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https://issues.apache.org/jira/browse/DERBY-2074?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Knut Anders Hatlen updated DERBY-2074:
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Attachment: d2074-1a.diff
Here's an alternative fix (d2047-1a.diff). I'm not able to reproduce the bug
when it's applied, and replication also works with this change. Will run the
full regression test suite to see if it introduces any other problems, and I'll
also see if I can add a JUnit test case.
In this patch, I've added a flag to ModuleInstance to indicate whether or not
the instance has finished booting. TopService.bootModule() checks this flag
when it walks through the moduleInstances list looking for an already booted
instance to use, and skips the module instance if it isn't fully booted. This
fixes the bug since the code that failed because the module was only partly
initialized, will no longer be called unless it's fully initialized.
In the cases where we'd get a NullPointerException before, we'll now create and
boot two separate instances of the module. But there's already a window in
which it is possible to end up booting two instances of the same module
(because we drop the synchronization while booting) and it is correctly handled
by the existing code, so widening the window shouldn't cause any problems.
TopService.bootModule() handles it by checking if someone else successfully
added an instance while we were initializing ours. If so, our instance will be
discarded and we'll fall back to the other newly created instance.
> Several times exception from derby implementation was thrown (were unable to
> eproduce and check if it caused by any our work)
> -----------------------------------------------------------------------------------------------------------------------------
>
> Key: DERBY-2074
> URL: https://issues.apache.org/jira/browse/DERBY-2074
> Project: Derby
> Issue Type: Bug
> Components: Store
> Affects Versions: 10.1.3.1
> Environment: WinXP Professional, Java 1.5.0_06
> Reporter: Kovylin Alexandr
> Assignee: Knut Anders Hatlen
> Priority: Minor
> Attachments: d2074-1a.diff, LoadSorter.java
>
>
> 12:34:45,323 ERROR [pool-1-thread-3] history.helpers.HistoryDataAccessHelper
> - failed to read measurements, filter = (fromTime=Mon Nov 06 12:34:00 MSK
> 2006, toTime=Mon Nov 13 12:34:00 MSK 2006, , properties=2-6-2-value)
> org.springframework.jdbc.UncategorizedSQLException:
> PreparedStatementCallback; uncategorized SQLException for SQL [SELECT
> COUNT(DISTINCT sshis.measurement_time) FROM sshis_property_measurement sshis
> INNER JOIN sstmp_filter_3 filtertbl ON sshis.property_id =
> filtertbl.property_id WHERE sshis.measurement_time >= ? AND
> sshis.measurement_time < ?]; SQL state [XJ001]; error code [0]; Java
> exception:':
> java.lang.NullPointerException'.; nested exception is
> org.apache.derby.impl.jdbc.EmbedSQLException: Java exception: ':
> java.lang.NullPointerException'.
> java.lang.NullPointerException
> at java.util.Hashtable.put(Unknown Source)
> at
> org.apache.derby.impl.store.access.RAMAccessManager.registerAccessMethod(Unknown
> Source)
> at
> org.apache.derby.impl.store.access.RAMAccessManager.findMethodFactoryByImpl(Unknown
> Source)
> at
> org.apache.derby.impl.store.access.RAMTransaction.createSort(UnknownSource)
> at
> org.apache.derby.impl.sql.execute.DistinctScalarAggregateResultSet.loadSorter(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.DistinctScalarAggregateResultSet.openCore(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.ProjectRestrictResultSet.openCore(Unknown
> Source)
> at
> org.apache.derby.impl.sql.execute.BasicNoPutResultSetImpl.open(Unknown Source)
> at org.apache.derby.impl.sql.GenericPreparedStatement.execute(Unknown
> Source)
> at org.apache.derby.impl.jdbc.EmbedStatement.executeStatement(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeStatement(Unknown
> Source)
> at
> org.apache.derby.impl.jdbc.EmbedPreparedStatement.executeQuery(Unknown Source)
> at
> org.springframework.jdbc.core.JdbcTemplate$1.doInPreparedStatement(JdbcTemplate.java:535)
> at
> org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:476)
> at
> org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:528)
> at
> org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:561)
> at
> org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:579)
> at
> org.springframework.jdbc.core.JdbcTemplate.query(JdbcTemplate.java:589)
> at
> org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:619)
> at
> org.springframework.jdbc.core.JdbcTemplate.queryForObject(JdbcTemplate.java:629)
> at
> org.springframework.jdbc.core.JdbcTemplate.queryForInt(JdbcTemplate.java:656)
> at
> com.meshnetics.wsn.ctrl.dispatcher.services.history.helpers.MeasurementsSaveGetHelper.getMeasurements(MeasurementsSaveGetHelper.java:81)
> at
> com.meshnetics.wsn.ctrl.dispatcher.services.history.helpers.HistoryDataAccessHelper$7.doInTransaction(HistoryDataAccessHelper.java:315)
> at
> com.meshnetics.wsn.ctrl.dispatcher.services.history.helpers.HistoryDataAccessHelper$7.doInTransaction(HistoryDataAccessHelper.java:314)
> at
> org.springframework.transaction.support.TransactionTemplate.execute(TransactionTemplate.java:117)
> at
> com.meshnetics.wsn.ctrl.dispatcher.services.history.helpers.HistoryDataAccessHelper.getMeasurements(HistoryDataAccessHelper.java:313)
> at
> com.meshnetics.wsn.ctrl.dispatcher.services.history.asyncread.MeasurementsReadTask.executeTask(MeasurementsReadTask.java:127)
> at
> com.meshnetics.wsn.ctrl.dispatcher.services.history.asyncread.MeasurementsReadTask.run(MeasurementsReadTask.java:97)
> at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
> at java.util.concurrent.FutureTask$Sync.innerRun(Unknown Source)
> at java.util.concurrent.FutureTask.run(Unknown Source)
> at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(Unknown
> Source)
> at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
> at java.lang.Thread.run(Unknown Source)
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