{"id":1778,"date":"2020-07-01T04:52:45","date_gmt":"2020-06-30T20:52:45","guid":{"rendered":"http:\/\/39.97.231.10\/?p=1778"},"modified":"2020-07-01T04:52:45","modified_gmt":"2020-06-30T20:52:45","slug":"hbase-wal%e8%a7%a3%e6%9e%90","status":"publish","type":"post","link":"http:\/\/www.weijing.co\/?p=1778","title":{"rendered":"HBase WAL\u89e3\u6790"},"content":{"rendered":"

\u4ec0\u4e48\u662f\u9884\u5199\u65e5\u5fd7WAL\uff08Write-Ahead-Log\uff09<\/h1>\n
HBase\u7684Write Ahead Log (WAL)\u63d0\u4f9b\u4e86\u4e00\u79cd\u9ad8\u5e76\u53d1\u3001\u6301\u4e45\u5316\u7684\u65e5\u5fd7\u4fdd\u5b58\u4e0e\u56de\u653e\u673a\u5236\u3002\u6bcf\u4e00\u4e2a\u4e1a\u52a1\u6570\u636e\u7684\u5199\u5165\u64cd\u4f5c\uff08PUT \/ DELETE\uff09\u6267\u884c\u524d\uff0c\u90fd\u4f1a\u8bb0\u8d26\u5728WAL\u4e2d\u3002<\/p>\n
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WAL\u6700\u91cd\u8981\u7684\u4f5c\u7528\u662f\u707e\u96be\u6062\u590d\u3002\u548cMySQL \u7684BIN log\u7c7b\u4f3c\uff0c\u5b83\u8bb0\u5f55\u6240\u6709\u7684\u6570\u636e\u6539\u52a8\u3002\u4e00\u65e6\u670d\u52a1\u5668\u5d29\u6e83\uff0c\u901a\u8fc7\u91cd\u653elog\uff0c\u6211\u4eec\u53ef\u4ee5\u6062\u590d\u5d29\u6e83\u4e4b\u524d\u7684\u6570\u636e\u3002\u8fd9\u4e5f\u610f\u5473\u5982\u679c\u5199\u5165WAL\u5931\u8d25\uff0c\u6574\u4e2a\u64cd\u4f5c\u5c06\u8ba4\u4e3a\u5931\u8d25\u3002
\n\u6211\u4eec\u5148\u770b\u770bHBase\u662f\u5982\u4f55\u505a\u5230\u7684\u3002\u9996\u5148\uff0c\u5ba2\u6237\u7aef\u521d\u59cb\u5316\u4e00\u4e2a\u53ef\u80fd\u5bf9\u6570\u636e\u6539\u52a8\u7684\u64cd\u4f5c\uff0c\u5982put(Put),delete(Delete) \u548c incrementColumnValue()\u3002\u8fd9\u4e9b\u64cd\u4f5c\u90fd\u5c06\u88ab\u5c01\u88c5\u5728\u4e00\u4e2aKeyValue\u5bf9\u8c61\u5b9e\u4f8b\u4e2d\uff0c\u901a\u8fc7RPC \u8c03\u7528\u53d1\u9001\u7ed9HRegionServer(\u6700\u597d\u662f\u6279\u91cf\u64cd\u4f5c)\u3002 \u4e00\u65e6\u8fbe\u5230\u4e00\u5b9a\u5927\u5c0f\uff0cHRegionServer \u5c06\u5176\u53d1\u9001\u7ed9HRegion\u3002\u8fd9\u4e2a\u8fc7\u7a0b\u4e2d\uff0c\u6570\u636e\u4f1a\u9996\u5148\u4f1a\u88ab\u5199\u5165WAL\uff0c\u4e4b\u540e\u5c06\u88ab\u5199\u5230\u5b9e\u9645\u5b58\u653e\u6570\u636e\u7684MemStore\u4e2d\u3002
\n\u5f53MemStore\u5230\u8fbe\u4e00\u5b9a\u5927\u5c0f\uff0c\u6216\u8005\u7ecf\u8fc7\u4e00\u6bb5\u65f6\u95f4\u540e\uff0c\u6570\u636e\u5c06\u88ab\u5f02\u6b65\u5730\u5199\u5165\u6587\u4ef6\u7cfb\u7edf\u4e2d\u3002\u7136\u800c\uff0c\u5728\u4e24\u6b21\u5199\u5165\u6587\u4ef6\u7cfb\u7edf\u4e4b\u95f4\u7684\u6570\u636e\uff0c\u662f\u4fdd\u7559\u5728\u5185\u5b58\u4e2d\u7684\u3002\u5982\u679c\u8fd9\u4e2a\u65f6\u5019\u7cfb\u7edf\u5d29\u6e83\uff0c\u90a3\u6570\u636e\u00b7\u00b7\u00b7\uff0c\u522b\u6025\uff0c\u6211\u4eec\u6709WAL\uff01
\n\u6211\u4eec\u5148\u6765\u770b\u770bWAL\u51e0\u4e2a\u91cd\u8981\u7684\u7c7b\u3002<\/p>\n

HLog<\/h2>\n

