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https://issues.apache.org/jira/browse/GEODE-4083?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16289764#comment-16289764
]
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_r156760447
##########
File path:
geode-core/src/test/java/org/apache/geode/internal/cache/versions/RegionVersionVectorTest.java
##########
@@ -567,7 +572,56 @@ public void
testRecordVersionAfterRegionInitThrowsException() {
rvv.recordVersion(ownerId, tag);
}
- public RegionVersionVector
createRegionVersionVector(InternalDistributedMember ownerId,
+ @Test
+ public void usesNewVersionIfGreaterThanOldVersion() throws Exception {
+ VersionSource<InternalDistributedMember> ownerId =
mock(VersionSource.class);
+ long oldVersion = 1;
+ long newVersion = 2;
+
+ RegionVersionVector rvv = new TestableRegionVersionVector(ownerId,
oldVersion);
+ rvv.updateLocalVersion(newVersion);
+ assertThat(rvv.getVersionForMember(ownerId)).isEqualTo(newVersion);
+ }
+
+ @Test
+ public void usesOldVersionIfGreaterThanNewVersion() throws Exception {
+ VersionSource<InternalDistributedMember> ownerId =
mock(VersionSource.class);
+ long oldVersion = 2;
+ long newVersion = 1;
+
+ RegionVersionVector rvv = new TestableRegionVersionVector(ownerId,
oldVersion);
+ rvv.updateLocalVersion(newVersion);
+ assertThat(rvv.getVersionForMember(ownerId)).isEqualTo(oldVersion);
+ }
+
+ @Test
+ public void doesNothingIfVersionsAreSame() throws Exception {
+ VersionSource<InternalDistributedMember> ownerId =
mock(VersionSource.class);
+ long oldVersion = 2;
+ long sameVersion = 2;
+
+ RegionVersionVector rvv = new TestableRegionVersionVector(ownerId,
oldVersion);
+ rvv.updateLocalVersion(sameVersion);
+ assertThat(rvv.getVersionForMember(ownerId)).isEqualTo(oldVersion);
+ }
+
+ @Test
+ public void doesNotHangIfOtherThreadChangedVersion() throws Exception {
+ VersionSource<InternalDistributedMember> ownerId =
mock(VersionSource.class);
+ long oldVersion = 1;
+ long newVersion = 2;
+
+ RegionVersionVector rvv = new
VersionRaceConditionRegionVersionVector(ownerId, oldVersion);
+ Future<Boolean> future = executor.submit(() -> {
Review comment:
I understand now that you did not want the test to hang forever if it does
hang.
I think the test method name "doesNotHangIfOtherThreadChangedVersion"
mislead me.
It made me think the test used another thread to change the version. But you
actually doing it inline in a single thread. So I suggest you rename this test
to not mention threads. Something like
"doesNotHangIfVersionChangesDuringUpdateLocalVersion".
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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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