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Lars Hofhansl updated HBASE-15453: ---------------------------------- Description: In HBASE-10015 back then I found that intrinsic locks (synchronized) in StoreScanner are slower that explicit locks. I was surprised by this. To make sure I added a simple perf test and many folks ran it on their machines. All found that explicit locks were faster. Now... I just ran that test again. On the latest JDK8 I find that now the intrinsic locks are significantly faster: (OpenJDK Runtime Environment (build 1.8.0_72-b15)) Explicit locks: 10 runs mean:2223.6 sigma:72.29412147609237 Intrinsic locks: 10 runs mean:1865.3 sigma:32.63755505548784 I confirmed the same with timing some Phoenix scans. We can save a bunch of time by changing this back Arrghhh... So maybe it's time to revert this now...? (Note that in trunk due to [~ram_krish]'s work, we do not lock in StoreScanner anymore) I'll attach the perf test and a patch that changes lock to synchronized, if some folks could run this on 0.98, that'd be great. was: In HBASE-10015 back then I found that intrinsic locks (synchronized) in StoreScanner are slower that explicit locks. I was surprised by this. To make sure I added a simple perf test and many folks ran it on their machines. All found that explicit locks were faster. Now... I just ran that test again. On the latest JDK8 I find that now the intrinsic locks are significantly faster: Explicit locks: 10 runs mean:2223.6 sigma:72.29412147609237 Intrinsic locks: 10 runs mean:1865.3 sigma:32.63755505548784 I confirmed the same with timing some Phoenix scans. We can save a bunch of time by changing this back Arrghhh... So maybe it's time to revert this now...? (Note that in trunk due to [~ram_krish]'s work, we do not lock in StoreScanner anymore) I'll attach the perf test and a patch that changes lock to synchronized, if some folks could run this on 0.98, that'd be great. > Considering reverting HBASE-10015 - reinstance synchronized in StoreScanner > --------------------------------------------------------------------------- > > Key: HBASE-15453 > URL: https://issues.apache.org/jira/browse/HBASE-15453 > Project: HBase > Issue Type: Bug > Reporter: Lars Hofhansl > Attachments: 15453-0.98.txt > > > In HBASE-10015 back then I found that intrinsic locks (synchronized) in > StoreScanner are slower that explicit locks. > I was surprised by this. To make sure I added a simple perf test and many > folks ran it on their machines. All found that explicit locks were faster. > Now... I just ran that test again. On the latest JDK8 I find that now the > intrinsic locks are significantly faster: > (OpenJDK Runtime Environment (build 1.8.0_72-b15)) > Explicit locks: > 10 runs mean:2223.6 sigma:72.29412147609237 > Intrinsic locks: > 10 runs mean:1865.3 sigma:32.63755505548784 > I confirmed the same with timing some Phoenix scans. We can save a bunch of > time by changing this back > Arrghhh... So maybe it's time to revert this now...? > (Note that in trunk due to [~ram_krish]'s work, we do not lock in > StoreScanner anymore) > I'll attach the perf test and a patch that changes lock to synchronized, if > some folks could run this on 0.98, that'd be great. -- This message was sent by Atlassian JIRA (v6.3.4#6332)