81f4\u88ab\u5220\u9664\u7684\u6570\u636e\u590d\u6d3b\u3002Repair\u64cd\u4f5c\u53ef\u4ee5\u540c\u6b65\u6240\u6709\u8282\u70b9\u7684\u6570\u636e\u4ece\u800c\u4fdd\u8bc1tombstone\u57283\u4e2a\u8282\u70b9\u4e2d\u90fd\u5b58\u5728\uff0c\u56e0\u6b64\u5982\u679c\u60f3\u786e\u4fdd\u5220\u9664100%\u6210\u529f\u4e0d\u4f1a\u590d\u6d3b\u9700\u8981\u4ee5\u5c0f\u4e8egc_grace_seconds\u7684\u5468\u671f\u5b9a\u671f\u6267\u884crepair\u64cd\u4f5c(\u6240\u4ee5\u5b98\u65b9\u5efa\u8bae&#8221;weekly&#8221;)\u3002<\/p>\n<p>\u7136\u800c\u5728select\u6570\u636e\u7684\u65f6\u5019\uff0c\u5728\u6bcf\u4e2aSSTable\u9047\u5230\u7684\u6240\u6709\u7b26\u5408\u67e5\u8be2\u6761\u4ef6\u7684tombstone\u8981\u653e\u5185\u5b58\u4e2d\u4ece\u800c\u5728\u5408\u5e76\u6bcf\u4e2aSSTable\u6587\u4ef6\u7684\u6570\u636e\u65f6\u5224\u65ad\u54ea\u4e9bcolumn\u6570\u636e\u6ca1\u88ab\u5220\u80fd\u6700\u7ec8\u8fd4\u56de\uff0ctombstone\u592a\u591a\u4f1a\u5bfc\u81f4heap\u88ab\u5927\u91cf\u5360\u7528\u9700\u8981\u5404\u79cdGC\u4ece\u800c\u5f71\u54cd\u6027\u80fd\uff0c\u6240\u4ee5cassandra\u9ed8\u8ba4\u8bfb\u5230100000\u4e2a(\u53ef\u914d\u7f6e)tombstone\u5c31\u5f3a\u5236\u53d6\u6d88\u8fd9\u6b21\u8bfb\u53d6\uff0c\u56e0\u4e3a\u9047\u5230\u8fd9\u79cd\u60c5\u51b5\u4e00\u5b9a\u662f\u4f60\u201cdoing 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