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https://issues.apache.org/jira/browse/GEODE-5314?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16624265#comment-16624265
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ASF subversion and git services commented on GEODE-5314:
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Commit be52507b73e46cf1b8578b23c4ea41ee40afc625 in geode's branch
refs/heads/feature/GEODE-5772 from Juan José Ramos
[ https://gitbox.apache.org/repos/asf?p=geode.git;h=be52507 ]
GEODE-5314: Cleanup and document MBeanStatsMonitor child classes
- Fixed minor warnings.
- Added JUnit Tests for all modified classes.
- There's only one thread updating the mutable values so it's been
decided to keep volatiles instead of moving to atomics.
- Documentation improved to better explain the thread-safety of the
classes.
> MBeanStatsMonitor child classes should use atomics instead of volatiles to
> avoid data race
> ------------------------------------------------------------------------------------------
>
> Key: GEODE-5314
> URL: https://issues.apache.org/jira/browse/GEODE-5314
> Project: Geode
> Issue Type: Bug
> Components: statistics
> Reporter: Galen O'Sullivan
> Assignee: Juan José Ramos Cassella
> Priority: Major
> Labels: pull-request-available
> Time Spent: 7h
> Remaining Estimate: 0h
>
> {{GcStatsMonitor}} has the following:
> {code}
> private volatile long collections = 0;
> private volatile long collectionTime = 0;
> {code}
> <snip>
> {code}
> collections -=
> statsMap.getOrDefault(StatsKey.VM_GC_STATS_COLLECTIONS,0).intValue();
> collectionTime -=
> statsMap.getOrDefault(StatsKey.VM_GC_STATS_COLLECTION_TIME,0).intValue();
> {code}
> Because these are volatile and not atomic fields, there will be a race
> condition. Other subclasses of {{MBeanStatsMonitor}} also use volatiles:
> AggregateRegionStatsMonitor, GatewaySenderOverflowMonitor,
> MemberLevelDiskMonitor, VMStatsMonitor.
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