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https://issues.apache.org/jira/browse/CASSANDRA-6879?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Jonathan Ellis updated CASSANDRA-6879:
--------------------------------------
Attachment: 6879.txt
I'm actually confused that this doesn't happen more often, because we invoke
maybeResolveForRepair every time we receive more responses than we need to
satisfy consistencylevel -- and for range slices it looks like we always send
the request to all replicas (possibly restricted to local DC). So at CL.ONE I
would expect to see this frequently.
Since we don't attempt read repair on range scans yet (CASSANDRA-967) it looks
to me like we can fix by simply restricting the replicas contacted to what is
required for the consistencylevel. Then resolve() will only be called by the
StorageProxy thread as intended, and there is no race.
> ConcurrentModificationException while doing range slice query.
> --------------------------------------------------------------
>
> Key: CASSANDRA-6879
> URL: https://issues.apache.org/jira/browse/CASSANDRA-6879
> Project: Cassandra
> Issue Type: Bug
> Components: Core
> Environment: 2.0.4
> Reporter: Shao-Chuan Wang
> Assignee: Mikhail Stepura
> Fix For: 2.0.7
>
> Attachments: 6879.txt
>
>
> The paging read request (either from thrift or native) would sporadically
> fail due to a race condition between read repair and requesting thread
> waiting for read repair results list. The READ_REPAIR is queued in
> ReadCallback.maybeResolveForRepair(), and it does not seem to have guarantee
> that its resolve() method (which internally create
> RangeSliceResponseResolver.Reducer and doing repairResults.addAll inside
> RangeSliceResponseResolver.Reducer) would be invoked before the requesting
> thread starts waiting on resolver.repairResults. So, there is a small window
> that the list is partially populated, while requesting thread starts waiting
> on repairResults. I believe for the most of the time, the requesting thread
> is either wait for the entire repair results or not waiting for repair
> results at all. The original intent here seems to be waiting for repair
> results always (if the repair is triggered by repair chance).
> {code}
> ERROR [Native-Transport-Requests:70827] 2014-03-18 05:00:12,774
> ErrorMessage.java (line 222) Unexpected exception during request
> java.util.ConcurrentModificationException
> at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
> at java.util.ArrayList$Itr.next(ArrayList.java:831)
> at
> org.apache.cassandra.utils.FBUtilities.waitOnFutures(FBUtilities.java:423)
> at
> org.apache.cassandra.service.StorageProxy.getRangeSlice(StorageProxy.java:1583)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:188)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:163)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:58)
> at
> org.apache.cassandra.cql3.QueryProcessor.processStatement(QueryProcessor.java:188)
> at
> org.apache.cassandra.cql3.QueryProcessor.processPrepared(QueryProcessor.java:358)
> at
> org.apache.cassandra.transport.messages.ExecuteMessage.execute(ExecuteMessage.java:131)
> at
> org.apache.cassandra.transport.Message$Dispatcher.messageReceived(Message.java:304)
> at
> org.jboss.netty.channel.SimpleChannelUpstreamHandler.handleUpstream(SimpleChannelUpstreamHandler.java:70)
> at
> org.jboss.netty.channel.DefaultChannelPipeline.sendUpstream(DefaultChannelPipeline.java:564)
> at
> org.jboss.netty.channel.DefaultChannelPipeline$DefaultChannelHandlerContext.sendUpstream(DefaultChannelPipeline.java:791)
> at
> org.jboss.netty.handler.execution.ChannelUpstreamEventRunnable.doRun(ChannelUpstreamEventRunnable.java:43)
> at
> org.jboss.netty.handler.execution.ChannelEventRunnable.run(ChannelEventRunnable.java:67)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> at java.lang.Thread.run(Thread.java:744)
> {code}
> {code}
> ERROR [Thrift:1] 2014-03-18 07:18:02,434 CustomTThreadPoolServer.java (line
> 212) Error occurred during processing of message.
> java.util.ConcurrentModificationException
> at java.util.ArrayList$Itr.checkForComodification(ArrayList.java:859)
> at java.util.ArrayList$Itr.next(ArrayList.java:831)
> at
> org.apache.cassandra.utils.FBUtilities.waitOnFutures(FBUtilities.java:423)
> at
> org.apache.cassandra.service.StorageProxy.getRangeSlice(StorageProxy.java:1583)
> at
> org.apache.cassandra.service.pager.RangeSliceQueryPager.queryNextPage(RangeSliceQueryPager.java:85)
> at
> org.apache.cassandra.service.pager.AbstractQueryPager.fetchPage(AbstractQueryPager.java:71)
> at
> org.apache.cassandra.service.pager.RangeSliceQueryPager.fetchPage(RangeSliceQueryPager.java:36)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.pageCountQuery(SelectStatement.java:202)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:169)
> at
> org.apache.cassandra.cql3.statements.SelectStatement.execute(SelectStatement.java:58)
> at
> org.apache.cassandra.cql3.QueryProcessor.processStatement(QueryProcessor.java:188)
> at
> org.apache.cassandra.cql3.QueryProcessor.process(QueryProcessor.java:222)
> at
> org.apache.cassandra.cql3.QueryProcessor.process(QueryProcessor.java:212)
> at
> org.apache.cassandra.thrift.CassandraServer.execute_cql3_query(CassandraServer.java:1958)
> at
> org.apache.cassandra.thrift.Cassandra$Processor$execute_cql3_query.getResult(Cassandra.java:4486)
> at
> org.apache.cassandra.thrift.Cassandra$Processor$execute_cql3_query.getResult(Cassandra.java:4470)
> at org.apache.thrift.ProcessFunction.process(ProcessFunction.java:39)
> at org.apache.thrift.TBaseProcessor.process(TBaseProcessor.java:39)
> at
> org.apache.cassandra.thrift.CustomTThreadPoolServer$WorkerProcess.run(CustomTThreadPoolServer.java:194)
> at
> java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
> at
> java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
> at java.lang.Thread.run(Thread.java:744)
> {code}
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