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Liu Shaohui commented on HBASE-8755: ------------------------------------ update the result table and add ops diff ||Thread number|| Time without Patch || Ops without Patch||Time with Patch || Ops with Patch || Time diff % || Ops diff % || |1|579.38|1725.983|625.937|1597.605|-8.04|-7.44| |1|580.307|1723.226|630.346|1586.43|-8.62|-7.94| |1|577.853|1730.544|654.205|1528.573|-13.21|-11.67| |5|799.579|6253.291|785.696|6363.785|1.74|1.77| |5|795.013|6289.206|780.642|6404.984|1.81|1.84| |5|826.27|6051.291|781.909|6394.606|5.37|5.67| |50|3290.482|15195.343|1165.773|42890|64.57|182.26| |50|3298.387|15158.925|1167.992|42808.516|64.59|182.40| |50|3224.495|15506.304|1154.921|43293.004|64.18|179.20| |75|4450.76|16851.055|1253.448|59834.953|71.84|255.08| |75|4506.143|16643.945|1269.806|59064.141|71.82|254.87| |75|4516.453|16605.951|1245.954|60194.84|72.41|262.49| |100|5561.074|17982.137|1493.102|66974.656|73.15|272.45| |100|5616.81|17803.699|1496.263|66833.172|73.36|275.39| |100|5612.268|17818.107|1468.5|68096.695|73.83|282.18| Time diff = (Time without Patch - Time with Patch) / Time without Patch * 100 Ops diff = (Ops with Patch - Ops without Patch) / Ops without Patch * 100 [~stack] What are the hdfs and hbase version of your test? We may rebo the tests in cluster with same hdfs and hbase versions as yours. > A new write thread model for HLog to improve the overall HBase write > throughput > ------------------------------------------------------------------------------- > > Key: HBASE-8755 > URL: https://issues.apache.org/jira/browse/HBASE-8755 > Project: HBase > Issue Type: Improvement > Components: Performance, wal > Reporter: Feng Honghua > Assignee: stack > Priority: Critical > Fix For: 0.96.1 > > Attachments: 8755trunkV2.txt, HBASE-8755-0.94-V0.patch, > HBASE-8755-0.94-V1.patch, HBASE-8755-trunk-V0.patch, HBASE-8755-trunk-V1.patch > > > In current write model, each write handler thread (executing put()) will > individually go through a full 'append (hlog local buffer) => HLog writer > append (write to hdfs) => HLog writer sync (sync hdfs)' cycle for each write, > which incurs heavy race condition on updateLock and flushLock. > The only optimization where checking if current syncTillHere > txid in > expectation for other thread help write/sync its own txid to hdfs and > omitting the write/sync actually help much less than expectation. > Three of my colleagues(Ye Hangjun / Wu Zesheng / Zhang Peng) at Xiaomi > proposed a new write thread model for writing hdfs sequence file and the > prototype implementation shows a 4X improvement for throughput (from 17000 to > 70000+). > I apply this new write thread model in HLog and the performance test in our > test cluster shows about 3X throughput improvement (from 12150 to 31520 for 1 > RS, from 22000 to 70000 for 5 RS), the 1 RS write throughput (1K row-size) > even beats the one of BigTable (Precolator published in 2011 says Bigtable's > write throughput then is 31002). I can provide the detailed performance test > results if anyone is interested. > The change for new write thread model is as below: > 1> All put handler threads append the edits to HLog's local pending buffer; > (it notifies AsyncWriter thread that there is new edits in local buffer) > 2> All put handler threads wait in HLog.syncer() function for underlying > threads to finish the sync that contains its txid; > 3> An single AsyncWriter thread is responsible for retrieve all the buffered > edits in HLog's local pending buffer and write to the hdfs > (hlog.writer.append); (it notifies AsyncFlusher thread that there is new > writes to hdfs that needs a sync) > 4> An single AsyncFlusher thread is responsible for issuing a sync to hdfs > to persist the writes by AsyncWriter; (it notifies the AsyncNotifier thread > that sync watermark increases) > 5> An single AsyncNotifier thread is responsible for notifying all pending > put handler threads which are waiting in the HLog.syncer() function > 6> No LogSyncer thread any more (since there is always > AsyncWriter/AsyncFlusher threads do the same job it does) -- This message is automatically generated by JIRA. If you think it was sent incorrectly, please contact your JIRA administrators For more information on JIRA, see: http://www.atlassian.com/software/jira