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https://issues.apache.org/jira/browse/DERBY-4269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13399698#comment-13399698
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Knut Anders Hatlen commented on DERBY-4269:
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FWIW, all the regression tests ran cleanly with the keys-only.diff patch. Even
if it doesn't fix the bug, I think it's an improvement as it slightly
simplifies the code.
> But do we have any guarantee that the returned keys aren't used to access
> values (and if so tat those are assumed to be non-null) elsewhere?
I don't know. However, what caused this particular bug, was that the override
of Properties.propertyNames() itself wasn't safe to use, so that it didn't give
the thread-safety guarantees that one would normally expect from Properties'
methods. Callers of Properties' methods should already be aware of the
limitations of the synchronization guarantees provided by Properties (for
example that there is a possibility that getProperty() returns null, as there
is no synchronization preventing the property from getting removed after a
check for the existence of a key). If they don't take that into consideration,
it's a bug that needs to be fixed. But in cases where the actual bug lies in
the override of a Properties method, like in this case, one cannot reasonably
expect the callers to handle the problem gracefully.
So although I cannot guarantee that all users of Properties instances in the
engine are free from bugs, I believe that the Properties class does provide the
functionality to be used in a thread-safe way, even without adding a semaphore
that guards the call to info.clear().
> Failover did not succeed in 2 min.: testReplication_Local_3_p6_autocommit_OK
> ----------------------------------------------------------------------------
>
> Key: DERBY-4269
> URL: https://issues.apache.org/jira/browse/DERBY-4269
> Project: Derby
> Issue Type: Bug
> Components: Replication
> Affects Versions: 10.4.1.3, 10.4.2.0, 10.5.1.1, 10.5.2.0, 10.5.3.0,
> 10.6.1.0, 10.6.2.1, 10.7.1.1, 10.8.1.2, 10.8.2.2
> Environment: OS:
> Microsoft© Windows VistaT Ultimate - 6.0.6001 Service Pack 1 - WindowsNT 0 6
> JVM:
> Sun Microsystems Inc.
> java version "1.4.2_16"
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.4.2_16-b05)
> Java HotSpot(TM) Client VM (build 1.4.2_16-b05 mixed mode 32-bit)
> Reporter: Ole Solberg
> Assignee: Dag H. Wanvik
> Labels: derby_triage10_5_2
> Attachments: 4269-client-jstack.txt, 4269-master.txt,
> 4269-slave-jstack-before-failover.txt, 4269-slave.txt, DERBY-4269.diff,
> DERBY-4269.stat, DERBY-4269b.diff, db_master-derby.log,
> db_slave-derby.log.gz, derby-4269-explicit-synch-2.diff,
> derby-4269-explicit-synch-3.diff, derby-4269-explicit-synch-3.status,
> derby-4269-explicit-synch.diff, derby-4269-typo.diff, keys-only.diff
>
>
> Failover did not succeed.
> 2)
> testReplication_Local_3_p6_autocommit_OK(org.apache.derbyTesting.functionTests.tests.replicationTests.ReplicationRun_Local_3_p6)junit.framework.AssertionFailedError:
> Failover did not succeed.
> at
> org.apache.derbyTesting.functionTests.tests.replicationTests.ReplicationRun.connectPing(ReplicationRun.java:270)
> at
> org.apache.derbyTesting.functionTests.tests.replicationTests.ReplicationRun_Local_3_p6.derby_3896(ReplicationRun_Local_3_p6.java:200)
> at
> org.apache.derbyTesting.functionTests.tests.replicationTests.ReplicationRun_Local_3_p6.testReplication_Local_3_p6_autocommit_OK(ReplicationRun_Local_3_p6.java:86)
> at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
> at
> sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
> at
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
> at
> org.apache.derbyTesting.junit.BaseTestCase.runBare(BaseTestCase.java:106)
> at junit.extensions.TestDecorator.basicRun(TestDecorator.java:24)
> at junit.extensions.TestSetup$1.protect(TestSetup.java:21)
> at junit.extensions.TestSetup.run(TestSetup.java:25)
> See
> http://dbtg.thresher.com/derby/test/Daily/jvm1.4/testing/testlog/vista-64/782274-suitesAll_diff.txt
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