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https://issues.apache.org/jira/browse/HBASE-8755?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13779607#comment-13779607
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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)
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