HLog\u662f\u5b9e\u73b0WAL\u7684\u7c7b\u3002\u4e00\u4e2aHRegionServer\u5bf9\u5e94\u4e00\u4e2aHLog\u5b9e\u4f8b\u3002\u5f53HRegion\u521d\u59cb\u5316\u65f6\uff0cHLog\u5c06\u4f5c\u4e3a\u4e00\u4e2a\u53c2\u6570\u4f20\u7ed9HRegion\u7684\u6784\u9020\u51fd\u6570\u3002
\nHLog\u6700\u6838\u5fc3\u7684\u662f\u8c03\u7528doWrite\u7684append() \u65b9\u6cd5\uff0c\u524d\u9762\u63d0\u5230\u7684\u53ef\u80fd\u5bf9\u6570\u636e\u6539\u52a8\u7684\u64cd\u4f5c\u90fd\u5c31\u5c06\u9996\u5148\u8c03\u7528\u8fd9\u4e2a\u65b9\u6cd5\u3002\u51fa\u4e8e\u6027\u80fd\u7684\u8003\u8651\uff0cput(), delete() \u548cincrementColumnValue()\u6709\u4e00\u4e2a\u5f00\u5173\u51fd\u6570setWriteToWAL(boolean) \uff0c \u8bbe\u4e3afalse\u5c06\u7981\u7528WAL\u3002\u8fd9\u662f\u4e3a\u4ec0\u4e48\u4e0a\u56fe\u4e2d\u5411\u4e0b\u7684\u7bad\u5934\u662f\u865a\u7ebf\u7684\u539f\u56e0\u3002\u9ed8\u8ba4\u65f6\u5019\u5f53\u7136\u9700\u8981WAL\uff0c\u4f46\u662f\u5047\u5982\u4f60\u8fd0\u884c\u4e00\u4e2a\u6570\u636e\u5bfc\u5165\u7684MapReduce Job\uff0c\u4f60\u53ef\u4ee5\u901a\u8fc7\u5173\u95edWAL\u83b7\u5f97\u6027\u80fd\u4e0a\u7684\u63d0\u5347\u3002
\n\u53e6\u4e00\u4e2a\u91cd\u8981\u7684\u7279\u6027\u662fHLog\u5c06\u901a\u8fc7\u201csequence number\u201d\u8ffd\u8e2a\u6570\u636e\u6539\u53d8\u3002\u5b83\u5185\u90e8\u4f7f\u7528AtomicLong\u4fdd\u8bc1\u7ebf\u7a0b\u5b89\u5168\u3002sequence number\u7684\u8d77\u59cb\u503c\u4e3a0\uff0c\u6216\u8005\u662f\u6700\u8fd1\u4e00\u6b21\u5b58\u5165\u6587\u4ef6\u7cfb\u7edf\u4e2dsequence number\u3002Region\u6253\u5f00\u5b58\u50a8\u6587\u4ef6\uff0c\u8bfb\u53d6\u6bcf\u4e2aHFile\u4e2d\u7684\u6700\u5927\u7684sequence number\uff0c\u5982\u679c\u8be5\u503c\u5927\u4e8eHLog \u7684sequence number, \u5c31\u5c06\u5b83\u4f5c\u4e3aHLog \u7684sequence number\u7684\u503c\u3002\u6700\u540e\uff0cHLog\u5c06\u5f97\u5230\u4e0a\u6b21\u5b58\u5165\u6587\u4ef6\u548c\u7ee7\u7eed\u8bb0log\u7684\u70b9\u3002\u8fc7\u4f1a\uff0c\u6211\u4eec\u5c06\u770b\u5230\u5b83\u7684\u5e94\u7528\u3002<\/p>\n

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\u4e0a\u56fe\u8868\u793a\u4e863\u4e2a\u4e0d\u540c\u7684region\uff0c\u6bcf\u4e00\u4e2a\u8d1f\u8d23\u4e00\u6bb5rowkey\u7684\u8303\u56f4\u3002\u8fd9\u4e9bregion\u5c06\u5171\u4eab\u540c\u4e00\u4e2aHLog\u5b9e\u4f8b\uff0c\u6211\u4eec\u53ef\u4ee5\u770b\u51fa\uff0c\u4ece\u4e0d\u540cregion\u6765\u7684\u6570\u636e\u5199\u5165WAL\u7684\u987a\u5e8f\u662f\u4e0d\u786e\u5b9a\u7684\u3002\u5728\u540e\u9762\u6211\u4eec\u4f1a\u518d\u8be6\u7ec6\u7684\u4ecb\u7ecd\u3002
\n\u6700\u540e\uff0cHlog\u5229\u7528HMaster\u6062\u590d\u548c\u5207\u5206\u4e00\u4e2a\u7531\u4e00\u4e2a\u5d29\u6e83\u7684HRegionServery\u9057\u7559\u4e0b\u6765\u7684Log\u3002\u4e4b\u540e\uff0c\u91cd\u65b0\u90e8\u7f72regions\u3002<\/p>\n

HLogKey<\/h2>\n

