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https://issues.apache.org/jira/browse/DERBY-2689?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel#action_12508615
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Daniel John Debrunner commented on DERBY-2689:
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>> On the same note, I'm not sure I understand why we have to do the following:
>>
>> for (int i = acts.size() - 1; i >= 0; i--) {
>>
>> // it maybe the case that a reset() ends up closing
>> // one or more activation leaving our index beyond
>> // the end of the array
>> if (i >= acts.size())
>> continue;
>
> BaseActivation.close(), which is called further down in the method, calls
> lcc.removeActivation() which removes only one activation and should therefore
> not cause any problems.
I'm not sure that is correct, that a close on an activation only closes one
other activation. Activations can have a relationship to each other, the main
case is a positioned update/delete on a cursor. Closing the cursor may close
the positioned statement. Maybe the code has changed such that isn't true, but
I wanted to throw it out there as an example. The current code is safe for that
situation, so if it is to be changed then that assumption (one close) must be
well documented in the code.
> Deadlock with GenericPreparedStatement
> --------------------------------------
>
> Key: DERBY-2689
> URL: https://issues.apache.org/jira/browse/DERBY-2689
> Project: Derby
> Issue Type: Bug
> Components: JDBC
> Affects Versions: 10.2.2.0
> Environment: Windows
> Reporter: Marc Ewert
> Assignee: Manish Khettry
> Priority: Critical
> Attachments: deadlock.patch.txt, TestDerbyPreparedStatements.java
>
>
> We encountered two times a deadlock inside of derby. It seems that we can't
> workaround it. The involved two threads are attached, it looks like a
> classical deadlock:
> "Thread-22" daemon prio=6 tid=0x0cdaa400 nid=0x1c0 waiting for monitor entry
> [0x1317f000..0x1317fd4c]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at org.apache.derby.impl.sql.GenericPreparedStatement.finish(Unknown
> Source)
> - waiting to lock <0x052f4d70> (a
> org.apache.derby.impl.sql.GenericPreparedStatement)
> at org.apache.derby.impl.sql.execute.BaseActivation.close(Unknown
> Source)
> at
> org.apache.derby.impl.sql.conn.GenericLanguageConnectionContext.addActivation(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.BaseActivation.initFromContext(Unknown
> Source)
> at
> org.apache.derby.impl.services.reflect.LoadedGeneratedClass.newInstance(Unknown
> Source)
> at
> org.apache.derby.impl.services.reflect.ReflectGeneratedClass.newInstance(Unknown
> Source)
> at org.apache.derby.impl.sql.GenericActivationHolder.<init>(Unknown
> Source)
> at
> org.apache.derby.impl.sql.GenericPreparedStatement.getActivation(Unknown
> Source)
> - locked <0x05306f88> (a
> org.apache.derby.impl.sql.GenericPreparedStatement)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement.<init>(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement20.<init>(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement30.<init>(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement40.<init>(Unknown
> Source)
> at org.apache.derby.jdbc.Driver40.newEmbedPreparedStatement(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown
> Source)
> - locked <0x047beb00> (a org.apache.derby.impl.jdbc.EmbedConnection40)
> at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown
> Source)
> [custom methods]
> "ThreadPoolThread-SyncScheduler-3-1" prio=2 tid=0x0e620400 nid=0xfec waiting
> for monitor entry [0x10a7e000..0x10a7fa14]
> java.lang.Thread.State: BLOCKED (on object monitor)
> at org.apache.derby.impl.sql.GenericPreparedStatement.finish(Unknown
> Source)
> - waiting to lock <0x05306f88> (a
> org.apache.derby.impl.sql.GenericPreparedStatement)
> at org.apache.derby.impl.sql.execute.BaseActivation.close(Unknown
> Source)
> at
> org.apache.derby.impl.sql.conn.GenericLanguageConnectionContext.addActivation(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.BaseActivation.initFromContext(Unknown
> Source)
> at
> org.apache.derby.impl.services.reflect.LoadedGeneratedClass.newInstance(Unknown
> Source)
> at
> org.apache.derby.impl.services.reflect.ReflectGeneratedClass.newInstance(Unknown
> Source)
> at org.apache.derby.impl.sql.GenericActivationHolder.<init>(Unknown
> Source)
> at
> org.apache.derby.impl.sql.GenericPreparedStatement.getActivation(Unknown
> Source)
> - locked <0x052f4d70> (a
> org.apache.derby.impl.sql.GenericPreparedStatement)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement.<init>(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement20.<init>(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement30.<init>(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedPreparedStatement40.<init>(Unknown
> Source)
> at org.apache.derby.jdbc.Driver40.newEmbedPreparedStatement(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown
> Source)
> - locked <0x04225178> (a org.apache.derby.impl.jdbc.EmbedConnection40)
> at org.apache.derby.impl.jdbc.EmbedConnection.prepareStatement(Unknown
> Source)
> [custom methods]
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