On Dec 24, 2017 00:05, "Lars Hofhansl (JIRA)" <j...@apache.org> wrote:
> > [ https://issues.apache.org/jira/browse/HBASE-15453?page= > com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ] > > Lars Hofhansl resolved HBASE-15453. > ----------------------------------- > Resolution: Won't Fix > > Lemme just close. In 1.3+ it's not an issue anyway (the need to > synchronize is gone there) > > > [Performance] Considering reverting HBASE-10015 - reinstate synchronized > in StoreScanner > > ------------------------------------------------------------ > ---------------------------- > > > > Key: HBASE-15453 > > URL: https://issues.apache.org/jira/browse/HBASE-15453 > > Project: HBase > > Issue Type: Improvement > > Components: Performance > > Reporter: Lars Hofhansl > > Assignee: Lars Hofhansl > > Priority: Critical > > 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 > (v6.4.14#64029) >