WAL\u4f7f\u7528Hadoop\u7684SequenceFile,\u5b83\u5c06\u8bb0\u5f55\u5b58\u50a8\u4e3akey\/values \u7684\u6570\u636e\u96c6\u3002\u5bf9\u4e8eWAL\uff0ckey\u662f\u4e00\u4e2aHLogKey\u7684\u5b9e\u4f8b\u3002KeyValue\u4e0d\u4ec5\u5305\u62ecrow\uff0ccolumn family, qualifier, timestamp, value, \u8fd8\u5305\u62ec\u201cKey Type\u201d\u2014\u6d3e\u4e0a\u7528\u573a\u5566\uff0c \u8fd9\u91cc\uff0c\u53ef\u4ee5\u7528Key Type\u4ee3\u8868\u4e00\u4e2a\u201cput\u201d\u6216\u201cdelete\u201d\u64cd\u4f5c\u3002<\/p>\n

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\u4f46\u662f\uff0c\u54ea\u91cc\u53bb\u5b58\u653eKeyValue\u7684\u5f52\u5c5e\u4fe1\u606f\uff0c\u6bd4\u5982region\u6216\u8005\u8868\u540d\u5462\uff1f\u8fd9\u4e9b\u5b58\u653e\u5728HLogKey\u4e2d\u3002\u540c\u65f6\u8fd8\u5305\u62ec sequence number\uff0c\u548c\u201c\u5199\u5165\u65f6\u95f4\u201d\uff0c \u662f\u4e00\u4e2a\u8bb0\u5f55\u6570\u636e\u4f55\u65f6\u5199\u5165\u5230log\u7684\u65f6\u95f4\u6233\u3002<\/p>\n

LogFlusher<\/h2>\n

\u524d\u9762\u63d0\u5230\uff0c\u6570\u636e\u4ee5KeyValue\u5f62\u5f0f\u5230\u8fbeHRegionServer\uff0c\u5c06\u5199\u5165WAL\uff0c\u4e4b\u540e\uff0c\u5199\u5165\u4e00\u4e2aSequenceFile\u3002\u770b\u8fc7\u53bb\u6ca1\u95ee\u9898\uff0c\u4f46\u662f\u56e0\u4e3a\u6570\u636e\u6d41\u5728\u5199\u5165\u6587\u4ef6\u7cfb\u7edf\u65f6\uff0c\u7ecf\u5e38\u4f1a\u7f13\u5b58\u4ee5\u63d0\u9ad8\u6027\u80fd\u3002\u8fd9\u6837\uff0c\u6709\u4e9b\u672c\u4ee5\u4e3a\u5728\u65e5\u5fd7\u6587\u4ef6\u4e2d\u7684\u6570\u636e\u5b9e\u9645\u5728\u5185\u5b58\u4e2d\u3002\u8fd9\u91cc\uff0c\u6211\u4eec\u63d0\u4f9b\u4e86\u4e00\u4e2aLogFlusher\u7684\u7c7b\u3002\u5b83\u8c03\u7528HLog.optionalSync(),\u540e\u8005\u6839\u636e\u201chbase.regionserver.optionallogflushinterval\u201d(\u9ed8\u8ba4\u662f10\u79d2)\uff0c\u5b9a\u671f\u8c03\u7528Hlog.sync()\u3002\u53e6\u5916\uff0cHLog.doWrite()\u4e5f\u4f1a\u6839\u636e\u201chbase.regionserver.flushlogentries\u201d(\u9ed8\u8ba4100\u79d2)\u5b9a\u671f\u8c03\u7528Hlog.sync()\u3002Sync() \u672c\u8eab\u8c03\u7528HLog.Writer.sync()\uff0c\u5b83\u7531SequenceFileLogWriter\u5b9e\u73b0\u3002<\/p>\n

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LogRoller<\/h2>\n

Log\u7684\u5927\u5c0f\u901a\u8fc7$HBASE_HOME\/conf\/hbase-site.xml \u7684\u201chbase.regionserver.logroll.period\u201d\u9650\u5236\uff0c\u9ed8\u8ba4\u662f\u4e00\u4e2a\u5c0f\u65f6\u3002\u6240\u4ee5\u6bcf60\u5206\u949f\uff0c\u4f1a\u6253\u5f00\u4e00\u4e2a\u65b0\u7684log\u6587\u4ef6\u3002\u4e45\u800c\u4e45\u4e4b\uff0c\u4f1a\u6709\u4e00\u5927\u5806\u7684\u6587\u4ef6\u9700\u8981\u7ef4\u62a4\u3002\u9996\u5148\uff0cLogRoller\u8c03\u7528HLog.rollWriter()\uff0c\u5b9a\u65f6\u6eda\u52a8\u65e5\u5fd7\uff0c\u4e4b\u540e\uff0c\u5229\u7528HLog.cleanOldLogs()\u53ef\u4ee5\u6e05\u9664\u65e7\u7684\u65e5\u5fd7\u3002\u5b83\u9996\u5148\u53d6\u5f97\u5b58\u50a8\u6587\u4ef6\u4e2d\u7684\u6700\u5927\u7684sequence number\uff0c\u4e4b\u540e\u68c0\u67e5\u662f\u5426\u5b58\u5728\u4e00\u4e2alog\u6240\u6709\u7684\u6761\u76ee\u7684\u201csequence number\u201d\u5747\u4f4e\u4e8e\u8fd9\u4e2a\u503c\uff0c\u5982\u679c\u5b58\u5728\uff0c\u5c06\u5220\u9664\u8fd9\u4e2alog\u3002<\/p>\n

