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https://issues.apache.org/jira/browse/GEODE-4083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16289710#comment-16289710
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ASF GitHub Bot commented on GEODE-4083:
---------------------------------------
dschneider-pivotal commented on a change in pull request #1161: GEODE-4083: fix
infinite loop caused by thread race changing version
URL: https://github.com/apache/geode/pull/1161#discussion_r156745899
##########
File path:
geode-core/src/main/java/org/apache/geode/internal/cache/versions/RegionVersionVector.java
##########
@@ -144,22 +145,56 @@
private final transient Object clearLockSync = new Object(); // sync for
coordinating thread
// startup and
lockOwner setting
- /** create a live version vector for a region */
+ /**
+ * constructor used to create a cloned vector
+ */
+ protected RegionVersionVector(T ownerId, ConcurrentHashMap<T,
RegionVersionHolder<T>> vector,
Review comment:
vector is an odd parameter name for a ConcurrentHashMap. Since this is a
copy constructor I'd expect "vector" to be the RegionVersionVector we are
copying. So I suggest renaming this parameter and updating the comment since we
are not passing in the "vector" we are cloning.
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> RegionVersionVector.updateLocalVersion can go into an infinite loop
> -------------------------------------------------------------------
>
> Key: GEODE-4083
> URL: https://issues.apache.org/jira/browse/GEODE-4083
> Project: Geode
> Issue Type: Bug
> Components: regions
> Reporter: Darrel Schneider
> Assignee: Eric Shu
>
> RegionVersionVector.updateLocalVersion can go into an infinite loop.
> The problem is this code:
> {code}
> private void updateLocalVersion(long version) {
> boolean repeat = false;
> do {
> long myVersion = this.localVersion.get();
> if (myVersion < version) {
> repeat = !this.localVersion.compareAndSet(myVersion, version);
> }
> } while (repeat);
> }
> {code}
> if version is "1" and localVersion.get() returns "0" the first time it is
> called but then compareAndSet returns false because localVersion has changed
> to "2" then the loop will never terminate because repeat will always be false
> and myVersion ("2" or more) will never be less than version ("1").
> The simple fix is to be sure repeat is set to false when myVersion is >= to
> version.
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