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Liang Xie commented on HDFS-5776: --------------------------------- Huge thanks, [~saint....@gmail.com] ! Here is the YCSB test result w/ the latest v21 patch: My test env, setting, data just same as the previous ones. hedged read thread pool size = 0: {code} [OVERALL], Throughput(ops/sec), 248.69758063844773 [READ], AverageLatency(us), 40152.776944654586 [READ], 50thPercentileLatency(us), 21023 [READ], 95thPercentileLatency(us), 151130 [READ], 99thPercentileLatency(us), 255973 [READ], 99.9thPercentileLatency(us), 420971 {code} hedged read thread pool size = 50, hedged read timeout = 250ms : {code} [OVERALL], Throughput(ops/sec), 231.90953643421446 [READ], AverageLatency(us), 43094.41323982726 [READ], 50thPercentileLatency(us), 23280 [READ], 95thPercentileLatency(us), 160024 [READ], 99thPercentileLatency(us), 258110 [READ], 99.9thPercentileLatency(us), 278328 {code} hedged read thread pool size = 50, hedged read timeout = 150ms : {code} [OVERALL], Throughput(ops/sec), 240.76033437917079 [READ], AverageLatency(us), 41507.364070480435 [READ], 50thPercentileLatency(us), 23316 [READ], 95thPercentileLatency(us), 158907 [READ], 99thPercentileLatency(us), 168504 [READ], 99.9thPercentileLatency(us), 218926 {code} hedged read thread pool size = 50, hedged read timeout = 100ms : {code} [OVERALL], Throughput(ops/sec), 271.0941444451295 [READ], AverageLatency(us), 36863.66854547243 [READ], 50thPercentileLatency(us), 21371 [READ], 95thPercentileLatency(us), 114943 [READ], 99thPercentileLatency(us), 121673 [READ], 99.9thPercentileLatency(us), 195467 {code} > Support 'hedged' reads in DFSClient > ----------------------------------- > > Key: HDFS-5776 > URL: https://issues.apache.org/jira/browse/HDFS-5776 > Project: Hadoop HDFS > Issue Type: Improvement > Components: hdfs-client > Affects Versions: 3.0.0 > Reporter: Liang Xie > Assignee: Liang Xie > Attachments: HDFS-5776-v10.txt, HDFS-5776-v11.txt, HDFS-5776-v12.txt, > HDFS-5776-v12.txt, HDFS-5776-v13.wip.txt, HDFS-5776-v14.txt, > HDFS-5776-v15.txt, HDFS-5776-v17.txt, HDFS-5776-v17.txt, HDFS-5776-v2.txt, > HDFS-5776-v3.txt, HDFS-5776-v4.txt, HDFS-5776-v5.txt, HDFS-5776-v6.txt, > HDFS-5776-v7.txt, HDFS-5776-v8.txt, HDFS-5776-v9.txt, HDFS-5776.txt, > HDFS-5776v18.txt, HDFS-5776v21.txt > > > This is a placeholder of hdfs related stuff backport from > https://issues.apache.org/jira/browse/HBASE-7509 > The quorum read ability should be helpful especially to optimize read outliers > we can utilize "dfs.dfsclient.quorum.read.threshold.millis" & > "dfs.dfsclient.quorum.read.threadpool.size" to enable/disable the hedged read > ability from client side(e.g. HBase), and by using DFSQuorumReadMetrics, we > could export the interested metric valus into client system(e.g. HBase's > regionserver metric). > The core logic is in pread code path, we decide to goto the original > fetchBlockByteRange or the new introduced fetchBlockByteRangeSpeculative per > the above config items. -- This message was sent by Atlassian JIRA (v6.1.5#6160)