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\n
\u8fd9\u91cc\u89e3\u91ca\u4e0b\u4f60\u53ef\u80fd\u5728log\u4e2d\u770b\u5230\u7684\u4ee4\u4eba\u8d39\u89e3\u7684\u5185\u5bb9\uff1a\n`2009-12-15 01:45:48,427 INFO org.apache.hadoop.hbase.regionserver.HLog: Too` `many hlogs: logs=130, maxlogs=96; forcing flush of region with oldest edits:`\n`foobar,1b2dc5f3b5d4,1260083783909`\n\u8fd9\u91cc\uff0c\u6211\u4eec\u770b\u5230\uff0clog file\u7684\u6570\u76ee\u8d85\u8fc7\u4e86log files\u7684\u6700\u5927\u503c\u3002\u8fd9\u65f6\uff0c\u4f1a\u5f3a\u5236\u8c03\u7528flush out \u4ee5\u51cf\u5c11log\u7684\u6570\u76ee\u3002\n\u201chbase.regionserver.hlog.blocksize\u201d\u548c\u201chbase.regionserver.logroll.multiplier\u201d\u4e24\u4e2a\u53c2\u6570\u9ed8\u8ba4\u5c06\u5728log\u5927\u5c0f\u4e3aSequenceFile(\u9ed8\u8ba4\u4e3a64MB)\u768495%\u65f6\u56de\u6eda\u3002\u6240\u4ee5\uff0clog\u7684\u5927\u5c0f\u548clog\u4f7f\u7528\u7684\u65f6\u95f4\u90fd\u4f1a\u5bfc\u81f4\u56de\u6eda\uff0c\u4ee5\u5148\u5230\u8fbe\u54ea\u4e2a\u9650\u5b9a\u4e3a\u51c6\u3002\n<\/pre>\n<\/div>\n
Replay<\/h2>\n
\u5f53HRegionServer\u542f\u52a8\uff0c\u6253\u5f00\u6240\u7ba1\u8f96\u7684region\uff0c\u5b83\u5c06\u68c0\u67e5\u662f\u5426\u5b58\u5728\u5269\u4f59\u7684log\u6587\u4ef6\uff0c\u5982\u679c\u5b58\u5728\uff0c\u5c06\u8c03\u7528Store.doReconstructionLog()\u3002\u91cd\u653e\u4e00\u4e2a\u65e5\u5fd7\u53ea\u662f\u7b80\u5355\u5730\u8bfb\u5165\u4e00\u4e2a\u65e5\u5fd7\uff0c\u5c06\u65e5\u5fd7\u4e2d\u7684\u6761\u76ee\u52a0\u5165\u5230Memstore\u4e2d\u3002\u6700\u540e\uff0cflush\u64cd\u4f5c\u5c06Memstore\u4e2d\u6570\u636eflush\u5230\u786c\u76d8\u4e2d\u3002
\n\u65e7\u65e5\u5fd7\u5f80\u5f80\u7531region server \u5d29\u6e83\u6240\u4ea7\u751f\u3002\u5f53HMaster\u542f\u52a8\u6216\u8005\u68c0\u6d4b\u5230region server \u5d29\u6e83\uff0c\u5b83\u5c06\u65e5\u5fd7\u6587\u4ef6\u62c6\u5206\u4e3a\u591a\u4efd\u6587\u4ef6\uff0c\u5c06\u5176\u5b58\u50a8\u5728region\u6240\u5c5e\u7684\u6587\u4ef6\u5939\u3002\u4e4b\u540e\uff0c\u6839\u636e\u4e0a\u9762\u63d0\u5230\u7684\u65b9\u6cd5\uff0c\u5c06\u65e5\u5fd7\u91cd\u653e\u3002\u9700\u8981\u6307\u51fa\u7684\u662f\uff0c\u5d29\u6e83\u7684\u670d\u52a1\u5668\u4e2d\u7684region\u53ea\u6709\u5728\u65e5\u5fd7\u88ab\u62c6\u5206\u548c\u62f7\u8d1d\u4e4b\u540e\u624d\u80fd\u88ab\u91cd\u65b0\u5206\u914d\u3002\u62c6\u5206\u65e5\u5fd7\u5229\u7528HLog.splitLog()\u3002\u65e7\u65e5\u5fd7\u88ab\u8bfb\u5165\u4e3b\u7ebf\u7a0b\u5185\u5b58\u4e2d\uff0c\u4e4b\u540e\uff0c\u5229\u7528\u7ebf\u7a0b\u6c60\u5c06\u5176\u5199\u5165\u6240\u6709\u7684region\u6587\u4ef6\u5939\u4e2d\uff0c\u4e00\u4e2a\u7ebf\u7a0b\u5bf9\u5e94\u4e8e\u4e00\u4e2aregion\u3002<\/p>\n
\u95ee\u9898<\/h2>\n
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  1. \u4e3a\u4ec0\u4e48\u8981\u4e00\u4e2aRegionServer \u5bf9\u5e94\u4e8e\u4e00\u4e2aHLog\u3002\u4e3a\u4ec0\u4e48\u4e0d\u662f\u4e00\u4e2aregion\u5bf9\u5e94\u4e8e\u4e00\u4e2alog file\uff1f
    \n\u5f15\u7528BigTable\u4e2d\u7684\u4e00\u6bb5\u8bdd\uff0c<\/li>\n<\/ol>\n
    \u5982\u679c\u6211\u4eec\u6bcf\u4e00\u4e2a\u201ctablet\u201d\uff08\u5bf9\u5e94\u4e8eHBase\u7684region\uff09\u90fd\u63d0\u4ea4\u4e00\u4e2a\u65e5\u5fd7\u6587\u4ef6\uff0c\u4f1a\u9700\u8981\u5e76\u53d1\u5199\u5165\u5927\u91cf\u7684\u6587\u4ef6\u5230GFS\uff0c\u8fd9\u6837\uff0c\u6839\u636e\u6bcf\u4e2aGFS server\u6240\u4f9d\u8d56\u7684\u6587\u4ef6\u7cfb\u7edf\uff0c\u5199\u5165\u4e0d\u540c\u7684\u65e5\u5fd7\u6587\u4ef6\u4f1a\u9020\u6210\u5927\u91cf\u7684\u78c1\u76d8\u64cd\u4f5c\u3002<\/p><\/blockquote>\n
    HBase\u4f9d\u7167\u8fd9\u6837\u7684\u539f\u5219\u3002\u5728\u65e5\u5fd7\u88ab\u56de\u6eda\u548c\u5b89\u5168\u5220\u9664\u4e4b\u524d\uff0c\u5c06\u4f1a\u6709\u5927\u91cf\u7684\u6587\u4ef6\u3002\u5982\u679c\u6539\u6210\u4e00\u4e2aregion\u5bf9\u5e94\u4e8e\u4e00\u4e2a\u6587\u4ef6\uff0c\u5c06\u4f1a\u4e0d\u597d\u6269\u5c55\uff0c\u8fdf\u65e9\u4f1a\u5f15\u53d1\u95ee\u9898\u3002<\/p>\n
      \n
    1. \u6f5c\u5728\u95ee\u9898<\/li>\n<\/ol>\n
      a. \u5f53server\u5d29\u6e83\uff0cHBase\u9700\u8981\u5c06\u5176log\u5207\u5206\u6210\u5408\u9002\u7684\u7247\u3002\u7136\u800c\uff0c\u7531\u4e8e\u6240\u6709\u7684\u6761\u76ee\u6df7\u6742\u5728\u65e5\u5fd7\u4e2d\uff0cHMaster\u53ea\u6709\u5728\u5c06log\u5b8c\u5168\u5206\u914d\u5230\u6bcf\u4e00\u4e2aserver\u540e\uff0c\u624d\u80fd\u5c06\u5d29\u6e83server\u4e2d\u7684region\u91cd\u65b0\u5206\u914d\u3002\u8fd9\u4e2a\u65f6\u95f4\u53ef\u80fd\u5f88\u957f\u3002
      \nb. \u6570\u636e\u5b89\u5168\u3002\u4f60\u5e0c\u671b\u80fd\u4fdd\u5b58\u4f60\u6240\u6709\u7684\u6570\u636e\uff0c\u867d\u7136\u4f60\u80fd\u5c06flush\u7684\u65f6\u95f4\u8c03\u5230\u5c3d\u53ef\u80fd\u7684\u4f4e\uff0c\u4f60\u4f9d\u7136\u4f9d\u8d56\u4e8e\u4e0a\u9762\u63d0\u5230\u7684\u6587\u4ef6\u7cfb\u7edf\u3002\u90a3\u4e9b\u7528\u4e8e\u5b58\u50a8\u6570\u636e\u4f9d\u65e7\u6709\u53ef\u80fd\u6ca1\u5199\u5230\u78c1\u76d8\u800c\u53d1\u751f\u6570\u636e\u4e22\u5931\u3002
      \n\u5f88\u660e\u663e\uff0c\u9700\u8981log\u6765\u4fdd\u8bc1\u6570\u636e\u5b89\u5168\u3002\u6700\u597d\u662f\u80fd\u8ba9\u4e00\u4e2a\u65e5\u5fd7\u4fdd\u63011\u4e2a\u5c0f\u65f6\uff08\u6216\u957f\uff09\u7684\u6253\u5f00\u72b6\u6001\u3002\u5f53\u6570\u636e\u6765\u65f6\uff0c\u5c06\u65b0\u7684key\/value\u5bf9\u5199\u5165SequenceFile\u4e2d\uff0c\u5e76\u5b9a\u671fflush\u6570\u636e\u5230\u78c1\u76d8\u4e2d\u3002\u4f46\u662fHadoop\u4e0d\u662f\u8fd9\u6837\u5de5\u4f5c\u7684\u3002\u4ed6\u63d0\u4f9b\u4e86\u4e00\u4e2aAPI\uff0c\u5141\u8bb8\u6253\u5f00\u4e00\u4e2a\u6587\u4ef6\uff0c\u5199\u5165\u5927\u91cf\u7684\u6570\u636e\uff0c\u7136\u540e\u9a6c\u4e0a\u5173\u95ed\u6587\u4ef6\uff0c\u6210\u4e3a\u4e00\u4e2a\u5bf9\u5176\u4ed6\u4eba\u53ea\u8bfb\u7684\u6587\u4ef6\u3002\u53ea\u6709\u5f53\u6587\u4ef6\u5173\u95ed\u65f6\u624d\u662f\u5bf9\u5176\u4ed6\u4eba\u53ef\u8bfb\u7684\u3002\u90a3\u4e48\uff0c\u5982\u679c\u4e00\u4e2a\u8fdb\u7a0b\u5728\u5199\u5165\u6587\u4ef6\u65f6\u50f5\u6b7b\uff0c\u90a3\u4e48\uff0c\u6570\u636e\u5f88\u53ef\u80fd\u4f1a\u4e22\u5931\u3002\u56e0\u6b64\uff0c\u6211\u4eec\u9700\u8981\u4e00\u4e2a\u529f\u80fd\uff0c\u80fd\u53d6\u5230\u4e00\u4e2a\u79bb\u5d29\u6e83\u670d\u52a1\u5668\u5199\u5165\u6570\u636e\u5c3d\u53ef\u80fd\u8fd1\u7684\u70b9\u3002
      \n\u63d2\u66f2\uff1a HDFS append\uff0chflush\uff0chsync\uff0csync\u00b7\u00b7\u00b7
      \n\u8fd9\u4e9b\u90fd\u8d77\u6e90\u4e8eHADOOP-1700\u3002Hadoop 0.19\u6ca1\u6709\u80fd\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u3002\u8fd9\u4e2a\u95ee\u9898\u540e\u6765\u53c8\u6210\u4e3aHADOOP-4379\u6216HDFS-200\uff0c\u5e76\u5b9e\u73b0\u4e86syncFS(),\u540e\u8005\u53ef\u4ee5\u540c\u6b65\u6587\u4ef6\u7684\u6539\u53d8\u3002\u540c\u65f6\uff0cHBase-1470\u4e2d\uff0c\u5c06\u8fd9\u4e2aAPI\u5f00\u653e\uff0c\u4f46\u662f\u4f9d\u7136\u6ca1\u6709\u89e3\u51b3\u8fd9\u4e2a\u95ee\u9898\u3002
      \n\u4e4b\u540e\u662fHDFS-265\uff0c\u91cd\u65b0\u63d0\u51faappend\u7684\u65b9\u6848\uff0c\u5e76\u5f15\u5165Syncable\u7684\u63a5\u53e3\uff0c\u5f00\u653ehsync()\u548chflush()\u3002
      \nSequenceFile.Writer.sync()\u548c\u4e0a\u9762\u7684\u5e76\u4e0d\u76f8\u540c\u3002 \u5b83\u53ea\u662f\u5c06\u4e00\u4e2a\u540c\u6b65\u6807\u8bb0\u5199\u5165\u6587\u4ef6\uff0c\u4ee5\u65b9\u4fbf\u6570\u636e\u6062\u590d\u3002
      \n\u867d\u7136append\u5bf9\u4e8eHDFS\u5f88\u6709\u7528\uff0c\u4f46\u5e76\u6ca1\u6709\u7528\u5728HBase\u4e2d\u3002HBase\u7528\u4e86hflush\uff0c\u5b83\u53ef\u4ee5\u5728log\u5199\u5b8c\u6210\u540e\u5c06\u6240\u6709\u6570\u636e\u5199\u5165\u78c1\u76d8\u3002\u5f53\u670d\u52a1\u5668\u5d29\u6e83\uff0c\u6211\u4eec\u53ef\u4ee5\u5b89\u5168\u5730\u5c06\u201c\u810f\u201d\u6587\u4ef6\u8bfb\u5230\u6700\u540e\u4e00\u6b21\u6539\u52a8\u3002Hadoop 0.19.0\u4e2d\uff0c\u5229\u7528Hadoop fsck \/\u53ef\u4ee5\u6839\u636eHBase\u6253\u5f00\u7684\u65e5\u5fd7\u6587\u4ef6\u6570\u76ee\u62a5\u544aDFS\u7684\u7834\u635f\u7a0b\u5ea6\u3002
      \n\u7ed3\u8bba\u662f\uff0c\u5728Hadoop 0.21.0\u4e4b\u524d\uff0c\u4f60\u975e\u5e38\u5bb9\u6613\u9047\u5230\u6570\u636e\u4e22\u5931\u3002\u5728Hadoop 0.21.0\u4e4b\u540e\uff0c\u4f60\u5c06\u5f97\u5230\u9876\u5c16\u7684\u7cfb\u7edf\uff08\u6709\u70b9\u5439\u725b\u5566\uff0c\u8bd1\u8005\u6ce8\uff09\u3002
      \n\u6539\u5584\u8ba1\u5212
      \n\u5728HBase0.21.0\u4e2d\uff0cWAL\u6784\u67b6\u4f1a\u6709\u76f8\u5f53\u5927\u7684\u6539\u8fdb\uff0c\u8fd9\u91cc\u5f3a\u8c03\u51e0\u70b9<\/p>\n
        \n
      1. \u66ff\u6362SequenceFile
        \nWAL\u7684\u6838\u5fc3\u4e4b\u4e00\u5c31\u662f\u5b58\u50a8\u683c\u5f0f\u3002SequenceFile\u6709\u4e0d\u5c11\u95ee\u9898\uff0c\u6700\u5927\u7684\u6027\u80fd\u95ee\u9898\u5c31\u662f\u6240\u6709\u7684\u5199\u5165\u90fd\u662f\u540c\u6b65\u7684\uff08HBase-2105\uff09\u3002
        \n\u5728HBase 0.20.0\u4e2d\uff0cHFile\u66ff\u6362\u4e86MapFile\uff0c\u6240\u4ee5\uff0c\u53ef\u4ee5\u8003\u8651\u4e00\u4e2a\u5b8c\u5168\u7684\u66ff\u6362\u3002\u9996\u5148\u8981\u505a\u7684\u662fHBase\u72ec\u7acb\u4e8e\u5e95\u5c42\u7684\u6587\u4ef6\u7cfb\u7edf\u3002HBase-2059\u4f7flog\u7684\u5b9e\u73b0\u65b9\u5f0f\u53ef\u914d\u3002
        \n\u53e6\u4e00\u4e2a\u60f3\u6cd5\u662f\u5b8c\u5168\u6362\u4e00\u79cd\u5e8f\u5217\u5316\u65b9\u5f0f\u3002HBase-2055\u63d0\u51fa\u5229\u7528Hadoop\u7684Avro\u4f5c\u4e3a\u5e95\u5c42\u7cfb\u7edf\u3002Avro\u4e5f\u53ef\u80fd\u6210\u4e3aHadoop\u65b0\u7684RPC\u683c\u5f0f\uff0c\u5e0c\u671b\u6709\u8d8a\u6765\u8d8a\u591a\u7684\u4eba\u719f\u6089\u5b83\u3002<\/li>\n
      2. Append\/Sync
        \n\u9891\u7e41\u7684\u8c03\u7528hflush()\u4f1a\u5bfc\u81f4\u7cfb\u7edf\u53d8\u6162\u3002\u4e4b\u524d\u7684\u6d4b\u8bd5\u53d1\u73b0\uff0c\u5982\u679c\u6bcf\u4e00\u4e2a\u8bb0\u5f55\u90fd\u8c03\u7528\u65e7\u7684syncFs()\uff0c\u5c06\u5927\u5927\u964d\u4f4e\u7cfb\u7edf\u7684\u6027\u80fd\u3002HBase-1939\u63d0\u51fa\u4e00\u79cd\u201c\u7ec4\u63d0\u4ea4\u201d\u7684\u65b9\u6cd5\uff0c\u53ef\u4ee5\u6279\u91cfflush\u6570\u636e\u3002\u53e6\u5916\uff0cHBase-1944\u4e2d\u63d0\u51fa\u5c06\u201c\u5ef6\u65f6flush log\u201d\u6700\u4e3a\u4e00\u4e2aColumn Family \u7684\u53c2\u6570\u3002\u8bbe\u4e3a\u201ctrue\u201d,\u5c06\u540c\u6b65\u6539\u52a8\u5230log\u7684\u5de5\u4f5c\u4ea4\u7ed9\u65b0\u7684LogSyncer\u7c7b\u548c\u7ebf\u7a0b\u3002\u6700\u540e\uff0c\u5728HBASE-2041\u4e2d\uff0c\u5c06flushlogentries \u8bbe\u7f6e\u4e3a1\uff0c optinallogflushinterval \u8bbe\u4e3a1000\u6beb\u79d2\u3002.META.\u6bcf\u6b21\u6539\u53d8\u90fd\u4f1a\u88ab\u540c\u6b65\uff0c\u7528\u6237\u8868\u53ef\u4ee5\u6839\u636e\u9700\u8981\u7c7b\u914d\u7f6e\u3002<\/li>\n<\/ol>\n
        3.\u5206\u5e03\u5f0f\u65e5\u5fd7\u5207\u5206
        \n\u4e4b\u524d\u8c08\u8fc7\uff0c\u5f53region\u9700\u8981\u88ab\u91cd\u65b0\u5206\u914d\u65f6\uff0c\u5207\u5206\u65e5\u5fd7\u5c06\u6210\u4e3a\u4e00\u4e2a\u95ee\u9898\u3002\u4e00\u4e2a\u65b9\u6cd5\u5c31\u662f\u5728zookeeper\u4e2d\u7ef4\u62a4\u4e00\u4e2aregions\u7684\u5217\u8868\u3002\u8fd9\u4e2a\u65b9\u6cd5\u81f3\u5c11\u80fd\u4fdd\u8bc1\u6240\u6709\u201c\u5e72\u51c0\u201d\u7684region\u80fd\u88ab\u5feb\u901f\u5730\u5206\u914d\u3002\u5269\u4e0b\u90a3\u4e9b\u9700\u8981\u7b49\u5f85\u65e5\u5fd7\u88ab\u5207\u5206\u7684\u6761\u76ee\u3002
        \n\u5269\u4e0b\u7684\u95ee\u9898\u5c31\u662f\u5982\u4f55\u66f4\u5feb\u5730\u5207\u5206\u65e5\u5fd7\u3002\u8fd9\u91cc\uff0cBigTable\u6709\u5982\u4e0b\u7684\u63cf\u8ff0\uff1a<\/p>\n
        \u4e00\u79cd\u65b9\u6848\u662f\u5bf9\u4e8e\u6bcf\u4e00\u4e2a\u65b0\u7684tablet server\uff08\u7c7b\u4f3cregionserver\uff09\uff0c\u9700\u8981\u8bfb\u53d6\u6574\u4e2a\u65e5\u5fd7\u6587\u4ef6\uff0c\u7136\u540e\uff0c\u5206\u914d\u90a3\u4e9b\u9700\u8981\u88ab\u4fee\u590d\u7684\u6761\u76ee\u3002\u7136\u800c\uff0c\u5728\u8fd9\u79cd\u60c5\u51b5\u4e0b\uff0c\u5982\u679c\u5c06\u4e00\u4e2a\u5931\u8d25\u7684tablet server\u91cd\u65b0\u5206\u914d\u5230100\u53f0\u673a\u5668\uff0c\u90a3\u4e48\u6bcf\u4e2a\u65e5\u5fd7\u6587\u4ef6\u9700\u8981\u8bfb100\u6b21\u3002<\/p><\/blockquote>\n
        \u6539\u8fdb\u65b9\u6848
        \n\u6211\u4eec\u6839\u636ekey\u5bf9log\u6761\u76ee\u8fdb\u884c\u6392\u5e8f\u3002\u4e4b\u540e\uff0c\u6240\u6709\u5bf9\u4e00\u4e2a\u7279\u5b9atablet\u7684\u6539\u52a8\u90fd\u5c06\u662f\u8fde\u7eed\u7684\uff0c\u987a\u5e8f\u8bfb\u53ef\u4ee5\u6709\u6548\u5730\u63d0\u9ad8\u78c1\u76d8\u68c0\u7d22\u7684\u6548\u7387\u3002\u4e3a\u4e86\u5e76\u884c\u5730\u6392\u5e8f\uff0c\u6211\u4eec\u5c06\u65e5\u5fd7\u5207\u5206\u4e3a64MB\u7684\u5206\u7247\u3002\u6bcf\u4e2a\u6392\u5e8f\u8fdb\u7a0b\u90fd\u5c06\u6709Master\u534f\u8c03\u7ba1\u7406\uff0c\u5e76\u5728tablet server\u7ed9\u51fa\u5b83\u5c06\u4ece\u90a3\u4e9b\u65e5\u5fd7\u6587\u4ef6\u4e2d\u6062\u590d\u65f6\u521d\u59cb\u5316\u3002
        \n<\/article>\n","protected":false},"excerpt":{"rendered":"
        \u4ec0\u4e48\u662f\u9884\u5199\u65e5\u5fd7WAL\uff08Write-Ahead-Log\uff09 HBase\u7684Write Ahead Log (WAL) …<\/p>\n
          HBase WAL\u89e3\u6790<\/span> \u67e5\u770b\u5168\u6587 »<\/a><\/p>\n","protected":false},"author":4,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","theme-transparent-header-meta":"default","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":""},"categories":[133,118],"tags":[],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false,"mailpoet_newsletter_max":false,"woocommerce_thumbnail":false,"woocommerce_single":false,"woocommerce_gallery_thumbnail":false,"shop_catalog":false,"shop_single":false,"shop_thumbnail":false},"uagb_author_info":{"display_name":"weijing","author_link":"http:\/\/www.weijing.co\/?author=4"},"uagb_comment_info":0,"uagb_excerpt":"\u4ec0\u4e48\u662f\u9884\u5199\u65e5\u5fd7WAL\uff08Write-Ahead-Log\uff09 HBase\u7684Write Ahead Log (WAL)…","_links":{"self":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/1778"}],"collection":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1778"}],"version-history":[{"count":0,"href":"http:\/\/www.weijing.co\/index.php?rest_route=\/wp\/v2\/posts\/1778\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1778"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1778"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.weijing.co\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1778"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}